Vibration Signal Denoising Method Based On Wavelet Transform

Large-scale structure, for example, bridge, will release the mechanical wave (vibration)when it is partial no stabilization (for example break, instantaneous distortion and so on) under load function. The moment when these mechanical wave taken place, the form of manifestation and the wave feature expressed the structure condition indirectly. Extracting these signals and the signal characteristic from the strong noise background has the vital significance to the structure condition monitor.As a new signal processing method, Wavelet analysis decomposed different kinds of frequency element to non-overlapped frequency bands and this method put forwards an effective way to signal filter, signal-noise separating and character picking-up, especially it has well de-noising capability. This paper studied the de-noising question using the wavelet transformation method and examined the effect of the de-noising method through the simulation and the actual vibration signal.This paper studied the wavelet transform theories, analyzed the characteristics of the wavelet transform,then introduced the classic de-noising method and as to it's applied of scope and results to carry on the analysis and comparison. Aim at the non-stable signal the system introduced the common use wavelet de-noising methods:Mold maximum de-noising method, Spatially Selective Noise Filtration,the wavelet threshold de-noising method. This paper analyzes the arthmetic of these three kinds methods and comes true through the MATLAB,make experiment by the vibration signal.It analyzed the result of the experiment. The processing results indicate that the Mold maximum value wavelet transform de-noising has advantage in the low signal-to-noise ratio date, and the method fits in the condition that contains white noise and many singularities. Spatially Selective Noise Filtration is more fit in the of higher signal-to-noise ratio, and its capability of edge reconstruction is better; Besides the WaveShrink method has widespread applicability and its effect of de-noising is also very good.In spite of the limited samples, the simulation result shows that using the wavelet analysis to signal de-noising is an efficient way of fault location.