A Grating Lobe Near-Field Image Enhancement Method: Sparse Reconstruction Based on Alternating Direction Method of Multipliers

In this study, a new sparse reconstruction algorithm based on near-field imaging is proposed to solve the grating lobe problem arising from sparse arrays. It derives the expression of the steering vector under near-field conditions and formulates the optimization problem. Moreover, the problem, by using the alternating direction method of multipliers (ADMM), is efficiently solved. Experiment results indicate that, in comparison to existing methods such as the phase coherent factor (PCF) and sum and difference beams, the proposed method significantly reduces the impact caused by grating lobes in near-field imaging. In addition, the proposed algorithm is accelerated by the ADMM, which significantly reduces the computational time. This work offers a perspective and potential solution to enhance grating lobe images.