Sinogram interpretability based CT artefact reduction for multi-material workpieces

Nondestructive Testing And Evaluation, vol. 37, pp. 679–691

Abstract

Computed tomography (CT) is a technology for the simultaneous inspection of internal and external features of workpieces. However, beam hardening and scattered radiation artefacts caused by the different material densities and atomic numbers commonly confound CT measurements of multi-material workpieces. Multispectral CT (MSP CT) measurements reduce artefacts by combining multiple CT volumes performed with different x-ray spectra. However, all known simulation-based CT parameter optimisation approaches for industrial applications consider only the single-spectrum case. This paper investigates the CT radon space, focusing on sinogram interpretability. Multispectral CT x-ray spectra can be determined by defining and analysing sinogram areas corresponding to equivalent volume slice artefacts. Validation indicates that the two MSP CT spectra recommended via a proposed CT simulation considering critical sinogram areas cause an artefact reduction. Results are quantified by a standard deviation reduction of measured geometrical features.

Authors 4

1. Natalia Grozmani corresponding Aachen Chair of Production Metrology and Quality Management

   RWTH Aachen University

   Affiliation as printed

   WZL , RWTH Aachen University, Chair of Production Metrology and Quality Management, Aachen, Germany

2. D. Chupina Aachen Chair of Production Metrology and Quality Management

   RWTH Aachen University

   Affiliation as printed

   WZL , RWTH Aachen University, Chair of Production Metrology and Quality Management, Aachen, Germany

3. Benjamin Montavon Aachen Chair of Production Metrology and Quality Management

   RWTH Aachen University

   Affiliation as printed

   WZL , RWTH Aachen University, Chair of Production Metrology and Quality Management, Aachen, Germany

4. Robert Heinrich Schmitt Aachen Department of Production Metrology and Quality Management Fraunhofer Institute for Production Technology IPT Chair of Production Metrology and Quality Management

   Fraunhofer Institute for Production Technology IPT · RWTH Aachen University

   Affiliation as printed

   Department of Production Metrology and Quality Management, Fraunhofer Institute for Production Technology IPT, Aachen, Germany

   WZL , RWTH Aachen University, Chair of Production Metrology and Quality Management, Aachen, Germany