Figure 2.

Object-color probability, rank-ordered by most frequent object colors. (A) Pixels across the 20,840 images were categorized into 240 bins (24 evenly spaced hue angles at 10 chroma values in u′ v′). Object-color probability was computed as follows: number of pixels having a given color in the objects divided by the number of pixels having the same color in the objects + backgrounds. The colors of the bars correspond to the sRGB colors of the bins. The bars are rank-ordered with the most frequently occurring object colors on the left. The error bars show the standard deviation of the probability of a given hue being in the foreground, computed over 1000 bootstraps (bar height is the mean of the bootstrapped values). During each bootstrap, 20000 images were picked randomly to generate probabilities. The results across bootstraps were averaged together to generate mean object-background probabilities (bar height); (B) as for panel (A), but using for each image only one randomly selected pixel for each object and one randomly selected pixel for each background. (C) Correlation of object-color probability as a function of u′, for all pixels (left) and single pairs of pixels per image (right). The colors were binned in 101 bins (0.0014 u′ bin widths), evenly sampling the u′ values symmetric over the white point (arrowhead); error bars show standard deviations, computed as in panel A.