US 11,988,616 B2
CT scanner calibration
Sergey Nikolskiy, Coto de Caza, CA (US); Fedor Chelnokov, Khimki (RU); and Grant Karapetyan, Moscow (RU)
Assigned to James R. Glidewell Dental Ceramics, Inc., Newport Beach, CA (US)
Filed by James R. Glidewell Dental Ceramics, Inc., Newport Beach, CA (US)
Filed on Feb. 16, 2023, as Appl. No. 18/170,309.
Application 18/170,309 is a continuation of application No. 16/887,437, filed on May 29, 2020, granted, now 11,585,766.
Prior Publication US 2023/0194442 A1, Jun. 22, 2023
Int. Cl. G01N 23/046 (2018.01); A61B 6/51 (2024.01); G01N 23/083 (2018.01)
CPC G01N 23/046 (2013.01) [A61B 6/51 (2024.01); G01N 23/083 (2013.01); G01N 2223/04 (2013.01); G01N 2223/303 (2013.01); G01N 2223/419 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A method of determining CT calibration settings, the method comprising:
receiving a plurality of radiographs from a CT scanner;
determining a location of a plurality of calibration objects in a first projection of the plurality of radiographs;
tracking a trajectory of each calibration object of the plurality calibration objects across a plurality of projections;
determining a projective transformation of each calibration object in the plurality of radiographs;
determining trajectory parameters from the projective transformation of each calibration object; and
determining one or more CT scanner calibration parameters from the trajectory parameters prior to CT reconstruction of the plurality of radiographs,
wherein determining the location of the plurality of calibration objects in the first projection comprises:
determining a histogram of pixel values in the first projection;
determining pixel values belonging to a first calibration object projection from the histogram; and
determining a first calibration object projection center from the pixel values belonging to one of the calibration objects in the first projection.