Contribution of noise to the variance of integrating detectors

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Date
2010-04Author
Meyer, Thomas Johan
Type
ThesisDegree Level
MastersMetadata
Show full item recordAbstract
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.
Degree
Master of Science (M.Sc.)Department
Electrical EngineeringProgram
Electrical EngineeringSupervisor
Johanson, Robert E; Kasap, Safa OCommittee
Degenstein, Doug; Dinh, Anh van; Chen, LiCopyright Date
April 2010Subject
CDS
X-ray imaging
1/f noise