Construction of error resilient synchronization codeword for variable-length code in image transmission

Abstract

Variable length code ( VLC ), also called Huffman code [1], is the most popular data compression technique used for image compression and transmission. But, it is vulnerable to loss of synchronization under transmission in a noisy channel. It will result in large drops in video transmission quality. For stopping error propagation, synchronization codeword ( SC ) is mostly used to localize error propagation effect. However, most of the SC cannot tolerate noise errors. We propose an iterative and efficient algorithm to construct error-resilient and variable-length SC for any application defined VLC table. They can be sed for synchronization of packet ( ERVL-SOP ). It can be appended at the end of certain number of symbols to form a packet. Thus, channel noise error can be localized. With using constructed SC as SOP, the result shows that it can achieve high signal-to-noise ratio ( PSNR=26dB ) compared to use normal VLC code as SOP at bit error rate ( BER ) of 10(-3) environment. In addition, the incorrect ERVL-SOP detection rate can be decreased to less than 0.0013% effectively.