Image contrast enhancement using dual apodization with cross-correlation and beamforming by spatial matched filtering

Dual apodization with cross-correlation, or DAX, is a technique for sidelobe and clutter suppression in ultrasound imaging. Previous studies have shown DAX can improve contrast of images constructed using delay-and-sum (DAS) beamforming, without worsening image resolution. However, artifactual black spots may arise in regions away from the transmit focus after DAX processing is performed. Beamforming by spatial matched filtering (SMF) is a novel method capable of focusing both transmit and receive beams throughout the field of view. In this method, instead DAS beamforming, echo signals from individual receive channels are passed through individual spatial matched filters built from the experimental impulse response of the imaging system. Then the filtered signals are summed up along the receive aperture. In this paper, we present our work on applying DAX to SMF beamforming to achieve enhanced image contrast at all imaging depths with minimum artifacts being introduced.