Surface Extraction from Multi-Material Components for Metrology using Dual Energy CT

Christoph Heinzl, Johann Kastner, Eduard Gröller

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)


This paper describes a novel method for creating surface models of multi-material components using dual energy computed tomography (DECT). The application scenario is metrology and dimensional measurement in industrial high resolution 3D x-ray computed tomography (3DCT). Based on the dual source / dual exposure technology this method employs 3DCT scans of a high precision micro-focus and a high energy macro-focus x-ray source. The presented work makes use of the advantages of dual x-ray exposure technology in order to facilitate dimensional measurements of multi-material components with high density material within low density material. We propose a workflow which uses image fusion and local surface extraction techniques: a prefiltering step reduces noise inherent in the data. For image fusion the datasets have to be registered. In the fusion step the benefits of both scans are combined. The structure of the specimen is taken from the low precision, blurry, high energy dataset while the sharp edges are adopted and fused into the resulting image from the high precision, crisp, low energy dataset. In the final step a reliable surface model is extracted from the fused dataset using a local adaptive technique. The major contribution of this paper is the development of a specific workflow for dimensional measurements of multi-material industrial components, which takes two x-ray CT datasets with complementary strengths and weaknesses into account. The performance of the workflow is discussed using a test specimen as well as two real world industrial parts. As result, a significant improvement in overall measurement precision, surface geometry and mean deviation to reference measurement compared to single exposure scans was facilitated.

Original languageEnglish
Pages (from-to)1520-1527
Number of pages8
JournalIEEE Transactions on Visualization and Computer Graphics
Issue number6
Publication statusPublished - Nov 2007


  • DECT image fusion
  • Dimensional measurement
  • Dual energy CT
  • Local surface extraction
  • Metrology
  • Variance comparison


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