Tutorial on Vectorial Color, 2008 November 11

Jim Worthey • Lighting & Color Research • jim@jimworthey.com • 301-977-3551 • 11 Rye Court, Gaithersburg, MD 20878-1901, USA

Vectorial Color
Tutorial
At Color Imaging Conference 16
Portland, Oregon
Tuesday, 2008 November 11, 1:30 - 3:30 pm
Instructor will be Jim Worthey

The 2007 tutorial (CIC 15) occurred with 10 Students, who kindly posed for a class picture. Below the picture is information for 2008.

For the full jpeg from the camera, right-click this link and save it.

Course Description: When the right color matching functions (CMFs) are used, vector methods demystify camera sensors, lighting, and other topics. In Jozef Cohen’s invariant formulation, the vectors of spectral lights at unit power define the “locus of unit monochromats” (LUM). Orthonormal opponent CMFs map lights into Cohen’s color space and establish intuitive axes: whiteness, red-green, and blue-yellow. If a camera’s LUM matches the eye’s, it meets Luther’s criterion. The instructor presented details at CIC12 and CIC 14. The course emphasizes the practical use of color vectors and the orthonormal CMFs. If you plan to bring a computer to the course, please install a VRML viewer prior to attending. For background, see below.

Benefits: This course will enable the attendee to

Use the orthonormal CMFs, and calculate color vectors.
Understand the Locus of Unit Monochromats and the role of vector amplitude.
Work with 3D plots of such data as color chips under a lighting change.
Compare light sources on the basis of vectorial composition.
Generate a camera’s orthonormal basis, and compare it to the eye’s. The algorithm is simple, then understanding may take a little time.

Intended audience: Scientists and engineers who design or apply camera systems or lights. While certain applications will be stressed, the vectorial approach applies to all color work. For example, multi-primary systems and image compression are natural applications.

James Worthey received a BS in EE and an MS in Physics, then a PhD in Physiological Optics from Indiana University. He researched lighting and color at the National Institute of Standards and Technology, and published several applications of opponent colors. A breakthrough came in 2003 when he combined opponent colors with Cohen’s ideas and computer graphics.

Background Information

VRML viewer: If you are considering the tutorial, or just want to browse this web site, it will be helpful to install the Cortona VRML Viewer, so you can view the 3-dimensional graphs:

Click this link: http://www.cortona3d.com/
Click the button that says VIEWERS.
Then install a 3D viewer as appropriate.
The Cortona (Parallel Graphics) web site apparently detects your browser. So, to install for different browsers, you need to start over, using the target browser to contact the web site.
As far as I know, there are versions for different Windows browsers, and also for Apple.
If you will bring a computer to the tutorial, please install the viewer on it.
If you have any issue about VRML viewers, please send email or call 1-301-977-3551 in the USA, or call by Skype to jimworthey .
For more info, you can try http://cic.nist.gov/vrml/vbdetect.html or http://en.wikipedia.org/wiki/VRML . But please feel free to contact me, because I am interested to know about your problem, and I may be able to help. Or, if you are a VRML expert, you can teach me.

Reading materials:

Update in 2013: Self-contained presentation:

James A. Worthey, "Vectorial color," Color Research and Application, 37(6):394-409 (December 2012).
http://onlinelibrary.wiley.com/doi/10.1002/col.20724/abstract

James A. Worthey, "Applications of vectorial color," Color Research and Application, 37(6):410-423 (December 2012).
http://onlinelibrary.wiley.com/doi/10.1002/col.20723/abstract

Thanks to Dr. Michael H. Brill, there is also a poem commenting on that article, "Applications of vectorial color:"
Michael H. Brill, “Fit-first to be tied,” Color Research and Application, 37(6):423 (December 2012).
http://onlinelibrary.wiley.com/doi/10.1002/col.20740/abstract
Obtain the articles above through normal channels, or please contact the author.
Draft article "Vectorial Color," and the Figures to go with it.
Paper as presented at Color Imaging Conference 12: Color Matching with Amplitude not Left Out . Concise introduction to color vectors.
The visuals for CIC 12, which include animated and 3D graphs.
Paper as presented at Color Imaging Conference 14 in 2006: Camera Design Using Locus of Unit Monochromats .
To study a few of the key ideas, separated from the larger discussion, check out the Questions and Answers.
The tutorial is intended to teach the practical use of vectorial ideas. Therefore, you might want to look at the Computer Programming Examples.
For total practicality, see the tabulation of the orthonormal functions.
After the tutorial, you may be interested in the set of 5 worked examples .
For some detailed ideas on lighting and color--perhaps after the tutorial--see the graphical materials on How White Light Works, or the short proceedings paper on that topic.
Class notes. (A pdf file, suitable for viewing or printing.)
Visuals for the oral presentation. (Similar to class notes, but with some 3D and animated graphs. )

¡See you in Portland! (The 2008 Portland meeting is past. But the short course can be done with a small or large audience almost anyplace.)

Jim Worthey Home Page: http://www.jimworthey.com