Image reading apparatus and shading correcting method for image reading apparatus
AssigneeCanon Kabushiki Kaisha
InventorsYoshiaki Watanabe, Tsuyoshi Yamauchi, Shigeru Kawasaki
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Abstract
First reference data acquired by reading a first white reference member placed in a read area of a document platen by a line sensor having a plurality of light receiving elements is stored in a storage unit. Second reference data acquired by reading a second white reference member by a capturing unit is compared with the first reference data stored in the storage unit. Output values from the plurality of light receiving elements are subjected to shading correction based on the comparison result.
Claims9
An image reading apparatus comprising:
- a line sensor configured to read an image of a document placed in a read area;
- a storage unit configured to previously store therein first reference data that is acquired by reading a first white reference member by the line sensor;
- a comparison unit configured to compare second reference data that is acquired by reading a second white reference member by the line sensor with the first reference data stored in the storage unit;
- and
- a correction unit configured to perform shading correction of outputs of the line sensor based on a comparison result of the comparison unit.
A shading correcting method for an image reading apparatus including a line sensor, the method comprising the steps of:
- acquiring first reference data by reading a first white reference member placed in a read area of a document by the line sensor;
- acquiring second reference data by reading a second white reference member having a uniform density by the line sensor with a lapse of time after the acquirement of the data;
- and
- comparing the first reference data with the second reference data so as to perform shading correction of output values of the line sensor.
Dependencies are inferred from the claim text.