Lecture 5.2: Vision: Color and Depth

• Color Vision
  • Fundamental, independent visual process
    • after-images
    • color deficient vision
  • Parvocellular pathway
    • role in vision
      • small detail
      • color
    • physiology
      • cones in retina
      • retinal ganglia: opponent color channel recoding
      • LGN -- chromatic layers
      • visual cortex
              visual area 1: blobs (color) and interblob (detail)
              visual area 2: stripes (thick,thin,pale) = (blob,interblob,magno)
              visual area 4
    • characteristics
      • wavelength sensitive
      • smaller (2-3 times) RF centers
      • slower response
  • color matching
  • visual characteristics -- revisited
    • equiluminance
    • relative judgements: chromatic
    • constancy
      • color
      • simultaneous contrast
    • interactions
            saturation-brightness: Helmholtz-Kohlraush effect
            brightness-hue: Bezold-Brucke effect
    • small field achrominance
    • effects of color on perceived size
  • Color Description
    • Color names -- crayons
    • Color models
      • device-derived
        • convenient for describing display device levels
        • RGB, CMY
      • intuitive
        • based in familiar color description terms
        • HSV, HLB, HLS
      • perceptually uniform
        • device independent, perceptually uniform
        • CIELUV, CIELAB, Munsell
• Depth Perception
  • motor cues
    • vergence
    • accomodation
    binocular cues
    • retinal disparity: > for close objects
    • neurons sensitive to particular disparities --> depth sensitive
  • monocular cues
    • occlusion (interposition, visibility)
    • size
    • perspective:
            line-angle
            texture gradient
            atmospheric effects
    • head-motion parallax
    • kinetic depth effect (object-motion parallax)
  • break down under equiluminance
    • depth-size illusions
    • linking by collinearity