| Zugriffsnummer | 11235 |
| Dokumenttyp | Konferenzartikel |
| Sprache | Englisch |
| Titel | Measurement of correlated noise in images of computed radiography systems and its influence to the detective quantum efficiency |
| Autor(in); Institution |
Illers, Hartmut; 4.2, Bild- und Wellenoptik, PTB-Braunschweig
Vandenbroucke, Dirk; Agfa Gevaert N.V., Mortsel, BELGIUM
Buhr, Egbert; 4.2, Bild- und Wellenoptik, PTB-Braunschweig
|
| Quelle/Jahr | Medical imaging 2004 - Physics of medical imaging:(2004), 639 - 647 |
| Schriftenreihe | Proceedings of SPIE: 5368,1 ; Progress in biomedical optics and imaging: 5,22 |
| Herausgeber(in) |
Yaffe, Martin J.
|
| ISSN | 0277-786X ; 1605-7422 |
| ISBN | 0-8194-5281-5 |
| Verlag | Bellingham, Wash.: SPIE |
| Konferenzangaben | SPIE's International Symposium Medical Imaging, San Diego, 15-17, February, 2004, USA |
| Freie Schlagworte | computed radiography CR ; noise power spectrum NPS ; correlated noise ; fixed pattern noise ; flat field correction ; detective quantum efficiency DQE |
| Zusammenfassung | The contributors to image noise of two computed radiography (CR) detector systems - a state-of-the-art and a well-chosen laboratory CR image plate - were studied by two different methods. Method 1 analyzes the image noise content of a series of images obtained at a wide range of different X-ray exposure levels. It uses a model to fit the observed exposure dependence of the normalized noise power spectrum (NNPS): It distinguishes between an NNPS component that is independent of the exposure level and mainly due to correlated noise, and an NNPS component which is inversely porportional to the exposure level and consists mainly of quantum noise. Method 2 analyzed several images taken at the same exposure level and distinguishes between correlated noise, which remains unchanged in repeated exposures, and uncorrelated noise which is different in each image. The results of the two methods allowed the relevant noise contributions in CR images to be quantitatively determined. The novel laboratory image plate showed a significant reduction of correlated noise with an accompanying increase in the DQE. The results also served to estimate a possible improvement of DQE if an appropriate flat field corrections is made for these CR systems. |
