Nonlinear signal processing for ultrasonic imaging of material complexity

Abstract

Ultrasonic imaging of material complexity is investigated theoretically and experimentally using the concept of symmetry analysis based signal processing in symbiosis with nonlinear elastic wave spectroscopy. These concepts were tested experimentally on several complex media with an advanced electronic system. This system exploits TR invariance, reciprocity, and coded excitation for an accurate extraction of the nonlinear signature of the medium under ultrasonic monitoring. Tested both in the context of the medical imaging of a tooth and in those of nondestructive testing of aeronautic composites, the basis of a new tomographic imaging of material complexity is presented with the help of algebraic concepts describing the TR operators.