X-ray medical imaging provides invaluable medical information, while subjecting patients
to hazardous ionizing radiation. The dosage that the patient is exposed to may
be reduced, at the cost of image resolution. A technology that promises lower dosage
for a given resolution is direct conversion digital imaging, typically based on amorphous
Selenium semiconductor. Sufficient exposure should be used for the first exposure to avoid
subsequent exposures; a challenge is then to reduce the necessary exposure for a suitable
image. To quantify how little radiation the detector can reliably discriminate, one needs
an analysis of the variance that 1/f and white noise contribute to the signal of such detectors.
An important consideration is that the dark current, which varies with time, is subtracted from the photo-current, to reduce the spurious spatial variance in the image. In this thesis, the variance that 1/f noise contributes to integrating detectors is analysed, for a very general integrating detector. Experiments were performed to verify the theoretical results obtained for the 1/f noise variance contribution.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-04162010-151504 |
| Date | 19 April 2010 |
| Creators | Meyer, Thomas Johan |
| Contributors | Degenstein, Doug, Dinh, Anh van, Chen, Li, Johanson, Robert E, Kasap, Safa O |
| Publisher | University of Saskatchewan |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-04162010-151504/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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