Advances in Automatic Evaluation of 3D-CT Data

S Oeckl, U Hassler, T Wenzel, M Maisl, R Hanke

Fraunhofer Institute for Integrated Circuits, Department EZRT, Am Weichselgarten 34, 91058 Erlangen, Germany

Email: {okl,has,wez,hnk}@iis.fhg.de, maisl@izfp.fhg.de

ABSTRACT

In this contribution we present an advanced evaluation method for 3D-CT data, which is especially adapted for the serial inspection of aluminium castings for voids and porosity. The main feature of the presented method is an irreferable inspection, i.e. there is no need for any prior knowledge of the geometry of the sample. This feature allows the evaluation of the sample volume for inner flaws without introducing a CAD model of the sample. A new image processing stage is used to recognize also flaws, which are connected to the surface of the sample. This is done by calculation and interpretation of the characteristics of the local curvature of the sample surface. In the case of simple objects, the proposed method may be used for a fully automatic evaluation of 3D-CT data. In the case of extremely complex samples a preclassification of critical regions may be performed. The performance of the proposed method is presented by the means of a sample from the automobile industry.

Keywords Computed tomography, Automatic evaluation, 3D, CT