The Algorithm Of Image Simultaneous Compression And Encryption Based On Compressive Sensing And Coupled Map Lattice

During the information age,when enjoying the convenience of information transmission,the exposure and transmission efficiency of information have become concerned topics increasingly.images,which are more intuitive visual information,have become one of the most important transmission media nowadays.However,because of the huge amount of data,the strong correlation between the adjacent pixels,the uneven distribution of energy and so on,the storage space is large,the transmission bandwidth is high,and for some confidential images(medical,military,financial and commercial),content protection and real-time transmission of images have become a topic of concern in practical applications.How to protect privacy images effectively and to improve their transmission efficiency or reduce transmission bandwidth have also become a hot topic for scholars.Traditional information compression encryption systems are insecure,and encryption and compression are asynchronous.Therefore,it is particularly important to study the consistency of image encryption and compression scheme.The common way of secure transmission of private images is to cover the information content by encrypting them to prevent illegal eavesdropping/tampering.Many fascinating features of chaotic systems,such as sensitivity to initial values and control parameters,ergodicity and mixed characteristics,just totally meet the requirements of cryptography.Therefore,the perfect combination of chaotic system and cryptography has become the focus of scholars' research in recent decades.In addition,due to compressive sensing theory can achieve two processes of compression and encryption at the same time,once proposed,it is widely used in the field of image encryption and becomes a breakthrough in the field of signal processing.In recent years,domestic and foreign scholars have proposed various encryption schemes according to the characteristics of chaos and compressive sensing to make up for the shortcomings of traditional image encryption and compression algorithms.This thesis first introduces the theory of chaos,the basic knowledge of cryptography,compressive sensing and wavelet packet transform.Next,author constructs a pseudorandom number generator,and the randomness of the pseudo-random sequences has been discussed.Then,chaotic sequences from the proposed pseudo-random generator are used to construct a bit plane image encryption scheme;author analyzes the security performance of the proposed encryption algorithm and finds that sole encryption processing merely ensure the security of information,but cannot guarantee the efficiency for realtime transmission of information.Based on the results of the previous discussion,author summarizes the existing compression and encryption algorithms,and figures out the shortcomings of these algorithms.Taking the encryption algorithm proposed in this paper into account,author puts forward an image simultaneous compression and encryption scheme based on compressive sensing,and discusses the consistency between information compression and encryption.Experimental results illustrate that the proposed algorithm not only guarantees the security of information transmission,but also solves the puzzle of traditional data compression and encryption,and perfectly balances the contradiction between data compression ratio and reconstruction quality.