Fig. 1.
Local distributions of light in natural scenes. (A) Natural images are discretized into 16 equipopulated grayscale levels. Central pixels with intensity σ0 are chosen randomly, and the distribution of intensities σ1 at a radius R from the center is sampled. The distance R is represented by the scale bar in pixels. (B), (C), and (D) Histograms of pixel intensities at different distances from the center (shown here for ) if the central pixel σ0 is black, gray, or white (black, gray, and white lines). Note the difference in histograms for black vs. white central pixel σ0 for small R (see SI Appendix for P(σ1) as a function of R).