Efficient strategies for estimating spatial coherence on matrix probes

Short-lag spatial coherence (SLSC) imaging has recently been introduced as a clutter reducing imaging technique. Thus far, SLSC has been implemented solely on one-dimensional (1D) array transducers, and the present definition is not readily applicable to two-dimensional (2D) matrix array transducers. We propose a strategy based on the physics of pulse-echo ultrasound in diffuse scatterers. The method utilizes subaperture beamforming, wherein groups of N elements are delay-and-summed to form individual channels of output, and estimates the spatial coherence between subapertures. Our simulation results show that there is no noticeable degradation in the spatial coherence estimates associated with subaperture beamforming for small subaperture sizes; further-more, the signal-to-noise ratio is improved by a factor of √N. These results suggest that SLSC implementations on 2D matrix array transducers should employ subaperture beamforming.