Dual apodization with cross-correlation in the presence of phase aberration and noise

We have recently presented a new method to suppress side lobes and clutter in ultrasound imaging called dual apodization with cross-correlation or DAX. This method uses two apodization functions in receive mode which yield point spread functions with very similar main lobes but different side lobes and clutter. These similarities and differences are quantified by using normalized cross-correlation of the radio frequency (RF) data in the axial direction. These cross-correlation coefficients serve as a pixel-by-pixel weighting or filter to pass main lobe dominated signals and suppress clutter dominated signals. In this paper, we evaluate the robustness of DAX in the presence of phase aberration and noise. Aberrating layers of pig skin, fat, and muscle were used experimentally to mimic different level of aberrators. Experimental results are also presented using DAX in the presence of noise. With system signal-to-noise ratio (SNR) of at least 15 dB, we have a contrast-to-noise ratio (CNR) improvement of over 100 % compared to standard beamforming. This work shows that DAX is able to reliably improve contrast-to-noise ratio in the presence of phase aberration and noise.