Education

Experience

Research Interests

Perceptual aspects of virtual simulation

• Improving 3D perception through tracking the trainee's head, even without stereo display
• Better simulation of veiling glare, either within image generation or with a display of much greater luminance range
• Assessing texture and geometry detail against perceptual limits, not just display resolution
• Understanding influence of field of view

Psychophysics of Material and Shape Perception

Camera-Based BRDF Measurement

Image-Based BRDF Measurement Including Human Skin, a paper by Steve Marschner and others (including me) on how to measure the BRDF of a curved object using only a good digital camera, an electronic flash, and a Cyberware scanner. This is a PDF file distilled from the actual PostScript^® file submitted for the conference proceedings, but one or two figures that were printed in black and white are color here.

In addition, two technical reports are avaliable, Image-Based BRDF Measurement and Reflectance Measurements of Human Skin. These provide added technical detail.

Publications

Papers

	Hongsong Li, Sing-Choong Foo, Kenneth E. Torrance, and Stephen H. Westin. Automated three-axis gonioreflectometer for computer graphics applications. Advanced Characterization Techniques for Optics, Semiconductors, and Nanotechnologies II, Proc. SPIE 5878, Aug. 2005.
	Stephen R. Marschner, Stephen H. Westin, Adam Arbree, and Jonathan T. Moon. Measuring and Modeling the Appearance of Finished Wood. ACM Transactions on Graphics, Proceedings of SIGGRAPH 2005.
	James A. Ferwerda, Stephen H. Westin, Randall C. Smith, and Richard Pawlicki. Effects of rendering on shape perception in automobile design. First ACM Symposium on Applied Perception in Graphics and Visualization, July 2004, 107-114.
	Stephen R. Marschner, Stephen H. Westin, Eric P. F. Lafortune, and Kenneth E. Torrance. Image-based bidirectional reflectance distribution function measurement. Applied Optics-OT, 39(16):2592--2600, June 2000.
	Stephen R. Marschner, Stephen H. Westin, Eric P. F. Lafortune, Kenneth E. Torrance, and Donald P. Greenberg. Image-based brdf measurement including human skin. In Eurographics Workshop on Rendering, 1999. This is a PDF file distilled from the actual PostScript® file submitted for the conference proceedings, but one or two figures that were printed in black and white are color here.
	Stephen H. Westin, James R. Arvo, and Kenneth E. Torrance. Predicting reflectance functions from complex surfaces. Computer Graphics (SIGGRAPH '92 Proceedings), 26:255--264, July 1992. This is a modified version of the PostScript® file used to make the camera-ready copy. I had to insert the images by hand, so cropping and alignment may be a bit different from the SIGGRAPH proceedings. Microgeometry for various surfaces and images used in the paper are also available.
	François X. Sillion, James R. Arvo, Stephen H. Westin, and Donald P. Greenberg. A global illumination solution for general reflectance distributions. Computer Graphics (SIGGRAPH '91 Proceedings), 25:187--196, July 1991.

Technical reports

	Stephen H. Westin, Hongsong Li, and Kenneth E. Torrance. A comparison of four brdf models. Technical report PCG-04-02, Program of Computer Graphics, Cornell University, April 2004.
	Stephen H. Westin, Hongsong Li, and Kenneth E. Torrance. A field guide to brdf models. Technical report PCG-04-01, Program of Computer Graphics, Cornell University, Jan 2004.
	Stephen R. Marschner, Eric P. F. Lafortune, Stephen H. Westin, , Kenneth E. Torrance, and Donald P. Greenberg. Image-based brdf measurement. Technical report PCG-99-1, Program of Computer Graphics, Cornell University, Jan 1999.
	Stephen R. Marschner, Stephen H. Westin, Eric P. F. Lafortune, Kenneth E. Torrance, and Donald P. Greenberg. Reflectance measurements of human skin. Technical report PCG-99-2, Program of Computer Graphics, Cornell University, Jan 1999.

Master's Thesis

Educational Material:

Torrance-Sparrow
	K. E. Torrance and E. M. Sparrow. Theory for Off-Specular Reflection from Rough Surfaces. Journal of the Optical Society of America, vol. 57, no. 9, pp. 1105-1114, 1967. I scanned this into a PDF file (0.9MB).
He-Torrance BRDF Implementation
	Xiao D. He, Kenneth E. Torrance, Francois X. Sillion, and Donald P. Greenberg. A comprehensive physical model for light reflection. Computer Graphics (SIGGRAPH '91 Proceedings), 25(4):175--186, July 1991. Liang Peng and I implemented the model in C++ and verified against the original C implementation of the 1991 paper.
Fresnel Reflectance
	About Fresnel Reflectance, a short sermon on what it is and why you probably want to use it.
Gamma Correction
	I have written a brief practical explanation of monitor gamma correction, including how to find out the correction for your display.
Kubelka-Munk
	I have translated the paper Ein Beitrag zur Optik der Farbanstriche, by Paul Kubelka and Franz Munk, in Zeitschrift für Technishen Physik 12(112). Get the Acrobat PDF file (about 118K). This translation is gradually improving; please send me your corrections and suggestions. Updated Friday, March 12, 2004. Since posting this translation on the Web, I was contacted by Paul Kubelka’s son Werner, who lives in Brazil. He graciously sent me an autobiographical sketch that his father wrote, apparently in the 1940s.
Lafortune BRDF Representation
	I have written a simple RenderMan shader to implement the BRDF representation presented in Non-linear approximation of reflectance functions, by Lafortune et al. at SIGGRAPH 97. A sample RIB file showing its application to modeling human skin from measured data, compared with Matt Pharr's quick hack, is here. The resulting image from BMRT is here.

Other stuff

Art work
	From time to time, I have dabbled in drawing, both with pencil and with pen and ink. Here are a few of my drawings.
Lens register list
	Willem-Jan Markerink compiled an extensive list of registers (flange-to-film distances) for many cameras. The list has unfortunately vanished from the Web, but I have made a nicely-formatted version of his list, with some additions and corrections. I also have sorted the list by flange distance to make it easier to see which adaptations might be feasible.
Leica Order Numbers
	I have compiled a list of Leica 5-digit order numbers from sources on the Web.
Camera resolution test chart
	In 2014, the International Standards Organization adopted ISO Standard 12233: Photography -- Electronic still-picture cameras -- Resolution measurements for the measurement of camera resolution. The procedure requires a standard test target, which I have converted to a vector format so you can print your own. In 2017, ISO revised the standard, and replaced this chart with several new ones which aren't available here.
Sigma SA lens mount vs. Pentax K
	Sigma SLR cameras use a unique lens mount that seems to be derived from the Pentax K bayonet mount. I have compared the two and offer a drawing with the results here. NOTE: this is an SVG document, so you may need to download a browser plugin to display it. The link to do so is on the page.
Windows Character Codes
	After years of mystification of how to generate special characters in Windows operating systems, I think I have learned something about Windows character codes.

Last modified: Mon Apr 16 08:49:45 EDT 2018