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US5144456A
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Image processing apparatus and method
Assignee: Ricoh Co Ltd
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Filing: 1990-01-02
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Granted: 1992-09-01
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Expires: 2010-01-02
Abstract
Abstract An image processing apparatus includes a comparator which determines whether input gradation levels of pixels included in a predetermined matrix are equal to or higher than a reference gradation level. The apparatus further includes a converter which converts the input gradation levels of the pixels equal to or higher than the reference gradation level into a predetermined gradation level less than the reference gradation level and for passing the input gradation levels of the pixels less than the reference gradation level as they are, and an averaging circuit which averages the predetermined gradation level of each of the pixels having the input gradation levels equal to or higher than the reference gradation level and the input gradation levels of the remaining pixels other than the pixels relating to the reference gradation level to thereby output an averaged gradation level of a pixel of concern. Moreover, the apparatus includes an output circuit which derives a background corrected gradation level of the pixel of concern from the predetermined gradation level relating to the pixel of concern and the averaged gradation level.
Inventors
- 👤 Yukio Sakano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:13
CPC Classifications
G; G06; G06T; G06T1/00; G06T1/20
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
190 words
An image processing apparatus for processing image data read out from a document comprising: comparing means for determining whether or not input gradation levels of pixels included in a predetermined matrix are equal to or higher than a reference gradation level, said pixels including a pixel of concern and a predetermined number of peripheral pixels; converting means for converting the input gradation levels of said pixels equal to or higher than said reference gradation level into a predetermined gradation level less than said reference gradation level and for passing the input gradation levels of said pixels less than said reference gradation level as they are; averaging means, coupled to said converting means, for averaging said predetermined gradation level of each of said pixels having the input gradation levels equal to or higher than said reference gradation level and said input gradation levels of the remaining pixels to thereby output an averaged gradation level of said pixel of concern; and output means for deriving a background corrected gradation level of said pixel of concern from said input gradation level of said pixel of concern and said averaged gradation level relating thereto.
Claim 2
Dependent Claim
190 words
An image processing apparatus for processing image data read out from a document comprising: comparing means for determining whether or not input gradation levels of pixels included in a predetermined matrix are equal to or higher than a reference gradation level, said pixels including a pixel of concern and a predetermined number of peripheral pixels; converting means for converting the input gradation levels of said pixels equal to or higher than said reference gradation level into a predetermined gradation level less than said reference gradation level and for passing the input gradation levels of said pixels less than said reference gradation level as they are; averaging means, coupled to said converting means, for averaging said predetermined gradation level of each of said pixels having the input gradation levels equal to or higher than said reference gradation level and said input gradation levels of the remaining pixels to thereby output an averaged gradation level of said pixel of concern; and output means for deriving a background corrected gradation level of said pixel of concern from said input gradation level of said pixel of concern and said averaged gradation level relating thereto.
Claim 3
Dependent Claim
22 words
An image processing apparatus as claimed in claim 1, wherein said predetermined gradation level is a gradation level corresponding to pure white.
Claim 4
Dependent Claim
27 words
An image processing apparatus as claimed in claim 1, wherein said predetermined gradation level is a gradation level close to a gradation level corresponding to pure white.
Claim 5
Dependent Claim
56 words
An image processing apparatus as claimed in claim 1, wherein said averaging means calculates an arithmetical average of said predetermined gradation level of each of said pixels having the input gradation levels equal to or higher than said reference gradation level and said input gradation levels of the remaining pixels less than said reference gradation level.
Claim 6
Dependent Claim
56 words
An image processing apparatus as claimed in claim 1, wherein said averaging means calculates a weighted average of said predetermined gradation level of each of said pixels having the input gradation levels equal to or higher than said reference gradation level and said input gradation levels of the remaining pixels less than said reference gradation level.
Claim 7
Dependent Claim
34 words
An image processing apparatus as claimed in claim 1, wherein said reference gradation level is based on an image density at which an image formed by said pixels is recorded on a recording media.
Claim 8
Dependent Claim
30 words
An image processing apparatus as claimed in claim 6, wherein when said image density is set so as to increase, said reference gradation level is set so as to increase.
Claim 9
Dependent Claim
27 words
An image processing apparatus as claimed in claim 1, further comprising input means for manually inputting said reference gradation level to be supplied to said comparing means.
Claim 10
Dependent Claim
27 words
An image processing apparatus as claimed in claim 1, further comprising input means for automatically inputting said reference gradation level on the basis of said image density.
Claim 11
Dependent Claim
48 words
An image processing apparatus as claimed in claim 1, wherein the number of pixels contained in said matrix is selected on the basis of the size of a background contamination because of the presence of flare occurring when said input gradation levels are obtained by reading said document.
Claim 12
Dependent Claim
50 words
An image processing apparatus as claimed in claim 1, wherein the input gradation levels of said pixels are data obtained by a process of converting observed gradation levels of said pixels into relative gradation levels on the basis of a peak gradation level of a background image of said document.
Claim 13
Dependent Claim
19 words
An image processing apparatus as claimed in claim 11, wherein said peak gradation level is closet to pure white.
Claim 14
Dependent Claim
22 words
An image processing apparatus as claimed in claim 11, wherein said reference gradation level is determined based on said peak gradation level.
Claim 15
Dependent Claim
25 words
An image processing apparatus as claimed in claim 1, wherein said predetermined gradation level is the lowest gradation level of a background of said document.
Claim 16
Dependent Claim
29 words
An image processing apparatus as claimed in claim 1, wherein said predetermined gradation level is the lowest one of the gradation levels of said pixels contained in said matrix.
Claim 17
Dependent Claim
185 words
An image processing method for processing image data read out from a document, comprising the steps of: determining whether input gradation levels of pixels included in a predetermined matrix are equal to or higher than a reference gradation level, said pixels including a pixel of concern and a predetermined number of peripheral pixels; converting the input gradation levels of said pixels equal to or higher than said reference gradation level into a predetermined gradation level less than said reference gradation level and for passing the input gradation levels of said pixels less than said reference gradation level as they are; averaging said predetermined gradation level of each of said pixels having the input gradation levels equal to or higher than said reference gradation level and said input gradation levels of the remaining pixels other than said pixels relating to said reference gradation level to thereby output an averaged gradation level of said pixel of concern; and deriving a background corrected gradation level of said pixel of concern from said predetermined gradation level relating to said pixel of concern and said averaged gradation level relating thereto.
Claim 18
Dependent Claim
185 words
An image processing method for processing image data read out from a document, comprising the steps of: determining whether input gradation levels of pixels included in a predetermined matrix are equal to or higher than a reference gradation level, said pixels including a pixel of concern and a predetermined number of peripheral pixels; converting the input gradation levels of said pixels equal to or higher than said reference gradation level into a predetermined gradation level less than said reference gradation level and for passing the input gradation levels of said pixels less than said reference gradation level as they are; averaging said predetermined gradation level of each of said pixels having the input gradation levels equal to or higher than said reference gradation level and said input gradation levels of the remaining pixels other than said pixels relating to said reference gradation level to thereby output an averaged gradation level of said pixel of concern; and deriving a background corrected gradation level of said pixel of concern from said predetermined gradation level relating to said pixel of concern and said averaged gradation level relating thereto.
Claim 19
Dependent Claim
22 words
An image processing method as claimed in claim 16, wherein said predetermined gradation level is a gradation level corresponding to pure white.
Claim 20
Dependent Claim
27 words
An image processing method as claimed in claim 16, wherein said predetermined gradation level is a gradation level close to a gradation level corresponding to pure white.
Claim 21
Dependent Claim
60 words
An image processing method as claimed in claim 16, wherein said averaging step comprises a step of calculating an arithmetical average of said predetermined gradation level of each of said pixels having the input gradation levels equal to or higher than said reference gradation level and said input gradation levels of the remaining pixels less than said reference gradation level.
Claim 22
Dependent Claim
60 words
An image processing method as claimed in claim 16, wherein said averaging step comprises a step of calculating a weighted average of said predetermined gradation level of each of said pixels having the input gradation levels equal to or higher than said reference gradation level and said input gradation levels of the remaining pixels less than said reference gradation level.
Claim 23
Dependent Claim
34 words
An image processing method as claimed in claim 16, wherein said reference gradation level is based on an image density at which an image formed by said pixels is recorded on a recording media.
Claim 24
Dependent Claim
30 words
An image processing method as claimed in claim 21, wherein when said image density is set so as to increase, said reference gradation level is set so as to increase.
Claim 25
Dependent Claim
20 words
An image processing method as claimed in claim 16, further comprising a step of manually inputting said reference gradation level.
Claim 26
Dependent Claim
27 words
An image processing method as claimed in claim 16, further comprising a step of automatically inputting said reference gradation level on the basis of said image density.
Claim 27
Dependent Claim
48 words
An image processing method as claimed in claim 16, wherein the number of pixels contained in said matrix is selected on the basis of the size of a background contamination because of the presence of flare occurring when said input gradation levels are obtained by reading said document.
Claim 28
Dependent Claim
50 words
An image processing method as claimed in claim 16, wherein the input gradation levels of said pixels are data obtained by a process of converting observed gradation levels of said pixels into relative gradation levels on the basis of a peak gradation level of a background image of said document.
Claim 29
Dependent Claim
19 words
An image processing method as claimed in claim 26, wherein said peak gradation level is closet to pure white.
Claim 30
Dependent Claim
22 words
An image processing method as claimed in claim 26, wherein said reference gradation level is determined based on said peak gradation level.
Claim 31
Dependent Claim
25 words
An image processing method as claimed in claim 16, wherein said predetermined gradation level is the lowest gradation level of a background of said document.
Claim 32
Dependent Claim
29 words
An image processing method as claimed in claim 16, wherein said predetermined gradation level is the lowest one of the gradation levels of said pixels contained in said matrix.
References Cited (Backward Citations)
US4298895A
Cited
JPS5558670A
Cited
JPS5753179A
Cited
JPS60263576A
Cited
US4851920A
Cited
JPS62186663A
Cited
US4760464A
Cited
US4984283A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-01 | 1996-03-02 | 1996-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-01 | 2000-03-02 | 2000-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-01 | 2004-03-02 | 2004-09-01 | $7700.00 | Window Closed / Lapsed |