Spatial frequency channels and perceptual grouping in texture segregation

The literature suggests that both spatial frequency components and grouping processes affect texture segregation. The experiments we report investigated texture segregation in a three-part (tripartite) pattern in which each part contains equal numbers of two different squares that are arranged in vertical stripes in the top and bottom parts and in a checkerboard in the center part. We found: (1) A difference in sign of contrast yields strong texture segregation. (2) Texture segregation is a negatively accelerated function of the ratio of the Rayleigh contrasts of the low-luminance and high-luminance squares. (3) Size and contrast are not independent attributes but can cancel each other. High spatial frequency differences are not sufficient to cause segregation in the presence of contradictory information from the low spatial frequency channels. (4) Hue is a weak feature relative to contrast. Hue differences are not sufficient to cause texture segregation in the presence of contradictory contrast information. The results of the experiments support the argument that the higher order processes in texture segregation have access to information corresponding to the outputs of the spatial frequency channels. They are qualitatively consistent with the hypothesis that tripartite segregation is primarily a function of spatial frequency components and not of grouping processes.