A New Synthetic-Aperture Focusing Method for Ultrasonic B-Scan Imaging by the Fourier Transform

This paper presents a new synthetic-aperture focusing method for ultrasonic E-scan imaging. The method involves the two- dimensional Fourier transform and is named Fourier domain recon- struction (FDR). The performance of FDR as well as the basis for the availability of the image is derived theoretically in some detail. Conven- tional synthetic-aperture focusing is referred to as delay and sum (D&S). The computational complexity of FDR is of the order of OW2 log N) as compared to O(N3) for delay and sum in reconstructing N X N pixels. In experiments, good images of several objects have been re- constructed by FDR.