Eye Movements and Spatial Pattern Vision

Models of lightness and color perception must take account of human color constancy, a tendency for apparent surface color to be relatively independent of the color and intensity of the illuminating light source. Observers matched the lightness and brightnesses of regions in simple and complex achromatic spatial patterns. The data showed that the observers knowledge of the surface reflectances revealed by lightness matches was unaffected by changing brightness of the same surfaces revealed by brightness matches. In the analogous chromatic experiments, observers matched the hue and saturation of patches or the patches apparent surface colors. The observers knowledge of the surface colors was not as reliable as in the achromatic case. Patches hues and saturations matched when their chromaticities were approximately the same. Shifts of hue attributable to simultaneous color contrast were in the correct direction but too small to produce hue constancy. Keywords Visual perception, Spatial pattern vision, Visual illusions, Color vision.