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.
© 2008 Optical Society of America
Vision, Color, and Visual Optics
Original Manuscript: August 29, 2007
Manuscript Accepted: December 18, 2007
Published: February 13, 2008
Vol. 3, Iss. 4 Virtual Journal for Biomedical Optics
Ali Yoonessi and Frederick A. A. Kingdom, "Comparison of sensitivity to color changes in natural and phase-scrambled scenes," J. Opt. Soc. Am. A 25, 676-684 (2008)