Stochastic optimization of linear sparse arrays for pulse-echo imaging systems

Abstract

We apply the simulated annealing optimization algorithm to linear arrays to be used in ultrasound imaging systems under wide-band operation. We address the optimization problem of both dense and sparse wide-band arrays. In the first case, we compare the optimized beam pattern with that obtained with a classical shading function. In the latter case, we consider either the optimization of the layout (element positions and weights) or the optimization of only element positions of sparse arrays which generate a beam pattern with minimum side-lobe level. We show that an about -7-dB further reduction of the side-lobe level can be achieved with a wide-band sparse array optimization, with respect to a narrow-band optimization. The performances of the optimized arrays are verified on some phantom images.