title: Noise correlations in images acquired simultaneously with a dual-energy sandwich detector.
abstract: 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 Na1 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.
authors.affiliation: Department of Radiology, Mt. Sinai Medical Center, Cleveland, Ohio 44106.
authors.forename: R A
authors.initials: RA
authors.lastname: Sones
authors.forename: G T
authors.initials: GT
authors.lastname: Barnes
mesh_terms: D011856:Radiographic Image Enhancement / Q000295:instrumentation* / Q000379:methods; D013382:Subtraction Technique