US 12,380,552 B2
Apparatus for inspecting defect of printed material, method, and storage medium
Tsubasa Ochiai, Chiba (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Mar. 29, 2022, as Appl. No. 17/707,670.
Claims priority of application No. 2021-061103 (JP), filed on Mar. 31, 2021.
Prior Publication US 2022/0318976 A1, Oct. 6, 2022
Int. Cl. G06T 7/00 (2017.01)
CPC G06T 7/001 (2013.01) [G06T 2207/10008 (2013.01); G06T 2207/30124 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An apparatus for inspecting a read image obtained by reading a printed sheet, the apparatus comprising:
a storage storing a lower limit value for each of a plurality of threshold values for inspection of the read of the printed sheet to be inspected; and
a controller, including a processor that executes instructions stored in a memory or including a circuitry, configured to:
calculate, for each contrast value in a designated range of contrast values for a blank-sheet read image obtained by reading a blank sheet of each sheet type including at least a first sheet type and a second sheet type, a maximum size of a pixel group representing a foreign substance included in the blank-sheet read image of the each sheet type;
store in the storage the calculated maximum size as a lower limit value for the each contrast value for the each sheet type;
register a reference image;
inspect the read image of the printed sheet based on at least the registered reference image and an inspection setting related to a set threshold value for the inspection; and
apply a different lower limit value to the set threshold value for the inspection depending on a sheet type of the printed sheet.