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.