| Summary: | 碩士 === 國立暨南國際大學 === 資訊工程學系 === 101 === Arithmetic coding (AC) is an efficient data compression technique and widely adopted in image and video compression standards. However, the high complexity of arithmetic coding in computation is the bottleneck that many researchers endeavor to overcome. Piecewise integer mapping based arithmetic coding can eliminate all multiplicative operations in both encoder and decoder by the technique of replacing them with the operations of comparison and addition. It can reduce the computational complexity with a little penalty of compression loss. A generalized piecewise integer mapping arithmetic coding can provide higher compression efficiency with maintaining almost the same coding speed.
The iterative decoding to a communication scheme of which an arithmetic code with forbidden symbol is used for source coding and a recursive systematic convolutional code is used for channel coding. In this system, it adopts a low complexity SISO technique (called modified SOVA algorithm) for arithmetic coding, where arithmetic code can be modeled as a finite state machine and then can be decoded by using a trellis structure.
Experimental results show that the piecewise integer mapping based AC or the generalized piecewise integer mapping based AC can not only eliminate all multiplicative operations to lower down the computational complexity, but also owns a little capability of error correcting. Besides, the compression efficiency of it sometime becomes better than that of the traditional integer AC. In general, the integer AC with forbidden symbol will outperform the integer AC without forbidden symbol in terms of the error correcting performance.Furthermore, the EXIT chart is also presented for analyzing the iterative decoding.
|
|---|
