Feature enhanced ultrasonic imaging—Application of signal processing and analysis

Abstract

Automatic systems with imaging capabilities are routinely used today for reliable inspection of nuclear reactor components. To provide additional quantitative measures to the operator for an objective decision, imaging capabilities are being augmented with a variety of signal processing techniques—feature enhanced imaging. These enhancements have included measures of the signal persistence and time-of-flight consistency which were found to be valuable for discriminating reflector types in boiling water reactor (BWR) recirculation piping welds; an ability to perform spatial averaging and filtering to minimize grain noise, particularly in cast steel components; and techniques for rapid display of images with user-selectable time gates to eliminate signals from spurious sources. The paper focuses on two systems developed recently with EPRI funding. The first is a field system for rapid scanning and display of ultrasonic inspection. The second is a class of personal computer (PC) based systems which have found increasing use because of their power and low cost. The PC-based systems are capable of acquiring, analyzing, imaging, and managing inspection data. Field experience with these systems is also discussed in this paper.