Signal Event Extraction by the Apex-shifted Radon Transform

Abstract

Complex structures, such as composite laminates with irregular shapes or with structural reinforcements, pose unique challenges for ultrasonic inspection. These material and geometric complexities interact with the ultrasonic waves and can bury damage-scattered waves in the time-space domain. An Apex-shifted Radon Transform is proposed in this research to convert these signals to an apex time-curvature-apex offset domain (τ − q − y). Through this process, the energy of damage-scattered events can be compressed to localized regions at their apex location for easy extraction. This method shows potential in complex signal extraction and is promising as a tool for damage detection in complex structures without using baseline subtraction.