Figure 3.

Statistical properties of natural scenes. (a) Power tends to be highest at low frequencies and fall off at high frequencies. Data taken from Ruderman & Bialek (1993). (b) Natural scenes have a positively skewed intensity distribution, so that light patches are far brighter than average, while dark patches are only a little darker than average. Data taken from Brady & Field (2000). (c,d) The power spectrum leads to (c) spatial correlations in natural scenes that become (d) spatiotemporal correlations when the scene moves. Panels c and d adapted from Fitzgerald & Clark (2015) (CC BY 4.0).