Digital Image Wavelet Transform And Chaotic Encryption And Their FPGA Technology Realization

With the rapid development of modern electronic technology, chaos research has also made considerable progress in many ways to get a wider application. The study of chaos is also increasing, this is saying the features are inseparable. Chaos as a nonlinear system performance situation, random, and early in the language, it is the beginning value of the sensitivity of the fractal dimension, universal, making it the voice and image encryption even with good prospects for the use of video encryption. In the past using discrete components to achieve chaos.The wavelet transform is a new transformation analysis method, it has inherited and developed the short-time Fourier transform the idea of localization, at the same time overcome the window size does not vary with the frequency change and other shortcomings, can provide a frequency dependent time-frequency window is processing and analysis of an ideal method to solve the time-frequency Fourier transform can not solve many difficult problems.Traditional cryptography is mainly used in the processing of text data encryption, the encryption technology of the digital image to provide the most direct theoretical basis, but its object is a binary data stream, ignoring the two-dimensional characteristics of the image at the same time, due to digital image data volume, and some also require encryption with real-time, traditional encryption methods are difficult to achieve. Chaos applications in the field of image encryption, computer simulation and hardware platforms above proved to obtain better encryption, image encryption chaos has practical value.The main contents include the following aspects:1. A study of two multi-scroll system switching control method, first by the Matlab simulation these two scroll the phase diagram, and then design their own circuit in Multisim software to observe the phase diagram and found that with us then the superposition of two scrolls and scrolls, the final observed five scrolls. 2. The image on the computer simulation, an image wavelet transform to get the high-frequency component and low frequency components, after a decomposition of the four images. To retain the low frequency components of the main factors of the image to the rest of the components set to0, the image is reconstructed by To get the compressed image. Then we get the image cat map encryption and decryption. Encryption and decryption of images. The decryption process is to transform the inverse of these coefficients.3. hardware description language programming constructs ROM, RAM memory, VGA timing, the VGA control, Wavelet line transform, wavelet transform, the IP phase-locked loop seven module in the FPGA hardware platform above. These modules to build the project file, the module uses the HDL text input mode, the top-level design entry using the schematic diagram of the input generated bsf file. Then compile, download and then extract the image of the line transform (L component), low-frequency component (LL component). Finally, we present experimental results.4. FPGA platform above the basic module of the above, then we will construct cat mapping encryption and cat map decryption module to achieve the image of the cat map encryption and decryption. The end result of the basic components and hardware design of the hardware design process, the system module.This work was supported by the National Natural Science Foundation of China under Grant Nos.60572073,60871025and61172023, the Specialized Research Foundation of Doctoral Subject Point of Education Ministry under Grant No.20114420110003, the Natural Science Foundation of Guangdong Province under Grant Nos.8151009001000060and S2011010001018, and the Science and Technology Program of Guangdong Province under Grant No.2009B010800037.