US5258783A
Expired / Lapsed
US
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Image processing method and apparatus with gamma-correction control
Assignee: Canon Inc
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Filing: 1992-02-21
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Granted: 1993-11-02
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Expires: 2012-02-21
Abstract
Abstract An image processing apparatus, which improves the image quality in gradation control, measures the density of a specified gradation pattern formed on a photosensitive drum with a photosensor and prepares a look-up table for gamma correction, based on thus measured density. Formation of a pseudo-contour is prevented by control of the inclination of the gamma correction curve represented by the data of the look-up table.
Inventors
- 👤 Nobuatsu Sasanuma
- 👤 Koji Amemiya
- 👤 Tatsuo Takeuchi
- 👤 Takao Ogata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:33
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/407; H04N1/4076; H04N1/4078; Y; Y10; Y10S; Y10S347/00; Y10S347/90
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
147 words
An image processing apparatus comprising: input means for inputting image data; correcting means for correcting density characteristics of the image data by using a predetermined gamma-correction curve and outputting corrected image data; image forming means for forming an image on a medium based on the corrected image data; memory means for storing pattern data; pattern forming means for forming a visible pattern on the medium, utilizing the pattern data stored in said memory means; detecting means for detecting a density of the visible pattern formed on the medium; and determining means for determining the predetermined gamma-correction curve to be used by said correcting means according to the density of the visible pattern detected by said detecting means, wherein said determining means determines the predetermined gamma-correction curve by comparing an inclination of a candidate gamma-correction curve based on the density of the visible pattern with a predetermined value.
Claim 2
Dependent Claim
147 words
An image processing apparatus comprising: input means for inputting image data; correcting means for correcting density characteristics of the image data by using a predetermined gamma-correction curve and outputting corrected image data; image forming means for forming an image on a medium based on the corrected image data; memory means for storing pattern data; pattern forming means for forming a visible pattern on the medium, utilizing the pattern data stored in said memory means; detecting means for detecting a density of the visible pattern formed on the medium; and determining means for determining the predetermined gamma-correction curve to be used by said correcting means according to the density of the visible pattern detected by said detecting means, wherein said determining means determines the predetermined gamma-correction curve by comparing an inclination of a candidate gamma-correction curve based on the density of the visible pattern with a predetermined value.
Claim 3
Dependent Claim
22 words
An apparatus according to claim 1, wherein said pattern forming means is adapted to form patterns for a plurality of color components.
Claim 4
Dependent Claim
16 words
An apparatus according to claim 1, wherein said detecting means includes means for emitting near-infrared light.
Claim 5
Dependent Claim
15 words
An apparatus according to claim 1, further comprising a look-up table storing the gamma-correction curves.
Claim 6
Dependent Claim
21 words
An apparatus according to claim 1, further comprising means for displaying information related to the inclination of the predetermined gamma-correction curve.
Claim 7
Dependent Claim
157 words
An image processing apparatus comprising: input means for inputting image data; correcting means for correcting density characteristics of the image data by using a predetermined gamma-correction curve and outputting corrected image data; image forming means for forming an image on a medium based on the corrected image data; memory means for storing pattern data; pattern forming means for forming a visible pattern on the pattern data stored in said memory means; detecting means for detecting a density of the visible pattern formed on the medium; and determining means for determining the predetermined gamma-correction curve to be used by said correcting means according to the density of the visible pattern detected by said detecting means, wherein said determining means further comprises: calculating means for calculating an inclination of a candidate gamma-correction curve according to the density detected by said detecting means, and display means for displaying information relating to a result of the calculation by said calculating means.
Claim 8
Dependent Claim
157 words
An image processing apparatus comprising: input means for inputting image data; correcting means for correcting density characteristics of the image data by using a predetermined gamma-correction curve and outputting corrected image data; image forming means for forming an image on a medium based on the corrected image data; memory means for storing pattern data; pattern forming means for forming a visible pattern on the pattern data stored in said memory means; detecting means for detecting a density of the visible pattern formed on the medium; and determining means for determining the predetermined gamma-correction curve to be used by said correcting means according to the density of the visible pattern detected by said detecting means, wherein said determining means further comprises: calculating means for calculating an inclination of a candidate gamma-correction curve according to the density detected by said detecting means, and display means for displaying information relating to a result of the calculation by said calculating means.
Claim 9
Dependent Claim
22 words
An apparatus according to claim 6, wherein said pattern forming means is adapted to form patterns for a plurality of color components.
Claim 10
Dependent Claim
17 words
An apparatus according to claim 6, wherein said detecting means further comprises means for emitting near-infrared light.
Claim 11
Dependent Claim
15 words
An apparatus according to claim 6, further comprising a look-up table storing the gamma-correction curves.
Claim 12
Dependent Claim
138 words
An image processing apparatus comprising: input means for inputting data; correcting means for correcting density characteristics of the image data by using a predetermined gamma-correction curve and outputting corrected image data; image forming means for forming an image on a medium based on the corrected image data; memory means for storing pattern data; pattern forming means for forming a visible pattern on the medium, utilizing the pattern data stored in said memory means; detecting means for detecting the density of the visible pattern; and determining means for determining the predetermined gamma-correction curve to be used by said correcting means according to the density of the visible pattern detected by said detecting means, wherein said determining means further comprises calculating means for calculating an inclination of a candidate gamma-correction curve according to the density detected by said detecting means.
Claim 13
Dependent Claim
138 words
An image processing apparatus comprising: input means for inputting data; correcting means for correcting density characteristics of the image data by using a predetermined gamma-correction curve and outputting corrected image data; image forming means for forming an image on a medium based on the corrected image data; memory means for storing pattern data; pattern forming means for forming a visible pattern on the medium, utilizing the pattern data stored in said memory means; detecting means for detecting the density of the visible pattern; and determining means for determining the predetermined gamma-correction curve to be used by said correcting means according to the density of the visible pattern detected by said detecting means, wherein said determining means further comprises calculating means for calculating an inclination of a candidate gamma-correction curve according to the density detected by said detecting means.
Claim 14
Dependent Claim
22 words
An apparatus according to claim 10, wherein said pattern forming means is adapted to form patterns for a plurality of color components.
Claim 15
Dependent Claim
16 words
An apparatus according to claim 10, wherein said detecting means includes means for emitting near-infrared light.
Claim 16
Dependent Claim
15 words
An apparatus according to claim 10, further comprising a look-up table storing the gamma-correction curves
Claim 17
Dependent Claim
86 words
An image processing method for determining a gamma-correction curve for correcting density characteristics of input image data, comprising the steps of: generating pattern data; forming a visible pattern on a medium utilizing the pattern data; detecting a density of the visible pattern; and determining the gamma-correction curve according to the density of the visible pattern, wherein, in said determining step, the gamma-correction curve is determined by comparing an inclination of a candidate gamma-correction curve based on the density of the visible pattern with a predetermined value.
Claim 18
Dependent Claim
86 words
An image processing method for determining a gamma-correction curve for correcting density characteristics of input image data, comprising the steps of: generating pattern data; forming a visible pattern on a medium utilizing the pattern data; detecting a density of the visible pattern; and determining the gamma-correction curve according to the density of the visible pattern, wherein, in said determining step, the gamma-correction curve is determined by comparing an inclination of a candidate gamma-correction curve based on the density of the visible pattern with a predetermined value.
Claim 19
Dependent Claim
93 words
An image processing method for determining a gamma-correction curve for correcting density characteristics of input image data, comprising the steps of: generating pattern data; forming a visible pattern on a medium utilizing the pattern data; detecting a density of the visible pattern; and determining the gamma-correction curve according to the density of the visible pattern, wherein said determining step further comprises the steps of: calculating an inclination of a candidate gamma-correction curve according to the density thus detected, and displaying information relating to a result of the calculation performed in said calculating step.
Claim 20
Dependent Claim
93 words
An image processing method for determining a gamma-correction curve for correcting density characteristics of input image data, comprising the steps of: generating pattern data; forming a visible pattern on a medium utilizing the pattern data; detecting a density of the visible pattern; and determining the gamma-correction curve according to the density of the visible pattern, wherein said determining step further comprises the steps of: calculating an inclination of a candidate gamma-correction curve according to the density thus detected, and displaying information relating to a result of the calculation performed in said calculating step.
Claim 21
Dependent Claim
78 words
An image processing method for determining a gamma-correction curve for correcting density characteristics of input image data, comprising the steps of: generating pattern data; forming a visible pattern on a medium utilizing the pattern data; detecting a density of the visible pattern; and determining the gamma-correction curve according to the density of the visible pattern, wherein said determining step further comprises the step of calculating an inclination of a candidate gamma-correction curve according to the density thus detected.
Claim 22
Dependent Claim
78 words
An image processing method for determining a gamma-correction curve for correcting density characteristics of input image data, comprising the steps of: generating pattern data; forming a visible pattern on a medium utilizing the pattern data; detecting a density of the visible pattern; and determining the gamma-correction curve according to the density of the visible pattern, wherein said determining step further comprises the step of calculating an inclination of a candidate gamma-correction curve according to the density thus detected.
References Cited (Backward Citations)
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