The visual system adjusts to stabilize object color appearance against changes in illumination. This proposal consists of experiments designed to study the adjustment, which is often called color constancy. Understanding color constancy is necessary for a complete theory of human color vision. In addition, color constancy is an example of a larger class of perceptual constancies (e.g. size constancy and shape constancy) that together allow us to perceive a stable physical world. As such, a detailed characterization of the color system may provide insights that generalize to these other perceptual systems. The first set of experiments is designed to characterize performance for natural viewing conditions. In these experiments the stimuli will consist of real illuminated objects. Asymmetric color matching procedures will be used to provide quantitative data. The results of the first set of experiments will be compared with similar data obtained using computer graphics simulations as stimuli. The purpose of this comparison is to establish whether computer graphics technology provides a valid method for studying real world color performance. Because many image parameters are technically difficult to manipulate and control in real images, a valid graphics simulation would make a richer set of experimental manipulations possible. The third set of experiments is designed to measure the action of early color mechanisms for spatially complex stimuli. To isolate early mechanisms, the stimuli will consist of multiple uniformly colored regions. These stimuli have the advantage that they can be described by a relatively small number of parameters. The proposed experiments are designed to provide quantitative tests of qualitative principles that might govern mechanisms of chromatic adaptation and simultaneous color contrast. If valid, these principles allow a finite set of measurements to predict the joint action of the mechanisms for a broad class of images. A final experiment is designed to ask whether early visual mechanisms are independent from higher-level processes that parse the image into objects and illuminants. If so, then the results of the proposed research can be used to determine the degree to which measured real image color constancy can be explained by the action of early mechanisms.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29EY010016-02
Application #
2163723
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1992-12-01
Project End
1997-11-30
Budget Start
1993-12-01
Budget End
1994-11-30
Support Year
2
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of California Santa Barbara
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
City
Santa Barbara
State
CA
Country
United States
Zip Code
93106
Persichetti, Andrew S; Thompson-Schill, Sharon L; Butt, Omar H et al. (2015) Functional magnetic resonance imaging adaptation reveals a noncategorical representation of hue in early visual cortex. J Vis 15:18
Yin, Lu; Smith, Robert G; Sterling, Peter et al. (2009) Physiology and morphology of color-opponent ganglion cells in a retina expressing a dual gradient of S and M opsins. J Neurosci 29:2706-24