[OPTICAL REVIEW Vol. 7, No. 3 (2000) 249-259]

Dynamics of Asymmetric Color Matching

Ichiro KURIKI,1,2 Yukio OGUMA2 and Keiji UCHIKAWA2

1Department of Mathematical Engineering and Information Physics, Graduate School of Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8656 Japan, 2Imaging Science and Engineering Laboratory, Tokyo Institute of Technology, 4259, Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan

(Received November 4, 1999; Accepted February 22, 2000)

It is known that the human color constancy is not complete. We conducted asymmetric color matching experiments to clarify a simple question: what was it that the observer matched. Observers made apparent-color matches between Munsell color chips under D65 illumination and a color chip presented on a CRT. The observers' matches showed incomplete color constancy. We applied relative cone-weight transformation to each observer's results under control condition, so as to equate the unique-white point for each illuminant condition. The result of this simple transformation showed good match to the actual data. Our results suggest what the observer was doing during the asymmetric color matches was picking up apparent-color signal, achieved from the test color chip under D65, and reconstructing it with respect to the unique-white by a simple cone response scaling.

Key words : color constancy, asymmetric matches, unique-white, apparent-color, relative cone weight