Efficient Imaging Techniques Using Sub-aperture Matrix Capture and Two-dimensional Sparse Array

Total focusing method (TFM) is a post-processing algorithm for ultrasonic imaging, usually used for processing linear array data. In this paper, TFM is extended to obtain three-dimensional (3D) image based on two-dimensional array data. However, it takes a long time to get 3D information from large amount of 2D array data by TFM. So Sub-aperture matrix capture (SMC) and sparse array are taken into account to solve this issue. The experimental results prove that TFM precisely reconstruct 3D information of defects through the optimized method. In a small angle imaging range, SMC can reach the same image quality and the same array performance indicator (API) as full matrix capture (FMC). In addition, it won't take more than one quarter of the time token by FMC for ultrasonic imaging. Although the spurious image is enhanced with the reducing sparseness, the processing time is reduced. Considering both image quality and real-time imaging, the imaging efficiency might be improved by 50 times through the combination of the two methods. The paper provides an optional approach to achieve real-time imaging system.