Image reading apparatus and control method thereof
AssigneeCanon Kabushiki Kaisha
InventorMakoto Arima
Life of this patent
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Abstract
When an auto document feeder feeds an original to an original image reading platen, a CCD line sensor reads the original along the main scanning direction perpendicular to the feeding direction of the original. A string detection circuit detects a streak parallel to the feeding direction in the image. A string correction circuit corrects the detected streak. In particular, for a predetermined number of sub-scanning positions that are located in the same main scanning position as the main scanning position at which the streak has been detected by the string detection circuit and that exist subsequent to the sub-scanning position at which the streak has been detected, correction is performed by the string correction circuit even when no streak is detected by the string detection circuit.
Claims8
An image reading apparatus comprising:
- a feeding unit which feeds an original to an original image reading platen;
- a reading unit which reads the original along a main scanning direction perpendicular to a feeding direction of the original;
- a detecting unit which detects, in accordance with predetermined detection conditions, a streak parallel to the feeding direction in the image read by said reading unit;
- a correcting unit which corrects the streak detected by said detecting unit;
- and
- a control unit which causes said correcting unit to perform correction for a predetermined number of sub-scanning positions that are located in a main scanning position at which the streak has been detected by the detecting unit and that exist subsequent to a sub-scanning position at which the streak has been detected, even when no streak is detected by said detecting unit.
A method for controlling an image reading apparatus comprising the steps of:
- feeding an original to an original image reading platen;
- reading the original along a main scanning direction perpendicular to a feeding direction of the original;
- detecting a streak parallel to the feeding direction in the image in accordance with predetermined detection conditions;
- and
- correcting the detected streak,
- wherein said method further comprises a control step of causing said correcting step to perform correction for a predetermined number of sub-scanning positions that are located in a main scanning position at which the streak has been detected in said detecting step and that exist subsequent to a sub-scanning position at which the streak has been detected, even when no streak is detected in said detecting step.
Dependencies are inferred from the claim text.