US 11,927,586 B2
Item inspection by radiation imaging using an iterative projection-matching approach
Jan De Beenhouwer, Geraardsbergen (BE); and Jan Sijbers, Duffel (BE)
Assigned to UNIVERSITEIT ANTWERPEN, Antwerp (BE); and IMEC VZW, Leuven (BE)
Appl. No. 17/252,145
Filed by UNIVERSITEIT ANTWERPEN, Antwerp (BE); and IMEC VZW, Leuven (BE)
PCT Filed Jul. 1, 2019, PCT No. PCT/EP2019/067600
§ 371(c)(1), (2) Date Dec. 14, 2020,
PCT Pub. No. WO2020/002705, PCT Pub. Date Jan. 2, 2020.
Claims priority of application No. 18180893 (EP), filed on Jun. 29, 2018.
Prior Publication US 2021/0116434 A1, Apr. 22, 2021
Int. Cl. G06K 9/00 (2022.01); G01N 23/046 (2018.01); G01N 33/36 (2006.01); G06T 7/00 (2017.01)
CPC G01N 33/367 (2013.01) [G01N 23/046 (2013.01); G06T 7/0004 (2013.01); G01N 2223/401 (2013.01); G01N 2223/405 (2013.01); G01N 2223/419 (2013.01); G06T 2207/30124 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A method for inspection of an item, the method comprising:
acquiring a plurality of projection images of said item at a plurality of projection angles, using a radiation imaging device;
obtaining a tomographic reconstruction based on said plurality of projection images;
detecting a plurality of objects in said tomographic reconstruction, each of said plurality of objects having a generic shape described by a parametric three-dimensional numerical model, wherein said detecting comprises determining initial estimates of position and/or orientation of each of said plurality of objects and at least one geometrical parameter of said three-dimensional model for each of said plurality of objects;
iteratively refining said initial estimates by using a projection-matching approach, wherein said refining comprises, at each iteration, simulating forward projection images according to operating parameters of the radiation imaging device at said plurality of projection angles for at least one of the plurality of objects, and reducing a difference metric between acquired projection images and simulated forward projection images.