Imaging of insulator debonding defect based on SSA-VMD-DTW

The high attenuation of composite insulator and the specificity of bonding structure will lead to abnormal highlight area in C-scan images. In order to effectively eliminate its influence on automatic discrimination, a C-scan imaging algorithm based on SSA-VMD-DTW was proposed. First, three groups of original signals at different distances were collected. The de-bonding signals, interface signals and abnormal highlight signals of the three groups of original data were analyzed and compared, which could clearly distinguish the signal differences. Then, the original signal was denoised by SSA-VMD mode decomposition, and the DTW distance between the IMF2 component and the standard reference signal was calculated, and the correlation coefficient matrix was obtained and weighted with the original C-scan images. Experimental results showed that the proposed method could effectively eliminate the abnormal highlights in C-scan images, and it laid a foundation for the automatic defect identification and provided an imaging idea for the defect detection of similar components.