Determination of Flaw Detector Impulse Response to Achieve Super-Resolution of Reflector Images Based on Echo Signals Measured by an Antenna Array

Abstract In ultrasonic inspection, digital aperture focusing (DAF) is increasingly being used to reconstruct reflector images. The reliability of inspection is determined by the quality of the DAF image—signal-to-noise ratio, ability to reconstruct the image of the entire reflector boundary, and resolution. Various methods are used to achieve super-resolution of echoes: maximum entropy method, methods of building autoregressive signal models, compressive sensing (CS) method, etc. To use these methods, it is important to know the impulse response of the ultrasound system, which can be measured or obtained using “blind” deconvolution methods used in image and signal processing. In this paper we consider the minimum entropy deconvolution (MED) method for estimating the impulse response of an ultrasonic flaw detector and achieving the effect of image super-resolution, where knowledge of the transfer function of the system is critical. The effectiveness of the proposed method is confirmed by the results of model experiments.