Multi-functional ultrasonic conditioning technology and its verification in hierarchical and phase arrayed laser ultrasonic inspection

Abstract

In many present ultrasonic measurement systems, conditioning in ultrasonic measurement involves techniques that improve understanding of the information contained in received ultrasonic data. Conditioning technique is often utilized to minimize unwanted noise coming from electrical background noise and enhance a received signal. The filtered output coming out from the sensor has the effect of attenuating the signals above and below the desired frequency range. It is also used as an anti-aliasing filter and applied to the small amplitude signal to improve the SNR of the output signal. And, it is well-known that the selection of a frequency for signals generation and data acquisition significantly affects the quality of ultrasonic measurement results. There are already complicated to find the best frequency range, and some systems have need of reading multiple sensors at the same time. So as to meet these requirements, a multi-functional ultrasonic conditioner with a Single-Input Multiple-Output system was designed to sweep quickly various frequency ranges at single scanning as utilizing the laser based broadband excitation. The multi-functional ultrasonic conditioner was implemented into a pulse-echo ultrasonic propagation imager (PE-UPI) system with a hierarchical inspection scheme to perform the inspection process automatically. Only two scans required was to search the optimal frequency range for unknown specimens and provided a tremendous reduction in the number of trial scanning over the investigation of whole frequency ranges. In addition, an upgrade of multi-functional ultrasonic conditioner (multiple programmable band-pass filters) was designed and verified in the phase-arrayed ultrasonic propagation imaging (PA-UPI) system with easily expandable and compact abilities.