Synthetic beamforming and dynamic source plane wave imaging of concrete

Abstract

A novel imaging algorithm using dynamic source beaming and plane wave imaging (DSPWI) is proposed for concrete inspection. Phased array data are synthetically derived from full matrix capture (FMC) data during post-processing. The method dynamically adjusts the source to investigate each pixel with a steering angle normal to its position. This minimizes incoherent energy, enhancing contrast and feature mapping. The technique is validated through simulations and experiments on concrete specimens with continuous cracks. Compared to TFM and conventional plane wave imaging, the proposed method achieved a minimum average enhancement of 44% in SNR, 120% in CNR and 10% in AC values in experiments, resulting in less noise and a more accurate reflector pattern. It accurately resolves curved reflectors that may appear fragmented in TFM images. Furthermore, volumetric imaging of a concrete slab with slanted reflectors demonstrated precise in-plan reflector mapping and reduced noise, surpassing conventional techniques in accuracy and clarity. The computation time of the method is comparable to that of TFM, which can be implemented for near-real-time array imaging.