Compressed Sensing Theory And Chaotic Encryption Algorithm In The Application Of The Image

In recent years, with the rapid development of internet informationtechnology, the demand of multimedia information is continuously increasing.Meanwhile,conflicts between the huge demands for information and thetraditional signal processing theory become more and more serious. Nyquistsampling theorem must be satisfied for accurately recovering original signal, butin practical applications, a high sampling rate will produce large amounts of rawsampling data, and substantially increase information transmission, storage andprocessing pressure. In this contex, Candès and other scholars found a novelsignal processing mothod—Compressed Sensing. For sparse or compressiblesignal, compressed sensing theory uses frequency which is far less than thesampling rate of Nyquist sampling therem required, sampling and compressedare implemented successfully, and accurately recover the original signal.First, briefly introduces compressed sensing theoretical framework,detailed analyzes sparse representation of signal, linear measurement and signalrecovery, describes the initial applications of compressed sensing theory, whichlays a theoretical foundation for further study; concludes some common signalrecovery algorithms, such as matching pursuits、orthogonal matching pursuits、compressive sampling matching pursuit, which can significantly reducecomputational complexity as compared to convex-programming approaches.Inthe text,serves iterative thresholding as an alternative to the greedy pursuits classof CS reconstruction.Secondly, makes a review on several commonly used multiple descriptioncoding,includes the definition and framework of two-channel MDC, and thenanalyzes these algorithm of MDC.At last, the paper presents a multipledescription coding of images based on Non-subsample Contourlet Transformand BCS,experimental results show that these two algorithms have perfectperformance.Finally, introduces and analyzes several commonly used encryptionmethods， presents a novel image encryption based on chaos theory.The algorithm use of chaotic system to produce a set of encryption sequence, whichis used for encrypting the information of the image.The simulation results showthat the encryption algorithm have a perfect performance.