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Noise correlations in images acquired simultaneously with a dual‐energy sandwich detector
Author(s) -
Sones Richard A.,
Barnes Gary T.
Publication year - 1989
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.596311
Subject(s) - detector , noise (video) , quantum noise , physics , photon , optics , shot noise , covariance , poisson distribution , energy (signal processing) , computational physics , acoustics , quantum , quantum mechanics , mathematics , statistics , computer science , image (mathematics) , artificial intelligence
An energy discriminating detector for dual‐energy radiography can be configured as a two‐layer sandwich, where the mean energy of photons detected by the two layers differs. To characterize the quantum noise of such a detector, the noise covariance between the two layers must be known in addition to the noise variance in each layer. A theory is presented which permits the calculation of the noise covariance, and it is found to be negligibly small. Experimental results, based on measurements with a Nal sandwich detector and an isotope gamma ray source, are reported and shown to confirm the theory. The quantum noise in each layer is independent and Poisson.