Denoising and Defect Diagnosis of Material Ultrasonic Detection signal Based on Best Wavelet Packet Base

The use of ultrasonic nondestructive testing of material internal defect，ultrasonic signal acquired at actual working spot usually includes large amount of noise.Extraction of the defect characteristic information will be influeced greatly if the ultrasonic signal is not effectively denoised. A new method based on best wavelet packet base is present to denoise and detect the ultrasonic signal. The superiority of new method is verified by simulation examples. Experiment of processing ultrasonic signal which comes from the 45 Steel specimen with flaws has been implemented. The accurate information that characterizes of defect size,location can be extracted from the processing result, the results show that the new method based on best wavelet packet base is in favor of enhancing the degree of accuracy for quantitatively analyzing the defect inside the material.