The parametric effects of texture on supratheshold color tolerance thresholds were investigated in two psychophysical experiments using simulated textures presented on a CRT. Textured images were created from scanned photographs of physical texture samples with semi-random textured pattern. Differences in appearance were created by varying the illumination geometry during the image capture stage. Two conditions were simulated: diffuse illumination of a standard light booth and directional lighting which accentuates texture relief. In the first experiment observers matched average perceived lightness of grayscale textured images by adjusting the lightness of a uniform gray field. Images varied in their average L*. The results showed that, on average, there was no statistically significant difference between the observer match and the average L of the image. The only exception was found for darker images of coarse texture. In the second experiment, an array of color images was created from three texture patterns: one simulating diffuse lighting conditions and two simulating directional illumination. The CTELAB coordinates of the images were centered around the five CEE color centers recommended for color tolerance research. Color differences were varied in the lightness, chroma, and hue dimensions. Color tolerance thresholds were measured in each dimension for each texture type and uniform patches. An adaptive psychophysical technique, QUEST, was utilized to determine color tolerances in a greater than/less than task using test pairs in comparison to a fixed anchor pair of 1 unit AE*94. The results indicated that the presence of texture increases tolerance thresholds for hue irrespective of the texture pattern. The chroma dimension remained unaffected. Less conclusive results were found for lightness dimension with a strong trend toward increased tolerance thresholds for textured stimuli. When the different textures were compared, it was found that the L* thresholds were significantly higher for the images simulating directional lighting compared to the images of diffusely illuminated surface. No differences in tolerances for chroma and hue were found in that case.
Library of Congress Subject Headings
Color vision--Industrial applications; Colorimetry--Industrial applications; Colorimetric analysis; Textures
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Krasnoselsky, Alexei, "Effects of texture on color difference evaluation of surface color" (2000). Thesis. Rochester Institute of Technology. Accessed from
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