title: An iterative synthetic aperture imaging algorithm with correction of diffraction effects.
abstract: In this paper we present an iterative version of the synthetic aperture imaging algorithm extended synthetic aperture technique (ESAFT) proposed recently. The algorithm is based on a linear model that accounts for the distortions effects of an imaging system used for acquisition of ultrasonic data. Improved resolution (both lateral and temporal) in the reconstructed image is obtained as a result of minimizing the reconstruction mean square error. In this work, the minimization is extended to parameters that characterize expected amplitudes of each image element in the area of interest. An iterative optimization scheme is proposed, which in each step performs minimization of the reconstruction error based on the parameter matrix found in the previous step. Comparing to ESAFT, the proposed approach yields a significant improvement in resolution and a high degree of robustness with regard to initial choice of the parameter matrix. Performance of the proposed algorithm is evaluated using both real and simulated ultrasonic data.
authors.affiliation: Uppsala University, Signals and Systems group, Uppsala, Sweden. ew@signal.uu.se
authors.forename: Erik
authors.initials: E
authors.lastname: Wennerström
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Stepinski
authors.forename: Tomas
authors.initials: T
authors.lastname: Olofsson