David
Brainard, Ph.D.
Professor
Department of Psychology
University of Pennsylvania
315C, 3401 Walnut Street
Philadelphia, PA 19104
(215) 573-7579
(voice)
(215) 746-6848 (FAX)
Email: brainard@psych.upenn.edu
More information http://color.psych.upenn.edu/brainard/
Click here for selected publications since Dr. Brainard's arrival at Penn
RESEARCH INTERESTS
Visual perception and its neural mechanisms; digital image processing.
RESEARCH TECHNIQUES
Psychophysics; computational modeling; fMRI.
RESEARCH SUMMARY
My primary research is concerned with human color constancy. Defined
broadly, this is the question of how color appearance provides us with
information about object identity. I consider color constancy an important
model problem because it nicely isolates the type of ambiguity that makes
perception difficult: the image confounds the spectral properties of objects
with those of the illumination.
Our psychophysical work has sought to extend our understanding of human color constancy to more naturalistic stimuli than have been studied previously. Under the rich viewing conditions used in my lab color constancy is a robust and regular phenomenon, and we have developed experimental techniques to explore systematically what image features contribute to color constancy. The psychophysical research has been guided by analyses of the computational problem posed by color constancy. Our computational work has led to an effective color constancy algorithm and we have elaborated this algorithm into a quantitative model of human performance. In addition, thinking about the computations the human visual system must perform to provide useful perceptual representations has led a line of research directly concerned with how to improve digital color image processing algorithms.
I would also like to understand the neural mechanisms that mediate color
constancy. We have begun to use fMRI in conjunction with psychophysics
to study the cortical representation of color, with the longer term aim
of developing techniques that would allow us to link physiological measurements
and color appearance.
KEY WORDS:
Color vision; color constancy; vision; adaptation; image processing
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