Visual pattern BTC with two principle colors for color images
Tak Po Chan, Bing Zeng, Ming Lei Liou · 2002
This paper presents an extension of the "block truncation coding with visual patterns (BTC-VP)" for color image compression. Our approach BTC-VP-2PC attributes its name to the fact that it, regardless of the variety of colors, encodes each 4/spl times/4 image block into two principle colors (PC) and one visual pattern (VP) (which are both visually significant to human observers). In BTC-VP-2PC, each VP is generated from a bitmap. This bitmap, obtained from a weighted trichromatic transform, quantizes all color components (i.e. it's actually BTC). Experimental results show that only two PCs and one VP for each block are enough to represent edge regions with high subjective quality. Also a substantial compression ratio has been achieved (for NTSC color TV images).