Complementary Steganography in Error-Diffused Block Truncation Coding Images

Block truncation coding is an efficient compression technique while offering good image quality. Nonetheless, the blocking effect inherent in BTC causes severe perceptual artifact in high compression ratio applications. In this paper, an error-diffused block truncation coding (EDBTC) is proposed to solve this problem. According to the EDBTC, the error caused by the difference between the original grayscale pixel value and the correspondingly high or low mean substitute is diffused to the predefined neighborhood, and hence the average grayscale will be maintained invariably. In addition, since the compressed data are widely distributed in the Internet transmission, the extra message conveying in a secret way also highly raises attention recently. In this paper, we propose the complementary steganography in error- diffused block truncation coding (CSEDBTC), which cooperates with error diffusion to achieve the objective of secret communication in BTC images. As documented in the experimental results, a low complexity with good image quality is obtained.