Local regions of natural images contain rich information about form and texture. Psychophysical experiments show that human observers are remarkably sensitive to these natural image regularities. Indeed, the visual system seems to know much more about the regularities in natural images than any current probabilistic model, even at very fine scales. These fail to capture contrast fluctuations and local contour information—features to which human observers are highly sensitive. See Gerhard et al.

Image Credit: Holly E. Gerhard, Werner Reichardt Centre for Integrative Neuroscience