Real-time imaging of microcracks on metallic surface using total focusing method and plane wave imaging with Rayleigh waves

摘要

We present a real-time surface inspection method based on ultrasonic synthetic imaging using Rayleigh waves. We show that both Total Focusing Method (TFM) from Full Matrix Capture (FMC) and Plane Wave Imaging (PWI) can be used to characterize precisely complex surface cracks on metallic parts. Compared to the FMC/TFM reference standard, PWI allows improvement in terms of signal-to-noise ratio and strongly reduces the amount of data allowing an increase of the maximum frame per second from 3 Hz up to 27 Hz for images containing up to 1.26 megapixels. Such work opens the door toward a new type of real-time surface inspection, available for large surfaces, free of chemical preparation and cleaning, and fully automated, from acquisition to decision.