The Effects of Spatial Pattern on Color Appearance

摘要

The color appearance of an image is different from that of a uniform color patch because of spatial pattern effects. We have studied how the color appearance of square wave bars varies with stimulus strength and spatial frequency. The asymmetric matching method is used in the experiments, which means the color of uniform patch is adjusted by an observer to match the color appearance of the bars in square wave patterns. The square wave patterns have relatively low spatial frequencies of 1,2,4 and 8 cycles per degree (c p d). The area of a square wave pattern box only spreads a 2° field to the observers which means the matching is established mainly in the fovea. We find the matches are not colorimetric matches. The experiment data are analyzed and a conclusion that the cone contrast of the uniform patch is nearly proportional to the square wave stimulus strength is obtained, which reveal the property of color-homogeneity. Therefore the matches would have the basic properties of a linear system. In the article, all analyses are based on the opponent-color system. Precision of the experiments and some reasons about the data diversity are also discussed. The final conclusion suggests that the pattern separable mode could be used to predict the matches.