US7477426B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Image correcting apparatus and method, program, storage medium, image reading apparatus, and image forming apparatus
Assignee: Ricoh Co Ltd
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Filing: 2003-02-06
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Granted: 2009-01-13
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Expires: 2023-02-06
Abstract
Abstract An image correcting apparatus is provided for preventing a degraded image quality which can be caused by a three-dimensional distortion correction made to a scanned image distorted in a trapezoidal shape. Divergent distortion angles α, β of a scanned image are detected using a page contour of a book document which can be found near the upper or lower edge of the scanned image in a main scanning direction. The scanned image is corrected for a divergent distortion based on the divergent distortion angles α, β, followed by a correction of the scanned image for a shape distortion in a sub-scanning direction. In this way, the image quality can be prevented from degradation possibly caused by the three-dimensional distortion correction, if made to such a scanned image distorted in a trapezoidal shape.
Inventors
- 👤 Haike Guan
- 👤 Tadashi Araki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:42
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/80; G06T5/73; G06T5/90; G06V; G06V30/00; G06V30/10; G06V30/14; G06V30/146; G06V30/1475; G06V30/1478; H; H04; H04N; H04N1/00; H04N1/387; G06T2207/00; G06T2207/10; G06T2207/10004; G06T2207/10008; G06T2207/30; G06T2207/30176
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
104 words
An image correcting apparatus for correcting a scanned image of a book document read by image reading means through a contact glass while said book document is in contact with said contact glass, said apparatus comprising: divergent angle detecting means for detecting a divergent angle of said scanned image using a linear portion included in said scanned image of said book document; and divergent distortion correcting means for correcting said scanned image for a divergent distortion based on said divergent distortion angle detected by said divergent distortion angle detecting means and subsequently correcting said scanned image for a shape distortion in a sub-scanning direction.
Claim 2
Dependent Claim
104 words
An image correcting apparatus for correcting a scanned image of a book document read by image reading means through a contact glass while said book document is in contact with said contact glass, said apparatus comprising: divergent angle detecting means for detecting a divergent angle of said scanned image using a linear portion included in said scanned image of said book document; and divergent distortion correcting means for correcting said scanned image for a divergent distortion based on said divergent distortion angle detected by said divergent distortion angle detecting means and subsequently correcting said scanned image for a shape distortion in a sub-scanning direction.
Claim 3
Dependent Claim
140 words
An image correcting apparatus according to claim 1 , wherein said divergent distortion correcting means comprises: three-dimensional shape detecting means for detecting a three-dimensional shape of said book document; main scanning direction distortion correcting means for spreading said scanned image in a main scanning direction based on the three-dimensional shape of said book document detected by said three-dimensional shape detecting means; image rotating means for dividing said scanned image spread by said main scanning direction distortion correcting means into a left and a right page, and rotating the left and right pages respectively about predetermined positions by said divergent distortion angles detected by said divergent distortion angle detecting means; and sub-scanning direction distortion correcting means for spreading said left and right pages in the sub-scanning direction based on the three-dimensional shape of said images rotated by said image rotating means.
Claim 4
Dependent Claim
46 words
An image correcting apparatus according to claim 2 , wherein said main scanning direction distortion correcting means spreads said scanned image in the main scanning direction based on an spreading rate for each pixel detected with reference to an optical axis of said image reading means.
Claim 5
Dependent Claim
108 words
An image correcting apparatus according to claim 2 , wherein said three-dimensional shape detecting means comprises: rising level detecting means for detecting a rising level of said book document from said contact glass based on the distance from a line extended from said straight sections on the left and right pages of said scanned image to a boundary in a binding margin to said curvilinear section of said linear portion; and linear interpolating means for selecting two rising levels for each column on lines parallel with said boundary in the binding margin to perform linear interpolation for each column on said lines based on said two rising levels.
Claim 6
Dependent Claim
50 words
An image correcting apparatus according to claim 4 , wherein said rising level detecting means estimates a boundary between said distortion region in which said book document rises over said contact glass and a region out of said distortion region, and sets the rising level at the boundary to zero.
Claim 7
Dependent Claim
46 words
An image correcting apparatus according to claim 1 , wherein said divergent distortion correcting means comprises pixel linear interpolating means for performing linear interpolation based on pixel values of four adjoining blocks for each pixel value of said scanned image rotated by said image rotating means.
Claim 8
Dependent Claim
22 words
An image correcting apparatus according to claim 1 , further comprising luminance correcting means for correcting said scanned image for a luminance.
Claim 9
Dependent Claim
22 words
An image correcting apparatus according to claim 1 , further comprising a blur correcting means for correcting said scanned image for blurs.
Claim 10
Dependent Claim
55 words
An image reading apparatus comprising: a contact glass; image reading means for reading a document image through said contact glass while said document image is in contact with said contact glass; and an image correcting apparatus according to any of claims 1 to 8 for correcting a scanned image read by said image reading means.
Claim 11
Dependent Claim
118 words
A computer readable medium encoded with a program for causing a computer to correct a scanned image of a book document read by image reading means through a contact glass while said book document is in contact with said contact glass, said program causing said computer to execute: a divergent angle detecting function for detecting a divergent angle of said scanned image using a linear portion included in said scanned image of said book document; and a divergent distortion correcting function for correcting said scanned image for a divergent distortion based on said divergent distortion angle detected by said divergent distortion angle detecting function and subsequently correcting said scanned image for a shape distortion in a sub-scanning direction.
Claim 12
Dependent Claim
118 words
A computer readable medium encoded with a program for causing a computer to correct a scanned image of a book document read by image reading means through a contact glass while said book document is in contact with said contact glass, said program causing said computer to execute: a divergent angle detecting function for detecting a divergent angle of said scanned image using a linear portion included in said scanned image of said book document; and a divergent distortion correcting function for correcting said scanned image for a divergent distortion based on said divergent distortion angle detected by said divergent distortion angle detecting function and subsequently correcting said scanned image for a shape distortion in a sub-scanning direction.
Claim 13
Dependent Claim
152 words
A computer readable medium encoded with a program according to claim 10 , wherein said divergent distortion correcting function executed by said computer includes: a three-dimensional shape detecting function for detecting a three-dimensional shape of said book document; a main scanning direction distortion correcting function for spreading said scanned image in a main scanning direction based on the three-dimensional shape of said book document detected by said three-dimensional shape detecting function; an image rotating function for dividing said scanned image spread by said main scanning direction distortion correcting function into a left and a right page, and rotating the left and right pages respectively about predetermined positions by said divergent distortion angles detected by said divergent distortion angle detecting function; and a sub-scanning direction distortion correcting function for spreading said left and right pages in the sub-scanning direction based on the three-dimensional shape of said images rotated by said image rotating function.
Claim 14
Dependent Claim
106 words
An image correcting method for correcting a scanned image of a book document read by image reading means, said method comprising the steps of: obtaining a scanned image of said book document scanned through a contact glass while said book document is in contact with said contact glass; detecting a divergent angle of said scanned image using a linear portion included in said scanned image of said book document; and correcting said scanned image for a divergent distortion based on said divergent distortion angle detected by said divergent distortion angle detecting step and subsequently correcting said scanned image for a shape distortion in a sub-scanning direction.
Claim 15
Dependent Claim
106 words
An image correcting method for correcting a scanned image of a book document read by image reading means, said method comprising the steps of: obtaining a scanned image of said book document scanned through a contact glass while said book document is in contact with said contact glass; detecting a divergent angle of said scanned image using a linear portion included in said scanned image of said book document; and correcting said scanned image for a divergent distortion based on said divergent distortion angle detected by said divergent distortion angle detecting step and subsequently correcting said scanned image for a shape distortion in a sub-scanning direction.
Claim 16
Dependent Claim
121 words
An image correcting method according to claim 12 , wherein said divergent distortion correcting step comprises the steps of: detecting a three-dimensional shape of said book document; spreading said scanned image in a main scanning direction based on the three-dimensional shape of said book document detected by said three-dimensional shape detecting step; dividing said scanned image spread by said main scanning direction distortion correcting step into a left and a right page, and rotating the left and right pages respectively about predetermined positions by said divergent distortion angles detected by said divergent distortion angle detecting step; and spreading said left and right pages in the sub-scanning direction based on the three-dimensional shape of said images rotated by said image rotating step.
Claim 17
Dependent Claim
108 words
An image correcting apparatus for correcting a scanned image of a book document read by a scanner through a contact glass while said book document is in contact with said contact glass of the scanner, said apparatus comprising: a divergent angle detector configured to detect a divergent angle of said scanned image using a linear portion included in said scanned image of said book document; and a divergent distortion corrector configured to correct said scanned image for a divergent distortion based on said divergent distortion angle detected by said divergent distortion angle detecting means and subsequently correcting said scanned image for a shape distortion in a sub-scanning direction.
Claim 18
Dependent Claim
108 words
An image correcting apparatus for correcting a scanned image of a book document read by a scanner through a contact glass while said book document is in contact with said contact glass of the scanner, said apparatus comprising: a divergent angle detector configured to detect a divergent angle of said scanned image using a linear portion included in said scanned image of said book document; and a divergent distortion corrector configured to correct said scanned image for a divergent distortion based on said divergent distortion angle detected by said divergent distortion angle detecting means and subsequently correcting said scanned image for a shape distortion in a sub-scanning direction.
Claim 19
Dependent Claim
142 words
An image correcting apparatus according to claim 14 , wherein said divergent distortion corrector comprises: a three-dimensional shape detector configured to detect a three-dimensional shape of said book document; a main scanning direction distortion corrector configured to spread said scanned image in a main scanning direction based on the three-dimensional shape of said book document detected by said three-dimensional shape detector; an image rotating mechanism configured to divide said scanned image spread by said main scanning direction distortion corrector into a left and a right page, and to rotate the left and right pages respectively about predetermined positions by said divergent distortion angles detected by said divergent distortion angle detector; and a sub-scanning direction distortion corrector configured to spread said left and right pages in the sub-scanning direction based on the three-dimensional shape of said images rotated by said image rotating mechanism.
Claim 20
Dependent Claim
43 words
An image correcting apparatus according to claim 15 , wherein said main scanning direction distortion corrector spreads said scanned image in the main scanning direction based on an spreading rate for each pixel detected with reference to an optical axis of said scanner.
Claim 21
Dependent Claim
110 words
An image correcting apparatus according to claim 14 , wherein said three-dimensional shape detector comprises: a rising level detector configured to detect a rising level of said book document from said contact glass based on the distance from a line extended from said straight sections on the left and right pages of said scanned image to a boundary in a binding margin to said curvilinear section of said linear portion; and a linear interpolating mechanism configured to select two rising levels for each column on lines parallel with said boundary in the binding margin to perform linear interpolation for each column on said lines based on said two rising levels.
Claim 22
Dependent Claim
49 words
An image correcting apparatus according to claim 17 , wherein said rising level detector estimates a boundary between said distortion region in which said book document rises over said contact glass and a region out of said distortion region, and sets the rising level at the boundary to zero.
Claim 23
Dependent Claim
47 words
An image correcting apparatus according to claim 14 , wherein said divergent distortion corrector comprises a pixel linear interpolating mechanism configured to perform linear interpolation based on pixel values of four adjoining blocks for each pixel value of said scanned image rotated by said image rotating mechanism.
Claim 24
Dependent Claim
23 words
An image correcting apparatus according to claim 14 , further comprising a luminance corrector configured to correct said scanned image for a luminance.
Claim 25
Dependent Claim
22 words
An image correcting apparatus according to claim 14 , further comprising a blur corrector configured to correct said scanned image for blurs.
Claim 26
Dependent Claim
53 words
An image reading apparatus comprising: a contact glass; a scanner configured to read a document image through said contact glass while said document image is in contact with said contact glass; and the image correcting apparatus according to any of claims 14 to 21 for correcting a scanned image read by said scanner.
Claim 27
Dependent Claim
74 words
An image forming apparatus comprising: a contact glass a scanner configured to read a document image through said contact glass while said document image is in contact with said contact glass; the image correcting apparatus according to any of claims 14 to 21 for correcting a scanned image read by said scanner; and an image printer configured to print an image on a sheet based on image data output from said image correcting apparatus.
References Cited (Backward Citations)
JPH05161002A
Cited
US5583662A
Cited
US5808756A
Cited
US5726775A
Cited
US5987163A
Cited
US6433896B1
Cited
JPH1141455A
Cited
US6097483A
Cited
US20020022898A1
Cited
US6954290B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2012-01-13 | 2012-07-14 | 2013-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2016-01-13 | 2016-07-14 | 2017-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2020-01-13 | 2020-07-14 | 2021-01-13 | $7700.00 | Window Closed / Lapsed |