Color Based Object Recognition

The purpose is to arrive at recognition of multicolored objects invariant to a substantial change in viewpoint, object geometry and illumination. Assuming dichromatic reflectance and white illumination, it is shown that normalized color rgb, saturation S and hue H, and the newly proposed color models c 1 c 2 c 3 and l 1 l 2 l 3 are all invariant to a change in viewing direction, object geometry and illumination. Further, it is shown that hue H and l 1 l 2 l 3 are also invariant to highlights. Finally, a change in spectral power distribution of the illumination is considered to propose a new color constant color model m 1 m 2 m 3 . To evaluate the recognition accuracy differentiated for the various color models, experiments have been carried out on a database consisting of 500 images taken from 3-D multicolored man-made objects. The experimental results show that highest object recognition accuracy is achieved by l 1 l 2 l 3 and hue H followed by c 1 c 2 c 3 , normalized color rgb and m 1 m 2 m 3 under the constraint of white illumination. Also, it is demonstrated that recognition accuracy degrades substantially for all color features other than m 1 m 2 m 3 with a change in illumination color. The recognition scheme and images are available within the PicToSeek and Pic2Seek systems on-line at: http: //www.wins.uva.nl/research/isis/zomax/. ( 1999 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.