Improved JPEG Scheme Based on Adaptive Block Encoding

In this paper, a new adaptive image compression scheme based on JPEG was proposed to improve the image quality of the JPEG baseline sequential image compression codec. In this scheme, the Hough transformation technique is employed as an edge-oriented classifier to categorize image blocks into four classes. Different types of image blocks are processed by different quantization and encoding ways for achieving an effective compression performance. In order to preserve edge information, the adaptive quantization tables based on the human visual system and zig-zag scan sequences are used. For both objective and subjective visual image quality, simulation results show that the performance of the proposed scheme is comparable to that of other compared schemes.