Ultrasound imaging optimization via frequency-dependent weighting for angular field-of-view

Delay-and-Sum (DAS) based ultrasound image reconstruction often suffers from grating-lobe artifacts and reduced signal-to-noise ratio when full-aperture array data are utilized. Although applying a fixed F-number weighting (effectively a step-function apodization) can suppress these artifacts, it inevitably degrades lateral resolution. Moreover, conventional DAS beamforming typically neglects the angular dependence of element receive sensitivity, which decreases as the incident angle deviates from the main beam direction. This paper proposes a frequency-dependent angular field-of-view (angular FOV) weighting method to suppress grating-lobe artifacts while enhancing the lateral resolution. The method incorporates element angular receive sensitivity into the beamforming process through a theoretically derived directivity-aware DAS weighting function. Additionally, two constraints are introduced to enhance resolution and suppress grating lobes, respectively. Experimental validation on a standard ultrasound phantom demonstrates that, compared with the conventional fixed F-number (F_# = 1.5) approach, the proposed method effectively suppresses near-field artifacts, delivers clearer targets, and achieves a maximum improvement in lateral resolution of 37.44%. This work provides a practical solution that effectively alleviates the traditional trade-off between artifact suppression and resolution preservation.