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Proceedings Paper

Noise power spectrum measurements under nonuniform gains and their compensations
Author(s): Dong Sik Kim; Eun Kim; Choul Woo Shin
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Paper Abstract

The fixed pattern noise, which is due to the nonuniform amplifier gains and scintillator sensitivities, should be alleviated in radiography imaging and should have less influence on measuring the noise power spectrum (NPS) of the radiography detector. In order to reduce the influence, background trend removing methods, which are based on low-pass filtering, polynomial fitting, and subtracting the average image of the uniform exposure images, are traditionally employed in the literature. In terms of removing the fixed pattern noise, the subtraction method shows a good performance. However, the number of images to be averaged is practically finite and thus the noise contained in the average image contaminates the image difference and inflates the NPS curve. In this paper, an image formation model considering the nonuniform gain is constructed and two measuring methods, which are based on the subtraction and gain correction, respectively, are considered. In order to accurately measure a normalized NPS (NNPS) in the measuring methods, the number of images to be averaged is considered for NNPS compensations. For several flat-panel radiography detectors, the NNPS measurements are conducted and compared with conventional approaches, which have no compensation stages. Through experiments it is shown that the compensation can provide accurate NNPS measurements less influenced by the fixed pattern noise.

Paper Details

Date Published: 29 March 2016
PDF: 9 pages
Proc. SPIE 9783, Medical Imaging 2016: Physics of Medical Imaging, 97833S (29 March 2016); doi: 10.1117/12.2216685
Show Author Affiliations
Dong Sik Kim, Hankuk Univ. of Foreign Studies (Korea, Republic of)
Eun Kim, DRTECH Co. (Korea, Republic of)
Choul Woo Shin, DRTECH Co. (Korea, Republic of)

Published in SPIE Proceedings Vol. 9783:
Medical Imaging 2016: Physics of Medical Imaging
Despina Kontos; Thomas G. Flohr, Editor(s)

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