Abstract

An oriented pyramid is an image representation consisting of the outputs of a set of linear filters that are tuned for a range of spatial frequencies and orientations. An oriented energy pyramid is derived from an oriented pyramid by squaring the outputs of the filters and spatially averaging them over a region that is proportional to the size of the underlying filter. This is somewhat analogous to computing the amplitude of the local response while discarding phase information. The distribution of intensities in an individual energy image gives an indication of the amount of a particular kind of structure within the integration region but not the spatial configuration of activity within that region. In this sense, oriented energy responses are similar to what is computed by complex cells in visual cortex. One interesting property of this image representation is that it converts many conspicuous texture differences into intensity differences. This suggests that the phenomenon of perceptual texture segregation may not require the postulation of novel physiological mechanisms.

© 1988 Optical Society of America