Abstract
It is an interesting issue to clarify properties of chromatic mechanisms that operate for colors away from an adaptation color. We employed the Classification Image method to compare the effects of heterochromatic noise on color perception for colors near and away from an adaptation color. The stimulus was two squares with an identical signal chromaticity each of which was superimposed on a chromatic noise textures composed of small square elements. Both signal and noise chromaticities were defined in the isoluminant plane of the DKL color space. The signal color direction was on either the four non-cardinal directions (45, 135, 215, or 315 deg). We had two experimental conditions regarding the noise color distributions: "near" and "away" conditions. For the away condition, the center of the noise color distribution was set at a color on the same color direction as the signal color. For the near condition, the distribution center was set at the adaptation color. The observer requested to answer which signal square seemed to have higher chromatic contrast. Classification Images (CIs) were derived from differences between two averaged noise textures corresponding to 'higher contrast' and 'lower contrast' categories defined by the observers' responses in each color condition. In the results, the color directions of the colors in the signal square region of the CIs did not necessarily correspond to the signal directions, suggesting some effects of properties of chromatic mechanisms on chromatic signal detection. In addition, they had large individual differences only for the away condition, while the perceptual chromatic contrast on a uniform stimulus measured in an additional experiment did not show such large individual differences. These results may suggest the existence of chromatic mechanisms whose individual differences become clear for colors away from an adaptation color only on a heterochromatic texture.
Meeting abstract presented at VSS 2012