EP0497537A2
Expired / Lapsed
EP
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Image processing method and apparatus
Assignee: Canon Inc
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Filing: 1992-01-27
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Granted: —
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Expires: 2012-01-27
Abstract
Abstract The invention relates to an image processing method and apparatus in which, when a binary image is converted to a higher density and interpolated, more effective conversion patterns are proposed and the interpolation upon conversion to higher density is performed by a simple logic operation without using a pattern memory. One original pixel is subdivided into 2 n portions (where n is an integer) in a main scanning direction and/or 2 m portions (where m is an integer) in a subordinate scanning direction, and a density value of a subdivided pixel of a pixel of interest, which has been subdivided, is decided based upon a density value of an original pixel of interest and density values of pixels peripheral thereto. An angle of inclination of a slanted line which is the object of interpolation processing is detected, and the number of subdivided pixels, which undergo a density conversion for interpolation processing, is changed in dependence upon the angle of inclination. Alternatively, the width of a slanted line which is the object of interpolation processing is detected, and the processing of density conversion for interpolation processing is controlled in dependence upon the width of the slanted line. As a result, it is possible to obtain an image in which contour smoothing of the slanted lines of a character image is performed more effectively, with no missing black lines.
Inventors
- 👤 Katsutoshi C/O Canon Kabushiki Kaisha Ushida
- 👤 Ikuo c/o Canon Kabushiki Kaisha Sobue
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 10:36
CPC Classifications
G; G06; G06T; G06T3/00; G06T3/40; G06T3/4007
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
126 words
An image processing apparatus for raising the density of an original pixel of a binary image and performing interpolation, comprising: a first process of subdividing one original pixel in a main scanning direction and/or in a subordinate scanning direction; and a second process of deciding a density value of a subdivided pixel of a pixel of interest, which has been subdivided by said first process, based upon a density value of an original pixel of interest and density values of pixels peripheral thereto; wherein said second process includes detecting an angle of inclination of a slanted line which is the object of interpolation processing, and varying the number of subdivided pixels, which undergo a density conversion for interpolation processing, in dependence upon said angle of inclination.
Claim 2
Dependent Claim
44 words
The apparatus according to claim 1, wherein said second process includes detecting the width of a slanted line which is the object of interpolation processing, and controlling, in dependence upon the width of said slanted line, the processing of density conversion for interpolation processing.
Claim 3
Dependent Claim
119 words
An image processing apparatus comprising: input means for inputting image data; detecting means for detecting the pattern of the image data inputted by said input means; discriminating means for discriminating whether a pixel of interest is contained in a character-image area and is part of a fine, slanted line; and output means for outputting image data in dependence upon pattern information detected by said detecting means; wherein, when said discriminating means has discriminated that said pixel of interest is contained in a character-image area and is part of a fine, slanted line, said output means controls the output duration, which is a minimum unit, of the image data in dependence upon said pattern information, and outputs the image data.
Claim 4
Dependent Claim
25 words
The apparatus according to claim 3, wherein said input means inputs binary image data in which a character image and a pseudo-half-tone image are mixed.
Claim 5
Dependent Claim
126 words
An image processing apparatus comprising: input means for inputting image data; contour-smoothing enlargement means for subdividing the image data, which has been inputted by said input means, in a main scanning direction and in a subordinate scanning direction, deciding a density value of a subdivided pixel of a pixel of interest is dependence upon the pixel of interest and a pattern of peripheral pixels, and smoothing the contour of a slanted-line portion by raising the density of the pixel of interest and performing interpolation; and pixel pulse-width control means, to which is inputted image data outputted by said contour-smoothing enlargement means, for controlling and outputting the output duration, which is a minimum unit, of the image data in dependence upon the pattern of the peripheral pixels.
Claim 6
Dependent Claim
103 words
The apparatus according to claim 5, wherein said pixel pulse-width control means includes: pattern detecting means for detecting a pixel array pattern which prevails prior to high-density conversion processing performed by said contour-smoothing enlargement means; and position detecting means for detecting a position at which a black pixel of image data, which has been subdivided into two portions in the main scanning direction by said contour-smoothing enlargement means, has been interpolated; wherein the output duration, which is a minimum unit, of the image data is controlled and outputted in dependence upon the pixel array pattern and the interpolated position of the black pixel.
Claim 7
Dependent Claim
126 words
An image processing method for raising the density of an original pixel of a binary image and performing interpolation, comprising: a first process of subdividing one original pixel in a main scanning direction and/or in a subordinate scanning direction; and a second process of deciding a density value of a subdivided pixel of a pixel of interest, which has been subdivided by said first process, based upon a density value of an original pixel of interest and density values of pixels peripheral thereto; wherein said second process includes detecting an angle of inclination of a slanted line which is the object of interpolation processing, and varying the number of subdivided pixels, which undergo a density conversion for interpolation processing, in dependence upon said angle of inclination.
Claim 8
Dependent Claim
128 words
An image processing method comprising: an input step of inputting image data; a detecting step of detecting the pattern of the image data inputted at said input step; a discriminating step of discriminating whether a pixel of interest is contained in a character-image area and is part of a fine, slanted line; and an output step of outputting image data in dependence upon pattern information detected at said detecting step; wherein, when it has been discriminated at step discriminating step that said pixel of interest is contained in a character-image area and is part of a fine, slanted line, the output duration, which is a minimum unit, of the image data is controlled in dependence upon said pattern information, and image data is outputted at said output step.
Claim 9
Dependent Claim
127 words
An image processing method comprising: an input step of inputting image data; a contour-smoothing enlargement step of subdividing the image data, which has been inputted by said input means, in a main scanning direction and in a subordinate scanning direction, deciding a density value of a subdivided pixel of a pixel of interest is dependence upon the pixel of interest and a pattern of peripheral pixels, and smoothing the contour of a slanted-line portion by raising the density of the pixel of interest and performing interpolation; and a pixel pulse-width control step of inputting image data outputted at said contour-smoothing enlargement step, and controlling and outputting the output duration, which is a minimum unit, of the image data in dependence upon the pattern of the peripheral pixels.
References Cited (Backward Citations)
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