Simulated annealing optimization of multi-element synthetic aperture imaging systems

In conventional ultrasound imaging systems with phased arrays, the improvement of lateral resolution of images requires enlarging of the number of array elements that in turn increases both, the complexity and the cost, of imaging systems. Multi-element synthetic aperture focusing (MSAF) systems are a very good alternative to conventional systems with phased arrays. The benefit of the synthetic aperture is in reduction of the system complexity, cost, and acquisition time. A general technique for parameter optimization of an MSAF system is described and evaluated in this paper. The locations of all "transmit-receive" subaperture centers over a virtual linear array are optimized using the simulated annealing algorithm. The optimization criterion is expressed in terms of the beam characteristics - beam width and side lobe level. The comparison analysis between an optimized MSAF system and an equivalent conventional MSAF system shows that the optimized system acquires images of equivalent quality much faster.