US 11,872,071 B2
Method for correcting a spectral image
Odran Pivot, Grenoble (FR); Joachim Tabary, Grenoble (FR); Clarisse Fournier, Grenoble (FR); Jean Michel Letang, Villeurbanne (FR); and Simon Rit, Villeurbanne (FR)
Assigned to COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES, Paris (FR); CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, Paris (FR); and INSTITUT NATIONAL DES SCIENCES APPLIQUEES DE LYON, Villeurbanne (FR)
Appl. No. 17/283,446
Filed by COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES, Paris (FR); CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE, Paris (FR); and INSTITUT NATIONAL DES SCIENCES APPLIQUEES DE LYON, Villeurbanne (FR)
PCT Filed Oct. 7, 2019, PCT No. PCT/FR2019/052376
§ 371(c)(1), (2) Date Apr. 7, 2021,
PCT Pub. No. WO2020/074820, PCT Pub. Date Apr. 16, 2020.
Claims priority of application No. 1859368 (FR), filed on Oct. 9, 2018.
Prior Publication US 2021/0364663 A1, Nov. 25, 2021
Int. Cl. A61B 6/00 (2006.01); G01N 23/041 (2018.01); G01N 23/10 (2018.01); G01N 23/18 (2018.01); G01N 23/20066 (2018.01); G01N 23/201 (2018.01); G01T 1/16 (2006.01); G01T 1/36 (2006.01); G01N 23/20091 (2018.01); G01T 1/29 (2006.01); A61B 6/06 (2006.01); G01N 23/04 (2018.01); G01N 23/046 (2018.01)
CPC A61B 6/5282 (2013.01) [A61B 6/06 (2013.01); A61B 6/4035 (2013.01); A61B 6/4208 (2013.01); A61B 6/482 (2013.01); A61B 6/483 (2013.01); A61B 6/5258 (2013.01); A61B 6/585 (2013.01); G01N 23/04 (2013.01); G01N 23/046 (2013.01); G01N 23/201 (2013.01); G01N 23/20066 (2013.01); G01N 23/20091 (2013.01); G01T 1/295 (2013.01); G01T 1/2914 (2013.01); G01T 1/36 (2013.01); G01N 2223/401 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method for correcting a spectral image formed by ionizing electromagnetic radiation transmitted by an object, the object being placed between a radiation source and a detector, the radiation source being configured to emit incident ionizing electromagnetic radiation toward the object;
the detector comprising pixels, each pixel being configured to detect ionizing electromagnetic radiation transmitted by the object to the detector, and to measure an energy spectrum thereof, the transmitted ionizing electromagnetic radiation comprising scattered radiation caused by scattering of the incident ionizing electromagnetic radiation in the object and primary radiation; and
a mask being interposed between the radiation source and the object, the mask comprising absorbent elements configured to attenuate one portion of the incident ionizing electromagnetic radiation, a projection of each absorbent element onto the detector forming one shadow region, such that the detector comprises a plurality of shadow regions that are spaced apart from one another, each shadow region corresponding to at least one pixel;
the method comprising:
a) irradiating the object and measuring, using the pixels of the detector, an energy spectrum representative of the ionizing electromagnetic radiation transmitted by the object;
b) defining a spatial model of an energy spectrum of the scattered radiation, so as to obtain, for various pixels of the detector, an estimate of the energy spectrum of the scattered radiation detected by each pixel, the spatial model being defined by parameters;
c) taking into account a cost function, the cost function being defined for various pixels and taking into account, for each pixel, a spatial variation in an estimate of an energy spectrum of the primary radiation that would be transmitted by the object in an absence of the mask, the estimate of the energy spectrum of the primary radiation in the absence of the mask being obtained by comparing, for each pixel:
the energy spectrum measured by each pixel in a), and
an estimate of the energy spectrum of the scattered radiation, wherein the estimate is obtained using the spatial model resulting from b);
d) determining the parameters of the spatial model, for which the cost function is minimal or maximal;
e) for at least one pixel, estimating the energy spectrum of the scattered radiation reaching each pixel, by applying the determined parameters of the spatial model resulting from d); and
for at least one pixel, correcting the energy spectrum measured in a) using the estimate of the energy spectrum of the scattered radiation resulting from e), so as to obtain a corrected energy spectrum corresponding to an estimate of the energy spectrum of the primary radiation reaching each pixel.