Image analysis – Pattern recognition – Feature extraction
Reexamination Certificate
2003-04-10
2004-08-24
Mehta, Bhavesh M. (Department: 2625)
Image analysis
Pattern recognition
Feature extraction
C345S419000, C345S606000, C345S611000, C382S240000, C382S258000, C382S260000, C382S300000
Reexamination Certificate
active
06782130
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of computer imaging and more particularly, to rendering of photorealistic computer graphic images.
BACKGROUND OF THE INVENTION
The ability to synthesize photorealistic images in real-time has been the goal of practitioners in the field of computer graphics for many years. A variety of different techniques are known for generating images of three-dimensional objects on a computer graphics display. One class of techniques divide a two-dimensional array of data values into shaded polygons, which are then projected onto the display screen. To accelerate the image generation process, many polygon-based techniques utilize a special graphics processor to alleviate the computational burden on the computer's central processing unit (CPU).
Another class of computer imaging techniques is known as ray tracing. Ray tracing is a pixel-based technique that is capable of producing highly realistic images in computer graphic systems. A chief drawback of ray tracing techniques, however, is the extensive computations required to generate each pixel of the display screen. These intensive computations often impose a severe burden on the computer processing hardware. The slow processing times associated with ray tracing techniques have limited their application in computer graphics systems. For example, an article entitled, “Outlook on Computer Graphics”, by D. P. Greenburg, IEEE Computer, 31(1): 36-36 (January 1998), suggests that it will not be until the year 2025 before computer systems have the display and computational capability to produce realistic, real-time images using pixel-based techniques.
An example of a computer system that utilizes ray tracing is described in “Antialiased Ray tracing by Adaptive Progressive Refinement,” by J. Painter and K. Sloan,
Computer Graphics
(SIGGRAPH '89 Proceedings), Vol. 23, pages 281-288 (July 1989). Further background in this area may be found in U.S. Pat. No. 5,872,902, which teaches a hardware implementation of a computationally intensive anti-aliasing technique for generating three-dimensional images on a workstation graphics processor. U.S. Pat. No. 5,831,623 discloses a volume rendering apparatus for visualizing an image on a display screen of an imaging device such as a computer tomagraphy scanner for a magnetic resonance imaging machine. A method and system for generating an anti-aliasing image of a three-dimensional surface is also described in U.S. Pat. No. 5,542,032, which teaches performing certain floating-point arithmetic and comparison operations on pixel data.
Despite the rapidly increasing power of computers, global illumination is far from being a real-time process. Accurate radiance evaluations often require hours of computation for complex scenes. To balance rendering speed and visual realism, global illumination algorithms have often adopted a progressive refinement approach, like that described in the Painter and Sloan article mentioned above. Progressive refinement methods typically sample densely where sharp features are identified. In areas of the image plane where there is an absence of sharp features—i.e., the image data changes slowly—progressive refinement techniques sample very sparsely, and then interpolate.
The problem with these past techniques is that image artifacts are often lost when the sampling criteria is minimized. For instance, if it is desired to keep the sampling rate below 10%, many prior art progressive refinement approaches prove to be inadequate. In other words, although such techniques provide a reasonable approach to the problem, they require relatively high sampling rates to provide fast rendering of photorealistic computer graphics images. At low sampling rates (e.g., less than 10%) previous techniques such as adaptive stochastic sampling suffer from artifacts including heavily jagged edges, missing object parts, and missing high-frequency details.
REFERENCES:
patent: 5031117 (1991-07-01), Minor et al.
patent: 5283859 (1994-02-01), Quarendon et al.
patent: 5542032 (1996-07-01), Pritt
patent: 5583975 (1996-12-01), Naka et al.
patent: 5831623 (1998-11-01), Negishi et al.
patent: 5872902 (1999-02-01), Kuchkuda et al.
patent: 5987172 (1999-11-01), Michael
patent: 6040911 (2000-03-01), Nozaki et al.
patent: 6101277 (2000-08-01), Go
patent: 6148115 (2000-11-01), Mackinnon et al.
patent: 6167154 (2000-12-01), Renaud et al.
patent: 6181802 (2001-01-01), Todd
patent: 6370279 (2002-04-01), Paik
C. Kolb. Rayshade User's Guide and Reference Manual. Rayshade home page at graphics.Stanford.edu, Jan. 1992.
J. Arvo. The Irradiance Jacobian for Partially Occluded Polyhedral Sources. In A. Glassner, editor,Computer Graphics Proceedings, Annual Conference Series, pp. 75-84, Jul. 1994.
L.D. Bergman et al., Image Rendering by Adaptive Refinement. In D.C. Evans and R.J. Athay, editors,Computer Graphics(SIGGRAPH '86 Proceedings), vol. 20, pp. 29-37, Aug. 1986.
J. Bloomenthal, Edge Inference with Applications to Antaliasing. InComputer Graphics(SIGGRAPH '83 Proceedings), vol. 17, pp. 157-162, Jul. 1983.
M.R. Bolin et al., A Frequency Based Ray Tracer. In R. Cook, editor,Computer Graphics Proceedings, Annual Conference Series, pp. 409-418, Aug. 1995.
A.T. Campbell III et al., Adaptive Mesh Generation for Global Diffuse Illumination. In Computer Graphics (SIGGRAPH '90 Proceedings), vol. 24, pp. 155-164, Aug. 1990.
S.E. Chen et al., A Progressive Multi-Pass Method for Global Illumination. In T.W. Sederberg, editor.Computer Graphics(SIGGRAPH '91 Proceedings) vol. 25, pp. 165-174, Jul. 1991.
N. Chin an S. Feiner. Near Real-Time Shadow Generation Using BSP Trees. In J. Lane, editor,Computer Graphics(SIGGRAPH '89 Proceedings) vol. 23, pp. 99-106, Jul. 1989.
M.F. Cohen et al., A Progressive Refinement Approach to Fast Radiosity Image Generation. In J. Dill, editor,Computer Graphics(SIGGRAPH '88 Proceedings), vol. 22, pp. 75-84, Aug. 1988.
R.L. Cook et al., Distributed Ray Tracing. InComputer Graphics(SIGGRAPH '84 Proceedings), vol. 18, pp. 137-145, Jul. 1984.
F. Crow. Shadow Algorithms for Computer Grapics. InComputer Graphics(SIGGRAPH '77 Proceedings), vol. 11, pp. 242-248, Jul. 1977.
G. Dretakkis and E. Fiume. A Fast Shadow Algorithm for Area Light Sources Using Backprojection. In A. Glassner, editor,Computer Graphics Proceedings, Annual Conference Series, pp. 223-230, Jul. 1994.
A. Fujimoto et al., ARTS: Accelerated Ray Tracing System. IEEEComputer Graphics and Applications, 6(4): Jul. 16-26, Jul. 1986.
R. Heckbert. Discontinuity Meshing for Radiosity.Third Eurographics Workshop on Rendering, pp. 203-226, May 1992.
A. Jain.Fundamentals of Digital Image Processing. Prentice Ha.., 1989.
J. Kajiya. The Rendering Equation. InComputer Graphics(SIGGRAPH '86 Proceedings), vol. 20, pp. 143-150, Aug. 1986.
M. Kunt et al., Second-Generation Image Coding Techniques.Proc. Of IEEE, 73(4):549-574, 1985.
M.E. Lee et al. Statistically Optimized Sampling for Distributed Ray Tracing. In B.A. Barsky, editorComputer Graphics(SIGGRAPH '85 Proceedings), vol. 19, pp. 61-67, Jul. 1985.
D. Lischinski et al., Combining Hierarchical Radiosity and Discontinuity Meshing. InComputer Graphics Proceedings, Annual Conference Series, pp. 199-208, 1993.
S. Mallat and S. Zhong. Characterization of Signals from Multiscale Edges.IEEE Trans. On Pattern Analysis and Machine Intelligence, 14(7):710-732, 1992.
D.P. Mitchell. Generating Antialiased Images at Low Sampling Densities. In M.C. Stone, editor,Computer Graphics(SIGGRAPH '87 Proceedings), vol. 21, pp. 65-72, Jul. 1987.
F. Pighin et al., Progressive Previewing of Ray-Traced Images Using Image-Plane Discontinuity Meshing.Eurographics Workshop on Rendering1997, May 1997.
H. Rushmeier and G. Ward. Energy Preserving Non-Linear Filters. In A. Glassner, editor,Computer Graphics Proceedings, Annual Conference Series, pp. 131-138, Jul. 1994.
P. Schroeder and P. Hanrahan. On the Form Factor Between Two Polygons. Technical Resport CS-404-93, Princeton University, Computer Scienc
Blakely , Sokoloff, Taylor & Zafman LLP
Desire Gregory
Intel Corporation
Mehta Bhavesh M.
LandOfFree
Rendering of photorealistic computer graphics images does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rendering of photorealistic computer graphics images, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rendering of photorealistic computer graphics images will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3361689