Research On Lossless Compression Algorithms For Time Domain Sequences

With the fast development of the communication systems and multimediaterminals, all kinds of data to be transmitted are increasing dramatically. Therefore, datacompression with high compression ratio and high quality to reduce communication andstorage load is absolutely needed. The classical statistic coding methods, such asHuffman Coding and Arithmetic Coding, can be applied to most types of datatheoretically, but the higher compression ratio can not be guaranteed for any kinds ofdata. So far, much effort has been made for the data compression methods to deal withdata sources that have various probability distributions.A new lossless compression algorithm for time domain sequences is designed andintroduced in the thesis. The framework of the new algorithm for lossless datacompression coding consists of four main modules: pre-processing modules, signprocessing module, higher segment bits coding module and lower segment bits codingmodule. The bit depth detecting and bit segment parts in the pre-processing module areused to divide the input signals into three sub-signals: the sign signals, higher segmentbits signals and lower segment bits signals. In this way, the input signals are separatedinto three parts and every part has their own statistical characteristic and is much easierto be compressed. The sign processing module gets polarity information of the originalsignal from the sign signals, the higher and the lower segment bits coding modulesseparately encode the higher and lower segment bits signals with different methods,here Huffman coding is used in the former one while the partition method based on thebit depth information is used in the later one. In addition, a lossy data compressioncoding method with constant bit rate in three compression mode based on the losslessone is designed. By complete test and performance evaluation, the designed datacompression coding algorithm has shown some improvements and advantages for thecompression of time sequences and satisfied the practical applications.