Contribution of noise to the variance of integrating detectors
Date
2010-04
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Degree Level
Masters
Abstract
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.
Description
Keywords
CDS, X-ray imaging, 1/f noise
Citation
Degree
Master of Science (M.Sc.)
Department
Electrical Engineering
Program
Electrical Engineering