•  1391
    Does colour constancy exist?
    Trends in Cognitive Sciences 7 (10): 439-443. 2003.
    For a stable visual world, the colours of objects should appear the same under different lights. This property of colour constancy has been assumed to be fundamental to vision, and many experimental attempts have been made to quantify it. I contend here, however, that the usual methods of measurement are either too coarse or concentrate not on colour constancy itself, but on other, complementary aspects of scene perception. Whether colour constancy exists other than in nominal terms remains uncl…Read more
  •  469
    Color Constancy
    Vision Research 51 674-700. 2011.
    A quarter of a century ago, the first systematic behavioral experiments were performed to clarify the nature of color constancy—the effect whereby the perceived color of a surface remains constant despite changes in the spectrum of the illumination. At about the same time, new models of color constancy appeared, along with physiological data on cortical mechanisms and photographic colorimetric measurements of natural scenes. Since then, as this review shows, there have been many advances. The th…Read more
  •  24
    Shepard's analysis of how shape, motion, and color are perceptually represented can be generalized. Apparent motion and shape may be associated with a group of spatial transformations, accounting for rigid and plastic motion, and perceived object color may be associated with a group of illuminant transformations, accounting for the discriminability of surface-reflectance changes and illuminant changes beyond daylight. The phenomenological and mathematical parallels between these perceptual domai…Read more
  •  11
    Variation of surface-colour judgments in natural scenes
    with K. Amano and S. M. C. Nascimento
    In Robert Schwartz (ed.), Perception, Blackwell. pp. 65-65. 2004.
  •  6
    Qualitative cues in the discrimination of affine-transformed minimal patterns
    with Helja T. Kukkonen, Jonathan R. Wood, Johan Wagemans, and Luc Van Gool
    In Enrique Villanueva (ed.), Perception, Ridgeview. pp. 195-206. 1996.
    An important factor in judging whether two retinal images arise from the same object viewed from different positions may be the presence of certain properties or cues that are 'qualitative invariants' with respect to the natural transformations, particularly affine transformations, associated with changes in viewpoint. To test whether observers use certain affine qualitative cues such as concavity, convexity, collinearity, and parallelism of the image elements, a 'same-different' discrimination …Read more
  •  3
    Why do strawberries look red? Natural colour constancy in retina and cortex
    with T. Vladusich and F. W. Cornelissen
    In Robert Schwartz (ed.), Perception, Blackwell. pp. 23-23. 2004.
    Colour constancy refers to the ability to extract information about surface colours independently of illumination conditions. A ripe strawberry, for example, appears the same red when viewed under a blue sky or a reddish sunset. Since Land's pioneering work, discussion has centred on the issue whether colour constancy is achieved primarily in the retina or visual cortex. Recently, the debate has shifted to a consideration of the constraints imposed by various psychophysical tasks and instruction…Read more
  •  3
    Variation of red-green dichromats' colour constancy in natural scenes
    with R. C. Baraas, K. Amano, and S. M. C. Nascimento
    In Robert Schwartz (ed.), Perception, Blackwell. pp. 44-44. 2004.
    The aim of this study was to test red - green dichromats' ability to discriminate between illuminant and surface-reflectance changes in natural scenes. Stimuli were simulations of natural scenes presented on a colour monitor with 10-bit resolution per gun. The natural scenes were obtained with a fast hyperspectral imaging system. Six different scenes (including rocks, foliage, and buildings) were tested. In each trial, two images were presented in sequence, each for 1 s, with no interval. The im…Read more