Ultrafast wide field-of-view ultrasonic diverging wave imaging based on delay p-th root and sum beamforming

Ultrafast ultrasonic phased array imaging has attracted considerable attention in automated inspection applications owing to its exceptionally high frame rates. Plane wave imaging (PWI) technique, utilizing the delay and sum (DAS) linear beamforming algorithm, offer high frame rates but is constrained by a narrow field-of-view (FOV). In this work, we proposed an ultrafast, wide FOV, and high-quality imaging method that combines diverging wave imaging with delay p-th root and sum (DWI-DpRAS) nonlinear beamforming algorithm. A wide emission ultrasonic field is generated by controlling the delay laws of elements to form a diverging wavefront. The DpRAS algorithm is then employed to suppress noise and artifacts, enabling high-quality imaging. The effectiveness of the proposed method is evaluated through simulations on scatterer targets and experiments conducted on aluminum, copper alloy, and rail standard samples. The results demonstrate that DWI-DpRAS imaging with 32 elements and 87,000 focal points on CUDA platform, achieves a frame rate of approximately 1010 fps. This represents a 7.81-times improvement over the traditional total focusing method (TFM). Additionally, the SNR of reconstructed images for aluminum, copper alloy, and rail standard samples is enhanced by at least 6.8 dB, 9.66 dB, and 11.77 dB, respectively.