Stephen H. Westin portrait

Stephen H. Westin

104 Eastern Heights Drive
Ithaca, NY 14850

I am looking to commit to 5-8 years in a challenging position where I can bring my strengths to bear: technical proficiency, visual thinking, and a creative, outside-the-box approach to solving problems.

My complete CV is available.


Year Institution Degree
1992 Cornell University Master of Science
1980 University of Michigan Bachelor of Science in Engineering
(Computer Engineering)


Years Organization Responsibilities
May 2014-March 2018
GrammaTech, Inc.
Developed and tested static analysis checks to enforce MISRA coding guidelines. Maintained and enhanced GUI code using wxWidgets, Python, and Javascript. Engaged in large-scale automatic and manual software testing.
November 2007-May 2014
Doron Precision Systems, Inc.
Developed new graphics software for interactive driving simulators. Consulted on hardware and software requirements. Assisted in maintaining and improving visual models for real-time display.
2005-2007 Animusic LLC, Lansing, NY Teamed with 1 other programmer to reimplement interactive application for animation and music production. Implemented real-time display using OpenSceneGraph. Partnered in creating custom skins for GUI using Qt toolkit. Installed RenderMan render farm on 13-node cluster.
1997-2005 Cornell University Program of Computer Graphics Head of Light Measurement Lab
1992-1997 Ford Motor Company, Dearborn, MI Supported electronic tools for creative design.
Produced HDTV renderings for market research and design evaluation.
Consulted on rendering and design issues.
1987-1990 Ford-Werke AG, Köln, Germany Coordinated development of CDRS CAD system for design studios.
Wrote specifications for CDRS and other development in collaboration with Ford personnel in U.S. and England.
1984-1987 Ford Motor Company, Dearborn, MI Researched advanced electronic tools for creative design.
1983-1984 Ford Motor Company, Dearborn, MI (contractor) Supported visualization software for structural analysis.
1975-1983 Environmental Research Institute of Michigan System programming and management of VAX and PDP-11 systems.
Supported software for remote sensing: image processing and atmospheric optics simulation.

Research Interests

Perceptual aspects of virtual simulation

It is no secret that training simulators (for aircraft, automobiles, ships, etc.) fall short of actually duplicating the actual situations for which we are trying to train. Given finite hardware and human resources, we can maximize “realism” (more practically, skill transfer) by applying existing knowledge of human perception. Some areas to be explored are:

Psychophysics of Material and Shape Perception

Much work has gone on in studying the physical accuracy of reflectance models, but the nagging feeling remains that perceptible differences between surfaces are not well represented by physical measurements. I worked with Jim Ferwerda to find ways to convert physical measurements into relevant perceptual metrics.

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.



Overview of gonioreflectometer 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.
Padauk: diffuse vs. new model 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.
Rendering of automotive shape 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.
Setup for camera measurement 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.

Renderings from measured skin BRDF 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.
Brushed aluminum wheel 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.
Kitchen with non-Lambertian surfaces 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

BRDF plots 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.
Two BRDF models for paper 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.
Setup diagram 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.
Setup diagram 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

Full text of thesis (PDF) This file is about 1.9MB and contains all the figures.

Educational Material:


BRDF graph 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

HeTorrance graph 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

Black glass sphere About Fresnel Reflectance, a short sermon on what it is and why you probably want to use it.

Gamma Correction

Gamma curve I have written a brief practical explanation of monitor gamma correction, including how to find out the correction for your display.


Albedo graph
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

Two spheres from 1997 paper 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

Drawings 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

Lens Register 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

Leica logo I have compiled a list of Leica 5-digit order numbers from sources on the Web.

Camera resolution test chart

ISO 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 mount compar 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

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.

Stephen H. Westin
Last modified: Mon Apr 16 08:49:45 EDT 2018 Valid HTML 5! Valid CSS!