Double Direction Minimum Variance 2D Array Beamformation for 3D Photoacoustic Imaging

Minimum variance (MV) beamformer has been commonly used to improve lateral resolution of photoacoustic imaging. Recently, photoacoustic imaging with 2D array transducer has been increasingly used for 3D imaging; therefore, 2D array beamforming algorithms are required to improve resolution in multiple axes. 2D MV beamformer can improve lateral and elevational resolution simultaneously but suffers high computational complexity which is O(N
⁶
). In this article, we proposed a simplified version of 2D MV – double direction MV (DDMV), applying MV on lateral and elevational direction while requiring less computational complexity, which is O(N
⁴
). Our simulation results show that, compared with delay and sum beamformation (DAS), DDMV can improve both lateral and elevational resolution by 48.8% and 84.9% respectively, and has similar resolution improvement as 2D MV.