Analysis of signal coherence in ultrasound beamforming

Coherence factor weighting is used to suppress sidelobes, reduce artifacts, and improve the contrast and spatial resolution. The method provides a less hardware demanding solution with acceptable results. We conduct an analysis on coherence factor (CF) and a two-aperture coherence (TAC) estimation for the purpose of general understanding and fast estimation. A simulation was implemented based on linear description of ultrasound system and a simplified lateral scatterer distribution at the region of interest to analyze differences. Characters of CF and TAC for a point, homogeneous speckle, and a point and a cyst within homogeneous speckle environment under narrow and broad band were simulated.