LOSSLESS COMPRESSION OF HYDROACOUSTIC IMAGE DATA

Despite rapid progress in improving mass-storage density and digital c ommunication system performance, compression of hydroacoustic image da ta is still significant in many engineering and research areas since i t can overcome data storage and transmission bandwidth limitations, In this paper, we present a novel and effective approach for lossless co mpression of hydroacoustic image data which consists of two stages, Th e first stage reduces the information redundancy, We propose several n ew techniques to remove redundancy between data samples, data blocks, and data frames. The second stage uses a newly developed cascade codin g scheme, This simple scheme can achieve an efficiency of 97%, A decom position algorithm is presented for finding the optimal cascade coding parameters, The algorithm decomposes a multivariable optimization pro blem into a series of one-variable optimizations. Our two-stage algori thm offers a compression ratio of 2-3 and provides an exact recovery o f the original data, Because of its simplicity, the algorithm can be i ncorporated into a variety of echo sounder systems, The compression al gorithms can also be implemented using low-level assembly language to meet the requirements of real-time applications.