Defect data image enhancement method based on all-focus imaging algorithm

Abstract

When the total focus imaging (TFM) algorithm is oriented to multi-layer media, the energy attenuation of the sound beam in the wedge coupling model results in a decrease in detection energy and imaging reliability. In this paper, a new defect data image enhancement method is proposed to calibrate the full-focus imaging model: the attenuation coefficients of different emission-received acoustic beams in the coupled model were measured by the plexiglass reflection method, and the whole matrix captured data were reconstructed. To enhance the image of defect data, multi-threshold fusion is proposed to eliminate the artifacts in the imaging region, especially the noise artifacts in the near field region. Experimental results show that compared with the traditional full-focus imaging algorithm, the self-built algorithm model proposed in this paper greatly improves the energy attenuation problem at the defect with large deflection angle. Especially in the range of excellent detection results, the energy uniformity of the defect is significantly improved, which has a certain inhibitory effect on the artifacts near the defect. The subsequent artifact elimination work improved the defect characterization ability and image signal-to-noise ratio of fully focused images while the effect of near-field artifact elimination was significant.