An efficient ultrasound full-matrix imaging method in polar coordinate

Circular measurement has found broad applications across medical and industrial domains. In the industrial field, total focus method (TFM) takes a superior position in full-matrix imaging methods, but conventional TFM efficiency has been restricted by computational complexity especially in multilayer structures. To improve the efficiency of full-matrix measurement, circular ultrasonic measurement was mathematically modeled in polar coordinate, and an efficient ultrasound full-matrix imaging method was proposed in this paper. In the proposed method, full-matrix dataset was endowed with five-dimensional information, and three kinds of wavefield reconstruction operators were designed to reconstruct wavefield in frequency-wavenumber domain. Moreover, simulations and experiments were conducted to compare performance between the proposed method and conventional ray-based TFM in one-layer and two-layer circular structures with internal defects. According to the results, the proposed method spends time cost just 1/309 and 1/35 of conventional ray-based TFM in two-layer simulation and experiment measurement, respectively. The results show that the proposed method has obvious advantages in measurement efficiency for circular structures and has great application potential in circular measurement.