Multitone block truncation coding

Block truncation coding (BTC) is an efficient image coding method with wide applications. However, most BTC methods produce only binary image blocks for display. Thus the limited representation power of binary images has been a major hindering factor for BTC performance improvement. A new multitone block truncation coding (MBTC) approach is presented, which breaks this limit by producing multitone pixel values. This approach uses a modified bilateral filtering algorithm to effectively extract the spatial information inherent in the binary coded image blocks. The proposed method significantly improves the code rate and the reconstructed image quality while keeping the processing efficiency among the best published results, making it suitable for high speed real time image and video communication and display.