title: Binary masks yielding gaussian light distributions in Maxwellian view.
abstract: Gaussian light distributions are important stimuli for vision research, but are difficult to produce for Maxwellian viewing conditions. In this 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 two masks on the retina were computed numerically and shown to be well described by gaussian functions. As an experimental test, a mask with the desired pattern of opaque squares was manufactured by evaporation of chromium over a quartz substrate; its quality, as assessed by micro-transmittance measurements, was found to be adequate for most visual applications.
authors.affiliation: Department of Physics, University of Minho, Braga Codex, Portugal.
authors.forename: S M
authors.initials: SM
authors.lastname: Nascimento
authors.forename: D H
authors.initials: DH
authors.lastname: Foster
authors.forename: P
authors.initials: P
authors.lastname: McKee
mesh_terms: D006801:Humans; D008027:Light; D008954:Models, Biological; D016011:Normal Distribution; D055095:Optics and Photonics; D010775:Photic Stimulation / Q000379:methods*; D011601:Psychophysics; D012160:Retina / Q000528:radiation effects