Beamforming for ultrasonic array imaging of plate structures using lamb waves

Abstract

This plan proposes a research internship in the Grupo de Evaluación por Ultrasonidos of the Centro de Acústica Aplicada y Evaluación No Destructiva - Consejo Superior de Investigaciones Científicas, in the area of acoustic imaging with arrays. Specifically, the topic of interest is in image formation/compounding techniques with linear and/or two-dimensional sparse arrays. The use of sparse arrays has the advantage of reducing the cost of the imaging system, since it decreases the number of array elements, therefore the number of channels, data acquisition time and data volume for storage and processing. Although its use results in unwanted features such as the presence of grating lobes and the increase of side lobes levels, which are related to reduction of the image quality and defect detection, image compounding techniques and processing using the phase of signals or different apodizations can be applied to reduce or eliminate those effects. By studying the concepts and features of sparse arrays, simulations and implementations of image formation techniques, it is expected to improve image quality when compared with those obtained by conventional methods. Furthermore, there will be the opportunity to work with commercial array probes and phased array systems, which are not available at the laboratory in Brazil. (AU)