Image reading apparatus, control method, and computer-readable, non-transitory medium

A control method of an image reading apparatus comprising an image capturing module for capturing a first image and a second image, a reference member provided at a position facing the image capturing module, and a light source that for emitting light to the reference member;

• the method comprising:
• determining whether or not a foreign object appears in a specific image captured by the image capturing module;
• and
• determining whether the foreign object exists on the image capturing module side or on the reference member side, based on an absolute value of a difference between a gradation value in a region included in the first image and corresponding to a region where the foreign object appears and a gradation value in a region included in the second image and corresponding to the region where the foreign object appears when the foreign object appears in the specific image;
• wherein the first image is an image of the reference member captured under illumination of light with a first light quantity from the light source, and the second image is an image of the reference member captured under illumination of light with a second light quantity from the light source, the second light quantity being different from the first light quantity.

A computer-readable, non-transitory medium storing a computer program, wherein the computer program causes an image reading apparatus comprising an image capturing module for capturing a first image and a second image, a reference member provided at a position facing the image capturing module, and a light source for emitting light to the reference member to execute a process, the process comprising:

• determining whether or not a foreign object appears in a specific image captured by the image capturing module;
• and
• determining whether the foreign object exists on the image capturing module side or on the reference member side, based on an absolute value of a difference between a gradation value in a region included in the first image and corresponding to a region where the foreign object appears and a gradation value in a region included in the second image and corresponding to the region where the foreign object appears when the foreign object appears in the specific image;
• wherein the first image is an image of the reference member captured under illumination of light with a first light quantity from the light source, and the second image is an image of the reference member captured under illumination of light with a second light quantity from the light source, the second light quantity being different from the first light quantity.