TY - CONF A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Jechow, Mirko A2 - Thompson, D. O. A2 - Chimenti, D. E. T1 - Concepts for evaluation of image quality in digital radiology T2 - Review of progress in quantitative nondestructive evaluation, volume 31 N2 - Concepts for digital image evaluation are presented for Computed Radiography (CR) and Digital Detector Arrays (DDAs) used for weld inspection. The precise DDA calibration yields an extra ordinary increase of contrast sensitivity up to 10 times in relation to film radiography. Restrictions in spatial resolution caused by pixel size of the DDA are compensated by increased contrast sensitivity. First CR standards were published in 2005 to support the application of phosphor imaging plates in lieu of X-ray film, but they need already a revision based on experiences reported by many users. One of the key concepts is the usage of signal-to-noise (SNR) measurements as equivalent to the optical density of film and film system class. The contrast sensitivity, measured by IQI visibility, depends on three essential parameters: The basic spatial resolution (SRb) of the radiographic image, the achieved signal-to-noise ratio (SNR) and the specific contrast (µeff - effective attenuation coefficient). Knowing these 3 parameters for the given exposure condition, inspected material and monitor viewing condition permits the calculation of the just visible IQI element. Furthermore, this enables the optimization of exposure conditions. The new ISO/FDIS 17636-2 describes the practice for digital radiography with CR and DDAs. It considers the first time compensation principles, derived from the three essential parameters. The consequences are described. PB - American Institute of Physics CY - Melville, NY T2 - 38th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Burlington, VT, USA DA - 2011-07-17 KW - Image resolution KW - Inspection KW - Production engineering computing KW - Radiography KW - Welding KW - X-ray imaging KW - ZfP KW - Radiographie KW - Bildqualität KW - Filmersatz KW - Digitale Detektoren PY - 2012 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/26697 AN - OPUS4-26697 SN - 978-0-7354-1013-8 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1430 SP - 589 EP - 596 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany