title: Definition and detection of binocular disparity.
abstract: Stereoacuity experiments tested definitions of binocularly disparate spatial positions by perturbing the binocular correspondence of the two half-images. Dichoptic translations perturbed zero-order retinal positions; expansions perturbed first-order horizontal separations; rotations perturbed first-order orientations; and anisotropic expansions deformed first-order two-dimensional (2D) structure. Each transformation perturbed relative positions in the two half-images by more than 100 arcsec, but stereoacuity thresholds remained about 10 arcsec. Binocular disparity involves second-order 2D differential structure of the monocular half-images, specifying local surface shape. Stereoacuity is much better than nonstereo acuity, suggesting that monocular spatial signals are binocularly correlated.
authors.affiliation: Department of Psychology, Vanderbilt University, Nashville, TN 37240-0009, USA. lappinjs@ctrvax.vanderbilt.edu
authors.forename: J S
authors.initials: JS
authors.lastname: Lappin
authors.forename: W D
authors.initials: WD
authors.lastname: Craft
mesh_terms: D003867:Depth Perception / Q000502:physiology*; D006801:Humans; D008960:Models, Psychological; D011594:Psychometrics; D011601:Psychophysics; D012399:Rotation; D012684:Sensory Thresholds; D015357:Vision Disparity / Q000502:physiology*; D014792:Visual Acuity