Characterization and Correction of Geometric Errors Induced by Thermal Drift in CT Measurements

Abstract:

The occurrence of thermal drift in industrial computed tomography (CT) systems has been reported as a significant source of error on geometrical evaluations. During CT-scans, heating inside the cabinet and varying environmental conditions may affect the position of the focal spot and distort the manipulator system, leading to relative displacement of X-ray projections and distortions in the reconstructed 3D image. This paper presents an experimental investigation on influence of the thermal effects on dimensional CT measurements. A correction method based on the manipulation of the projections was developed and evaluated. The method consists in repeating the acquisition of first projection at the end of the scan and calculating the displacement vector between these projections. The remaining projections are then corrected proportionally to this displacement. The results showed a significant reduction of the roundness deviation values measured on a precision sphere after the correction.

• Periodical: Key Engineering Materials (Volume 613)
• Pages: 327-334
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.613.327
• Online since: May 2014
• Authors: Fabrício Borges de Oliveira, Maurício de Campos Porath, Vitor Camargo Nardelli, Francisco Augusto Arenhart, Gustavo Daniel Donatelli
• Keywords: Computed Tomography, Dimensional Metrology, Thermal Drift, Thermal Errors

References

[1] Welkenhuyzen, F., Kiekens, K., Pierlet, M., Dewulf, W., Bleys, P., Kruth, J.P. and Voet, A., Industrial Computer Tomography for Dimensional Metrology: Overview of Influence Factors and Improvement Strategies, Proc. of 4th International Conference on Optical Measurement Techniques (OPTIMESS2009), Antwerp, Belgium, (2009).

DOI: 10.1088/0957-0233/22/11/115502

[2] Weiβ, D., Lettenbauer, H., Optimized CT metrology through adaptive image processing techniques, Proc. XII. International Colloquium on Surfaces, Chemnitz, Germany, (2008).

[3] Steffen, J. P., Fröba T., Reducing the Focal Spot Shift of Microfocus X-ray Tubes to Increase the Accuracy of CT-Based Dimensional Measurement, Abstract in International Symposium on Digital Industrial Radiology and Computed Tomography, Berlin, Germany, (2011).

[4] Kruth, J.P., Bartscher, M., Carmignato, S., Schmitt, R., De Chiffre, L. and Weckenmann, A., Computed Tomography for Dimensional Metrology, Annals of CIRP, Vol 60/1, 821–842, (2011).

DOI: 10.1016/j.cirp.2011.05.006

[5] Kumar, J., Attridge, A., Wood, P. K. C. and Williams, M. A., Analysis of the effect of cone-beam geometry and test object configuration on the measurement accuracy of a computed tomography scanner used for dimensional measurement, Measurement Science and Technology. 22035105, (2011).

DOI: 10.1088/0957-0233/22/3/035105

[6] Canny, J. A computational approach to edge detection, IEEE Trans. Patt. Anal. Machine Intell., vol. PAMI-8, pp.679-698, (1986).

DOI: 10.1109/tpami.1986.4767851

[7] Vogeler, F., Verheecke, W., Voet, A., Kruth, J. -P., Dewulf, W. Positional stability of 2D X-ray images for computed tomography,. International Symposium on Digital Industrial Radiology and Computed Tomography, Berlin, Germany, (2011).

[8] Nardelli, V. C., Arenhart, F. A., Donatelli, G. D., Porath, M. C., Niggemann, C., Schmitt, R., Feature-based analysis for quality assessment of x-ray computed tomography measurements, Measurement Science and Technology. 23105006, (2012).

DOI: 10.1088/0957-0233/23/10/105006

[9] Arenhart, F. A., Donatelli, G. D., Porath, M. C., Nardelli, V. C., Design and Implementation of an Application for the Analysis of Extracted Circumferential Lines,. Proc. of II International Congress on Mechanical Metrology (CIMMEC), Natal, Brazil. (2011).

[10] Arenhart, F. A., Nardelli, V. C., Porath, M. C., Donatelli, G. D., Isenberg, C., Schmitt. R., Design of a multi-wave standard for evaluating the frequency response of CT measuring systems, Proc. 11th International Symposium on Measurement and Quality Control (ISMQC), Cracow, Poland, September 2013 (accepted for publication).

[11] Wheeler, D. J. , Advanced Topics in Statistical Process Control: The Power of Shewhart's Charts., Second Edition. Knoxville, USA. SPC Press, Jan/2004. 484 pages.