Novel Method to Improve the Imaging Accuracy of Defect Based on Zero-Signal Filling for the Plate

Many effective image-based imaging algorithms are available for detecting and locating the defects for plate-like structures. The discrete ellipse imaging algorithm is widely applied in plate-like structures. However, the scattering-wave extracted by the baseline subtraction may easily be impacted by noise and the reflect wave from boundary, which significantly reduces the signal-to-noise (STN) of the scattering wave, and then leads to the degrading of imaging accuracy. To enhance the STN and improve imaging accuracy, a novel method of zero-signal filling is used in the discrete ellipse imaging in this paper. To verify its effectiveness, the imaging experiment with a circular sparse array has been conducted. The experimental results show that the method can effectively resolve the signal delay and enhance the STN of the scattering wave. The imaging accuracy can be improved obviously by this method and the defect can be located accurately.