Influence of scale and orientation on the visual perception of natural scenes

It is well known that the distribution of spatial content with respect to spatial scale in real-world scenes falls in accordance with a 1/ f α relation. Equally well known is the tendency for an orientation bias in scene content with the predominant bias in content at the horizontal and vertical orientations. This has led to the suggestion of a relationship in which the mechanisms of the human visual system are optimized for processing such regularities. Here we review current literature concerning the measurement of these regularities (via Fourier analysis) of natural scenes in the context of other work that has psychophysically assessed the extent to which visual perception exploits such regularities of spatial content. In addition, 2 psychophysical experiments are presented that extend this literature and argue for the importance of these regularities in perceiving orientation in real-world visual stimuli.