Based On Signal Matching And The Optimal Decomposition Level Of Wavelet Denoising Method Research

In the process of signal acquisition, transmission and processing, inevitably contains noise, directly affect the results of subsequent processing, So how to deal with the noise signal, which is currently one of research hot topic at home and abroad in the field of signal processing.Now there are a lot of research on signal denoising method,common denoising methods based on Fourier transform of signal to noise,Fourier transform frequency due to the unity, signal denoising effect is poorer. Wavelet transform has the characteristics of time domain localization and multi-resolution characteristics, decorrelation characteristics, choose base flexibility and so on, it has been widely used in radar signal processing, speech recognition, data compression, signal processing, pattern recognition, signal denoising, etc. For different noise signals, seven kinds of conventional wavelet denoising performan analysis and experimental comparison, constructs the9/7wavelet filter based on structured group and7/13wavelet filter, and its performance analysis and comparison of filter groups.Different wavelet base with different time-frequency characteristics, choice of wavelet base is different, the corresponding denoising effect is not the same, so in the process of denoising, the choice of wavelet base, will directly affect the effect of wavelet denoising, how to select the best wavelet base according to the characteristics of the signal, is the key issue in the research of scholars both at home and abroad. Aiming at the shortcomings of the existing wavelet base, put forward a kind of optimal wavelet denoising based on signal matching method. The method according to the signal on the largest scale space projection and the structure of energy matching criterion, using structured wavelet filter bank, combined with the genetic algorithm, constructs the consistent with signal energy optimal wavelet energy matching. And according to the waveform matching criterion, combined with structured wavelet filter bank, consistent with the signal waveform is constructed using the optimization function of the optimal wavelet waveform matching. Experiment results show that based on signal to match the optimal wavelet denoising method of denoising effect is better than the other wavelet.In view of the different signal denoising, in addition to the research on different wavelet base and the optimal wavelet base selection, but also to the layers of signal denoising based on wavelet decomposition was studied, found that the layer number of wavelet decomposition and contaminated with noise signal level there is a certain relationship. In an actual signal wavelet de-noising process, the different noise signal, the wavelet decomposition layers is not fixed, and different decomposition layers will have great influence on denoising effect, in order to solve this problem, puts forward the optimal decomposition level based on denoising method, this method takes advantage of the wavelet decomposition layers energy relations, namely the signal-to-noise ratio, combined with the optimization algorithm to determine the optimal decomposition level are denoising. Experiment results show that the optimal decomposition level of its de-noising effect on up to the best.