Eddy Current Imaging of Titanium Plate Surface Defects Based on Compressed Sensing

Abstract

Titanium has excellent comprehensive properties, and its alloys are widely used in aerospace, petrochemical, bioengineering and other industries, among which plate is the most widely used. Before using titanium plate, visual eddy current testing of surface defects is particularly important. However, a large amount of data will be generated in the detection process, most of which are redundant data unrelated to defect imaging. Imaging with this data is not only inefficient, but also a waste of detection resources. In order to solve this problem, this paper proposes an eddy current imaging method of titanium plate surface defects based on compressed sensing. The induced voltage signal in the process of eddy current probe C-scan is sampled at a frequency far lower than that required by Nyquist sampling theorem, which shortens the sampling time and improves the sampling efficiency. The sampled signal is reconstructed by reconstruction algorithm, which can achieve almost the same effect as the original signal. The experimental results show that the proposed method only uses 3 / 8 of the original signal for imaging, and the reconstruction algorithm used in this method has faster reconstruction speed, lower reconstruction error and better reconstruction effect than other mainstream reconstruction algorithms. The use of this method improves the efficiency of the eddy current imaging detection of titanium plate surface defects, and compresses the space occupied by the imaging data. It can not only provide important technical support for optimizing the eddy current detection process of titanium plate surface defects, but also has important significance for the eddy current detection of other metals.