Research on Ultrasonic Imaging Noise Processing of Concrete Defects Based on VMD Method
Time inversion multi-signal classification(TR-MUSIC)algorithm for ultrasonic imaging of concrete structures with de-fects can break the diffraction limit and realize super resolution imaging,with the excitation frequency unchanged and the detection distance guaranteed;However,it has a disadvantage to be easily disturbed by noise,and generate additional singular values in the process of imaging division signal subspace and noise subspace,which affects the accuracy and precision of ultrasonic imaging;In or-der to further improve the quality and stability of the TR-MUSIC algorithm in ultrasonic imaging and suppress the interference of noise,a noise processing method based on variable mode decomposition(VMD)is proposed;Firstly,the variable mode component af-ter the VMD decomposition is determined by combining energy entropy and barycentric entropy to determine the noise component of signal spectrum divergence and uneven energy distribution.Then,the noise components are processed by wavelet threshold denoising method,and the noise components and other components were processed and reconstructed by the Savitzky-Golay filtering.The inver-sion imaging of the improved signal achieves the distinction of the corresponding singular values of the signal subspace and noise sub-space.Finally,the results show through the setting thresholds,the proposed method improves the imaging resolution,and suppres-ses the artifacts caused by noise.
ultrasonic imagingvariable mode decompositionconcretenoise reductionsingular valueentropy of center of grav-ityenergy entropy
万方数据
维普
