Full Focus Imaging of Concrete Ultrasonic Array Based on Semi Sparse Matrix

The versatility, excellent durability, plasticity, and relatively economical production cost of concrete make it the primary material choice in today's construction and infrastructure fields. The interior of concrete is composed of cement slurry, mortar, aggregates, voids, bubbles, possible steel bars, and additives, which make ultrasonic energy easily attenuated in concrete. In this paper, the finite element model of concrete is established by comsol simulation, and the signal received by the probe is preprocessed. In order to avoid noise errors, the signal is transformed by Hilbert. Aiming at the problems of large data scale and long computation time of full-focus imaging algorithm, a semi-sparse matrix full-focus imaging algorithm is studied. The full-focus imaging of full matrix, half matrix and sparse array matrix is compared. The simulation results show that the semi-sparse matrix full-focus imaging algorithm can effectively reduce the computational load, reduce the imaging time, achieve higher signal-to-noise ratio, and reduce the defect sidelobe by controlling the number of transmitting array elements.