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Abstract

As we move about a room, inspecting its contents, we ordinarily do not confuse our own change of viewpoint with changes in the content of the scene. As we move, the image of a single object or location may fall successively on parts of the retina with markedly different optical qualities and photoreceptor densities. Yet we typically manage not to confuse the particular characteristics of a retinal region with the appearance of an object imaged on it. An object fixated and then viewed in periphery does not seem to move or change. nor does an object first viewed peripherally and then fixated, although, once fixated, we are likely able to answer questions about the detailed appearance of the fixated object that we could not answer when it was viewed peripherally. This transformational constancy is all the more remarkable if we examine the initial visual information, the pattern of excitation of photoreceptors in each retinal region. This chapter analyzes the retina as a sampling array in motion, discussing the consequences of motion for reconstruction, aliasing, and visual representation.