Enhanced Row–Column-Addressed Array Imaging With Retrospective Filtering

To address the inherent complexity associated with fabricating fully-sampled (FS) 2-D arrays, row-column-addressed (RCA) arrays offer a promising alternative by significantly reducing the number of active elements. However, RCA arrays are limited by reduced image quality, as they only allow one-way focusing along both the x- and y-axes. This study introduces a post-filtering scheme that leverages a retrospective filtering method combined with filter-derived coherence-index (FCI) weighting to enhance RCA focusing quality, aiming to emulate the performance of FS arrays. Preliminary simulations were conducted to assess the efficacy of this approach, including point spread function (PSF) analysis and anechoic vessel phantom imaging. In the PSF analysis, our method achieved a 14.63-dB reduction in the sidelobe level, with improvements of 11.3% and 14.29% observed in the -6 dB and -20 dB full-width at half-maximum (FWHM), respectively. For anechoic vessel phantom imaging, the proposed scheme demonstrated substantial gains, with a 15.77 dB enhancement in contrast ratio (CR), a 1.615 increase in contrast-to-noise ratio (CNR), and a 27.03% improvement in generalized contrast-to-noise ratio (gCNR).