Detection of light transformations and concomitant changes in surface albedo

Holly E. Gerhard, Laurence T. Maloney

Research output: Contribution to journalArticle

Abstract

We report two experiments demonstrating that (1) observers are sensitive to information about changes in the light eld not captured by local scene statistics and that (2) they can use this information to enhance detection of changes in surface albedo. Observers viewed scenes consisting of matte surfaces at many orientations illuminated by a collimated light source. All surfaces were achromatic, all lights neutral. In the rst experiment, observers attempted to discriminate small changes in direction of the collimated light source (light transformations) from matched changes in the albedos of all surfaces (non-light transformations). Light changes and non-light changes shared the same local scene statistics and edge ratios, but the latter were not consistent with any change in direction to the collimated source. We found that observers could discriminate light changes as small as 5 degrees with sensitivity d'> 1 and accurately judge the direction of change. In a second experiment, we measured observers' ability to detect a change in the surface albedo of an isolated surface patch during either a light change or a surface change. Observers were more accurate in detecting isolated albedo changes during light changes. Measures of sensitivity d' were more than twice as great.

Original languageEnglish (US)
Article number1
JournalJournal of vision
Volume10
Issue number9
DOIs
StatePublished - 2010

Keywords

  • 3D perception
  • Albedo perception
  • Binocular disparity
  • Illumination perception
  • Lightness constancy

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems

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