title: Comparison of sensitivity to color changes in natural and phase-scrambled scenes.
abstract: Traditionally, thresholds for detecting photometric changes have been measured by using stimuli such as disks or gratings and accounted for in terms of relatively low-level mechanisms in the visual pathway. Therefore one might not expect the higher-order structures that characterize natural scenes to influence thresholds for detecting uniform photometric changes. We compared thresholds for detecting uniform photometric changes for natural and phase-scrambled versions of images of natural scenes. The chromaticity and luminance of every pixel was represented as a vector in a modified version of the MacLeod-Boynton color space and was translated, rotated, or compressed within that color space. Thresholds for all types of transformation were significantly lower in the raw compared with phase-scrambled scenes, and we attribute this to the influence of higher-order structure.
authors.affiliation: McGill University, Department of Ophthalmology, McGill Vision Research Unit, 687 Pine Avenue West, Room H4-14, Montréal, Québec H3A1A1, Canada. ali.yoonessi@mcgill.ca
authors.forename: Ali
authors.initials: A
authors.lastname: Yoonessi
authors.forename: Frederick A A
authors.initials: FA
authors.lastname: Kingdom
mesh_terms: D000221:Adaptation, Ocular / Q000502:physiology*; D003118:Color Perception / Q000502:physiology*; D015350:Contrast Sensitivity; D011601:Psychophysics; D012680:Sensitivity and Specificity; D012684:Sensory Thresholds / Q000502:physiology