Method for extracting rim ultrasonic flaw detection signal on the basis of wavelet transformation

Abstract

The invention discloses a method for extracting rim ultrasonic flaw detection signals on the basis of wavelet transformation, and particularly relates to an effective signal identifying method provided aiming at complex discrete signals collected by an online automatic flaw detection device for a locomotive wheel on an industrial site. The method mainly comprises the following steps of loading collected initial data, carrying out wavelet multi-resolution analysis to original signals, carrying out threshold value processing to each layer coefficient obtained after the wavelet transformation, and then inversely transforming wavelet coefficient to reconstruct signals. After the denoising is accomplished, the effective signals can extract positive detection enveloping curves so as to read flaw detection reports to be displayed in a user interface. Compared with the traditional digital filter in the aspect of extracting effective signals, the method has the advantages that the loss of an echo peak value is small, thus the defect detection rate is greatly enhanced, and the false dismissal possibility is avoided; and the denoising effect is obvious, and the effective signals are smooth, thus pulse signals can be effectively extracted from high-frequency noise, so as to avoid the possibility of false detection.

Description

technical field [0001] The invention relates to the field of non-destructive testing, is mainly applied in the field of online automatic flaw detection of locomotive wheels, and in particular relates to a method for extracting wheel rim ultrasonic flaw detection signals based on wavelet transform. Background technique [0002] In recent years, with the implementation of the high-speed and heavy-duty strategy and the successive opening of a large number of passenger dedicated lines, my country's railways have shown an unprecedented development trend. Since the late 1990s, my country's railways have successfully increased their speed six times. At the same time, the steady improvement of railway transportation speed and capacity means that higher requirements have been put forward for high-speed passenger and heavy-duty freight trains, especially for train wheels. safety is particularly important. [0003] The locomotive rim shares the pressure of the whole vehicle. With the s...

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Problems solved by technology

[0006] The technical problem that the present invention aims to solve is to find an applicable signal processing technology to fill the technical gap in signal processing of the existing on-line automatic flaw detection system for locomotive rims, and to be able to extrac

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