Artefact Reference Images for Industrial Computed Tomography

Speaker:
Ewert, Uwe; BAM Bundesanstalt fur Materialforschung und -prufung; Germany

Authors:
Ewert, U.; Federal Institute for Materials Research and Testing (BAM); Germany

ID: ECNDT-0352-2018
Session: X-ray & CT modeling 1
Room: G3
Date: 2018-06-14
Time: 09:40 - 10:00

Computed tomography has been developed from a very specialized research method in medicine and industry to a routine method which is even applied in industry for in-line inspection. Precondition was the rapid development of computers and digital detector arrays in the last 20 years. CT is applied to find and characterize flaws and decide if they are defects by dimensional measurement. The ability to measure accurately dimensions and substitute coordinate measurement machines made the CT even more interesting for quality assurance in industrial production. Consequently CT standards were updated and new standards were developed considering the dimensional measurements in the last few years. About available standards and standard developments will be reported. The German society started to develop training courses and certification schemes for CT personnel. EN 16016-3 and ISO 15708-2 provide information on artefacts which may distort the accuracy of CT images and measurements. For the development of a new German guideline on CT application for car industry a set of CT artefact images was simulated to enhance the training of personnel. The main artefacts are: cupping by hardening, detector back scatter, and object scatter, insufficient number of projections, cone beam artefacts of FDK and artefacts due to distortions of adjustment of the rotational axis. The simulation was performed with the modelling software aRTist, which permits to calculate projections with and without scatter and hardening using monochromatic and polychromatic radiation.