US 12,256,046 B2
Controlling inspection of printed material based on reference image and scan image with alignment performed based on the number of feature points in the reference image
Kenichirou Haruta, Chiba (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Nov. 8, 2022, as Appl. No. 18/053,542.
Claims priority of application No. 2021-183017 (JP), filed on Nov. 10, 2021.
Prior Publication US 2023/0142237 A1, May 11, 2023
Int. Cl. H04N 1/00 (2006.01); G06T 7/33 (2017.01)
CPC H04N 1/00068 (2013.01) [G06T 7/337 (2017.01); H04N 1/00039 (2013.01); H04N 1/00087 (2013.01); H04N 1/0044 (2013.01); H04N 1/00702 (2013.01); H04N 1/00015 (2013.01); H04N 1/00045 (2013.01); H04N 1/00074 (2013.01)] 19 Claims
OG exemplary drawing
 
14. A method for controlling an inspection system, the method comprising:
generating a scan image by scanning a printed material including a printed image;
extracting one or more feature points from each of the scan image and a reference image;
performing alignment of the scan image and the reference image based on at least some corresponding pair among the feature points extracted from the scan image and from the reference image having been registered in advance;
carrying out inspection of the printed material by using the reference image having been subjected to the alignment and the scan image having been subjected to the alignment; and
performing processing in accordance with a method selected from among a plurality of methods including at least a first method and a second method in a case where a number of the feature points in the reference image is less than a predetermined number,
wherein the processing is performed such that, in the case where the number of the feature points in the reference image is less than the predetermined number, the alignment using at least the extracted feature points is performed when the first method is selected, and the inspection is then carried out, whereas the inspection is not carried out when the second method is selected.
 
19. A method for controlling an inspection system, the method comprising:
generating a scan image by scanning a printed material including a printed image;
extracting one or more feature points from each of the scan image and a reference image;
performing alignment based on at least one or more corresponding pair among the feature points extracted from the scan image and from the reference image having been registered in advance;
carrying out inspection based on whether or not a difference between a pixel value of a target pixel in the reference image having been subjected to the alignment and a pixel value of a target pixel in the scan image having been subjected to the alignment is not greater than a threshold value; and
performing processing of, in a case where a number of the feature points in the reference image is less than a predetermined number, performing the alignment by using at least a position of a sheet vertex of an area depicting the printed material in the scan image and a position of a sheet vertex of the reference image, and setting the threshold value to a predetermined value.