title: Three-dimensional spatial grouping affects estimates of the illuminant.
abstract: The brightnesses (i.e., perceived luminance) of surfaces within a three-dimensional scene are contingent on both the luminances and the spatial arrangement of the surfaces. Observers viewed a CRT through a haploscope that presented simulated achromatic surfaces in three dimensions. They set a test patch to be approximately 33% more intense than a comparison patch to match the comparison patch in brightness, which is consistent with viewing a real scene with a simple lightning interpretation from which to estimate a different level of illumination in each depth plane. Randomly positioning each surface in either depth plane minimized any simple lighting interpretation, concomitantly reducing brightness differences to approximately 8.5%, although the immediate surrounds of the test and comparison patches continued to differ by a 5:1 luminance ratio.
authors.affiliation: Department of Psychology, Wake Forest University, Winston-Salem, North Carolina 27109, USA.
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Perkins
authors.forename: James A
authors.initials: JA
authors.lastname: Schirillo
mesh_terms: D000328:Adult; D006801:Humans; D021621:Imaging, Three-Dimensional; D008027:Light; D010775:Photic Stimulation; D013028:Space Perception / Q000502:physiology*