Research On Audio Detection Of Pavement Void Based On Time-Frequency Analysis

Nondestructive testing is a kind of important means. It can realize quality control,improve the process and labor productivity. It is an indispensable effective tool during thedevelopment of modern industrial society. Acoustic-vibration testing is a nondestructivetesting. Through exciting tested specimens, so as to produce mechanical vibration, and getsound waves from the measured results. It can judge the quality of the object.Based on the analysis of nondestructive testing method of pavement void in recent years,this article selects the acoustic-vibration testing. It combines with time-frequency analysis of theaudio signals, to determine the void condition of cement concrete pavement. This articlefocuses on the time-frequency analysis of audio signals generated by the hammer incentives,which is different from the common processing of stationary signals, sound signals is a typicalnon-stationary signals. Select short time Fourier transform and Wigner-Ville distribution, anduse the different time-frequency analysis methods determine whether is in the void state. Inaddition, in order to get a more intuitive, visual time-frequency diagram to distinguishbetween different sound signals, spectrogram in the voiceprint recognition technology isintroduced. Through MATLAB software simulation, carry on theoretical analysis andperformance comparison. Adding white Gaussian noise to the experimental signal andemploying wavelet threshold denoising method is to extract the original signal, and close tothe actual road detection.In the processing and analysis of sound signals collected in the experiment, the vibrationtesting method based on acoustic properties, using Fourier transform, extract the signalfrequency characteristic as the parameter, by which determine whether the road is in the voidstate. Analyzing the pavement void in spectrum diagram, with its point value of spectrumdiagram as the parameters, through a large number of experimental data statistics andcomparison, find out the theory basis and judge the pavement void.