Wavefront backpropagation and focus correction [medical ultrasonics]

Wavefront distortion encountered in transmission through human abdominal wall is modelled as the result of propagation in a uniform medium after passing through a phase screen. To compensate for the waveform distortion developed during propagation, wavefront backpropagation is employed. The position of the equivalent phase screen is identified by maximization of a waveform similarity factor. The wavefront at that position is then time-shift compensated using arrival time estimates obtained by a reference waveform method. The compensated wavefront is subsequently focussed. The results indicate that wavefront backpropagation reduces the waveform distortion, and that the backpropagated and time-shift compensated wavefront produces a better focus than that obtained by time-shift compensation in the aperture