Delay-and-Sum Beamforming Technique on Ultrasonic Propagation Imaging System

초록

The ultrasonic propagation imaging (UPI) system, which is the one of the ultrasonic testing method for NDT & E has advantages of very fast inspection speed and various applications. However, the system may not secures high signal to noise ratio (SNR) of acquired ultrasonic signals because it has used to utilize laser, which have lower excitation energy than other manners. Hence, the UPI system is being required to have improved SNR for enhancement of damage detection and evaluation ability of the system. In this study, we schemed that SNR securing for laser-induced ultrasonic signals by applying delay-and-sum beamforming technique and sensor array to the UPI system. The delay-and-sum beamforming technique, which is the one of spatial filtering, is able to amplify SNR of signals that reach to sensor array by being propagated from specific angle. The digitizer, which is the one of the ADC that support multi-channel acquisition with multiple sensors are integrated to the UPI system to apply delay-and-sum beamforming. The algorithm has been validated through comparisons between the 1-D time domain signals of raw and beamforming.