Resolving the Effect of Phase Errors on Ultrafast Ultrasound Plane Wave Imaging

The phase error caused by non-ideal physical transducer characteristics can affect the ultrasonic wave front during beamforming. If not compensated, the phase error can degrade the focusing capability and reduce the B-mode image spatial resolution. In this paper, the effect of the phase error on ultrafast coherent plane wave imaging (CPWI) was investigated using a bespoke ultrasound imaging system, ultrasound array research platform II (UARP II). The phase deviations between the aligned radio frequency (RF) signals from all active elements were calculated by applying cross-correlation techniques with the RF signal from the first active element as the registration reference. A sign-reversed lag technique has been applied to the RF signals to encounter the phase error. When the phase error was corrected, the lateral resolution at -6 dB and -20 dB showed improvements from 0.42 mm to 0.34 mm and from 1.18 mm to 0.56 mm, respectively. No significant changes occurred for the axial main lobe.