An Information Processing Approach to Understanding the Visual Cortex
An outline description is given of the experimental work on the visual acuity and hyperacuity of human beings. The very high resolution achieved in hyperacuity corresponds to a fraction of the spacing between adjacent cones in the fovea. We briefly outline a computational theory of early vision, according to which (a) retinal image is filtered through a set of approximately bandpass, spatial filters and (b) zero-crossings may contain sufficient information for much of the subsequent processing. Consideration of the optimum filter lead to one which is equivalent to a cell with a particular center-surround type of response. An "edge" in the visual field then corresponds to a line of zero-crossings in the filtered image. The mathematics of sampling and of Logan's zero-crossing theorem are briefly explained.