Patent EP0415722A2 successfully refreshed from Google Patents.
EP0415722A2
Expired / Lapsed
EP
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Image forming apparatus
Assignee: Canon Inc
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Filing: 1990-08-29
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Granted: —
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Expires: 2010-08-29
Abstract
Abstract The present invention provides an image forming apparatus for reproducing an image from an original, wherein a character portion and an intermediate contrast portion of an original is discriminated, different density converting tables are used to the character portion and the intermediate contrast portion. When the original includes both the character portion and the intermediate contrast portion, the density converting table for character portion is applied to the character portion and the density converting table for intermediate contrast portion is applied to the intermediate contrast portion to form the image.
Inventors
- 👤 Yoshito C/O Canon Kabushiki Kaisha Mizoguchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 09:03
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/407; H04N1/4072; H04N1/40062
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
129 words
An image forming apparatus for reproducing an image from an original, comprising: an original density detecting means for detecting a maximum density and a minimum density of the original; a calculating means for making a density converting table for character portion and a density converting table for intermediate contrast portion, on the basis of maximum density and the minimum density detected by said original density detecting means; a discriminating means for discriminating the character portion and the intermediate contrast portion of the original;and when the original includes both the character portion and the intermediate contrast portion, said density converting table for character portion is applied to the character portion and said density converting table for intermediate contrast portion is applied to the intermediate contrast portion to form the image.
Claim 2
Dependent Claim
129 words
An image forming apparatus for reproducing an image from an original, comprising: an original density detecting means for detecting a maximum density and a minimum density of the original; a calculating means for making a density converting table for character portion and a density converting table for intermediate contrast portion, on the basis of maximum density and the minimum density detected by said original density detecting means; a discriminating means for discriminating the character portion and the intermediate contrast portion of the original;and when the original includes both the character portion and the intermediate contrast portion, said density converting table for character portion is applied to the character portion and said density converting table for intermediate contrast portion is applied to the intermediate contrast portion to form the image.
Claim 3
Dependent Claim
17 words
An image forming apparatus according to claim 1, wherein said intermediate contrast portion is a photograph portion.
Claim 4
Dependent Claim
21 words
An image forming apparatus according to claim 1, wherein said original density detecting means measures the original in one line thereof.
Claim 5
Dependent Claim
33 words
An image forming apparatus according to claim 3, wherein the maximum density from said original density detecting means is sought from a frequency distribution of maximum density in one line of the original.
Claim 6
Dependent Claim
33 words
An image forming apparatus according to claim 3, wherein the minimum density from said original density detecting means is sought from a frequency distribution of minimum density in one line of the original.
Claim 7
Dependent Claim
42 words
An image forming apparatus according to claim 1, wherein said density converting table for character portion applied to said character portion has output density greater than that of said density converting table for intermediate contrast portion applied to said intermediate contrast portion.
Claim 8
Dependent Claim
147 words
An image forming apparatus for reproducing an image from an original, comprising: an original density detecting means for detecting a maximum density and a minimum density of the original per one line thereof by using a solid image taking element; a calculating means for making a density converting table for character portion and a density converting table for intermediate contrast portion, on the basis of maximum density and the minimum density detected by said original density detecting means; a discriminating means for discriminating the character portion and the intermediate contrast portion of the original; and when the original includes both of the character portion and the intermediate contrast portion, said density converting table for character portion having output density greater than that of said density converting table for intermediate contrast portion applied to said intermediate contrast portion is applied to the character portion to form the image.
Claim 9
Dependent Claim
147 words
An image forming apparatus for reproducing an image from an original, comprising: an original density detecting means for detecting a maximum density and a minimum density of the original per one line thereof by using a solid image taking element; a calculating means for making a density converting table for character portion and a density converting table for intermediate contrast portion, on the basis of maximum density and the minimum density detected by said original density detecting means; a discriminating means for discriminating the character portion and the intermediate contrast portion of the original; and when the original includes both of the character portion and the intermediate contrast portion, said density converting table for character portion having output density greater than that of said density converting table for intermediate contrast portion applied to said intermediate contrast portion is applied to the character portion to form the image.
Claim 10
Dependent Claim
17 words
An image forming apparatus according to claim 7, wherein said intermediate contrast portion is a photograph portion.
Claim 11
Dependent Claim
33 words
An image forming apparatus according to claim 7, wherein the maximum density from said original density detecting means is sought from a frequency distribution of maximum density in one line of the original.
Claim 12
Dependent Claim
33 words
An image forming apparatus according to claim 7, wherein the minimum density from said original density detecting means is sought from a freqeuncy distribution of minimum density in one line of the original.
Claim 13
Dependent Claim
32 words
An image forming apparatus according claim 7, wherein the discrimination of the character portion and the intermediate contrast portion of the original is judged by the change in density between adjacent pixels.
Claim 14
Dependent Claim
140 words
An image forming apparatus for reproducing an image from an original, comprising: an original density detecting means for detecting a maximum density and a minimum density of the original; a calculating means for making a density converting table for character portion and a density converting table for intermediate contrast portion, on the basis of maximum density and the minimum density detected by said original density detecting means; a discriminating means for discriminating the character portion and the intermediate contrast portion of the original; wherein if the original includes both of the character portion and the intermediate contrast portion, when said density converting table for character portion is applied to the character portion and said density converting table for intermediate contrast portion is applied to the intermediate contrast portion the made density converting tables are further altered to form the image.
Claim 15
Dependent Claim
140 words
An image forming apparatus for reproducing an image from an original, comprising: an original density detecting means for detecting a maximum density and a minimum density of the original; a calculating means for making a density converting table for character portion and a density converting table for intermediate contrast portion, on the basis of maximum density and the minimum density detected by said original density detecting means; a discriminating means for discriminating the character portion and the intermediate contrast portion of the original; wherein if the original includes both of the character portion and the intermediate contrast portion, when said density converting table for character portion is applied to the character portion and said density converting table for intermediate contrast portion is applied to the intermediate contrast portion the made density converting tables are further altered to form the image.
Claim 16
Dependent Claim
24 words
An image forming apparatus according to claim 12, wherein the further alteration of said density converting tables is calculated on the basis of coefficiency.
References Cited (Backward Citations)
No citation records indexed.
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