Optimum exposure conditions for computed radiography depending on fixed pattern noise and efficiency of imaging plate-scanner systems
- The presently active standards on Computed Radiography (CR) need a major revision. It was observed by many users that the image quality for class B of EN 14784-2 is not achievable under the same exposure conditions as used for film exposure. A mathematical model was developed and tested, which allows the calculation of the image quality, proven by image quality indicators (IQI), depending on the fixed pattern noise and the efficiency of the used imaging plate (IP) scanner system. All tested IP scanner systems provide a fixed correlation between the measured signal/noise ratio (SNR) and the grey values in the digital images. The maximum achievable SNRmax depends on the fixed pattern noise of the plate (high dose limit). Depending on the exposure dose an optimum visibility of IQIs can be predicted by calculation and measured considering the attenuation coefficient for calculation of the contrast/noise ratio (CNR). The diameter of the just visible wire is proportional to 1/sqrt(CNR). TheThe presently active standards on Computed Radiography (CR) need a major revision. It was observed by many users that the image quality for class B of EN 14784-2 is not achievable under the same exposure conditions as used for film exposure. A mathematical model was developed and tested, which allows the calculation of the image quality, proven by image quality indicators (IQI), depending on the fixed pattern noise and the efficiency of the used imaging plate (IP) scanner system. All tested IP scanner systems provide a fixed correlation between the measured signal/noise ratio (SNR) and the grey values in the digital images. The maximum achievable SNRmax depends on the fixed pattern noise of the plate (high dose limit). Depending on the exposure dose an optimum visibility of IQIs can be predicted by calculation and measured considering the attenuation coefficient for calculation of the contrast/noise ratio (CNR). The diameter of the just visible wire is proportional to 1/sqrt(CNR). The optimum tube voltage for best visibility of IQIs and maximum CNR depend on the exposure dose. The optimum tube voltage for best visibility is achieved only at exposures with high dose. A dose dependant optimal tube voltage was not observed for film radiography.…
Autor*innen: | Uwe Ewert, Klara Heyne, Uwe ZscherpelORCiD, Mirko Jechow, K. Bavendiek |
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Persönliche Herausgeber*innen: | D.O. Thompson, D.E. Chimenti |
Dokumenttyp: | Beitrag zu einem Tagungsband |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | Review of progress in quantitative nondestructive evaluation, volume 30 |
Jahr der Erstveröffentlichung: | 2011 |
Verlag: | American Institute of Physics |
Verlagsort: | Melville, NY |
Ausgabe/Heft: | 1335 |
Erste Seite: | 493 |
Letzte Seite: | 500 |
Freie Schlagwörter: | Computed radiography; Computed radiology; Contrast-to-noise ratio; Image quality; Imaging plates; Non destructive testing; Optimum tube voltage; Signal-to-noise ratio; Standards |
Veranstaltung: | 37th Annual Review of Progress in Quantitative Nondestructive Evaluation |
Veranstaltungsort: | San Diego, CA, USA |
Beginndatum der Veranstaltung: | 18.07.2010 |
Enddatum der Veranstaltung: | 23.07.2010 |
DOI: | 10.1063/1.3591892 |
ISSN: | 0743-0760 |
ISSN: | 0094-243X |
ISBN: | 978-0-7354-0888-3 |
Bemerkung: | Serientitel: AIP conference proceedings – Series title: AIP conference proceedings |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 20.02.2016 |
Referierte Publikation: | Ja |
Datum der Eintragung als referierte Publikation: | 10.01.2013 |