Phase Aberration Correction of Ultrasonic Phased Array Signals

By properly adjusting the time delays, phased arrays can dynamically phase-steer and focus the ultrasonic beams. But phase aberration due to perturbation of system and materials degrade ultrasound performance by disrupting the ultrasound beam focus. Such phase aberration exists both in phased array transmission and reception focusing procedure. Currently, phase correction methods are implemented by adjusting the electronic phase delays used to steer and focus the ultrasound beam. In this article, time reversal method, take advantage of the invariance of the wave equation in a lossless medium under a time reversal operation, is proposed to correct the phase aberration. It is suggested to be implemented in reception focusing process instead of transmission focusing process. The correction experiments are applied to the signals obtained from defect in a specimen in ultrasonic phased array non-destructive testing. Correction results show that time reversal method has good phase correction capacity and super performance in terms of high resolution, contrast and signal-to-noise ratio.