Radiosity Abstracts 1989-1996

1989

89-1
Doc Type: Conference Paper
Title: Shading models for realistic image synthesis
Authors: Knox, W.J., Jr.
Affiliation: Loral Defense Syst., Akron, OH, USA
Conf. Title: Proceedings of the IEEE 1989 National Aerospace and Electronics Conference NAECON 1989 (Cat. No.89CH2759-9)
p. 596-603 vol.2
Publisher: IEEE
New York, NY, USA
Date: 1989 4 vol. 2102 pp.
Country of Publication: USA
CCC: CH2759-9/89/0000-0596$01.00
Language: English
Conf. Date: 22-26 May 1989
Conf. Loc: Dayton, OH, USA
Conf. Sponsor: IEEE
Treatment: Theoretical/Mathematical
Abstract: A tutorial that presents a technical-level chronology of illumination model development is provided. The basic techniques and capabilities of certain algorithms that changed the direction of computer graphics research are described. Included are treatments of Lambertian (constant) shading, Gouraud shading, Phong shading, the Torrence-Sparrow illumination model, Whitted's original ray-tracing based illumination model, and interreflections between diffuse surfaces (radiosity). (19 Refs.)
Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Modelling
Free Terms: Lambertian shading; Constant shading; Realistic image synthesis; Illumination model development; Computer graphics; Gouraud shading; Phong shading; Torrence-Sparrow illumination model; Ray-tracing based illumination model; Interreflections; Diffuse surfaces; Radiosity

89-2
Doc Type: Journal Paper
Title: A VLSI system architecture for high-speed radiative
transfer 3D image synthesis
Authors: Bu, J.; Deprettere, E.F.
Affiliation: Dept. of Electr. Eng., Delft Univ. of Technol.,
Netherlands
Journal: Visual Computer
Vol: 5 Iss: 3 p. 121-33
Date: 1989
Country of Publication: West Germany
ISSN: 0178-2789 CODEN: VICOE5
Language: English
Treatment: Practical
Abstract: The authors describe a VLSI system architecture for high-speed synthesis of 3D images composed of diffusely reflective surfaces. The system consists of two loosely coupled sub-systems. The first sub-system computes the form-factor matrix F. The form-factors are computed by an efficient ray-tracing algorithm. The second sub-system, a multiprocessor Gauss-Seidel iterative system solver, solves the sparse system of radiosity equations (I- Lambda F)b=e. (12 Refs.)
Classification: C5540 (Terminals and graphic displays); C5260B (Computer vision and picture processing); C6130B (Graphics techniques)
Thesaurus: Computer graphic equipment; Computer graphics; Computerised picture processing; VLSI
Free Terms: VLSI system architecture; High-speed radiative transfer 3D image synthesis; Diffusely reflective surfaces; Form-factor matrix; Ray-tracing algorithm; Multiprocessor Gauss-Seidel iterative system solver; Radiosity equations

89-3
Doc Type: Journal Paper
Title: Light reflection models for computer graphics
Authors: Greenberg, D.P.
Affiliation: Cornell Univ., Ithaca, NY, USA
Journal: Science
Vol: 244 Iss: 4901 p. 166-73
Date: 14 April 1989
Country of Publication: USA
ISSN: 0036-8075 CODEN: SCIEAS
Language: English
Treatment: General/Review
Abstract: During the past 20 years, computer graphic techniques for simulating the reflection of light have progressed so that today images of photorealistic quality can be produced. Early algorithms considered direct lighting only, but global illumination phenomena with indirect lighting, surface interreflections, and shadows can now be modeled with ray tracing, radiosity, and Monte Carlo simulations. This article describes the historical development of computer graphic algorithms for light reflection and pictorially illustrates what will be commonly available in the near future. (26 Refs.) Classification: C6130B (Graphics techniques)
Thesaurus: Computational geometry; Computer graphics; Geometrical optics; History; Light reflection; Monte Carlo methods Free Terms: Light reflection models; Computer graphics; Photorealistic quality; Algorithms; Global illumination phenomena; Indirect lighting; Surface interreflections; Shadows; Ray tracing; Radiosity; Monte Carlo simulations; Historical development

89-4
Doc Type: Conference Paper
Title: Form-factors for general environments
Authors: Ping-Ping Shao; Qun-Sheng Peng; You-Dong Liang
Affiliation: Dept. of Math., Zhejiang Univ., China
Conf. Title: EUROGRAPHICS '88. Proceedings of the European Computer Graphics Conference and Exhibition
p. 499-510
Editors: Duce, D.A.; Jancene, P.
Publisher: North-Holland
Amsterdam, Netherlands
Date: 1988 xv+550 pp.
Country of Publication: Netherlands
ISBN: 0 444 70499 X
Language: English
Conf. Date: 12-16 Sept. 1988
Conf. Loc: Nice, France
Treatment: Practical
Abstract: An algorithm, based on the hemi-cube formulation, which calculates the form-factors required by the solution of the rendering equation, is presented. The concept of form-factors of the standard radiosity method is developed. In particular, the concept of specular form-factors is proposed. These new form-factors are also purely geometric terms describing the transfer of energy from one surface to another within a non-diffuse environment. The new form-factor is evaluated by numerical integrations based on the hemi-cube algorithm. The equations of the effective diffuse radiosity are presented and solved by numerical methods. The extension fully develops the characteristic of radiosity method and successfully solves the view-independent energy transfer in a general environment. (11 Refs.) Classification: C6130B (Graphics techniques); C4160 (Numerical integration and differentiation)
Thesaurus: Computer graphics; Integration
Free Terms: Illumination; Hemi-cube formulation; Form-factors;
Rendering equation; Standard radiosity method; Geometric terms; Surface; Numerical integrations; Diffuse radiosity

89-5
Doc Type: Conference Paper
Title: Complex scene generation
Authors: Dzwig, P.
Affiliation: Parsys Ltd., Hayes, UK
Conf. Title: IEE Colloquium on 'Practical Applications of Parallel Signal Processing' (Digest No.111)
p. 7/1-7
Publisher: IEE
London, UK
Date: 1988 56 pp.
Country of Publication: UK
Language: English
Conf. Date: 1 Nov. 1988
Conf. Loc: London, UK
Conf. Sponsor: IEE
Treatment: Practical; Product review
Abstract: The Parsys SN 1000 series of parallel processing computer systems is considered as a vehicle for the generation of complex scenes using techniques such as ray-tracing and radiosity. The use of high throughput data capture peripherals is also considered as a tool for the manipulation of images. (2 Refs.)
Classification: C5260B (Computer vision and picture processing); C5440 (Multiprocessor systems and techniques)
Thesaurus: Computerised picture processing; Parallel processing Free Terms: Complex scene generation; Image manipulation; Parsys SN 1000; Parallel processing computer systems; Ray-tracing; Radiosity; High throughput data capture peripherals

89-6
Doc Type: Conference Paper in Journal
Title: A new radiosity approach by procedural refinements for realistic image synthesis
Authors: Min-zhi Shao; Qun-sheng Peng; You-dong Liang
Affiliation: CAD/CAM Res. Center, Zhejiang Univ., China Journal: Computer Graphics
Vol: 22 Iss: 4 p. 93-102
Date: Aug. 1988
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/88/008/0093$00.75
Language: English
Conf. Title: SIGGRAPH 88 Conference
Conf. Date: 1-5 Aug. 1988
Conf. Loc: Atlanta, GA, USA
Conf. Sponsor: ACM; IEEE
Treatment: Practical
Abstract: According to the rendering equation, the diffuse and the specular components of the outgoing intensity of each surface patch should be solved simultaneously. Rather than establishing a huge set of linear equations defining the unknown directional intensities for all directions and all surface patches, the authors expand the concept of the delta form-factor which concerns the light energy transfer of a surface path along a respective direction. As the delta form-factor for non-diffuse surface patches are dependent on the spatial and spectral distributions of light energy, they could not be calculated geometrically. In this paper, the authors present a new radiosity approach which progressively approximates the delta form-factors and the light energy distributions within a general environment to the correct solution. The nucleus of the approach is procedural iteration. Statistics indicate the potentials of this method for complex non-diffuse environments. (14 Refs.) Classification: C6130B (Graphics techniques); C5260B (Computer vision and picture processing)
Thesaurus: Computer graphics; Computerised picture processing Free Terms: Spatial distributions; Radiosity approach; Procedural refinements; Realistic image synthesis; Rendering equation; Specular components; Linear equations; Delta form-factor; Light energy transfer; Surface path; Spectral distributions

89-7
Doc Type: Conference Paper in Journal
Title: A progressive refinement approach to fast radiosity image generation
Authors: Cohen, M.F.; Chen, S.E.; Wallace, J.R.; Greenberg, D.P.
Affiliation: Cornell Univ., Ithaca, NY, USA
Journal: Computer Graphics
Vol: 22 Iss: 4 p. 75-84
Date: Aug. 1988
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/88/008/0075$00.75
Language: English
Conf. Title: SIGGRAPH 88 Conference
Conf. Date: 1-5 Aug. 1988
Conf. Loc: Atlanta, GA, USA
Conf. Sponsor: ACM; IEEE
Treatment: Practical
Abstract: A reformulated radiosity algorithm is presented that produces initial images in time linear to the number of patches. The enormous memory costs of the radiosity algorithm are also eliminated by computing form-factors on-the-fly. The technique is based on the approach of rendering by progressive refinement. The algorithm provides a useful solution almost immediately which progresses gracefully and continuously to the complete radiosity solution. In this way the competing demands of realism and interactivity are accommodated. The technique brings the use of radiosity for interactive rendering within reach and has implications for the use and development of current and future graphics workstations. (19 Refs.)
Classification: C6130B (Graphics techniques); C5260B (Computer vision and picture processing)
Thesaurus: Computer graphics; Computerised picture processing
Free Terms: Progressive refinement approach; Fast radiosity image generation; Reformulated radiosity algorithm; Form-factors; Graphics workstations

89-8
Doc Type: Journal Paper
Title: Hierarchical data structures and algorithms for computer graphics. II. Applications
Authors: Samet, H.; Webber, R.E.
Affiliation: Maryland Univ., College Park, MD, USA
Journal: IEEE Computer Graphics and Applications
Vol: 8 Iss: 4 p. 59-75
Date: July 1988
Country of Publication: USA
ISSN: 0272-1716 CODEN: ICGADZ
CCC: 0272-1716/88/0700-0059$01.00
Language: English
Treatment: Practical
Abstract: For pt.I see ibid., vol.8, no.3, p.48-68, May (1988). Advanced applications for preliminary display methods are focused on, with emphasis on the octree. Topics include use of the quadtree as a basis for hidden-surface algorithms, parallel and perspective projection methods to display a collection of objects represented by an octree, and the use of octrees to facilitate such image-rendering techniques as ray tracing and radiosity. (93 Refs.) Classification: C6120 (File organisation); C6130B (Graphics techniques) Thesaurus: Computer graphics; Data structures; Trees [mathematics] Free Terms: Parallel projection methods; Computer graphics; Display methods; Octree; Quadtree; Hidden-surface algorithms; Perspective projection methods; Image-rendering; Ray tracing; Radiosity

1990

90-1
Doc Type: Conference Paper in Journal
Title: VOXEL based modeling and rendering irregular solids
Authors: Prakash, C.E.; Nandy, S.L.
Affiliation: Indian Inst. of Sci., Bangalore, India
Journal: Microprocessing & Microprogramming
Vol: 30 Iss: 1-5 p. 341-6
Date: Aug. 1990
Country of Publication: Netherlands
ISSN: 0165-6074 CODEN: MMICDT
Language: English
Conf. Title: Sixteenth EUROMICRO Symposium on Microprocessing and Microprogramming (EUROMICRO 90). Hardware and Software in
System Engineering
Conf. Date: 27-30 Aug. 1990
Conf. Loc: Amsterdam, Netherlands
Treatment: Practical
Abstract: Proposes a VOXEL model for obtaining the octree of sculptured surfaces and solids. This model is obtained through a serial stacking of solid cross-sections (slice) to build the octree. The authors show how rendering can be done using the VOXEL model by associating a voxel-type viz. face, edge and vertex to capture the orientation of the underlying primitive solid element and hence assigning a normal for every voxel. The VOXEL model can be easily extended to perform radiosity analysis which is highlighted in the paper. (17 Refs.)
Classification: C6130B (Graphics techniques)
Thesaurus: Solid modelling
Free Terms: Irregular solids; VOXEL model; Octree; Sculptured surfaces; Primitive solid element; Radiosity analysis

90-2
Doc Type: Conference Paper in Journal
Title: Development of a radiometric model for the detection of plastic coating omissions on aluminum substrate
Authors: Orlove, G.L.
Affiliation: Inframetrics Inc., Billerica, MA, USA
Journal: Proceedings of the SPIE - The International Society for
Optical Engineering
Vol: 1313 p. 184-9
Date: 1990
Country of Publication: USA
ISSN: 0277-786X CODEN: PSISDG
Language: English
Conf. Title: Thermosense XII. International Conference on Thermal Sensing and Imaging Diagnostic Applications
Conf. Date: 18-20 April 1990
Conf. Loc: Orlando, FL, USA
Conf. Sponsor: SPIE
Treatment: Theoretical/Mathematical; Experimental
Abstract: The author describes the basic methodology used to develop a radiometric model to verify that a plastic coating skip can be detected on an aluminum web substrate. Experimental results confirmed that the model is accurate in predicting the radiation contrast between the coated and uncoated aluminum. (2 Refs.) Classification: B0590 (Materials testing); B7320R (Thermal variables) Thesaurus: Aluminium; Infrared imaging; Nondestructive testing; Plastics; Protective coatings; Radiometry; Substrates Free Terms: Paint skip detection; Radiosity; Radiometric model; Plastic coating; Web substrate; Radiation contrast; 54 DegC; 70 DegC; Al Numerical Index: Temperature 3.27E+02 K; Temperature 3.43E+02 K Chemical Index: Al/sur Al/el

90-3
Doc Type: Conference Paper in Journal
Title: Manufacturer's recommended body of knowledge for thermographic diagnostics
Authors: Madding, R.P.
Affiliation: McDonnell Douglas Technol. Inc., San Diego, CA, USA Journal: Proceedings of the SPIE - The International Society for
Optical Engineering
Vol: 1313 p. 72-6
Date: 1990
Country of Publication: USA
ISSN: 0277-786X CODEN: PSISDG
Language: English
Conf. Title: Thermosense XII. International Conference on Thermal Sensing and Imaging Diagnostic Applications
Conf. Date: 18-20 April 1990
Conf. Loc: Orlando, FL, USA
Conf. Sponsor: SPIE
Treatment: General/Review
Abstract: The realities involved in performing thermographic diagnostic surveys are often not well understood by the
thermographer. With an interest in the growth of the thermographic community, and an understanding that proper application promotes growth, equipment manufacturers have considered training and education a worthwhile investment. The author summarizes the training and technical assistance experience of one manufacturer as a recommended body of knowledge for thermographers. Five key areas are presented: radiosity, spatial resolution, heat transfer, equipment operation, and target behavior. (0 Refs.)
Classification: B0170L (Inspection and quality control); B7320R (Thermal variables); B0160 (Plant engineering, maintenance and safety); B0120 (Education and training)
Thesaurus: Heat transfer; Infrared imaging; Inspection; Radiometry; Training
Free Terms: Thermal imaging; IR; NDT; Thermographic diagnostics; Training; Education; Radiosity; Spatial resolution; Heat transfer

90-4
Doc Type: Journal Paper
Title: Distributed supercomputing to achieve real-time representation and manipulation of complex scenes
Authors: Encarnacao, J.; Koberle, G.; Ning Zhang
Affiliation: ZGDV, Darmstadt, West Germany
Journal: Computers in Industry
Vol: 14 Iss: 1-3 p. 23-33
Date: May 1990
Country of Publication: Netherlands
ISSN: 0166-3615 CODEN: CINUD4
CCC: 0166-3615/90/$03.50
Language: English
Treatment: Practical
Abstract: Besides the ray tracing technique, the radiosity method is another major approach for global illumination modeling in the field of computer graphics. Since this method needs a huge amount of storage space (both memory and disk) and a long pre-computation cycle, it is not suitable to implement it on conventional workstations. Supercomputers seem to be necessary for such kind of graphics applications. However, some problems appear with the integration of supercomputers and workstations in a distributed computing environment, especially for graphics application. The major problems are: (i) unavailability of standard higher-level mechanisms for building distributed application; (ii) transparent access to supercomputers without remote login or file transfer sessions; (iii) computation balance to make the best use of the performance of supercomputers and workstations; (iv) data transfer/storage strategy between supercomputers and workstations; and (v) conflict between interaction and response time for graphics applications. This paper suggests, solutions to the above mentioned problems based on the remote procedure call (RPC) and the client/server model, for the radiosity package implementation. After the introduction of the radiosity method, the authors concentrate on the integration between supercomputers and high-performance workstations. They also convey some general issues related to distributed computing and present the experience with their implementation, such as the application protocol definition, error recovery, code debugging etc. The radiosity package has been implemented at ZGDV in Darmstadt, FRG in a network environment including a Multiflow TRACE 7/300 supercomputer connected to several VAX, SUN and HP workstations. (12 Refs.) Classification: C5440 (Multiprocessor systems and techniques); C6130B (Graphics techniques); C7400 (Engineering)
Thesaurus: CAD; Computer graphics; Distributed processing; Parallel processing
Free Terms: Distributed supercomputing; Complex scenes manipulation; Real-time representation; Global illumination modeling; Computer graphics; Remote procedure call; Client/server model; Radiosity package implementation; Application protocol; Error recovery; Code debugging; Network environment; Multiflow TRACE 7/300 supercomputer; VAX; SUN; HP workstations

90-5
Doc Type: Journal Paper
Title: Accelerated radiosity method for complex environments
Authors: Hau Xu; Qun-Sheng Peng; You-Dong Liang
Affiliation: Zhejiang Univ., Hangzhou, China
Journal: Computers & Graphics
Vol: 14 Iss: 1 p. 65-71
Date: 1990
Country of Publication: UK
ISSN: 0097-8493 CODEN: COGRD2
CCC: 0097-8493/90/$3.00+.00
Language: English
Treatment: Practical; Theoretical/Mathematical
Abstract: As form-factor calculation costs about 90% of the computing time when applying the radiosity approach for realistic image synthesis, it is of great significance to reduce the required computation. An accelerated radiosity algorithm for general complex environments, based on environment localization and the directional form-factor concept, is presented. First, the authors subdivide the object space into many regions. Objects contained in each region are adjacent to each other and pose more global illumination effects to their neighbours. Next, form-factors are calculated in each local environment. The radiant light energy transfer between different regions is evaluated at their common boundaries. Directional form-factors are introduced to simulate the interaction of light between local environments and between nondiffuse surfaces. Comparisons are made to existing algorithms. (13 Refs.) Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics
Free Terms: Complex environments; Form-factor calculation; Realistic image synthesis; Accelerated radiosity algorithm; Environment localization; Directional form-factor; Object space; Global illumination; Neighbours; Radiant light energy transfer; Common boundaries; Nondiffuse surfaces

90-6
Doc Type: Journal Paper
Title: Radiosity redistribution for dynamic environments
Authors: George, D.W.; Sillion, F.X.; Greenberg, D.P.
Affiliation: Cornell Univ., Ithaca, NY, USA
Journal: IEEE Computer Graphics and Applications
Vol: 10 Iss: 4 p. 26-34
Date: July 1990
Country of Publication: USA
ISSN: 0272-1716 CODEN: ICGADZ
CCC: 0272-1716/90/0700-0026$01.00
Language: English
Treatment: Practical; Theoretical/Mathematical
Abstract: The radiosity algorithm is extended to dynamic environments, providing global-illumination simulations to scenes that are modified interactively. The illumination effects introduced by a change in position, shape, or attributes of any object in the scene are computed very rapidly by redistributing the energy already exchanged between objects. Corrections are made by shooting positive and negative energy, accounting for increased illumination and the creation of shadows. Object coherence is used to minimize computation, and progressive-refinement techniques are used to accelerate convergence. The extended algorithm yields excellent approximations to the exact solutions at interactive speeds. (9 Refs.)
Classification: C6130B (Graphics techniques); C4130 (Interpolation and function approximation)
Thesaurus: Computational geometry; Computer graphics; Convergence of numerical methods; Geometrical optics
Free Terms: Radiosity distribution; Dynamic environments;
Global-illumination simulations; Illumination effects; Negative energy; Shadows; Progressive-refinement techniques; Convergence; Approximations; Interactive speeds

90-7
Doc Type: Journal Paper
Title: Thermal cooling techniques of electronic components (using infrared radiometer)
Authors: Okamoto, Y.; Kaminaga, F.; Ogawa, K.; Marui, Y.
Affiliation: Dept. of Mech. Eng., Ibaraki Univ., Hitachi, Japan Journal: Journal of the Faculty of Engineering, Ibaraki University
Iss: no.37 p. 127-36
Date: 1989
Country of Publication: Japan
ISSN: 0367-7389 CODEN: IDKSAB
Language: Japanese
Treatment: Practical; Experimental
Abstract: Two-dimensional temperature distribution of a heated flat plane with a perforated cylindrical promotor through a plastic transparent wall is visualized by using a coated thermo-sensitive liquid crystal and an infrared radiation sensor. Thermo-view of the base plane is obtained by these methods. Heat transfer augmentation is studied by the remote sensing radiometer. Thermo-view of an IC package plate array is derived by the radiosity coefficient of the tested surface. Steady and unsteady state and local temperature distribution of the IC package and an electronic component is analysed by the remote sensing radiometer. (4 Refs.) Classification: B0170J (Product packaging); B7320P (Optical variables); B7320R (Thermal variables); B0170E (Production facilities and engineering)
Thesaurus: Cooling; Electronic equipment testing; Infrared imaging; Packaging; Radiometry; Temperature distribution
Free Terms: Two dimensional temperature distribution; Thermal cooling techniques; Electronic components; Infrared radiometer; Heated flat plane; Perforated cylindrical promotor; Plastic transparent wall; Coated thermo-sensitive liquid crystal; Infrared radiation sensor; Remote sensing radiometer; IC package plate array; Radiosity coefficient

90-8
Doc Type: Journal Paper
Title: Measurement of radiosity coefficient by using an infrared radiometer and its application
Authors: Okamoto, Y.; Kaminaga, F.; Osakabe, M.; Maekawa, K.;
Ishi, T.; Ohoka, N.; Eto, M.
Journal: Journal of the Faculty of Engineering, Ibaraki University
Iss: no.37 p. 121-5
Date: 1989
Country of Publication: Japan
ISSN: 0367-7389 CODEN: IDKSAB
Language: Japanese
Treatment: Application; Experimental
Abstract: An infrared radiometer has been used for measuring and visualizing radiation temperature distribution of a surface in many fields as a remote sensing device. Measured radiation flux is a summation of an emitted radiation and a reflection, which is called a radiosity flux. The authors show characteristics of the radiosity of tested materials. The infrared sensor is used to detect the small surface flaw and to measure the erosion rate of the graphite by ion beam injection and the temperature distribution of a cutter. (8 Refs.)
Classification: A0762 (Detection of radiation (bolometers, photoelectric cells, i.r. and submillimetre waves detection)); A0720 (Thermal instruments and techniques); A0760D (Photometry and radiometry); A8170C (Nondestructive testing); B7230G (Image sensors); B7320P (Optical variables); B0590 (Materials testing); B7320R (Thermal variables)
Thesaurus: Flaw detection; Graphite; Infrared imaging; Radiometers; Radiometry; Temperature distribution
Free Terms: NDT; Radiosity coefficient; Infrared radiometer; Radiation temperature distribution; Infrared sensor; Surface flaw; Erosion rate; Graphite; Ion beam injection; C
Chemical Index: C/sur C/el

90-9
Doc Type: Journal Paper
Title: Extending the radiosity method to include specularly reflecting and translucent materials
Authors: Rushmeier, H.E.; Torrance, K.E.
Affiliation: Cornell Univ., Ithaca, NY, USA
Journal: ACM Transactions on Graphics
Vol: 9 Iss: 1 p. 1-27
Date: Jan. 1990
Country of Publication: USA
ISSN: 0730-0301 CODEN: ATGRDF
CCC: 0730-0301/90/0100-0001$01.50
Language: English
Treatment: Practical
Abstract: An extension of the radiosity method is presented that rigorously accounts for the presence of a small number of specularly reflecting surfaces in an otherwise diffuse scene, and for the presence of a small number of specular or ideal diffuse transmitters. The relationship between the extended method and earlier radiosity and ray-tracing methods is outlined. It is shown that all three methods are based on the same general equation of radiative transfer. A simple superposition of the earlier radiosity and ray-tracing methods in order to account for specular behavior is shown to be physically inconsistent, as the methods are based on different assumptions. Specular behavior is correctly included in the present method. The extended radiosity method and example images are presented. (14 Refs.)
Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Geometrical optics
Free Terms: Specularly reflecting materials; 3D graphics; Global illumination; Image synthesis; Radiosity method; Translucent
materials; Diffuse scene; Ideal diffuse transmitters; Ray-tracing methods

90-10
Doc Type: Journal Paper
Title: 3D images and computer graphics
Authors: Kanou, Y.; Saito, F.
Journal: Information Processing Society of Japan
Vol: 31 Iss: 2 p. 265-73
Date: 1990
Country of Publication: Japan
ISSN: 0447-8053 CODEN: JOSHA4
Language: Japanese
Treatment: Bibliography; Practical
Abstract: Computer graphics techniques for producing 3D images are discussed. The authors look at ray-tracing and radiosity. Computational geometry methods are proposed. CRT displays are also considered. MRI, CAD, shading and shadowing and various systems for producing 3D images are discussed. (57 Refs.)
Classification: C6130B (Graphics techniques); C5540 (Terminals and graphic displays); C4190 (Other numerical methods); C5260B (Computer vision and picture processing)
Thesaurus: Cathode-ray tube displays; Computational geometry; Computer graphic equipment; Computer graphics; Computerised picture processing Free Terms: Computational geometry; Computer graphics; Graphics techniques; 3D images; Ray-tracing; Radiosity; CRT displays; MRI; CAD; Shading; Shadowing

90-11
Doc Type: Conference Paper in Journal
Title: Real time radiosity through parallel processing and hardware acceleration
Authors: Baum, D.R.; Winget, J.M.
Affiliation: Silicon Graphics Comput. Syst., Mountain View, CA, USA Journal: Computer Graphics
Vol: 24 Iss: 2 p. 67-75
Date: March 1990
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/90/0003/0067$1.50
Language: English
Conf. Title: 1990 Symposium on Interactive 3D Graphics
Conf. Date: 25-28 March 1990
Conf. Loc: Snowbird, UT, USA
Conf. Sponsor: ACM; Office of Naval Res.; NSF; et al
Treatment: Practical
Abstract: This paper describes a novel implementation of the progressive refinement radiosity algorithm. Algorithm performance is greatly enhanced using the capabilities of a multiprocessor graphics workstation. Hemi-cube item buffers are produced using the graphics hardware while the remaining computations are performed in parallel on the multiple host processors. Speedups of a factor of 40 or more over the equivalent software implementation are observed. Load balancing issues are discussed and a system performance model is developed based on actual results. Additionally, a new user interface scheme is presented where the radiosity calculations and walk-through tasks are separated. At each new iteration, the radiosity algorithm automatically updates colors used by the viewing program via shared memory while simultaneously obtaining hints on where to further refine the solution. (12 Refs.)
Classification: C6130B (Graphics techniques); C5440 (Multiprocessor systems and techniques); C6180 (User interfaces)
Thesaurus: Computer graphics; Parallel processing; User interfaces Free Terms: Real time radiosity; Load balancing; Parallel processing; Hardware acceleration; Progressive refinement radiosity algorithm; Multiprocessor graphics workstation; Graphics hardware; Software implementation; User interface; Walk-through tasks; Shared memory

90-12
Doc Type: Conference Paper in Journal
Title: Acceleration techniques for progressive refinement radiosity
Authors: Recker, R.J.; George, D.W.; Greenberg, D.P.
Affiliation: Program of Comput. Graphics, Cornell Univ., Ithaca, NY, USA
Journal: Computer Graphics
Vol: 24 Iss: 2 p. 59-66
Date: March 1990
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/90/0003/0059$1.50
Language: English
Conf. Title: 1990 Symposium on Interactive 3D Graphics
Conf. Date: 25-28 March 1990
Conf. Loc: Snowbird, UT, USA
Conf. Sponsor: ACM; Office of Naval Res.; NSF; et al
Treatment: Practical
Abstract: The progressive refinement radiosity method provides a means for computing the global illumination of an environment in time proportional to the size of the environment. Additionally, the method supplies a sequence of solutions that monotonically converge to a high-quality result, allowing it to be used for interactive applications that deliver 'near real-time' updates as the computation proceeds. This paper presents two methods for accelerating the radiosity method. First, the traditional hemi-cube algorithm is modified to accelerate the expensive form-factor calculation. Second, the radiosity method is parallelized across a coarse-grain network, and the efficiency of the parallel system is discussed. (12 Refs.) Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics
Free Terms: Acceleration techniques; Progressive refinement radiosity; Global illumination; Interactive applications; Hemi-cube algorithm; Coarse-grain network

90-13
Doc Type: Conference Paper in Journal
Title: Improving interaction with radiosity-based lighting simulation programs
Authors: Puech, C.; Sillion, F.; Vedel, C.
Affiliation: Lab. d'Inf., Ecole Normale Superieure, Paris, France Journal: Computer Graphics
Vol: 24 Iss: 2 p. 51-7
Date: March 1990
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/90/0003/0051$1.50
Language: English
Conf. Title: 1990 Symposium on Interactive 3D Graphics
Conf. Date: 25-28 March 1990
Conf. Loc: Snowbird, UT, USA
Conf. Sponsor: ACM; Office of Naval Res.; NSF; et al
Treatment: Practical
Abstract: The authors describe the main algorithms used in an interactive lighting simulation program based on a two-pass extension of the radiosity method. The system allows interactive walk-through as other systems based on radiosity calculations. Moreover, it offers increased realism in the lighting effects by use of extended form factors which accounts for 'specular reflection of diffuse light', fast production and display of progressively refined images by distribution of the calculations, good quality of the images in the early stages of the refinement by the use of 'hardware light sources', 'cheap' rendering of some of the specular highlights at any time by use of the built-in specular shading model, lighting modification (color, intensity of the light sources) by use of 'negative light', fast simulation of mirror effects and interactive tools for controlling the quality of the final image. (6 Refs.) Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Interactive systems
Free Terms: Radiosity-based lighting simulation programs; Two-pass extension; Form factors; Interactive tools; Final image

90-14
Doc Type: Conference Paper in Journal
Title: Towards image realism with interactive update rates in complex virtual building environments
Authors: Airey, J.M.; Rohlf, J.H.; Brooks, F.P., Jr.
Affiliation: Dept. of Comput. Sci., North Carolina Univ., Chapel Hill, NC, USA
Journal: Computer Graphics
Vol: 24 Iss: 2 p. 41-50
Date: March 1990
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/90/0003/0041$1.50
Language: English
Conf. Title: 1990 Symposium on Interactive 3D Graphics
Conf. Date: 25-28 March 1990
Conf. Loc: Snowbird, UT, USA
Conf. Sponsor: ACM; Office of Naval Res.; NSF; et al
Treatment: Practical
Abstract: Two strategies, pre-computation before display and adaptive refinement during display, are used to combine interactivity with high image quality in a virtual building simulation. Pre-computation is used in two ways. The hidden-surface problem is partially solved by automatically pre-computing potentially visible sets of the model for sets of related viewpoints. Rendering only the potentially visible subset associated with the current viewpoint, rather than the entire model, produces significant speedups on real building models. Solutions for the radiosity lighting model are precomputed for up to twenty different sets of lights. Linear combinations of these solutions can be manipulated in real time. The authors use adaptive refinement to trade image realism for interactivity as the situation requires. When the user is stationary they replace a coarse model using few polygons with a more detailed model. Image-level linear interpolation smooths the transition between differing levels of image realism. (16 Refs.) Classification: C6130B (Graphics techniques); C5260B (Computer vision and picture processing)
Thesaurus: Computer graphics; Computerised picture processing Free Terms: Image level linear interpolation; Image realism; Interactive update rates; Complex virtual building environments; Interactivity; High image quality; Virtual building simulation; Hidden-surface problem; Radiosity lighting model; Adaptive refinement; Coarse model; Polygons

90-15
Doc Type: Conference Proceedings in Journal
Conf. Title: 1990 Symposium on Interactive 3D Graphics
Journal: Computer Graphics
Vol: 24 Iss: 2
Date: March 1990
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
Language: English
Conf. Date: 25-28 March 1990
Conf. Loc: Snowbird, UT, USA
Conf. Sponsor: ACM; Office of Naval Res.; NSF; et al
Abstract: The following topics were dealt with: manipulating 3D structures; virtual worlds; radiosity; visualisation; curve and surface modelling; interactive modelling; performance evaluation; and user interfaces.
Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics
Free Terms: Curve modelling; Interactive 3D graphics; Manipulating 3D structures; Virtual worlds; Radiosity; Visualisation; Surface modelling; Interactive modelling; Performance evaluation; User interfaces

90-16
Doc Type: Conference Paper in Journal
Title: A general two-pass method integrating specular and diffuse reflection
Authors: Sillion, F.; Puech, C.
Affiliation: Lab. d'Inf. Ecole Normale Superieure, Paris, France Journal: Computer Graphics
Vol: 23 Iss: 3 p. 335-44
Date: July 1989
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/89/007/0335
Language: English
Conf. Title: SIGGRAPH '89. Conference Proceedings
Conf. Date: 31 July-4 Aug. 1989
Conf. Loc: Boston, MA, USA
Treatment: Theoretical/Mathematical
Abstract: Analyses some recent approaches to the global illumination problem by introducing the corresponding reflection operators, and demonstrates the advantages of a two-pass method. A generalization of the system introduced by Wallace et al. (1987) to integrate diffuse as well as specular effects is presented. It is based on the calculation of extended form-factors, which allows arbitrary geometries to be used in the scene description, as well as refraction effects. The authors also present a new sampling method for the calculation of form-factors, which is an alternative to the hemi-cube technique introduced by Cohen and Greenberg (1985) for radiosity calculations. This method is particularly well suited to the extended form-factors calculation. The problem of interactive display of the picture being created is also addressed by using hardware-assisted projections and image composition to recreate a complete specular view of the scene. (19 Refs.)
Classification: A4210H (Diffraction and scattering from extended bodies); A4210F (Edge and boundary effects, refraction); C6130B (Graphics techniques); C4290 (Other computer theory) Thesaurus: Brightness; Computer graphics; Geometrical optics; Interactive systems; Light reflection; Light refraction; Light scattering; Lighting
Free Terms: Specular reflection; Interreflection; Z-buffer; Progressive refinement; 3D computer graphics; Two-pass method; Diffuse reflection; Global illumination; Reflection operators; Extended form-factors; Arbitrary geometries; Scene description; Refraction effects; Sampling method; Form-factors; Radiosity calculations; Interactive display; Hardware-assisted projections; Image composition; Specular view; Scene

90-17
Doc Type: Conference Paper in Journal
Title: Improving radiosity solutions through the use of analytically determined form-factors
Authors: Baum, D.R.; Rushmeier, H.E.; Winget, J.M.
Affiliation: Silicon Graphics Comput. Syst., Mountain View, CA, USA Journal: Computer Graphics
Vol: 23 Iss: 3 p. 325-34
Date: July 1989
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/89/007/0325
Language: English
Conf. Title: SIGGRAPH '89. Conference Proceedings
Conf. Date: 31 July-4 Aug. 1989
Conf. Loc: Boston, MA, USA
Treatment: Practical; Theoretical/Mathematical
Abstract: Current radiosity methods rely on the calculation of geometric factorsl known as form-factors, which describe energy exchange between pairs of surfaces in the environment. The most computationally efficient method for form-factor generation is a numerical technique known as the hemi-cube algorithm. Use of the hemi-cube is based on assumptions about the geometry of the surfaces involved. First, this paper examines the types of errors and visual artifacts that result when these assumptions are violated. Second, the paper shows that these errors occur more frequently in progressive refinement radiosity than in the originally proposed full matrix radiosity solution. Next, a new analytical technique for determining form-factors that is immune to the errors of the hemi-cube algorithm is introduced. Finally, a hybrid progressive refinement method that invokes the new technique to correctly compute form-factors when hemi-cube assumptions are violated is presented. (18 Refs.)
Classification: A4210 (Propagation and transmission in homogeneous media); C6130B (Graphics techniques); C4100 (Numerical analysis) Thesaurus: Brightness; Computational geometry; Computer graphics; Geometrical optics; Numerical methods
Free Terms: Surface pairs; Global illumination; Z-buffer; Viewing algorithms; Radiosity; Analytically determined form-factors; Geometric factors; Energy exchange; Computationally efficient method; Numerical technique known; Hemi-cube algorithm; Errors; Visual artifacts; Hybrid progressive refinement method

90-18
Doc Type: Conference Paper in Journal
Title: A ray tracing algorithm for progressive radiosity
Authors: Wallace, J.R.; Elmquist, K.A.; Haines, E.A.
Affiliation: 3D/EYE Inc., Ithaca, NY, USA
Journal: Computer Graphics
Vol: 23 Iss: 3 p. 315-24
Date: July 1989
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/89/007/0315
Language: English
Conf. Title: SIGGRAPH '89. Conference Proceedings
Conf. Date: 31 July-4 Aug. 1989
Conf. Loc: Boston, MA, USA
Treatment: Practical; Theoretical/Mathematical
Abstract: A new method for computing form-factors within a progressive radiosity approach is presented. Previously, the progressive radiosity approach has depended on the use of the hemi-cube algorithm to determine form-factors. However, sampling problems inherent in the hemi-cube algorithm limit its usefulness for complex images. A more robust approach is described in which ray tracing is used to perform the numerical integration of the form-factor equation. The approach is tailored to provide good, approximate results for a low number of rays, while still providing a smooth continuum of increasing accuracy for higher numbers of rays. Quantitative comparisons between analytically derived form-factors and ray traced form-factors are presented. (20 Refs.) Classification: A4210D (Wave-front and ray tracing); C6130B (Graphics techniques); C4160 (Numerical integration and differentiation) Thesaurus: Brightness; Computational geometry; Computer graphics; Geometrical optics; Integration
Free Terms: Global illumination; Ray tracing algorithm; Progressive radiosity; Form-factors; Sampling problems; Hemi-cube algorithm; Complex images; Numerical integration; Smooth continuum; Accuracy

90-19
Doc Type: Conference Paper
Title: Supercomputing with transputers
Authors: Wallace, D.J.
Affiliation: Dept. of Phys., Edinburgh Univ., UK
Conf. Title: Applications of Transputers 1. Proceedings of the First International Conference
p. 72-81
Editors: Freeman, L.; Phillips, C.
Publisher: IOS
Amsterdam, Netherlands
Date: 1990 ix+332 pp.
Country of Publication: Netherlands
Language: English
Conf. Date: 23-25 Aug. 1989
Conf. Loc: Liverpool, UK
Treatment: Experimental
Abstract: The Edinburgh Concurrent Supercomputer Project (ECS) is built around a Meiko Computing Surface with presently some 400 floating-point transputers and 1.7 Gbytes of memory. The first part of the paper gives an overview of the Project's origins and status and describes experience gained in providing a multi-user service. The second part gives examples of applications which are able to exploit effectively this processing power. Tools which facilitate the use of the machine for large scale computation and visualisation are also briefly described. Applications mentioned include: visualization and image processing (i.e. radiosity and fractal landscapes); lattice field theory; high temperature superconductors; neural network models; chemical process simulation and control; and optimisation in stressed membrane surface structures. (17 Refs.)
Classification: C5440 (Multiprocessor systems and techniques); C7320 (Physics and Chemistry); C7440 (Civil and mechanical engineering); C6130B (Graphics techniques)
Thesaurus: Computer graphics; Digital simulation; Parallel machines; Physics computing
Free Terms: Edinburgh Concurrent Supercomputer Project; Meiko Computing Surface; 400 Floating-point transputers; 1.7 Gbytes of memory; Multi-user service; Large scale computation; Visualisation; Image processing; Radiosity; Fractal landscapes; Lattice field theory; High temperature superconductors; Neural network models; Chemical process simulation; Stressed membrane surface structures

90-20
Doc Type: Conference Paper
Title: Radiosity in parallel
Authors: Price, M.; Truman, G.
Affiliation: Central Res. Labs., Thorn EMI, Hayes, UK
Conf. Title: Applications of Transputers 1. Proceedings of the First International Conference
p. 40-7
Editors: Freeman, L.; Phillips, C.
Publisher: IOS
Amsterdam, Netherlands
Date: 1990 ix+332 pp.
Country of Publication: Netherlands
Language: English
Conf. Date: 23-25 Aug. 1989
Conf. Loc: Liverpool, UK
Treatment: Practical
Abstract: The radiosity method models the interreflection of light between diffuse surfaces giving an accurate prediction of global illumination. Recent work has concentrated on refining this algorithm in order to reduce the amount of computation required. Such refinements mean that photorealistic images are now possible in reasonable time-scales, allowing the benefits of good quality visualizations to become available to a wider field of disciplines. A further technique for improving interactivity is to implement these refinements within a parallel architecture. This paper explores the advantages of a parallel radiosity system and the constraints imposed by a parallel architecture. A description is given of a prototype system implemented within a parallel environment, based upon a Parsys SN1000 multiple Transputer network. Typically, this system deals with around 1000 surfaces in under one minute. Experiments have shown that a further linear increase in speed is achievable by a corresponding linear expansion of the network. (7 Refs.)
Classification: C6130B (Graphics techniques); C5440 (Multiprocessor systems and techniques)
Thesaurus: CAD; Lighting; Parallel architectures; Solid modelling Free Terms: Diffuse interreflection; Radiosity method; Interreflection; Diffuse surfaces; Global illumination; Photorealistic images; Visualizations; Parallel radiosity system; Parallel architecture; Parallel environment; Parsys SN1000 multiple Transputer network

90-21
Doc Type: Conference Proceedings
Conf. Title: Applications of Transputers 1. Proceedings of the First International Conference
Editors: Freeman, L.; Phillips, C.
Publisher: IOS
Amsterdam, Netherlands
Date: 1990 ix+332 pp.
Country of Publication: Netherlands
Language: English
Conf. Date: 23-25 Aug. 1989
Conf. Loc: Liverpool, UK
Treatment: Application; Practical; Experimental
Abstract: The following topics were dealt with: Ada on transputers; signal processing; radiosity in parallel; Fortnet a parallel FORTRAN harness for porting code; BOO1260 MIMD programming; CSOUND; tuned generalized Hough transforms; high energy physics Monte Carlo; symmetric eigenvalue problem; electronic assembly design system; Tokamak COMPASS-D control system; Hopscotch algorithm for linear elliptic equations; multimedia databases; rule based system; macromolecular interaction; variational studies of 2D Hubbard model; back propagation algorithm on Meiko computing surface; oil reservoir simulation; protein structure refinement; bispectral analysis; text scanning of bibliographic databases; image processing; and graphical environment for OCCAM programming.
Classification: C7300 (Natural sciences); C7400 (Engineering); C7250 (Information storage and retrieval); C6100 (Software techniques and systems)
Thesaurus: Computer applications; Parallel processing; Transputers Free Terms: Ada; Signal processing; Radiosity; Fortnet; Parallel FORTRAN harness; BOO1260 MIMD programming; CSOUND; Tuned generalized Hough transforms; High energy physics Monte Carlo; Symmetric eigenvalue problem; Electronic assembly design system; Tokamak COMPASS-D control system; Hopscotch algorithm; Linear elliptic equations; Multimedia databases; Rule based system; Macromolecular interaction; Variational studies; 2D Hubbard model; Back propagation algorithm; Meiko computing surface; Oil reservoir simulation; Protein structure refinement; Bispectral analysis; Text scanning; Bibliographic databases; Image processing; Graphical environment; OCCAM programming

90-22
Doc Type: Conference Paper in Journal
Title: Pixel-Planes 5: a heterogeneous multiprocessor graphics system using processor-enhanced memories
Authors: Fuchs, H.; Poulton, J.; Eyles, J.; Greer, T.;
Goldfeather, J.; Ellsworth, D.; Molnar, S.; Turk, G.;
Tebbs, B.; Israel, L.
Affiliation: Dept. of Comput. Sci., North Carolina Univ., Chapel Hill, NC, USA
Journal: Computer Graphics
Vol: 23 Iss: 3 p. 79-88
Date: July 1989
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/89/007/0079$00.75
Language: English
Conf. Title: SIGGRAPH '89. Conference Proceedings
Conf. Date: 31 July-4 Aug. 1989
Conf. Loc: Boston, MA, USA
Treatment: Practical
Abstract: An introduction is given to the architecture and initial algorithms for Pixel-Planes 5, a heterogeneous multi-computer designed both for high speed polygon and sphere rendering (1M Phong-shaded triangles/second) and for supporting algorithm and application research in interactive 3D graphics. Techniques are described for volume rendering at multiple frames per second, font generation directly from conic spline descriptions and rapid calculation of radiosity form-factors. The hardware consists of up to 32 math-oriented processors, up to 16 rendering units and a conventional 1280*1024-pixel frame buffer, interconnected by a 5 gigabit ring network. Each rendering unit consists of a 128*128-pixel array of processors-with-memory with parallel quadratic expression evaluation for every pixel. Implemented on 1.6 micron CMOS chips designed to run at 40 MHz, this array has 208 bits/pixel on-chip and is connected to a video RAM memory system that provides 4096 bits of off-chip memory. Rendering units can be independently reassigned to any part of the screen or to non-screen-oriented computation. (41 Refs.)
Classification: C5540 (Terminals and graphic displays); C5440 (Multiprocessor systems and techniques); C6130B (Graphics techniques); C5320G (Semiconductor storage)
Thesaurus: Buffer storage; Computer graphic equipment; Computer graphics; Multiprocessing systems; Random-access storage; Splines [mathematics]
Free Terms: Heterogeneous multiprocessor graphics system; Processor-enhanced memories; Architecture; Initial algorithms; Pixel-Planes 5; Heterogeneous multi-computer; High speed polygon; Sphere rendering; 1M Phong-shaded triangles/second; Application research; Interactive 3D graphics; Volume rendering; Font generation; Conic spline descriptions; Radiosity form-factors; Math-oriented processors; Rendering units; Frame buffer; Ring network; Processors-with-memory; Parallel quadratic expression evaluation; CMOS chips; Video RAM memory system; Off-chip memory; 128 Pixels; 16384 Pixels
Numerical Index: Picture size 1.28E+02 pixel; Picture size 1.6384E+04 pixel

90-23
Doc Type: Conference Proceedings in Journal
Conf. Title: SIGGRAPH '89. Conference Proceedings
Journal: Computer Graphics
Vol: 23 Iss: 3
Date: July 1989
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
Language: English
Conf. Date: 31 July-4 Aug. 1989
Conf. Loc: Boston, MA, USA
Treatment: Practical; Theoretical/Mathematical
Abstract: The following topics were dealt with: natural graphical models; computer graphics hardware; rendering; graphics interfaces; geometric modelling; visualization; computer animation; 3D textures; ray tracing; radiosity; and graphics algorithms.
Classification: C6130B (Graphics techniques); C5540 (Terminals and graphic displays); C4190 (Other numerical methods); C5260B (Computer vision and picture processing); C6180 (User interfaces) Thesaurus: Computational geometry; Computer graphic equipment; Computer graphics; Computerised picture processing; Interactive systems; User interfaces
Free Terms: Natural graphical models; Computer graphics hardware; Rendering; Graphics interfaces; Geometric modelling; Visualization; Computer animation; 3D textures; Ray tracing; Radiosity; Graphics algorithms

90-24
Doc Type: Journal Paper
Title: Computer synthesis of realistic images: a survey
Authors: Peng Qunsheng; Liang Youdong
Affiliation: CAD/CAM Res. Centre, Zhejiang Univ., China
Journal: Chinese Journal of Computers
Vol: 12 Iss: 3 p. 226-37
Date: 1989
Country of Publication: China
ISSN: 0254-4164 CODEN: JIXUDT
Language: Chinese
Treatment: General/Review; Practical
Abstract: Realistic image synthesis is one of the most significant research fields in computer graphics. This paper surveys most of the major issues concerning realistic image synthesis, including illumination models, rendering algorithms, texture mapping, shadow generation and environment modelling with emphasis on the application of global illumination models and their associated rendering techniques, in particular, the ray tracing algorithms and radiosity approaches. (43 Refs.)
Classification: B6140 (Signal processing and detection); C1250 (Pattern recognition); C5260B (Computer vision and picture processing) Thesaurus: Computerised picture processing
Free Terms: Realistic image synthesis; Survey; Computer graphics; Illumination models; Rendering algorithms; Texture mapping; Shadow generation; Environment modelling; Global illumination models; Ray tracing algorithms; Radiosity approaches

90-25
Doc Type: Conference Paper
Title: Advances in global illumination algorithms
Authors: Greenberg, D.P.
Affiliation: Cornell Univ., Ithaca, NY, USA
Conf. Title: EUROGRAPHICS '89. Proceedings of the European Computer Graphics Conference
p. 401
Editors: Hansmann, W.; Hopgood, F.R.A.; Strasser, W.
Publisher: North-Holland
Amsterdam, Netherlands
Date: 1989 xvi+552 pp.
Country of Publication: Netherlands
ISBN: 0 444 88013 5
Language: English
Conf. Date: 4-8 Sept. 1989
Conf. Loc: Hamburg, West Germany
Treatment: Practical
Abstract: Summary form only given, as follows. Global illumination algorithms such as ray tracing and radiosity can simulate physical phenomena such as shading, shadows or colour bleeding and the inter-reflections of light between neighbouring surfaces. Until recently, the uses of such approaches were restricted to representation graphics only since the computational times required for the generation of these realistic images were excessive. The author describes recent algorithmic advances which make the image synthesis calculation far more tractable. When combined with graphics hardware accelerators, solutions will be available within interaction times on tomorrow's workstation environments. (0 Refs.) Classification: C5260B (Computer vision and picture processing); C5540 (Terminals and graphic displays); C5430 (Microcomputers) Thesaurus: Computer graphic equipment; Computerised picture processing; Workstations
Free Terms: Global illumination algorithms; Ray tracing; Radiosity; Physical phenomena; Shading; Shadows; Colour bleeding; Inter-reflections; Neighbouring surfaces; Realistic images; Algorithmic advances; Image synthesis calculation; Graphics hardware accelerators; Interaction times; Workstation environments

90-26
Doc Type: Conference Paper
Title: Delaunay triangulations and the radiosity approach
Authors: Schuierer, S.
Affiliation: Inst. fur Inf., Freiburg Univ., West Germany
Conf. Title: EUROGRAPHICS '89. Proceedings of the European Computer Graphics Conference
p. 345-53
Editors: Hansmann, W.; Hopgood, F.R.A.; Strasser, W.
Publisher: North-Holland
Amsterdam, Netherlands
Date: 1989 xvi+552 pp.
Country of Publication: Netherlands
ISBN: 0 444 88013 5
Language: English
Conf. Date: 4-8 Sept. 1989
Conf. Loc: Hamburg, West Germany
Treatment: Practical
Abstract: The radiosity approach requires the subdivision of complex surfaces into simple components called patches. Since it is assumed the intensity is constant over a patch, the generation of regular patches is a desirable property of the subdivision algorithm. The author shows that constrained Delaunay triangulations produce patches that are as close to equilateral triangles as possible and thus are well suited for the partitioning of surfaces into patches. Since a number of optimal algorithms to generate constrained Delaunay triangulations have been published, the implementation presented made use of one of these (L.P. Chew, 1987). The implementation consists of a rather simple modeling tool called POLY, a fast triangulation algorithm for arbitrary polygons and the form factor computation combined with a z-buffer output module. (16 Refs.)
Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics
Free Terms: Radiosity; Patches; Constrained Delaunay triangulations; Equilateral triangles; Optimal algorithms; POLY; Fast triangulation algorithm; Form factor computation; Z-buffer output module

90-27
Doc Type: Journal Paper
Title: Global illumination modeling using radiosity
Authors: Burgoon, D.A.
Journal: Hewlett-Packard Journal
Vol: 40 Iss: 6 p. 78-88
Date: Dec. 1989
Country of Publication: USA
ISSN: 0018-1153 CODEN: HPJOAX
Language: English
Treatment: Practical
Abstract: Radiosity is a complementary method to ray tracing for global illumination modeling. HP9000 TurboSRX graphics workstations now offer three illumination models: radiosity, ray tracing, and a local illumination model. (17 Refs.)
Classification: C6130B (Graphics techniques); C5540 (Terminals and graphic displays)
Thesaurus: Computer graphics; Workstations
Free Terms: Global illumination modeling; HP9000 TurboSRX graphics workstations; Illumination models; Radiosity; Ray tracing; Local illumination model

90-28
Doc Type: Conference Paper
Title: Accelerated radiosity method for complex environments
Authors: Hau Xu; Qun-Sheng Peng; You-Dong Liang
Affiliation: CAD/CAM Res. Center, Zhejiang Univ., China Conf. Title: EUROGRAPHICS '89. Proceedings of the European Computer Graphics Conference
p. 51-61
Editors: Hansmann, W.; Hopgood, F.R.A.; Strasser, W.
Publisher: North-Holland
Amsterdam, Netherlands
Date: 1989 xvi+552 pp.
Country of Publication: Netherlands
ISBN: 0 444 88013 5
Language: English
Conf. Date: 4-8 Sept. 1989
Conf. Loc: Hamburg, West Germany
Treatment: Practical; Theoretical/Mathematical
Abstract: A form-factor calculation costs about 90% of the computing time when applying the radiosity approach for realistic image synthesis, it is of great significance to reduce the required computation. An accelerated radiosity algorithm for general complex environments, based on environment localization and the directional form-factor concept, is presented in this paper. First one subdivides the object space into many regions. Objects contained in each region are adjacent to each other and pose more illumination effects to their neighbours. Then form-factors are calculated in each local environment. The radiant light energy transfer between different regions is evaluated at their common boundaries. Directional form-factors are introduced to simulate the interaction of light between local environments and between nondiffuse surfaces. Comparison is made to existing algorithms. Statistical results and theoretical analysis show that the new algorithm is much faster than previous ones. The technique is especially useful for interactive design and animation sequences since modification to the shape or location of objects usually happens in local environments. (13 Refs.) Classification: C6130B (Graphics techniques); C4290 (Other computer theory)
Thesaurus: Brightness; Computational geometry; Computer graphics Free Terms: Object space subdivision; Shape modification; Complex environments; Computing time; Realistic image synthesis; Accelerated radiosity algorithm; Environment localization; Directional form-factor; Illumination effects; Radiant light energy transfer; Local environments; Nondiffuse surfaces; Interactive design; Animation sequences

1991

91-1
Doc Type: Journal Paper
Title: A simple light simulation algorithm for massively parallel machines
Authors: Kochevar, P.
Affiliation: Digital Equipment Corp., Palo Alto, CA, USA
Journal: Journal of Parallel and Distributed Computing
Vol: 13 Iss: 2 p. 193-201
Date: Oct. 1991
Country of Publication: USA
ISSN: 0743-7315 CODEN: JPDCER
CCC: 0743-7315/91/$3.00
Language: English
Treatment: Practical; Theoretical/Mathematical
Abstract: A new computer graphics algorithm which simulates the propagation of light and its interaction with matter on a massively parallel machine is presented. This algorithm, called the Tagged Shooting Method, is designed for a virtual computer containing a great number of simple, communicating processors arrayed into a cubical, three-dimensional lattice. Only nearest-neighbor communication among processors is assumed and there is no reliance on global shared memory. The algorithm is similar in spirit to the classical Progressive Refinement Radiosity Method designed for more conventional computers but is not an adaptation of that technique to massive parallelism. Instead, the new algorithm uses a discretization of the wave equation as a local rule for shuttling radiant energy values between processors which correspond to regions of space. A number of example images that were created with an implementation of the algorithm on a Connection Machine are depicted and critiqued. (6 Refs.)
Classification: A4210 (Propagation and transmission in homogeneous media); A4220 (Propagation and transmission in inhomogeneous media); A0270 (Computational techniques); C6130B (Graphics techniques); C5440 (Multiprocessor systems and techniques)
Thesaurus: Computer graphics; Digital simulation; Light propagation; Parallel algorithms
Free Terms: Light propagation simulation; Light simulation algorithm; Massively parallel machines; Computer graphics algorithm; Tagged Shooting Method; Virtual computer; Communicating processors; Three-dimensional lattice; Nearest-neighbor communication; Progressive Refinement Radiosity Method; Discretization; Wave equation; Local rule; Radiant energy values; Connection Machine

91-2
Doc Type: Conference Paper
Title: State of the art in image synthesis
Authors: Cohen, M.F.; Painter, J.S.
Affiliation: Dept. of Comput. Sci., Utah Univ., Salt Lake City, UT, USA
Conf. Title: Advances in Computer Graphics VI. Images: Synthesis, Analysis, and Interaction
p. 59-111
Editors: Garcia, G.; Herman, I.
Publisher: Springer-Verlag
Berlin, Germany
Date: 1991 vii+448 pp.
Country of Publication: Germany
ISBN: 3 540 53455 5
Language: English
Conf. Date: 4-7 Sept. 1990
Conf. Loc: Montreux, Switzerland
Treatment: Bibliography; Practical
Abstract: The advent of the computer, and the image synthesis techniques which are described bring the ability to create realistic images to a wide group. Creating a realistic synthetic image on a computer requires two steps: describing the geometry of the environment to be rendered and the material properties of the objects which make up the environment, and simulating the propagation of light through the synthetic environment and displaying the results of the simulation. The authors focus on the second part of the problem, that of simulating and displaying the interaction of light in the synthetic environment. They look at: human perception and CRTs, spatial discretization and anti-aliasing, local reflection models, ray tracing and radiosity. (84 Refs.)
Classification: C5260B (Computer vision and picture processing); C1250 (Pattern recognition)
Thesaurus: Computerised pattern recognition; Computerised picture processing; Technological forecasting
Free Terms: Image synthesis techniques; Realistic synthetic image; Light; Synthetic environment; Human perception; CRTs; Spatial discretization; Anti-aliasing; Local reflection models; Ray tracing; Radiosity

91-3
Doc Type: Journal Paper
Title: A cross-indexed guide to the ray tracing literature
Authors: Speer, L.R.
Affiliation: Animation Res., Boulder, CO, USA
Journal: Computer Graphics Forum
Vol: 10 Iss: 2 p. 145-74
Date: June 1991
Country of Publication: Netherlands
ISSN: 0167-7055 CODEN: CGFODY
Language: English
Treatment: Bibliography; Practical
Abstract: Research on ray-tracing for image synthesis has accelerated in recent years. Areas of active investigation currently include ray-tracing in data visualization, fast spatial subdivision traversal, ray-tracing for radiosity, stochastic sampling, efficient intersection culling and parallel ray-tracing. Research groups are active on at least three continents and perhaps ten times as many countries. The author catalogs and provides access to much of the large amount of literature available on ray-tracing. Over 400 references from 1968 to early 1991 are cited, and cross-indices by keyword and author are included. A special set of keywords and terms, including many unique to ray-tracing, has been developed and used. A glossary of these terms is also provided. (414 Refs.) Classification: C5260B (Computer vision and picture processing); C1250 (Pattern recognition); C6130B (Graphics techniques) Thesaurus: Computer graphics; Computerised pattern recognition; Computerised picture processing
Free Terms: Cross-indexed guide; Ray tracing literature; Image synthesis; Data visualization; Fast spatial subdivision traversal; Radiosity; Stochastic sampling; Intersection culling; Parallel ray-tracing; Keywords

91-4
Doc Type: Conference Paper in Journal
Title: A rapid hierarchical radiosity algorithm
Authors: Hanrahan, P.; Salzman, D.; Aupperle, L.
Affiliation: Dept. of Comput. Sci., Princeton Univ., NJ, USA Journal: Computer Graphics
Vol: 25 Iss: 4 p. 197-206
Date: July 1991
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/91/007/0197$00.75
Language: English
Conf. Title: SIGGRAPH 91
Conf. Date: 28 July-2 Aug. 1991
Conf. Loc: Las Vegas, NV, USA
Conf. Sponsor: ACM
Treatment: Practical; Theoretical/Mathematical
Abstract: A discussion is given on a rapid hierarchical radiosity algorithm for illuminating scenes containing large polygonal patches. The algorithm constructs a hierarchical representation of the form factor matrix by adaptively subdividing patches into subpatches according to a user-supplied error bound. The algorithm guarantees that all form factors are calculated to the same precision, removing many common image artifacts due to inaccurate form factors. More importantly, the algorithm decomposes the form factor matrix into at most O(n) blocks (where n is the number of elements). Previous radiosity algorithms represented the element-to-element transport interactions with n/sup 2/ form factors. Visibility algorithms are given that work well with this approach. Standard techniques for shooting and gathering can be used with the hierarchical representation to solve for equilibrium radiosities, but the authors also discuss using a brightness-weighted error criteria, in conjunction with multigridding, to even more rapidly progressively refine the image. (12 Refs.)
Classification: C5260B (Computer vision and picture processing); C4140 (Linear algebra); C4240 (Programming and algorithm theory); C7320 (Physics and Chemistry); C4130 (Interpolation and function approximation)
Thesaurus: Approximation theory; Computational complexity; Computerised picture processing; Lighting; Matrix algebra; Physics computing Free Terms: Rapid hierarchical radiosity algorithm; Large polygonal patches; Hierarchical representation; Form factor matrix; User-supplied error bound; Common image artifacts; Element-to-element transport interactions; Hierarchical representation; Equilibrium radiosities; Brightness-weighted error criteria; Multigridding

91-5
Doc Type: Conference Paper in Journal
Title: A global illumination solution for general reflectance distributions
Authors: Sillion, F.X.; Arvo, J.R.; Westin, S.H.; Greenberg, D.P.
Affiliation: Program of Comput. Graphics, Cornell Univ., Ithaca, NY, USA
Journal: Computer Graphics
Vol: 25 Iss: 4 p. 187-96
Date: July 1991
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/91/007/0187$00.75
Language: English
Conf. Title: SIGGRAPH 91
Conf. Date: 28 July-2 Aug. 1991
Conf. Loc: Las Vegas, NV, USA
Conf. Sponsor: ACM
Treatment: Practical; Theoretical/Mathematical
Abstract: A general light transfer simulation algorithm for environments composed of materials with arbitrary reflectance functions is presented. This algorithm removes the previous practical restriction to ideal specular and/or ideal diffuse environments, and supports complex physically based reflectance distributions. This is accomplished by extending previous two-pass ray-casting radiosity approaches to handle nonuniform intensity distributions and resolving all possible energy transfers between sample points. An implementation is described based on a spherical harmonic decomposition for encoding both bidirectional reflectance distribution functions for materials, and directional intensity distributions for illuminated surfaces. The method compares favorably with experimental measurements. (20 Refs.)
Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Digital simulation; Lighting
Free Terms: BRDF; Global illumination solution; General light transfer simulation algorithm; Arbitrary reflectance functions; Physically based reflectance distributions; Two-pass ray-casting radiosity; Nonuniform intensity distributions; Energy transfers; Spherical harmonic decomposition; Bidirectional reflectance distribution functions

91-6
Doc Type: Conference Paper in Journal
Title: A progressive multi-pass method for global illumination
Authors: Chen, S.E.; Rushmeier, H.E.; Miller, G.; Turner, D.
Affiliation: Adv. Technol. Group, Apple Comput. Inc., New York, NY, USA
Journal: Computer Graphics
Vol: 25 Iss: 4 p. 165-74
Date: July 1991
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/91/007/0165$00.75
Language: English
Conf. Title: SIGGRAPH 91
Conf. Date: 28 July-2 Aug. 1991
Conf. Loc: Las Vegas, NV, USA
Conf. Sponsor: ACM
Treatment: Practical
Abstract: A progressive global illumination method is presented which produces approximate images quickly, and then continues to systematically produce more accurate images. The method combines the existing methods of progressive refinement radiosity, Monte Carlo path tracing and light ray tracing. The method does not place any limitation on surface properties such as ideal Lambertian or mirror-like. To increase efficiency and accuracy, the concepts of light source reclassification, caustics reconstruction, Monte Carlo path tracing with a radiosity preprocess and an interruptible radiosity solution are introduced. The method presents the user with most useful information about the scene as early as possible to reorganizing the method into a radiosity pass, a high frequency refinement pass and a low frequency refinement pass. The implementation of the method is demonstrated, and sample images are presented. (29 Refs.)
Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Geometrical optics
Free Terms: Progressive global illumination method; Approximate images; Progressive refinement radiosity; Monte Carlo path tracing; Light ray tracing; Light source reclassification; Caustics reconstruction; Interruptible radiosity solution

91-7
Doc Type: Conference Paper in Journal
Title: Making radiosity usable: automatic preprocessing and meshing techniques for the generation of accurate
radiosity solutions
Authors: Baum, D.R.; Mann, S.; Smith, K.P.; Winget, J.M.
Affiliation: Silicon Graphics Comput. Syst., Mountain View, CA, USA Journal: Computer Graphics
Vol: 25 Iss: 4 p. 51-60
Date: July 1991
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/91/007/0051$00.75
Language: English
Conf. Title: SIGGRAPH 91
Conf. Date: 28 July-2 Aug. 1991
Conf. Loc: Las Vegas, NV, USA
Conf. Sponsor: ACM
Treatment: Practical
Abstract: Generating accurate radiosity solutions of real world environments is user-intensive and requires significant knowledge of the method. As a result, few end-users such as architects and designers use it. The output of most commercial modeling packages must be substantially 'cleaned up' to satisfy the geometrical and topological criteria imposed by radiosity solution algorithms. Furthermore, the mesh used as the basis of the radiosity computation must meet several additional requirements for the solution to be accurate. A set of geometrical and topological requirements is formalized that when satisfied yields an accurate radiosity solution. A series of algorithms is introduced that automatically processes raw model databases to meet these requirements. Thus, the end-user can concentrate on the design rather than on the details of the radiosity solution process. These algorithms are generally independent of the radiosity solution technique used, and thus apply to all mesh band radiosity methods. (18 Refs.)
Classification: C6130B (Graphics techniques)
Thesaurus: Computational geometry; Computer graphics; Geometrical optics
Free Terms: 3D graphics; FEM; Surface geometry; Automatic
preprocessing; Meshing techniques; Accurate radiosity solutions; Topological criteria; Raw model databases

91-8
Doc Type: Conference Paper in Journal
Title: Design and simulation of opera lighting and projection effects
Authors: Dorsey, J.O'B.; Sillion, F.X.; Greenberg, D.P.
Affiliation: Program of Comput. Graphics, Cornell Univ., Ithaca, NY, USA
Journal: Computer Graphics
Vol: 25 Iss: 4 p. 41-50
Date: July 1991
Country of Publication: USA
ISSN: 0097-8930 CODEN: CGRADI
CCC: 0097-8930/91/007/0041$00.75
Language: English
Conf. Title: SIGGRAPH 91
Conf. Date: 28 July-2 Aug. 1991
Conf. Loc: Las Vegas, NV, USA
Conf. Sponsor: ACM
Treatment: Practical
Abstract: A major problem challenging opera designers is the inability to coordinate lighting, projection systems, and set designs in the preliminary planning phase. New computer graphics techniques, which provide the set and lighting designer the opportunity to evaluate, test, and control opera designs prior to the construction of full scale systems are presented. These techniques-light source input, simulation of directional lighting, modeling of scenic projection systems, and full three-dimensional simulation-show the potential for the use of computer graphics in theater design. The light source input component consists of a program for assigning light source attributes with a set of theater lighting icons. This module allows a designer to specify light source characteristics in a way familiar to the discipline and to make preliminary evaluations of the lighting conditions. An extended progressive radiosity method is introduced to simulate the directional lighting characteristics which are specified by the input program. A projection approach is presented to simulate the optical effects of scenic projectors. In addition, a solution to the distortion problem produced by angular projections is described. The components are integrated to produce full three-dimensional simulations of the global illumination effects in an opera scene. (28 Refs.)
Classification: C6130B (Graphics techniques); C7820 (Humanities) Thesaurus: Art; CAD; Computer graphics; Geometrical optics; Lighting Free Terms: 3D simulation; Opera lighting; Projection effects; Set designs; Computer graphics techniques; Light source input; Directional lighting; Scenic projection systems; Theater design; Light source attributes; Theater lighting icons; Extended progressive radiosity method; Distortion problem; Angular projections; Global illumination effects

91-9
Doc Type: Conference Paper
Title: A hardware algorithm for fast realistic image synthesis
Authors: Yilmaz, A.C.; Hagestein, S.; Deprettere, E.; Dewilde, P.
Conf. Title: Advances in Computer Graphics Hardware IV p. 37-60
Editors: Grimsdale, R.L.; Strasser, W.
Publisher: Springer-Verlag
Berlin, Germany
Date: 1991 viii+276 pp.
Country of Publication: Germany
ISBN: 3 540 53473 3
Language: English
Conf. Date: 3-4 Sept. 1989
Conf. Loc: Hamburg, West Germany
Treatment: Practical; Theoretical/Mathematical
Abstract: A VLSI oriented algorithm, for the implementation of a generalized two-pass radiosity method is presented. The method allows any reflection behavior, varying from purely diffuse to perfect mirroring. Moreover, objects may be defined in terms of curved Bezier surfaces. All computations in the pre- and postprocess are similar and ray-tracing based, consequently a single architecture can be devised for both passes. This architecture, when built on ray-rotating and ray-tracing pipeline processors such as Cordics, results in a very high throughput VLSI implementation of the proposed generalized two-pass procedure. (0 Refs.)
Classification: C6130B (Graphics techniques); C4130 (Interpolation and function approximation); C5220 (Computer architecture) Thesaurus: Computer graphics; Curve fitting; Parallel algorithms; Parallel architectures
Free Terms: Ray rotating pipelined processors; Hardware algorithm; Realistic image synthesis; VLSI oriented algorithm; Two-pass radiosity method; Reflection behavior; Purely diffuse; Perfect mirroring; Curved Bezier surfaces; Ray-tracing pipeline processors; Cordics; Throughput

91-10
Doc Type: Journal Paper
Title: The research and development of parallel processing in computer graphics
Authors: Wu Enhua; He Ruirong
Affiliation: Inst. of Software, Acad. Sinica, Beijing, China
Journal: Chinese Journal of Computers
Vol: 14 Iss: 5 p. 380-8
Date: 1991
Country of Publication: China
ISSN: 0254-4164 CODEN: JIXUDT
Language: Chinese
Treatment: Practical
Abstract: The generation and progress of computer graphics parallel processing are described, with an emphasis on the research and development of parallel processing functional components as well as parallel algorithms and architectures for polygon rendering, global illumination models (ray-tracing and radiosity), physical field data and volume data rendering, animation and parallelized graphics standards. The work conducted by the authors in this field is also given, and finally the future development of parallel processing for computer graphics is briefly described. (29 Refs.)
Classification: C6130B (Graphics techniques); C5440 (Multiprocessor systems and techniques)
Thesaurus: Computer graphics; Parallel processing
Free Terms: Parallel processing; Computer graphics; Research; Development; Parallel algorithms; Polygon rendering; Global illumination models; Ray-tracing; Physical field data; Volume data rendering

91-11
Doc Type: Journal Paper
Title: The radiosity method in optical remote sensing of structured 3-D surfaces
Authors: Borel, C.C.; Gerstl, S.A.W.; Powers, B.J.
Affiliation: Space Sci. & Technol. Div., Los Alamos Nat. Lab., NM, USA Journal: Remote Sensing of Environment
Vol: 36 Iss: 1 p. 13-44
Date: April 1991
Country of Publication: USA
ISSN: 0034-4257 CODEN: RSEEA7
CCC: 0034-4257/91/$3.50
Language: English
Treatment: Bibliography; Theoretical/Mathematical
Abstract: The radiosity method is a mathematical concept for describing the scattering of light between ideally diffuse (Lambertian) surfaces. The method takes reflections, transmission, and multiple scattering into account. Algorithms for finding view factors and for solving the radiosity equations using the Gauss-Seidel iteration method are described. An example for a layered plant canopy model shows the relation between the radiosity method and radiative transfer. The application of the radiosity method to remote sensing problems of 3-D surfaces, e.g. calculation of a BRDF including internal shadowing effects, is illustrated. Numerical results of radiosity calculations are compared with equivalent radiative transfer results. The radiosity method is a valuable tool to model the transport of light in vegetative canopies as well as a tool to evaluate the bidirectional reflectance characteristics of discrete leaf canopy structures, such as angular reflectance signatures. (50 Refs.)
Classification: A9385 (Instrumentation and techniques for geophysical, hydrospheric and lower atmosphere research); A9265D (Propagation through the atmosphere, radiation transfer)
Thesaurus: Atmospheric light propagation; Geophysical techniques; Light reflection; Light scattering; Radiative transfer; Remote sensing Free Terms: Lambertian surfaces light scattering; Ideally diffuse surfaces scattering; Light transmission; Light transport modelling; Radiative flux density; Leaf reflectance; Bidirectional reflectance distribution function; Radiosity method; Optical remote sensing; Structured 3-D surfaces; Multiple scattering; View factors; Radiosity equations; Gauss-Seidel iteration method; Layered plant canopy model; Radiative transfer; Internal shadowing effects; Vegetative canopies; Bidirectional reflectance characteristics; Discrete leaf canopy structures; Angular reflectance signatures

91-12
Doc Type: Conference Paper
Title: Fast radiosity by parallelization
Authors: Purgathofer, W.; Zeiller, M.
Affiliation: Inst. fur Praktische Inf., Vienna, Austria
Conf. Title: Eurographics Workshop on Photosimulation, Realism and Physics in Computer Graphics. Conference Proceedings
p. 173-83
Publisher: INRIA/IRISA
Rennes, France
Date: 1990 227 pp.
Country of Publication: France
Language: English
Conf. Date: 11-13 June 1990
Conf. Loc: Rennes, France
Treatment: Practical; Theoretical/Mathematical
Abstract: A parallel solution of the radiosity approach for realistic image rendering is presented. The tremendous costs of computation power and memory of radiosity implementations are met by parallelization on a computer architecture based on transputers. Form-factors are computed in parallel and independently on several processors, thus giving a high acceleration of this most computationally intensive task. parallel solutions for equation solving and rendering are also introduced. These parallelizations of the radiosity approach lead to an extraordinary speed-up in image generation and can be adapted for different kinds of parallel computer architectures. (11 Refs.)
Classification: C6130B (Graphics techniques); C4290 (Other computer theory); C4130 (Interpolation and function approximation); C4240 (Programming and algorithm theory)
Thesaurus: Computational geometry; Computer graphics; Geometrical optics; Iterative methods; Parallel algorithms
Free Terms: Computer graphics; Computational geometry; Iterative methods; Light; Radiosity; Parallelization; Image rendering; Transputers; Equation solving; Image generation

91-13
Doc Type: Conference Paper
Title: A rapid hierarchical radiosity algorithm for unoccluded environments
Authors: Hanrahan, P.; Salzman, D.
Affiliation: Dept. of Comput. Sci., Princeton Univ., NJ, USA
Conf. Title: Eurographics Workshop on Photosimulation, Realism and Physics in Computer Graphics. Conference Proceedings
p. 151-71
Publisher: INRIA/IRISA
Rennes, France
Date: 1990 227 pp.
Country of Publication: France
Language: English
Conf. Date: 11-13 June 1990
Conf. Loc: Rennes, France
Treatment: Theoretical/Mathematical
Abstract: The paper presents a radiosity algorithm for scenes containing large mutually unoccluded polygonal patches. It subdivides pairs of patches adaptively to build a hierarchical data structure with O(n) elements at the leaves, and it encodes all the light transport between component polygonal elements. Given a required numerical precision, determined by the specified bounds for maximum solid angle F/sub in / and minimum area A/sub in /, the algorithm reduces the number of form factor calculations and interactions to O(n) in the worst case and O( square root n) in the best case. Previous radiosity algorithms represented the element-to-element transport interactions with a form factor matrix containing n/sup 2/ entries. (0 Refs.)
Classification: C6130B (Graphics techniques); C4240 (Programming and algorithm theory); C4290 (Other computer theory); C6120 (File organisation)
Thesaurus: Computational complexity; Computational geometry; Computer graphics; Data structures; Geometrical optics; Matrix algebra Free Terms: Computational geometry; Computational complexity; Computer graphics; Rapid hierarchical radiosity algorithm; Unoccluded environments; Polygonal patches; Hierarchical data structure; Light transport; Component polygonal elements; Form factor

91-14
Doc Type: Conference Paper
Title: Exploiting coherence for clipping and view transformations in radiosity algorithms
Authors: Vilaplana, J.; Pueyo, X.
Affiliation: Dept. Llenguatges i Sistemes Informatics, Univ. Politechnica de Cataluna, Barcelona, Spain
Conf. Title: Eurographics Workshop on Photosimulation, Realism and Physics in Computer Graphics. Conference Proceedings
p. 137-50
Publisher: INRIA/IRISA
Rennes, France
Date: 1990 227 pp.
Country of Publication: France
Language: English
Conf. Date: 11-13 June 1990
Conf. Loc: Rennes, France
Treatment: Practical; Theoretical/Mathematical
Abstract: In radiosity techniques, a visibility computation process is repeatedly applied for different 'view points'. Because of the close relationship between these 'view points', one can take advantage of several kinds of coherence in order to speed up the different steps of the rendering pipeline. The authors focus on the clipping and the view transformation steps. (19 Refs.) Classification: C6130B (Graphics techniques); C4290 (Other computer theory)
Thesaurus: Computational geometry; Computer graphics; Geometrical optics; Light coherence
Free Terms: Computer graphics; Computational geometry; Clipping; View transformations; Radiosity; Visibility computation process; Coherence; Rendering pipeline

91-15
Doc Type: Conference Paper
Title: The hemisphere radiosity method: a tale of two algorithms
Authors: Spencer, S.N.
Affiliation: Adv. Comput. Center for the Arts & Design, Ohio State Univ., Columbus, OH, USA
Conf. Title: Eurographics Workshop on Photosimulation, Realism and Physics in Computer Graphics. Conference Proceedings
p. 127-35
Publisher: INRIA/IRISA
Rennes, France
Date: 1990 227 pp.
Country of Publication: France
Language: English
Conf. Date: 11-13 June 1990
Conf. Loc: Rennes, France
Treatment: Practical
Abstract: The most important and most computationally-intensive operation within the radiosity illumination model is the calculation of form-factors, the geometric measure of the fraction of the radiant energy leaving one surface and received by another surface. This form-factor calculation must account for potential obstructions between the target surfaces yet be computationally efficient and accurate. The paper presents two efficient variations on the hemi-cube form-factor calculation algorithm, using the hemisphere as the projection volume. These methods represent an evolution of the algorithm through continued research, in a search for improved accuracy and efficiency. (8 Refs.)
Classification: C6130B (Graphics techniques); C4290 (Other computer theory)
Thesaurus: Computational geometry; Computer graphics; Geometrical optics; Lighting
Free Terms: Computer graphics; Computational geometry; Hemisphere radiosity method; Radiosity illumination model; Form-factors; Hemi-cube

91-16
Doc Type: Conference Paper
Title: A two-pass radiosity method for Bezier patches
Authors: Kok, A.J.F.; Yilmaz, C.; Bierens, L.H.J.
Affiliation: Delft Univ. of Technol., Netherlands
Conf. Title: Eurographics Workshop on Photosimulation, Realism and Physics in Computer Graphics. Conference Proceedings
p. 117-26
Publisher: INRIA/IRISA
Rennes, France
Date: 1990 227 pp.
Country of Publication: France
Language: English
Conf. Date: 11-13 June 1990
Conf. Loc: Rennes, France
Treatment: Practical
Abstract: A restriction of the radiosity method has been the difficulty of processing environments consisting of curved surfaces. In order to apply current radiosity methods, such surfaces are usually subdivided into many polygonal patches. However, as the computational complexity of the radiosity method depends on the number of patches, this approach results in a very inefficient use of the available processing time and data storage capacity. A ray tracing based radiosity method for diffuse and specular reflective Bezier surfaces is presented. The original Bezier surface description is used throughout the entire algorithm which makes the subdivision of each Bezier path into many polygonal patches unnecessary. (9 Refs.)
Classification: C6130B (Graphics techniques); C4290 (Other computer theory)
Thesaurus: Computational complexity; Computational geometry; Computer graphics; Curve fitting; Geometrical optics; Light; Photometry Free Terms: Computer graphics; Computational geometry; Two-pass radiosity; Bezier patches; Curved surfaces; Polygonal patches; Computational complexity; Ray tracing; Bezier surfaces

91-17
Doc Type: Conference Paper
Title: A progressive ray-tracing-based radiosity with general reflectance functions
Authors: Le Saec, B.; Schlick, C.
Affiliation: LaBRI, Bordeaux, France
Conf. Title: Eurographics Workshop on Photosimulation, Realism and Physics in Computer Graphics. Conference Proceedings
p. 103-16
Publisher: INRIA/IRISA
Rennes, France
Date: 1990 227 pp.
Country of Publication: France
Language: English
Conf. Date: 11-13 June 1990
Conf. Loc: Rennes, France
Treatment: Theoretical/Mathematical
Abstract: The authors present a progressive and interactive rendering method to solve the global illumination problem. The method, currently under implementation at LaBRI, in Bordeaux (France), can be considered as an extension of Wallace's paper, at the SIGGRAPH'89 conference, about a progressive ray-tracing-based radiosity. The method is intended to remove the limitation to purely diffuse phenomenons that exists in Wallace's paper and allow the use of general reflectance functions. (20 Refs.)
Classification: C6130B (Graphics techniques); C4290 (Other computer theory)
Thesaurus: Computational geometry; Computer graphics; Geometrical optics; Light; Light reflection; Photometry
Free Terms: Image synthesis; Photorealism; Computational geometry; Photometry; Progressive ray-tracing; Radiosity; General reflectance; Interactive rendering; Global illumination; LaBRI

91-18
Doc Type: Conference Paper
Title: Efficient radiosity methods for non-separable reflectance models
Authors: Neumann, L.; Neumann, A.
Affiliation: Oktatrend Ltd., Budapest, Hungary
Conf. Title: Eurographics Workshop on Photosimulation, Realism and Physics in Computer Graphics. Conference Proceedings
p. 83-102
Publisher: INRIA/IRISA
Rennes, France
Date: 1990 227 pp.
Country of Publication: France
Language: English
Conf. Date: 11-13 June 1990
Conf. Loc: Rennes, France
Treatment: Theoretical/Mathematical
Abstract: Determination of interreflection of non-diffuse environments goes back a few years. In the case of N patches, separable (or, in particular, diffuse) reflectance leads to an equation system of N unknowns; in the case of general bidirectional reflectance there are O(N/sup 2/) unknowns. The paper describes two new, efficient methods for this latter extended, sparse matrix problem. Applying decomposition to diffuse+specular, sorted gathering+shooting method is effective in the case of small specular cones. The other method, relying on albedo-equivalent separable reflectance, offers a fast approximating radiosity solution, primarily suiting specular reflectances, with flat, indistinctive characteristics. (16 Refs.)
Classification: C6130B (Graphics techniques); C4290 (Other computer theory); C4140 (Linear algebra); C4130 (Interpolation and function approximation)
Thesaurus: Computational complexity; Computational geometry; Computer graphics; Iterative methods; Light; Light reflection; Matrix algebra Free Terms: Computer graphics; Image display; Photosimulation; Iterative methods; Radiosity; Reflectance models; Interreflection; Sparse matrix; Specular cones; Albedo-equivalent separable reflectance

91-19
Doc Type: Conference Paper
Title: Trends in radiosity for image synthesis
Authors: Wallace, J.R.
Conf. Title: Eurographics Workshop on Photosimulation, Realism and Physics in Computer Graphics. Conference Proceedings
p. 1-14
Publisher: INRIA/IRISA
Rennes, France
Date: 1990 227 pp.
Country of Publication: France
Language: English
Conf. Date: 11-13 June 1990
Conf. Loc: Rennes, France
Treatment: Practical; Theoretical/Mathematical
Abstract: The author looks at early developments in the radiosity method, which was introduced to computer graphics in 1984. Extensions of the method are covered. Recent developments in radiosity have been directed towards improving the quality and speed of the algorithm. Improved sampling methods are providing more accurate shading and parallel and hardware implementations are achieving very fast solution times. (24 Refs.)
Classification: C6130B (Graphics techniques); C4240 (Programming and algorithm theory); C4290 (Other computer theory)
Thesaurus: Computational complexity; Computational geometry; Computer graphics; Geometrical optics; Solid modelling
Free Terms: Shading algorithm; Computational complexity; Computational geometry; Radiosity; Image synthesis; Computer graphics; Sampling methods

91-20
Doc Type: Conference Proceedings
Conf. Title: Eurographics Workshop on Photosimulation, Realism and Physics in Computer Graphics. Conference Proceedings
Publisher: INRIA/IRISA
Rennes, France
Date: 1990 227 pp.
Country of Publication: France
Language: English
Conf. Date: 11-13 June 1990
Conf. Loc: Rennes, France
Abstract: The following topics were dealt with: radiosity; ray tracing methods; global illumination models, photometric algorithms; form factor calculation; and physics based methods. Classification: C6130B (Graphics techniques); C4290 (Other computer theory); C7320 (Physics and Chemistry)
Thesaurus: Colour; Computational geometry; Computer graphics; Geometrical optics; Light; Photometry; Physics computing Free Terms: Computer graphics; Radiosity; Ray tracing; Global illumination models; Photometric algorithms; Form factor; Physics

91-21
Doc Type: Journal Paper
Title: A generalization of the radiosity-based solution
Authors: Takabatake, K.
Affiliation: Kansai Inf. & Commun. Res. Lab., Matsushita Electr. Ind. Co. Ltd., Kadoma, Japan
Journal: Transactions of the Institute of Electronics, Information
and Communication Engineers D-II
Vol: J74D-II Iss: 4 p. 585-7
Date: April 1991
Country of Publication: Japan
CODEN: DTGDE7
Language: Japanese
Treatment: Practical
Abstract: The radiosity-based solution is an efficient solution to the rendering equation in some particular conditions of surfaces. A condition under which light from a point is determined by the radiosity of the point. A generalization of the radiosity-based solution is shown. (3 Refs.)
Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Geometrical optics
Free Terms: Computer graphics; Ray training; Radiosity-based solution; Rendering equation

91-22
Doc Type: Conference Paper
Title: An adapted solution of progressive radiosity and ray-tracing methods for nondiffusive environments
Authors: Hong Chen; En-Hua Wu
Affiliation: Inst. of Software, Acad. Sinica, Beijing, China Conf. Title: CG International '90. Computer Graphics Around the World p. 477-90
Editors: Chua, T.S.; Kunii, T.L.
Publisher: Springer-Verlag
Berlin, Germany
Date: 1990 x+606 pp.
Country of Publication: Germany
ISBN: 3 540 70062 5
Language: English
Conf. Date: 25-29 June 1990
Conf. Loc: Singapore
Conf. Sponsor: Inst. Syst. Sci
Treatment: Theoretical/Mathematical
Abstract: The newly appeared rendering technique of progressive refinement radiosity method has reduced the computation and storage cost dramatically in comparison with the standard radiosity approaches, though the method is still constrained to perfect diffuse environments. In the paper, an adapted two-pass approach with a combination of progressive refinement radiosity and ray tracing methods is presented. The method proposed has inherited the merits and practical value of the progressive refinement radiosity solution, and at the same time is capable of dealing with non-diffuse environments by an improved calculation of specular reflections and postprocessing step of ray tracing. Besides, treatment has also been provided in a postprocessor for improving shadow effect caused by point-like light sources within a non-diffuse environment. (20 Refs.) Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Computerised picture processing; Geometrical optics
Free Terms: Progressive radiosity; Ray-tracing methods; Nondiffusive environments; Rendering technique; Adapted two-pass approach; Specular reflections; Shadow effect

91-23
Doc Type: Conference Paper
Title: Highly realistic visual simulation of outdoor scenes under various atmospheric conditions
Authors: Kaneda, K.; Okamoto, T.; Nakamae, E.; Nishita, T.
Affiliation: Fac. of Eng., Hiroshima Univ., Japan
Conf. Title: CG International '90. Computer Graphics Around the World p. 117-31
Editors: Chua, T.S.; Kunii, T.L.
Publisher: Springer-Verlag
Berlin, Germany
Date: 1990 x+606 pp.
Country of Publication: Germany
ISBN: 3 540 70062 5
Language: English
Conf. Date: 25-29 June 1990
Conf. Loc: Singapore
Conf. Sponsor: Inst. Syst. Sci
Treatment: Practical; Theoretical/Mathematical
Abstract: A method for creating realistic images is proposed from the view point of displaying simulation results when designing a building in which various weather conditions are taken into account. So far, in order to create realistic images for interior design, the concept of radiosity as ambient light including spectral distribution has been developed. The method can display not only the brightness but also the hue and saturation of color. In contrast, for designing a building sky light has been treated as ambient light, in which the brightness under various weather conditions could be calculated, but the influences on the hue and saturation of color were ignored. The proposed method creates realistic images considering the brightness, hue and saturation under various atmospheric conditions by taking into account the spectral distribution of both direct sunlight and sky light. Views of buildings including the influences of the particles in the atmosphere, i.e. clouds, fog, and beams, are useful for design not only of new buildings but also of new city areas. (15 Refs.)
Classification: A9265M (Scattering, polarization); A9265V (Clouds, fog, haze, aerosols, effects of pollution); C6130B (Graphics techniques) Thesaurus: Atmospheric optics; Computer graphics; Digital simulation Free Terms: Building design; Visual simulation; Outdoor scenes; Atmospheric conditions; Realistic images; Simulation results; Weather conditions; Interior design; Radiosity; Ambient light; Spectral distribution; Brightness; Hue; Saturation; Color; Direct sunlight; Sky light; Clouds; Fog; Beams

91-24
Doc Type: Conference Proceedings
Conf. Title: CG International '90. Computer Graphics Around the World Editors: Chua, T.S.; Kunii, T.L.
Publisher: Springer-Verlag
Berlin, Germany
Date: 1990 x+606 pp.
Country of Publication: Germany
ISBN: 3 540 70062 5
Language: English
Conf. Date: 25-29 June 1990
Conf. Loc: Singapore
Conf. Sponsor: Inst. Syst. Sci
Treatment: Practical; Theoretical/Mathematical
Abstract: The following topics were dealt with: computer animation, user interface management systems, design automation, modelling and realism, rendering; graphics algorithms, object oriented graphics, visual languages and visualization, computational geometry, ray tracing and radiosity; and curves and surfaces.
Classification: C6130B (Graphics techniques); C4190 (Other numerical methods); C4290 (Other computer theory); C6110 (Systems analysis and programming)
Thesaurus: Computational geometry; Computer animation; Computer graphics; Object-oriented programming
Free Terms: Computer animation; User interface management systems; Design automation; Modelling; Realism; Rendering; Graphics algorithms; Object oriented graphics; Visual languages; Visualization; Computational geometry; Ray tracing; Radiosity; Curves; Surfaces

91-25
Doc Type: Conference Paper
Title: Applications and comparison of different mathematical methods to compute form factors for radiosity images
Authors: Bresciani, F.; Rinaldi, P.P.; Tapparo, F.
Affiliation: Aeritalia, Torino, Italy
Conf. Title: Workstations for Experiments. IFIP WG 5.10 International Working Conference
p. 82-96
Editors: Encarnacao, J.L.; Grinstein, G.G.
Publisher: Springer-Verlag
Berlin, Germany
Date: 1991 viii+225 pp.
Country of Publication: Germany
ISBN: 3 540 52898 9
Language: English
Conf. Date: July 1989
Conf. Loc: Lowell, MA, USA
Treatment: Theoretical/Mathematical
Abstract: A fundamental problem in synthetic images is to determine a correct light interaction between surfaces in an environment. The radiosity method is an algorithm based on theories used in thermal engineering that includes effects of reflection between ideal diffuse surfaces. The computation of geometric factors (form factors), which describes the energy exchange between surfaces, represents the most expensive part of computational time necessary to generate a synthetic image. The paper aims to analyze different approaches to compute form factors. Subsequently, it makes a numerical comparison of the results and provides the evaluation of the relative errors and of the computational time. At the end it presents some simple images generated with the different approaches discussed. (4 Refs.) Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Heat transfer
Free Terms: Image generation; Light reflection; Light scattering; Mathematical methods; Form factors; Radiosity images; Synthetic images; Correct light interaction; Algorithm; Thermal engineering; Reflection; Ideal diffuse surfaces; Geometric factors; Energy exchange

91-26
Doc Type: Conference Paper
Title: A ray tracing method for illumination calculation in diffuse-specular scenes
Authors: Shirley, P.
Affiliation: Dept. of Comput. Sci., Illinois Univ., Urbana, IL, USA Conf. Title: Proceedings. Graphics Interface '90
p. 205-12
Publisher: Canadian Inf. Process. Soc
Toronto, Ont., Canada
Date: 1990 xi+301 pp.
Country of Publication: Canada
Availability: Morgan Kaufmann Publishers, P.O.Box 50490, Palo Alto, CA, USA
Language: English
Conf. Date: 14-18 May 1990
Conf. Loc: Halifax, NS, Canada
Conf. Sponsor: Canadian Man-Comput. Commun. Soc.;
Canadian Image Process. Pattern Recognition
Soc.; Canadian Inf. Process. Soc.; ACM; et al
Treatment: Practical; Theoretical/Mathematical
Abstract: Several ways of improving the realism of the results of traditional ray tracing are presented. The essential physical quantities of spectral radiant power and spectral radiance and their use in lightning calculations are discussed. Global illumination terms are derived by employing illumination ray tracing for calculation of quickly changing indirect lightning components, and radiosity ray tracing for slowly changing indirect lighting components. Direct lightning is calculated during the viewing phase allowing the use of bump maps. Finally, a method is introduced that reduces the total number of shadow rays to no more than the total number of viewing rays for a given picture. (22 Refs.) Classification: C6130B (Graphics techniques); C4290 (Other computer theory)
Thesaurus: Computational geometry; Computer graphics
Free Terms: Direct lighting; Ray tracing method; Illumination calculation; Diffuse-specular scenes; Spectral radiant power; Radiosity; Bump maps

91-27
Doc Type: Conference Paper
Title: Octant priority for radiosity image rendering
Authors: Yigong Wang; Davis, W.A.
Affiliation: Dept. of Comput. Sci., Alberta Univ., Edmonton, Alta., Canada
Conf. Title: Proceedings. Graphics Interface '90
p. 83-91
Publisher: Canadian Inf. Process. Soc
Toronto, Ont., Canada
Date: 1990 xi+301 pp.
Country of Publication: Canada
Availability: Morgan Kaufmann Publishers, P.O.Box 50490, Palo Alto, CA, USA
Language: English
Conf. Date: 14-18 May 1990
Conf. Loc: Halifax, NS, Canada
Conf. Sponsor: Canadian Man-Comput. Commun. Soc.;
Canadian Image Process. Pattern Recognition
Soc.; Canadian Inf. Process. Soc.; ACM; et al
Treatment: Practical; Theoretical/Mathematical
Abstract: This paper presents a new scheme for image display using radiosity methods. An octree technique performs subdivision of polygons which is required in any radiosity method. The octree-based subdivision not only subdivides polygons into patches, but also produces a sequence of leaf octants implicitly sorted in the octree. By traversing the octree, a depth priority of these leaf octants with respect to a given viewer position can be found efficiently. Since each octant contains a certain number of patches, octant priority implies a patch depth priority that is used to determine visibility in computing form-factors by a front-to-back list priority algorithm. This list-priority method has many advantages over the z-buffer and can avoid some unnecessary computation. (21 Refs.)
Classification: C4290 (Other computer theory); C1250 (Pattern recognition); C5260B (Computer vision and picture processing) Thesaurus: Computational geometry; Picture processing Free Terms: Octant priority; Radiosity image rendering; Octree technique; Polygons; Leaf octants; Patch depth priority; Form-factors; List priority algorithm; Z-buffer

91-28
Doc Type: Conference Paper
Title: Image and intervisibility coherence in rendering
Authors: Marks, J.; Walsh, R.; Christensen, J.; Friedell, M.
Affiliation: Aiken Comput. Lab., Harvard Univ., Cambridge, MA, USA Conf. Title: Proceedings. Graphics Interface '90
p. 17-30
Publisher: Canadian Inf. Process. Soc
Toronto, Ont., Canada
Date: 1990 xi+301 pp.
Country of Publication: Canada
Availability: Morgan Kaufmann Publishers, P.O.Box 50490, Palo Alto, CA, USA
Language: English
Conf. Date: 14-18 May 1990
Conf. Loc: Halifax, NS, Canada
Conf. Sponsor: Canadian Man-Comput. Commun. Soc.;
Canadian Image Process. Pattern Recognition
Soc.; Canadian Inf. Process. Soc.; ACM; et al
Treatment: Practical
Abstract: Researchers in computer graphics have long regarded the exploitation of image coherence as one of the fundamental opportunities for improving the efficiency of image rendering. The authors describe in this paper a theoretical and experimental investigation of the potential benefits of exploiting this phenomenon through the use of hybrid rendering strategies that combine area-sampling and point-sampling techniques. They also examine the impact of a related phenomenon, intervisibility coherence, on the calculation of form factors for radiosity-based rendering. (9 Refs.) Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Picture processing
Free Terms: Image coherence; Intervisibility coherence; Rendering; Computer graphics; Hybrid rendering; Area-sampling; Point-sampling

91-29
Doc Type: Journal Paper
Title: Thermal contact electronic packaging in solar pointing space environment
Authors: Lund, K.O.; Colangelo, A.M.; McKim, G.S.
Affiliation: Dept. of Mech. Eng., San Diego State Univ., CA, USA Journal: Transactions of the ASME. Journal of Solar Energy
Engineering
Vol: 113 Iss: 1 p. 42-50
Date: Feb. 1991
Country of Publication: USA
ISSN: 0199-6231 CODEN: JSEEDO
Language: English
Treatment: Practical; Theoretical/Mathematical; Experimental
Abstract: A thermal design for a solar pointing Space Shuttle mission is presented. The apparatus, which will measure solar flux intensity variations, contains sensors and data acquisition electronics which must be maintained within certain temperature constraints. The thermal design, which utilizes parallel heat flow paths and conduction fins to reject dissipated heat, is shown by finite difference thermal modeling to maintain component temperatures within these constraints. In the thermal modeling, arithmetic nodes are used to represent surface radiosity for radiation heat transfer. Also, the concept of mean fin conduction length and effective fin capacitance are introduced as means of simplifying the model representation of the conduction fins. An experiment was conducted to evaluate the chip/fin contact conductance. (12 Refs.) Classification: B0170J (Product packaging)
Thesaurus: Heat transfer; Packaging
Free Terms: Thermal contact electronic packaging; Solar pointing Space Shuttle mission; Solar flux intensity; Sensors; Data acquisition electronics; Parallel heat flow paths; Conduction fins; Finite difference thermal modeling; Surface radiosity; Radiation heat transfer; Mean fin conduction length; Effective fin capacitance; Chip/fin contact conductance

91-30
Doc Type: Conference Paper
Title: Too many cooks don't spoil the broth: light simulation on massively parallel computers
Authors: Kochevar, P.
Affiliation: Program of Comput. Graphics, Cornell Univ., Ithaca, NY, USA
Conf. Title: Third Symposium on the Frontiers of Massively Parallel Computation. Proceedings. (Cat. No.90CH2908-2)
p. 100-9
Editors: Jaja, J.
Publisher: IEEE Comput. Soc. Press
Los Alamitos, CA, USA
Date: 1990 xiv+531 pp.
Country of Publication: USA
ISBN: 0 8186 2053 6
CCC: CH2908-2/90/0000-0100$01.00
Language: English
Conf. Date: 8-10 Oct. 1990
Conf. Loc: College Park, MD, USA
Conf. Sponsor: IEEE; NASA; Univ. Maryland
Treatment: Application; Practical
Abstract: A computer graphics algorithm for simulating the propagation of light and its interaction with matter on a massively parallel computer is presented. This algorithm, called the tagged shooting method, is designed for a virtual machine containing a great number of simple communicating processors arrayed into a cubical three-dimensional lattice. Only nearest neighbor communication among processors is assumed, and there is no reliance on global shared memory. The algorithm is similar in spirit to the classical progressive refinement radiosity method designed for more conventional computers but is not an adaptation of that technique to massive parallelism. Instead, the new algorithm uses a discretization of the wave equation as a local rule for shuttling radiant energy values between processors that correspond to regions of space. A number of example images that were created with an implementation of the algorithm on a Connection Machine are depicted and critiqued. (6 Refs.)
Classification: C6130B (Graphics techniques); C7320 (Physics and Chemistry)
Thesaurus: Computer graphics; Digital simulation; Physics computing Free Terms: Light simulation; Massively parallel computers; Computer graphics algorithm; Tagged shooting method; Virtual machine; Nearest neighbor communication; Discretization; Wave equation; Connection Machine

91-31
Doc Type: Journal Paper
Title: Reality in the shadow
Authors: Wallace, J.R.; Elmquist, K.A.; Haines, E.A.
Affiliation: Hewlett Packard Nederland, Amstelveen, Netherlands Journal: Elektronica
Vol: 39 Iss: 4 p. 19-21, 23, 25, 28-31
Date: 22 Feb. 1991
Country of Publication: Netherlands
ISSN: 0168-7840 CODEN: LKTNDO
Language: Dutch
Treatment: Theoretical/Mathematical
Abstract: Models for determining indirect light, using light ray tracing and radiosity are described. Various algorithms for
progressive radiosity are explained and compared, discussing their mathematical bases, qualitative and quantitative differences, advantages and limitations. An improved algorithm, based on light ray tracing and using numerical integration is described more fully, and examples of its use are shown. (22 Refs.)
Classification: A4210D (Wave-front and ray tracing); B8530D (Lighting) Thesaurus: Geometrical optics; Light reflection; Lighting; Reflectivity Free Terms: Indirect light; Light ray tracing; Progressive radiosity; Algorithm; Numerical integration

91-32
Doc Type: Conference Paper
Title: Experimental distributed processing system for global illumination algorithms
Authors: Tampieri, F.; Greenberg, D.P.
Affiliation: Program of Comput. Graphics, Cornell Univ., Ithaca, NY, USA
Conf. Title: International Conference and Exhibition. Computational Intelligence 88
p. 161-71
Publisher: Univ. Milan
Milan, Italy
Date: 1988 222 pp.
Country of Publication: Italy
Language: English
Conf. Date: 26-30 Sept. 1988
Conf. Loc: Milan, Italy
Treatment: Practical
Abstract: The current global illumination algorithms for three-dimensional realistic image synthesis are computationally intractable. These approaches are surveyed and then modified and implemented on a distributed processing system to reduce computation times. Different strategies for subdividing the work and balancing the computational load among processors are discussed for the ray tracing and Monte Carlo techniques and a distributed version of the progressive refinement radiosity is outlined. (42 Refs.) Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Distributed processing; Geometrical optics
Free Terms: 3D images; Global illumination algorithms; Realistic image synthesis; Distributed processing system; Computation times; Computational load; Ray tracing; Monte Carlo techniques; Progressive refinement radiosity

91-33
Doc Type: Journal Paper
Title: Computer graphics (for CAD/CAM applications)
Authors: Gambini, M.
Journal: Tecnologie Elettriche
Vol: 17 Iss: 12 p. 108-13
Date: Dec. 1990
Country of Publication: Italy
ISSN: 0390-6698 CODEN: TEELDN
Language: Italian
Treatment: Application; Practical
Abstract: The use of computer graphics has had two main impacts on productivity creativity, these being speed and the realism given. The author describes some typical examples of available equipment and the performances offered by them. This field has made rapid progress in the last few years. One system described is Turbo VRX, of high speed and used for modelling and engineering design. Another is the Starbase Radiosity and E Ray Tracing system of Hewlett-Packard. Others include the Personal VRX (based on RISC technology), the VRX Color (in colour and of very high resolution) and the VRX Mono, monochromatic, but of high resolution. (0 Refs.)
Classification: C6130B (Graphics techniques); C7400 (Engineering) Thesaurus: CAD/CAM; Engineering graphics
Free Terms: CAD/CAM; Computer graphics; Turbo VRX; Modelling; Engineering; Starbase Radiosity and E Ray Tracing; Personal VRX; RISC; VRX Color; VRX Mono

91-34
Doc Type: Conference Paper
Title: Calibration of thermal images of integrated circuit chips
Authors: Sabata, B.; Pearce, J.A.
Affiliation: Electr. & Comput. Eng., Texas Univ., Austin, TX, USA Conf. Title: Midcon/88 Conference Record
p. 151-4
Publisher: Electron. Conventions Manage
Ventura, CA, USA
Date: 1988 iv+397 pp.
Country of Publication: USA
Availability: Western Periodicals Co., 13000 Raymer Street, North Hollywood, CA 91605, USA
Language: English
Conf. Date: 30 Aug.-1 Sept. 1988
Conf. Loc: Dallas, TX, USA
Conf. Sponsor: IEEE; ERA
Treatment: Practical
Abstract: In semiconductor integrated circuits many failure mechanisms are temperature dependent; hence, it is necessary to study temperature distributions and local temperature gradients in the chip. Calibrated thermal images provide a nearly instantaneous determination of the surface temperature distributions. But the main problem with such an approach is that the images do not read out the temperature directly but measure the surface radiosity. To get the temperature the image has to be calibrated thermally. Also the imaging technique causes distortion in the geometry of the object, which must be corrected and the image recalibrated. A region-growing algorithm was used to identify the features used for the geometrical calibration of the image. The regions in the chip layout corresponding to the 'hot spots' were also identified, and lateral thermal gradients calculated. (18 Refs.)
Classification: B2570 (Semiconductor integrated circuits); B7130 (Measurement standards and calibration)
Thesaurus: Calibration; Infrared imaging; Integrated circuit
technology; Monolithic integrated circuits
Free Terms: Hot spots; Thermal images; Integrated circuit chips; Semiconductor integrated circuits; Failure mechanisms; Temperature distributions; Local temperature gradients; Instantaneous determination; Surface temperature distributions; Region-growing algorithm; Geometrical calibration; Chip layout; Lateral thermal gradients

91-35
Doc Type: Conference Paper
Title: Fast rendering of arbitrary distributed volume densities
Authors: Sakas, G.
Affiliation: Tech. Hochschule Darmstadt, Germany
Conf. Title: Eurographics '90. Proceedings of the European Computer Graphics Conference and Exhibition
p. 519-30
Editors: Vandoni, C.E.; Duce, D.A.
Publisher: North-Holland
Amsterdam, Netherlands
Date: 1990 xiv+562 pp.
Country of Publication: Netherlands
ISBN: 0 444 88683 4
Language: English
Conf. Date: 4-7 Sept. 1990
Conf. Loc: Montreux, Switzerland
Treatment: Practical
Abstract: In recent years a number of techniques have been developed for rendering volume effects (haze, fog, smoke, clouds, etc.). These techniques are either time consuming (ray-tracing, radiosity) or do not account for arbitrary density distributions. The authors briefly analyze the physics of illuminations of volumes and they propose several simplifications suitable for computer graphics practice. In particular, they present a method for rendering arbitrary distributions by means of projective polygonal rendering and solid texturing techniques in approximately the time needed for a usual polygonal object. The proposed method provides good results in a fraction of the computing time required for approaches like ray-tracing or radiosity. Solid texturing is used to define the density distribution and a point-sampling Monte-Carlo method with user-adjustable accuracy to evaluate the illumination model along the path through the volume. Thus, a trade-off between computing time and picture quality exists. With this technique one can move through or around the volume and to place objects and/or light sources in the volume. By means of rendering methods like shadowing polyhedra, objects can cast shadows on the volume and/or the volume can shadow the ground. (16 Refs.)
Classification: C6130B (Graphics techniques)
Thesaurus: Computer graphics; Monte Carlo methods
Free Terms: Fractal clouds; Rendering; Arbitrary distributed volume densities; Volume effects; Computer graphics; Projective polygonal rendering; Solid texturing; Density distribution; Point-sampling Monte-Carlo method; User-adjustable accuracy; Illumination model; Computing time; Picture quality; Shadowing polyhedra

91-36
Doc Type: Journal Paper
Title: Realism and interactivity in picture synthesis
Authors: Giralt, J.; Torres, E.; Tost, D.; Pueyo, X.
Affiliation: Dept. Llenguatges i Sistemes Informatics, Univ. Politecnica de Catalunya, Barcelona, Spain
Journal: Novatica
Vol: 16 Iss: 86 p. 19-23, 37
Date: 1990
Country of Publication: Spain
ISSN: 0211-2124 CODEN: NOVAEC
Language: Spanish
Treatment: Practical
Abstract: Since the first rendering algorithm appeared in the 60's, increasing efficiency of these programs and improving the realism of the generated images have been the goal of image synthesis research contributions. The paper presents the recent work done in this field in the Computer Graphics Section of the department LiSI of the UPC. These contributions deal with different aspects of rendering techniques: scene organization, frame-to-frame coherence and realistic image synthesis. (11 Refs.)
Classification: C6130B (Graphics techniques)
Thesaurus: Computer animation; Computer graphics; Geometrical optics Free Terms: Animation; BSP; Ray tracing; Radiosity; Realism;
Interactivity; Picture synthesis; Rendering algorithm; Image synthesis research; Rendering techniques; Scene organization; Frame-to-frame coherence; Realistic image synthesis

91-37
Doc Type: Conference Paper in Journal
Title: Adaptive mesh generation for global diffuse illumination
Authors: Camp