Artifact reduction in non-destructive testing by means of complementary data fusion of x-ray computed tomography and ultrasonic pulse-echo testing

Abstract

In industrial non-destructive testing, x-ray computed tomography (CT) and ultrasonic pulse-echo testing play an important role in the investigation of large-scale samples. One major artifact arises in CT, when the x-ray absorption in specific directions is too intense, so that the material cannot be fully penetrated. Due to different physical interaction principles, ultrasonic imaging is able to show features which are not visible in the CT image. In this contribution, we present a novel fusion method for the complementary data provided by x-ray CT and ultrasonic testing. The ultrasonic data are obtained by an adapted synthetic aperture focusing technique (SAFT) and complement the missing edge information in the CT image. Subsequently, the full edge map is incorporated as a priori information in a modified simultaneous iterative reconstruction method (SIRT) and allows a significant reduction of artifacts in the CT image.