Ultrasound Background Cancellation Based on Time-Varying Synthesis

Abstract

Fault detection based on ultrasonic imaging is a common technique used in non destructive testing. Correct interpretation of the scans requires training so that responses from unwanted echoes such as the background are discriminated from echoes corresponding to faults. Thus, enhancement in the form of displaying the desired echoes without the background response can offer an advantage for detection or further quantification of the fault. A fast way to achieve this goal and detect the background signatures and isolate them from the fault ones is to use time-frequency analysis. When time-varying filtering is used, the tendency is to recover the echoes coming from the faults. These echoes are reconstructed with no phase distortion because the system is linear and the scans c in which the background was cancelled in different specimens where faults were located very close to the surface buried within the initial pulse response and close to each other deeper in the specimen. This technique uses a single reference scan fast enough so that to finish the processing earlier than the time required to acquire a new scan.