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US 10,567,621 B2Granted
Image reading apparatus
AssigneeCanon Kabushiki Kaisha
InventorsDaisuke Akagi, Katsuhiro Ishido
Life of this patent
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Abstract
An original image is read as an aggregate of a plurality of pixels in which adjacent pixels have different colors (R, G, and B) in a main scanning direction and in a sub-scanning direction, and the read pixels of the respective colors are stored in a line memory in association with information on relative positions of the pixels with respect to another pixel. Then, the stored pixels are sorted so that pixels having the same color are adjacent to each other, and an abnormal pixel (dust) not present in the original image is detected based on the state of the sorted pixels. With this, the dust not present in the original image is detected without increasing the cost, and the dust is corrected without forming a conspicuous trace of correction.
Claims15
An image reading apparatus, comprising:
- a sensor to receive reflected light from an object, the sensor including first and second line sensors,
- the first line sensor including a first plurality of light receiving elements, being arranged in a first direction, which include a light receiving element receiving light of a first color and a light receiving element receiving light of a second color that is different from the first color
- the second line sensor including a second plurality of light receiving elements, being arranged in the first direction, which include a light receiving element receiving light of the first color and a light receiving element receiving light of the second color, and
- the first line sensor and the second line sensor being arranged at a predetermined interval in a second direction orthogonal to the first direction;
- a processor;
- and
- a memory storing instructions which, when executed by the processor, cause the processor:
- to detect an abnormal pixel of the first color based on:
- image data of a first light receiving element receiving light of the first color which is disposed at a first position in the first direction in the first line sensor;
- and
- image data of a second light receiving element receiving light of the first color which is disposed at a second position in the first direction in the second line sensor, the second position being a position which is different from the first position in the first direction, and
- to detect an abnormal pixel of the second color based on:
- image data of a third light receiving element receiving light of the second color which is disposed at a third position in the first direction in the first line sensor;
- and
- image data of a fourth light receiving element receiving light of the second color which is disposed at a fourth position in the first direction in the second line sensor, the fourth position being a position which is different from the third position in the first direction.
12 more elements
An image forming apparatus, comprising:
- a sensor to receive reflected light from an object, the sensor including first and second line sensors,
- the first line sensor including a first plurality of light receiving elements, being arranged in a first direction, which include a light receiving element receiving light of a first color and a light receiving element receiving light of a second color that is different from the first color
- the second line sensor including a second plurality of light receiving elements, being arranged in the first direction, which include a light receiving element receiving light of the first color and a light receiving element receiving light of the second color, and
- the first line sensor and the second line sensor being arranged at a predetermined interval in a second direction orthogonal to the first direction;
- an image forming unit configured to form image on a sheet based on a receiving result of the sensor;
- a processor;
- and
- a memory storing instructions which, when executed by the processor, cause the processor:
- to detect an abnormal pixel of the first color based on:
- image data of a first light receiving element receiving light of the first color which is disposed at a first position in the first direction in the first line sensor;
- and
- image data of a second light receiving element receiving light of the first color which is disposed at a second position in the first direction in the second line sensor, the second position being a position which is different from the first position in the first direction, and
- to detect an abnormal pixel of the second color based on:
- image data of a third light receiving element receiving light of the second color which is disposed at a third position in the first direction in the first line sensor;
- and
- image data of a fourth light receiving element receiving light of the second color which is disposed at a fourth position in the first direction in the second line sensor, the fourth position being a position which is different from the third position in the first direction.
13 more elements
An image reading apparatus, comprising:
- a sensor to receive reflected light from an object, the sensor including a first line sensor, a second line sensor and a third line sensor,
- the first line sensor including a plurality of light receiving elements, being arranged in a first direction, which include a light receiving element receiving light of a first color, a light receiving element receiving light of a second color that is different from the first color and a light receiving element receiving light of a third color that is different from both the first color and the second color,
- the second line sensor including a plurality of light receiving elements, being arranged in the first direction, which include a light receiving element receiving light of the first color, a light receiving element receiving light of the second color, and a light receiving element receiving light of the third color,
- the third line sensor including a plurality of light receiving elements, being arranged in the first direction, which include a light receiving element receiving light of the first color, a light receiving element receiving light of the second color, and a light receiving element receiving light of the third color, and
- the first line sensor, the second line sensor and the third line sensor being arranged at a predetermined interval in a second direction orthogonal to the first direction;
- in the first line sensor, the second line sensor and the third line sensor, a light receiving element receiving light of the first color, a light receiving element receiving light of the second color, and a light receiving element receiving light of the third color being periodically arranged in the first direction, and
- a light receiving element disposed on a first position in the first direction in the first line sensor, a light receiving element disposed on the first position in the first direction in the second line sensor and a light receiving element disposed on the first position in the first direction in the third line sensor being light receiving elements each of which receives different light with each other,
- a processor;
- and
- a memory storing instructions which, when executed by the processor, cause the processor:
- to detect an abnormal pixel of a first color based on:
- image data of a first light-receiving-element receiving light of the first color which is disposed at a second position in the first direction in the first line sensor;
- image data of a second light-receiving-element receiving light of the first color which is disposed at a third position in the first direction in the second line sensor;
- and
- image data of a third light-receiving-element receiving light of the first color which is disposed at a fourth position in the first direction in the third line sensor,
- the second position, the third position and the fourth position being different positions with each other.
13 more elements
Dependencies are inferred from the claim text.