Latitude and longitude vertical disparities (2009)

Author(s): Read JCA, Phillipson GP, Glennerster A

    Abstract: The literature on vertical disparity is complicated by the fact that several different definitions of the term "vertical disparity" are in common use, often without a clear statement about which is intended or a widespread appreciation of the properties of the different definitions. Here, we examine two definitions of retinal vertical disparity: elevation-latitude and elevation-longitude disparities. Near the fixation point, these definitions become equivalent, but in general, they have quite different dependences on object distance and binocular eye posture, which have not previously been spelt out. We present analytical approximations for each type of vertical disparity, valid for more general conditions than previous derivations in the literature: we do not restrict ourselves to objects near the fixation point or near the plane of regard, and we allow for non-zero torsion, cyclovergence, and vertical misalignments of the eyes. We use these expressions to derive estimates of the latitude and longitude vertical disparities expected at each point in the visual field, averaged over all natural viewing. Finally, we present analytical expressions showing how binocular eye position-gaze direction, convergence, torsion, cyclovergence, and vertical misalignment-can be derived from the vertical disparity field and its derivatives at the fovea.

      • Date: 09-12-2009
      • Journal: Journal of Vision
      • Volume: 9
      • Issue: 13
      • Pages: 11
      • Publisher: Association for Research in Vision and Ophthalmology
      • Publication type: Article
      • Bibliographic status: Published

      Keywords: Author Keywords: binocular vision; stereopsis; depth perception; induced effect; vertical disparity; computational vision KeyWords Plus: STEREOSCOPIC SLANT PERCEPTION; PRIMARY VISUAL-CORTEX; DEPTH-PERCEPTION; HORIZONTAL DISPARITY; BINOCULAR STEREOPSIS; COMPUTATIONAL MODEL; RECEPTIVE-FIELDS; MOTION PARALLAX; SIZE DISPARITY; SURFACE SLANT


      Professor Jennifer Read
      Professor of Vision Science