BINARY MASKS YIELDING GAUSSIAN LIGHT DISTRIBUTIONS IN MAXWELLIAN VIEW

Gaussian light distributions are important stimuli for vision research , but are difficult to produce for Maxwellian viewing conditions. In t his study, two binary Maxwellian-view masks which produce smooth light distributions on the retina were considered: one was an out-of-focus circular aperture; the other was an in-focus pattern of opaque squares with a prescribed size distribution. The diffraction images of the tw o masks on the retina were computed numerically and shown to be well d escribed by gaussian functions. As an experimental test, a mask with t he desired pattern of opaque squares was manufactured by evaporation o f chromium over a quartz substrate; its quality, as assessed by micro- transmittance measurements, was found to be adequate for most visual a pplications. (C) 1977 Elsevier Science Ltd.