The Research Of Image De-noising And Enhancement Based On Wavelet Theory

Wavelet analysis in the image processing applications are very important. In this paper, the direction of its image noise reduction and image enhancement are researched in the application. Wavelet analysis is the development of Fourier analysis of the way of thinking and extension. Two-dimensional images of wavelet analysis for noise reduction and image enhancement application of wavelet analysis is an important aspect. Wavelet analysis for noise reduction and enhance the image has obvious advantages. Based on wavelet analysis of the image means a lot of noise, the more successful a wavelet threshold method, air-related laws, modulus maximum reconstruction, projection and so on. And the wavelet-based image enhancement methods than the traditional image enhancement methods more effective.The fundamental theories of wavelet analysis are discussed in detail. Continuous wavelet transform, discrete wavelet transfonn and dyadic wavelet transform are introduced. The fast algorithm of discrete dyadic wavelet transform is given. Finally, an analysis is made on the influence of the wavelet bases on practical applications by studying their mathematical properties.Based on the profound comprehension and generalization of a lot of existing literature on wavelet de-noising, the applications in the image de-noising are described; second, the wavelet image de-noising methods are classified and introduced, moreover, the shortcomings of threshold de-noising method are specially analyzed; in the end, after analyzing and comparing the classical threshold de-noising methods, a new threshold selecting method and a new threshold function are proposed. Simulation experiments are implemented by Matlab wavelet tool box. And experiment results show that the new methods usually obtain better performance than classical threshold de-noising methods.Image enhancement based on wavelet transform are studied in the thesis. Firstly, the concept of wavelet transform is described, and the characters after wavelet transform are analyzed; secondly, an adaptive local threshold scheme is proposed namely by threshold of the wavelet transform; At last, the way that wavelet cooperate with image enhancement realize the arithmetic, which balance de-noising and image enhancement. The Matlab simulation experiment indicates the new adaptive image enhancement is effective and excellent.This paper elaborated on the wavelet-based image noise reduction and enhancement of the theoretical basis to Matlab as a platform for noise reduction and image enhancement algorithm to achieve process and the corresponding image processing results were analyzed and compared in order to arrive at a comprehensive performance distinctions based on wavelet of the noise reduction and image enhancement algorithm program.