US4954913A
Expired / Lapsed
US
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Image reading apparatus
Assignee: Canon Inc
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Filing: 1989-01-23
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Granted: 1990-09-04
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Expires: 2009-01-23
Abstract
Abstract An image reading apparatus providing boundary shading correction includes reading circuitry for reading an image line by line and outputting image data, a first moving device for repeatedly moving the reading position of the reading circuitry in a main scanning direction a plurality of times, and a second moving device for moving the reading position of the reading circuitry in a subscanning direction every time the reading position of the reading circuitry is moved in the main scanning direction. Detection circuitry is provided for detecting a difference between image data outputted from the reading circuitry during a preceding movement of the reading position in the main scanning direction and image data outputted from the reading circuitry during a current movement of the reading position in the main scanning direction. Finally, correction circuitry is provided for correcting the image data outputted from the reading circuitry based on the difference detected by the detection circuitry.
Inventors
- 👤 Koji Kajita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:19
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/401
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
142 words
An image reading apparatus comprising: reading means for reading an image line by line and outputting image data; first moving means for repeatedly moving a reading position of said reading means in a main scanning direction a plurality of times; second moving means for moving the reading position of said reading means in a subscanning direction every time the reading position of said reading means is moved in the main scanning direction; detection means for detecting a difference between image data outputted from said reading means during a preceding movement of the reading position in the main scanning direction and image data outputted from said reading means during a current movement of the reading position in the main scanning direction; and correction means for correcting the image data outputted from said reading means based on the difference detected by said detection means.
Claim 2
Dependent Claim
142 words
An image reading apparatus comprising: reading means for reading an image line by line and outputting image data; first moving means for repeatedly moving a reading position of said reading means in a main scanning direction a plurality of times; second moving means for moving the reading position of said reading means in a subscanning direction every time the reading position of said reading means is moved in the main scanning direction; detection means for detecting a difference between image data outputted from said reading means during a preceding movement of the reading position in the main scanning direction and image data outputted from said reading means during a current movement of the reading position in the main scanning direction; and correction means for correcting the image data outputted from said reading means based on the difference detected by said detection means.
Claim 3
Dependent Claim
19 words
An apparatus according to claim 1, wherein said reading means comprises a linear image sensor for reading the image.
Claim 4
Dependent Claim
52 words
An apparatus according to claim 1, wherein said detection means detects a difference of image data in a boundary portion of an image area read by said reading means during the preceding movement and image data in a boundary portion of an image read by said reading means during the current movement.
Claim 5
Dependent Claim
23 words
An apparatus according to claim 1, further comprising storage means for storing image data outputted from said reading means during the preceding movement.
Claim 6
Dependent Claim
51 words
An apparatus according to claim 1, wherein said correction means performs a correction processing so as to provide alignment of a level of the image data outputted from said reading means during the preceding movement and a level of the image data outputted from said reading means during the current movement.
Claim 7
Dependent Claim
45 words
An apparatus according to claim 1, wherein said detection means detects a ratio of a level of the image data outputted from said reading means during the preceding movement and a level of the image data outputted from said reading means during the current movement.
Claim 8
Dependent Claim
131 words
An image reading apparatus comprising: reading means for reading an image line by line and outputting image data; first moving means for repeatedly moving a reading position of said reading means in a main scanning direction a plurality of times; second moving means for moving the reading position of said reading means in a subscanning direction every time the reading position of said reading means is moved in the main scanning direction; storage means for storing image data outputted from said reading means during a preceding movement of the reading position in the main scanning direction; and correction means for correcting image data outputted from said reading means during a current movement of the reading position in the main scanning direction based on the image data stored in said storage means.
Claim 9
Dependent Claim
131 words
An image reading apparatus comprising: reading means for reading an image line by line and outputting image data; first moving means for repeatedly moving a reading position of said reading means in a main scanning direction a plurality of times; second moving means for moving the reading position of said reading means in a subscanning direction every time the reading position of said reading means is moved in the main scanning direction; storage means for storing image data outputted from said reading means during a preceding movement of the reading position in the main scanning direction; and correction means for correcting image data outputted from said reading means during a current movement of the reading position in the main scanning direction based on the image data stored in said storage means.
Claim 10
Dependent Claim
19 words
An apparatus according to claim 7, wherein said reading means comprises a linear image sensor for reading the image.
Claim 11
Dependent Claim
34 words
An apparatus according to claim 7, further comprising detection means for detecting a difference between image data stored in said storage means and image data outputted from said reading means during the current movement.
Claim 12
Dependent Claim
23 words
An apparatus according to claim 9, wherein said correction means performs a correction processing based on the difference detected by said detection means.
Claim 13
Dependent Claim
41 words
An apparatus according to claim 9, wherein said detection means detects a ratio of a level of the image data stored in said storage means and a level of the image data outputted from said reading means during the current movement.
Claim 14
Dependent Claim
50 words
An apparatus according to claim 7, wherein said storage means stores image data of a boundary portion of an image area read by said reading means during the preceding movement and image data of a boundary portion of an image area read by said reading means during the current movement.
Claim 15
Dependent Claim
51 words
An apparatus according to claim 7, wherein said correction means performs a correction processing so as to provide alignment of a level of the image data outputted from said reading means during the preceding movement and a level of the image data outputted from said reading means during the current movement.
Claim 16
Dependent Claim
151 words
An image reading apparatus comprising: reading means for reading an image line by line and outputting image data; first moving means for repeatedly moving a reading position of said reading means in a main scanning direction a plurality of times; second moving means for moving the reading position of said reading means in a subscanning direction every time the reading position of said reading means is moved in the main scanning direction; correction means for correcting a level of image data outputted from said reading means; and control means for controlling a correction processing of said correction means, said control means controlling the correction processing to be provided for image data outputted from said reading means during a current movement of the reading position in the main scanning direction, based on image data outputted from said reading means during a preceding movement of the reading position in the main scanning direction.
Claim 17
Dependent Claim
151 words
An image reading apparatus comprising: reading means for reading an image line by line and outputting image data; first moving means for repeatedly moving a reading position of said reading means in a main scanning direction a plurality of times; second moving means for moving the reading position of said reading means in a subscanning direction every time the reading position of said reading means is moved in the main scanning direction; correction means for correcting a level of image data outputted from said reading means; and control means for controlling a correction processing of said correction means, said control means controlling the correction processing to be provided for image data outputted from said reading means during a current movement of the reading position in the main scanning direction, based on image data outputted from said reading means during a preceding movement of the reading position in the main scanning direction.
Claim 18
Dependent Claim
19 words
An apparatus according to claim 14, wherein said reading means comprises a linear image sensor for reading the image.
Claim 19
Dependent Claim
23 words
An apparatus according to claim 14, further comprising storage means for storing image data outputted from said reading means during the preceding movement.
Claim 20
Dependent Claim
51 words
An apparatus according to claim 14, wherein said control means controls the correction processing so as to provide alignment of a level of the image data outputted from said reading means during the preceding movement and a level of the image data outputted from said reading means during the current movement.
Claim 21
Dependent Claim
44 words
An apparatus according to claim 14, wherein said control means controls the operation processing based on a difference between the image data outputted from said reading means during the preceding movement and the image data outputted from said reading means during the current movement.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-03 | 1994-03-05 | 1994-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-03 | 1998-03-05 | 1998-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-03 | 2002-03-05 | 2002-09-04 | $7700.00 | Window Closed / Lapsed |