Article Article
Computational Technique for the Qualification of Focal Spot Size and Shape of Industrial Radioscopy Equipment Using Star Patterns

This paper presents a focal spot qualification technique for industrial radioscopy equipment employing star pattern testing devices. The results indicate that star patterns are more reliable than alternative end-user methodologies for anisotropy evaluations, and that they have the same capacity to determine focal spot size as the technique described in ASTM E1165 (2012). The research is based on the edge detection technique, a well-known computational technique. This suggests an alternative way to calculate focal spots, which can be applied to other practices in nondestructive testing such as digital radiography and computed tomography. The proposed focal spot evaluation with star patterns employing the edge detection technique has proven to be in good agreement with the integrated line profile (IPL) technique, recommended in ASTM E1165. In this study, we have used a known-size tungsten ball (sphere) as a testing device. The star pattern test presented mean and standard deviation values below 5%, which indicates a strong compatibility with the technique described in ASTM E1165.



ABNT, 2011, NBR IEC 60601-2-7, Medical Electrical Equipment, Part 2-7: Particular Requirements for the Safety of High-Voltage Generators of Diagnostic X-ray Generators, Associação Brasileira De Normas Técnicas.

ASTM, 2009a, ASTM E1000-1998-R2009: Standard Guide for Radioscopy, American Society for Testing and Materials, West Conshohocken, PA.

ASTM, 2009b, ASTM E1411-2009: Standard Practice for Qualification of Radioscopic Systems, American Society for Testing Materials, West Conshohocken, PA.

ASTM, 2012, ASTM E1165, Standard Test Method for Measurement of Focal Spots of Industrial X-ray Tubes by Pinhole Imaging, West Conshohocken, PA.

Bavendiek, K., U. Ewert, A. Riedo, U. Heike, and U. Zscherpel, 2012, “New Measurement Methods of Focal Spot Size and Shape of X-ray Tubes in Digital Radiological Applications in Comparison to Current Standards,” 18th World Conference on Nondestructive Testing, Durban, South Africa.

Beserra, M.T.F., 2018, “Methodology for the Qualification of Industrial Radioscopy Equipment,” doctoral thesis, Federal University of Rio de Janeiro, Brazil.

Fluke Biomedical, 2005, Radiographic and Mammographic Focal Spot Measurements Products, Manual No. 38659.

BSI, 1999, BS EN 12543-5-1999: Non-Destructive Testing–Characteristics of Focal Spots in Industrial X-ray Systems for Use in Non-Destructive Testing–Measurement of the Effective Focal Spot Size of Mini and Micro Focus X-Ray Tubes, British Standards Institution, London, United Kingdom.

Carmignato, S., W. Dewulf, and R. Leach, 2018, Industrial X-ray Computed Tomography, Springer International Publishing, New York City, NY.

Dahi, B., 2009, “Spatial Resolution Analysis of a Variable Resolution X-ray Cone-Beam Computed Tomography System,” Ph.D. thesis, University of Tennessee, doi: 10.21007/etd.cghs.2009.0063.

González-López, A., and C. Ruiz-Morales, 2015, “Technical Note: MTF Determination from a Star Bar Pattern Image,” Medical Physics: The International Journal of Medical Physics Research and Practice, Vol. 42, No. 9, pp. 5060–5065.

IEC, 2005, IEC 60336-2005: Medical Electrical Equipment–X-ray Tube Assemblies for Medical Diagnosis–Characteristics of Focal Spots, International Electrotechnical Commission, Geneva, Switzerland.

ISO, 2011, EN 12543-2: Non-Destructive Testing–Characteristics of Focal Spots in Industrial X-ray Systems for Use in Non-Destructive Testing–Pinhole Camera Radiographic Method, International Organization for Standardization, Geneva, Switzerland.

Leeds Test Objects Ltd., 2011, Star Test Patterns (User Manual), North Yorkshire, United Kingdom.

Maini, R., and H. Aggarwal, 2009, “Study and Comparison of Various Image Edge Detection Techniques,” International Journal of Image Processing, Vol. 3, No. 1, pp. 1–11.

Marr, D., and E. Hildreth, 1980, “Theory of Edge Detection,” Proceedings of the Royal Society of Biological Sciences, Vol. 207, pp. 187–217.

Mery, D., 2015, Computer Vision for X-ray Testing: Imaging, Systems, Image Databases, and Algorithms, Springer International Publishing, Switzerland.

Norbert, D., and B. Schanklies, n.d., “X-ray Inspection: Evolution from Microfocus to Nanofocus,” Solid State Technology, available at Accessed 15 January 2018.

Raad, J.A., 2006, Industrial Radiography: Image Forming Techniques, GE Inspection Technologies, No. GEIT-30158EN.

Weiß, D., Q. Shi, and C. Kuhn, 2012, “Measuring the 3D Resolution of a Micro-Focus X-ray CT Setup,” Industrial Computed Tomography, Wels, Austria.

Usage Shares
Total Views
40 Page Views
Total Shares
0 Tweets
0 PDF Downloads
0 Facebook Shares
Total Usage