US7099045B2
Expired / Lapsed
US
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Image processing apparatus, image forming apparatus, and image processing method for judging pixels in edge area of character in halftone-dot area
Assignee: Minolta Co Ltd
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Filing: 2002-03-08
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Granted: 2006-08-29
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Expires: 2022-03-08
Abstract
Abstract Disclosed are an image processing apparatus and an image processing method that can decrease image quality deterioration caused by unsuitable image correction processing performed on a pixel in a halftone-dot area due to a misjudgment of an image type, and an image forming apparatus that utilizes the image processing apparatus. A characteristic of a halftone-dot area is judged by, for example, counting the number of isolated pixels detected by an isolated pixel detection filter with a predetermined size. A parameter such as a threshold for the number of inner edge pixels for use in a judgment of an edge area of a character that is present on a halftone-dot area is switched (between thresholds 503 and 504 ), based on the characteristic of the halftone-dot area.
Inventors
- 👤 Takayuki Nabeshima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:33
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/20; G06T7/00; G06T7/10; G06T7/12; H; H04; H04N; H04N1/00; H04N1/40; H04N1/40062; G06T2200/00; G06T2200/28; G06T2207/00; G06T2207/10; G06T2207/10004; G06T2207/10008; G06T2207/20; G06T2207/20004; G06T2207/20012; G06T2207/20172; G06T2207/20192; G06T2207/30; G06T2207/30176
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
86 words
An image processing apparatus, comprising: a character-on-halftone area judgment unit for judging whether a target pixel is in an edge area of a character that is present on a halftone-dot area, using a parameter; a halftone-dot characteristic judgment unit for judging a characteristic of a halftone-dot area, when the target pixel is in the halftone-dot area; and a selector for switching between a plurality of parameters to be used by the character-on-halftone area judgment unit, based on a judgment result of the halftone-dot characteristic judgment unit.
Claim 2
Dependent Claim
86 words
An image processing apparatus, comprising: a character-on-halftone area judgment unit for judging whether a target pixel is in an edge area of a character that is present on a halftone-dot area, using a parameter; a halftone-dot characteristic judgment unit for judging a characteristic of a halftone-dot area, when the target pixel is in the halftone-dot area; and a selector for switching between a plurality of parameters to be used by the character-on-halftone area judgment unit, based on a judgment result of the halftone-dot characteristic judgment unit.
Claim 3
Dependent Claim
74 words
The image processing apparatus of claim 1 , wherein the character-on-halftone area judgment unit includes: an edge detection unit for detecting an edge pixel, the edge pixel being a pixel in an edge area; an edge pixel counter for counting a number of edge pixels detected in a predetermined area by the edge detection unit; and a comparator for comparing the number of edge pixels counted by the edge pixel counter with a threshold.
Claim 4
Dependent Claim
23 words
The image processing apparatus of claim 2 , wherein the selector switches between a plurality of thresholds that are the plurality of parameters.
Claim 5
Dependent Claim
41 words
The image processing apparatus of claim 1 , wherein the halftone-dot characteristic judgment unit judges a size of a dot that constitutes the halftone-dot area, and the selector switches between the plurality of parameters, based on the size of the dot.
Claim 6
Dependent Claim
103 words
The image processing apparatus of claim 1 , wherein the halftone-dot characteristic judgment unit includes: an isolated pixel judgment unit for judging that the target pixel is an isolated pixel, when a relationship between (a) brightness of the target pixel and (b) brightness of a plurality of pixels at predetermined positions with respect to the target pixel satisfies a predetermined condition; and an isolated pixel counter for counting a number of isolated pixels in a predetermined area, and the halftone-dot characteristic judgment unit judges the characteristic of the halftone-dot area, based on the number of isolated pixels counted by the isolated pixel counter.
Claim 7
Dependent Claim
51 words
The image processing apparatus of claim 5 , wherein the isolated pixel judgment unit includes a filter used for judging that the target pixel is an isolated pixel, when the target pixel is included in a dot whose size is substantially within a predetermined range and that constitutes the halftone-dot area.
Claim 8
Dependent Claim
60 words
The image processing apparatus of claim 5 , further comprising: a second isolated pixel counter for counting a number of isolated pixels in a predetermined area; and a halftone-dot area judgment unit for judging whether the target pixel is in a halftone-dot area, by comparing the number of isolated pixels counted by the second isolated pixel counter with a threshold.
Claim 9
Dependent Claim
37 words
The image processing apparatus of claim 1 , wherein the halftone-dot characteristic judgment unit judges resolution of the halftone-dot area, and the selector switches between the plurality of parameters, based on the resolution of the halftone-dot area.
Claim 10
Dependent Claim
37 words
The image processing apparatus of claim 1 , wherein the halftone-dot characteristic judgment unit judges density of the halftone-dot area, and the selector switches between the plurality of parameters, based on the density of the halftone-dot area.
Claim 11
Dependent Claim
30 words
The image processing apparatus of claim 1 , further comprising an image correction unit for correcting image data, in accordance with a judgment result of the character-on-halftone area judgment unit.
Claim 12
Dependent Claim
126 words
An image forming apparatus, comprising: a character-on-halftone area judgment unit for judging whether a target pixel is in an edge area of a character that is present on a halftone-dot area, using a parameter; a halftone-dot characteristic judgment unit for judging a characteristic of a halftone-dot area, when the target pixel is in the halftone-dot area; and a selector for switching between a plurality of parameters to be used by the character-on-halftone area judgment unit, based on a judgment result of the halftone-dot characteristic judgment unit; an image correction unit for correcting image data, in accordance with a judgment result of the character-on-halftone area judgment unit; and an image forming unit for forming an image, based on the image data corrected by the image correction unit.
Claim 13
Dependent Claim
126 words
An image forming apparatus, comprising: a character-on-halftone area judgment unit for judging whether a target pixel is in an edge area of a character that is present on a halftone-dot area, using a parameter; a halftone-dot characteristic judgment unit for judging a characteristic of a halftone-dot area, when the target pixel is in the halftone-dot area; and a selector for switching between a plurality of parameters to be used by the character-on-halftone area judgment unit, based on a judgment result of the halftone-dot characteristic judgment unit; an image correction unit for correcting image data, in accordance with a judgment result of the character-on-halftone area judgment unit; and an image forming unit for forming an image, based on the image data corrected by the image correction unit.
Claim 14
Dependent Claim
106 words
An image forming method, comprising: a halftone-dot characteristic judgment step of judging a characteristic of a halftone-dot area, when a target pixel is in the halftone-dot area; a parameter determination step of determining, based on a judgment result in the halftone-dot characteristic judgment step, a parameter to be used for judging whether the target pixel is in an edge area of a character that is present on the halftone-dot area; and a character-on-halftone area judgment step of judging whether the target pixel is in an edge area of a character that is present on the halftone-dot area, using the parameter determined in the parameter determination step.
Claim 15
Dependent Claim
106 words
An image forming method, comprising: a halftone-dot characteristic judgment step of judging a characteristic of a halftone-dot area, when a target pixel is in the halftone-dot area; a parameter determination step of determining, based on a judgment result in the halftone-dot characteristic judgment step, a parameter to be used for judging whether the target pixel is in an edge area of a character that is present on the halftone-dot area; and a character-on-halftone area judgment step of judging whether the target pixel is in an edge area of a character that is present on the halftone-dot area, using the parameter determined in the parameter determination step.
Claim 16
Dependent Claim
83 words
The image processing method of claim 12 , wherein the halftone-dot characteristic judgment step includes: an isolated pixel extraction substep of extracting, using a filter, an isolated pixel to be used for judging the characteristic of the halftone-dot area; an isolated pixel count substep of counting a number of isolated pixels in a predetermined area; and a halftone-dot characteristic judgment substep of judging the characteristic of the halftone-dot area, based on the number of isolated pixels counted in the isolated pixel count substep.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2009-08-28 | 2010-02-27 | 2010-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2013-08-28 | 2014-02-27 | 2014-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2017-08-28 | 2018-02-27 | 2018-08-29 | $7700.00 | Window Closed / Lapsed |