Study On Selective Encryption Technology For Underwater Acoustic Image Based On Compression Coding

This paper studies the compression encoding with selective encryption technology based on underwater acoustic image. By analyzing the existing coding scheme, the method used in this paper has the advantage of dealing with any size images.Firstly, this paper describes the existing compression coding and coding theory. Because EZW coding is one of the most classic compression algorithms based on wavelet transform,the performance of EZW coding algorithm is analyzed deeply. By introducing PSNR, SSIM and other evaluation criteria, the result will be judged more conveniently.Secondly, current common image chaos algorithms are described. A chaos encryption algorithm based on RC4 is implemented in this paper. In order to avoid the descend of image compression ratio caused by encryption, a solution that can make a better fusion of the EZW compression coding and encryption algorithm is found. Because the processing object is the underwater acoustic image, the function of automatically selecting the object of the image is realized according to the characteristics of underwater acoustic image. Automatically selecting a target implements selective encryption.Finally through the experiments, the new encryption algorithm is proved to have the capable of dealing with any size image, and the encryption performance has advantages compared with common algorithms. Because of the perfect fusion with EZW algorithm, any additional data affect is not brought to the image compression ratio, and the expected algorithm functions are achieved.