Bruit multiplex en gammagraphie par codage

Brunol, J.; Fonroget, J.

doi:10.1016/s0030-4018(97)90015-8

Cited by 18 publications

(3 citation statements)

References 6 publications

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“…On the contrary, when SNR(u,v) >1, the spatial frequencies that are reconstructed depend on the relative position between E(u,v) and M CM [8] is chosen such that the minimum reconstructed source size should be as close as possible to the optimum spatial resolution corresponding to the quantity of information.. Whenever SNR(u,v) <1, c(u,v)=EM = Sups<i(E(u,v).…”

Section: The Reconstruction Processmentioning

confidence: 99%

<title>High-spatial-resolution imaging system for high-energy neutrons in inertial confinement fusion experiments</title>

Delage

Dague

et al. 2001

SPIE Proceedings

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The penumbral imaging technique has proven to be ideally suited for neutron imaging. The French CEA has successfully installed a neutron imaging system at the LLE (Rochester-New York) in June 2000.Images ofthe 14MeV fusion neutrons produced in the target have been recorded in the range 1012 to 1014 with a two-point resolution of 45 micrometers. The detector used was a 1 5cm diameter circular array composed ofplastic scintillator elements. For several ofthe CEA experiments, bubble detectors developed for General Atomics simultaneously recorded neutron images. The SIRINC (Simulation and Reconstruction Imaging Neutron Code) code has been used to unfold neutron images obtained both with the segmented scintillator detector and with the bubble detector. We first describe the experimental setup and detector designs, then compare the sensitivity, quantity of information, and signal to noise ratio for those two detectors. Then raw and unfolded images are presented. The spatial resolution obtained for the unfolded images are estimated and compared for the two detectors types

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Section: The Reconstruction Processmentioning

confidence: 99%

<title>High-spatial-resolution imaging system for high-energy neutrons in inertial confinement fusion experiments</title>

Delage

Dague

et al. 2001

SPIE Proceedings

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“…The code can be an annular thin aperture ( [5], [6], [7], [8]), or concentric annular thin apertures (called a Fresnel-zone, [14]). Sometimes the code function C is approximated by distributional measures, so that the scope of the RTC is enlarged: In [1] or [24] authors use regular grids of pinholes (modeled by ponctual Dirac δ measures).…”

Section: 22mentioning

confidence: 99%

Radon Transform over Cones and Related Deconvolution Problems

Crouzet¹

2001

J. Integral Equations Applications

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We introduce a new kind of radon transform, consisting in integrating a function (to be recovered) over a special family of cones. It is in fact a formal generalization of the "Coded-aperture gammagraphy" imaging method, encountered in medicine and astronomy. We show that it is a natural geometric operation, but which does not have the fine properties of similar integral transform. Nevertheless, several inverse problems (like classical radon transform, deconvolution) are related to it, and also new kinds on integral transforms : essentially the "Quasi-convolution". After this study, where we show that the problem is severely ill-posed (essentially because of insufficient data), an inversion is performed in the case of complete data.

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“…Choose a coordinate system (x, y, z) on the mask such that its origin O coincides with the cen/er of the code. If C is the indicator function of the hole, then the image on the screen is given by the formula Sometimes the code is a small ring-shaped hole (see [2,4,5]) or a system of concentric ring-shaped holes (called Fresnel zones). It is possible to choose, similarly to [6], regular grids of needle-shaped holes or systems of rectilinear cross-cuts as in [3].…”

Section: W Recognition Of Images In Medicine and A Quasi-convolutionmentioning

confidence: 99%