Improvement of signal correlation for adaptive imaging using the translating transmit aperture algorithm

Phase aberration correction techniques require highly correlated signals at different receiver positions in order to estimate and correct for the time shifts imposed by the aberrator. The translating transmit aperture algorithm is a technique for improving the signal correlation from speckle signals at different receiver positions. The efficacy of this technique in improving signal correlation is demonstrated both in phantom studies across an inhomogeneous medium, as well as in in vivo studies. The corresponding improvement in time shift estimates and image quality when the translating aperture geometry is used instead of a fixed transmit aperture geometry is also shown. Limitations of the translating aperture algorithm are generated by quantization of the transmit focal delays, depth of field considerations, and a bias in the time shift estimates made using this algorithm.