On independent color space transformations for the compression of CMYK images

Device- and image-independent color space transformations for the compressi on of CMYK images were studied. A new transformation (to a YYCC color space ) was developed and compared to known ones. Several tests were conducted le ading to interesting conclusions. Among them, color transformations are not always advantageous over independent compression of CMYK color planes. Ano ther interesting conclusion is that chrominance subsampling is rarely advan tageous in this context. Also, it is shown that transformation to YYCC cons istently outperforms the transformation to YCbCrK, while being competitive with the image-dependent KLT-based approach.