Block truncation coding with entropy coding

Block truncation coding (BTC) is a simple and fast image compression algorithm which achieves a constant bit rate of 2.0 bits per pixel. The method is however suboptimal. We propose a modification of BTC in which the compression ratio is improved by coding the quantization data and the bit plane by arithmetic coding with an adaptive modelling scheme. The results compare favorable with other BTC variants. The bit rate for test image Lena is 1.53 bits per pixel with a mean square error of 16.51.<
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