The Research On Multiple Ultrasonic Signal Processing Technology And Its Application

Ultrasonic testing technology is widely used in various fields of modern industry due to its advantages such as high penetration,high sensitivity and portable equipment.In the process of ultrasonic testing of metal members,we mainly through the received multiple ultrasonic signal to analysis location,quantity and quality.However,the target signals are often mixed with some interference multiple echoes such as noise,which interfere with the identification of usefulness signal.In order to get the clear and effective signal,we need to pre-process the receive multiple ultrasonic.So the research of multiple ultrasonic signal processing and analysis technology is a very important work.The technology of multi-ultrasonic signal processing mainly includes the processing technology of the noise in the received signal and the extraction of the target signal characteristic.As multi-ultrasonic signal is nonlinear and non-stationary,so we need to obtain its instantaneous frequency information for research.However,the traditional Fourier transform method can not analyze the instantaneous frequency information in the time-frequency domain.Therefore,this paper starts from the time-frequency analysis method which is suitable for the analysis and processing of nonlinear unsteady signals: wavelet transform and empirical mode decomposition(EMD).Based on the study of the above two methods,we applied the methods to the multi-ultrasonic signal processing and analyze the effects.The experimental results show that the EMD method is especially suitable for the decomposition of nonlinear unsteady signals as it's based on the fluctuation or trend of the different scales of the signal itself.Based on the above research,this paper presents a new method of multiple ultrasonic echo signal based on EMD.Simulation results show that the signal-to-noise ratio is improved and the mean square error is reduced by using the new method.Smoothness is improved,the denoising effect is better than the traditional denoising method.Finally,the energy extraction algorithm based on energy operator is used to estimate the signal parameter of the denoise reduction.The experimental results show that the denoise method is suitable for the low SNR.And the estimation of the parameters based on the envelope reduces the computational complexity and the accuracy is improved,and the engineering application is good.