Adaptive 3D Algorithm to Detect Bridging Ligaments during Intergranular Stress Corrosion Cracking of Stainless Steel

M. Janaszewski1,3, T. J. Marrow2 and L. Babout1

1 Department of Computer Engineering, Technical University of Lodz, Poland, Email: lbabout@kis.p.lodz.pl

2 Materials Performance Centre, School of Materials, University of Manchester, UK

3 The College of Computer Science in Lodz, Poland

ABSTRACT

This paper presents an adaptive algorithm to identify holes in 3D objects which cannot be labelled with standard techniques, such as 6 or 26-connectivity based methods. The algorithm consists of two stages. The first one lies in the application of a voxel coding technique to make a transformation of an object into a set of clusters, where a cluster is a set of connected voxels. The set of clusters gives important information about the object topology. In the second step, the algorithm extracts and analyses clusters to detect holes. The algorithm was satisfactorily tested on several 3D crack images from a stress corrosion cracking experiment on a stainless steel sample. In this case, the “holes” in the crack are bridging ligaments of solid material which connect the opposing faces of the crack. Discussion of results obtained and proposals for future work are presented.

Keywords X-ray microtomography, image analysis, voxel coding, hole detection