Adaptive beamforming using Van Cittert-Zernicke criterion

This paper proposes a phase aberration correction technique, which copes with the issue related to the classical correlation method, which widens images of punctual coherent scatters. This artifact is due to the fact that the correlation maximization process realigns strong echoes coming from these targets even when the beam formed line is adjacent to the target. Our approach chooses to apply this correlation in selected areas, where there is only speckle. To identify these regions, we use a criterion derived from the Van Cittert-Zernicke (VCZ) theorem, which distinguishes between coherent and diffuse scattering. The result of the delay estimation in areas corresponding to punctual targets is then deduces from delays estimated within speckle regions using interpolation. Results of the proposed method, applied on string phantoms as well as on excised breast tissue samples containing microcalcifications, show improvement in contrast and lateral resolution of punctual scatterers.