Shanshan YU^1*, Yuri MURAKAMI^1,2, Takashi OBI³, Masahiro YAMAGUCHI^1,2 and Nagaaki OHYAMA^1,2

¹Imaging Science and Engineering Lab., Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
²Akasaka Natural Vision Research Center, Telecommunication Advancement Organization of Japan, 1-8-6 Akasaka, Minato-ku, Tokyo 107-0052, Japan
³Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan

(Received January 6, 2006; Accepted May 30, 2006)

The article proposes a multispectral image compression scheme using nonlinear spectral transform for better colorimetric and spectral reproducibility. In the method, we show the reduction of colorimetric error under a defined viewing illuminant and also that spectral accuracy can be improved simultaneously using a nonlinear spectral transform called Labplus, which takes into account the nonlinearity of human color vision. Moreover, we show that the addition of diagonal matrices to Labplus can further preserve the spectral accuracy and has a generalized effect of improving the colorimetric accuracy under other viewing illuminants than the defined one. Finally, we discuss the usage of the first-order Markov model to form the analysis vectors for the higher order channels in Labplus to reduce the computational complexity. We implement a multispectral image compression system that integrates Labplus with JPEG2000 for high colorimetric and spectral reproducibility. Experimental results for a 16-band multispectral image show the effectiveness of the proposed scheme.

Key words: multispectral image compression, nonlinear spectral transform, color reproduction, spectral accuracy, L^*a^*b^* color space

^*E-mail address: yss@isl.titech.ac.jp