Industrial radiography is a very mature non-destructive testing (NDT) technique for volumetric investigation. It provides high throughput in inspection particularly for aircraft structural components and, therefore, an important NDT tool for aircraft structural maintenance. Use of film for NDT applications is gradually diminishing because of time, increased cost, and the lack of digital advantages. Industrial radiography community is making an intense effort to replace the conventional film technique with digital technologies (e.g., computed radiography or CR) which allow faster/easier image acquisition digitally. Despite numerous benefits when compared to conventional film-based radiography, its widespread application still poses significant challenges (e.g. cost, steep learning curve, lack of procedures to choose parameters, lack of demonstrated system performance, imaging artifacts, etc.). Before replacing film-based radiography with CR, performance assessment of the new technology is required to determine if the current CR technology can effectively provide equal or better performance than the existing film-based technology. This paper highlights the existing CR qualification practices, lessons learned and key issues faced while performing experimental validation for qualification of a computed radiography system in accordance with ASTM E2445 standard. The major CR system quality parameters such as spatial resolution, contrast sensitivity, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), as well as other system hardware integrity parameters were measured as part of qualification process and assessment of suitability of CR for aerospace applications.
1. Korner, M., et al., “Advances in digital radiography: Physical principles and system overview”, Radiographics 27:675–686, 2007.
2. Nondestructive Inspection Methods, Basic Theory, NAVAIR Technical Manual T.O.33B-1-1, May 2014.
3. Khan, M., “Film and Digital Radiography System” NRC Technical Report LM-SMPL-2010-0032, February, 2010.
4. Federal Working Group on Industrial Digital Radiography “Guide for the Qualification of Digital Radiography Systems and Processes”, Paper No. 002-12, February 2012.
5. ASTM E2445 / E2445M-14, Standard Practice for Performance Evaluation and Long-Term Stability of Computed Radiography Systems, ASTM International, West Conshohocken, PA, 2014, www.astm.org.
6. Ewert, U. et al., “Performance Control, Nondestructive Testing and Reliability Evaluation”, in Springer Handbook of Metrology and Testing, (Ed. Czichos, H., Saito, T., Smith, L), pp-904, Springer, Heidelberg, 2006.
7. Hussein, E.M.A., “Handbook on Radiation Probing, Gauging, Imaging and Analysis, Volume I: Basics and Techniques”, Kluwer Academic Publishers, May 2003, pp: 276.
8. NDT Wiki X-ray – the Digital X-ray Encyclopedia, www.vidisco.com [Accessed November 2015].
9. ASTM E1647-03, “Standard Practice for Determining Contrast Sensitivity in Radioscopy”, ASTM International, West Conshohocken, PA, 2003, www.astm.org.
10. ASTM E746-07(2014), “Standard Practice for Determining Relative Image Quality Response of Industrial Radiographic Imaging Systems”, ASTM International, West Conshohocken, PA, 2014, www.astm.org
11. International Standard 16371-1:2011 “Nondestructive Testing Industrial Computed Radiography with Storage Phospor Imaging Plates, Part 1 Classification of Systems”, ISO, Switzerland 2011.
12. LaCivita, K.J., “Development of the USAF Computed Radiography (CR) Process Control”, Air Force Research Laboratory Technical Report AFRL-RX-WP-TR-2009-4069, November, 2008.
13. Papp, J., “Quality Management in the Imaging Science”, Elsevier Health Sciences, Sep 30, 2014.
14. Mango, S.A., “How to Evaluate Radiographic Performance and Long-Term Stability of A Computed Radiography System”, V Pan American Conference on NDT, Buenos Aires, October 2007.
15. “Certification of CR Imaging Plate HD-CR 35 NDT Plus using Imaging Plates UH-IP”, Federal Institute for Materials Research and Testing, (BAM) Germany, May 2015.
424 Page Views
0 PDF Downloads
1 Facebook Shares