Optimized algorithm for synthetic aperture imaging

We present a novel synthetic aperture imaging algorithm based on concepts used in synthetic aperture radar (SAR) and sonar (SAS). The algorithm, based on a convolution model of the imaging system developed in the frequency domain, accounts for the beam-pattern of the finite sized transducer used in the synthetic aperture. A 2D Fourier transform is used for the calculation of the 2D spectrum of the ultrasonic data. The spectrum is then interpolated to convert the polar coordinate system used for the acquisition of ultrasonic signals to rectangular coordinates. After windowing, the transformed spectrum is subjected to the 2D inverse Fourier transform to get the time domain image again. Performance of the proposed algorithm and the classical time-domain SAFT (synthetic aperture focusing technique) are compared using both simulated and real ultrasonic data.