US4491875A
Expired / Lapsed
US
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Apparatus and method for tonal image processing
Assignee: Canon Inc
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Filing: 1984-02-28
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Granted: 1985-01-01
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Expires: 2004-02-28
Abstract
Abstract An apparatus for processing an image having half-tone and composed of plural pixels by dividing each of said pixels into small sections arranged in a matrix and respectively constituting micro-pixels with luminosity that can be respectively designated according to a determined gradation, by representing the luminosity to be designated to each of the first-mentioned pixels by the luminosity in the form of systematic dither method for the plural micro-pixels in said pixel.
Inventors
- 👤 Naoto Kawamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 00:20
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/40087; H04N1/405; H04N1/4055; H04N1/4057
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
10 words
An intermediate tone image processing method comprising the steps of:
Claim 2
Dependent Claim
10 words
An intermediate tone image processing method comprising the steps of:
Claim 3
Dependent Claim
96 words
providing one of a plurality of potential levels, including an intermediate potential level, to each of a plurality of small areas on an image carrier adapted to bear an electrostatic latent image thereon; forming pixels having different gradation levels from combinations of the small areas, the gradation level of each pixel being determined by the combination of small areas; forming a pattern composed of a set of the pixels; detecting the density level of the pattern; and variably controlling the potential of the intermediate potential level in response to an output obtained in the detecting step.
Claim 4
Dependent Claim
96 words
providing one of a plurality of potential levels, including an intermediate potential level, to each of a plurality of small areas on an image carrier adapted to bear an electrostatic latent image thereon; forming pixels having different gradation levels from combinations of the small areas, the gradation level of each pixel being determined by the combination of small areas; forming a pattern composed of a set of the pixels; detecting the density level of the pattern; and variably controlling the potential of the intermediate potential level in response to an output obtained in the detecting step.
Claim 5
Dependent Claim
30 words
The method according to claim 1, wherein the image carrier is a photosensitive member which is subjected to a laser beam of different intensities to provide the different potential levels.
Claim 6
Dependent Claim
25 words
The method according to claim 2, wherein the laser beam has three intensity levels, with the beam intensity in the intermediate level being variably controlled.
Claim 7
Dependent Claim
37 words
The method according to claim 1, wherein the pattern forming, detecting and controlling steps are carried out prior to an actual image formation, and a surface potential is detected for a density level in the detecting step.
Claim 8
Dependent Claim
118 words
An intermediate tone image processing apparatus comprising: semiconductor laser means for generating a laser beam in response to a drive signal; first switching means connected in series to said semiconductor laser means; seocnd switching means connected in series to said semiconductor laser means and connected in parallel with said first switching means; control means for changing over the drive signal to one of a plurality of stages by controlling the combination of the ON and OFF states of said first and second switching means in response to a signal representative of the image density; and a recording medium on which information is recorded by irradiating laser light generated by said semiconductor laser means in at least three intenisties.
Claim 9
Dependent Claim
118 words
An intermediate tone image processing apparatus comprising: semiconductor laser means for generating a laser beam in response to a drive signal; first switching means connected in series to said semiconductor laser means; seocnd switching means connected in series to said semiconductor laser means and connected in parallel with said first switching means; control means for changing over the drive signal to one of a plurality of stages by controlling the combination of the ON and OFF states of said first and second switching means in response to a signal representative of the image density; and a recording medium on which information is recorded by irradiating laser light generated by said semiconductor laser means in at least three intenisties.
Claim 10
Dependent Claim
23 words
The apparatus according to claim 5, further comprising first constant current means for maintaining constant the current flowing through said first switching means.
Claim 11
Dependent Claim
25 words
The apparatus according to claim 6, further comprising means for introducing a signal for controlling the constant current supplied by said first constant current means.
Claim 12
Independent Claim
179 words
A method for forming an intermediate tone image in which the image is composed of a set of pixels each of which is composed of a plurality of small areas, said method comprising the steps of: generating an electrical signal representative of an image density; providing a first dither pattern having a plurality of threshold levels; providing a second dither pattern different from said first dither pattern and having a plurality of threshold levels; generating binary signals in response to the electrical signal and in accordance with the first and second dither patterns; forming a dot having a first density in a small area in one of said pixels in response to the binary signals generated in accordance with the first dither pattern; or forming a dot having a second density, higher than the first density, in the small area in response to the binary signals generated in accordance with the second dither pattern; formation of a dot having the second density in the small area precluding formation of a dot having the first density in the small area.
Claim 13
Independent Claim
179 words
A method for forming an intermediate tone image in which the image is composed of a set of pixels each of which is composed of a plurality of small areas, said method comprising the steps of: generating an electrical signal representative of an image density; providing a first dither pattern having a plurality of threshold levels; providing a second dither pattern different from said first dither pattern and having a plurality of threshold levels; generating binary signals in response to the electrical signal and in accordance with the first and second dither patterns; forming a dot having a first density in a small area in one of said pixels in response to the binary signals generated in accordance with the first dither pattern; or forming a dot having a second density, higher than the first density, in the small area in response to the binary signals generated in accordance with the second dither pattern; formation of a dot having the second density in the small area precluding formation of a dot having the first density in the small area.
Claim 14
Dependent Claim
24 words
The method according to claim 8, wherein a dot having the first density is smaller in size than a dot having the second density.
Claim 15
Dependent Claim
37 words
The method according to claim 8, wherein no dot is formed in a small area when the level of the electrical signal is lower than both of the threshold levels of said first and second dither patterns.
Claim 16
Dependent Claim
28 words
The method according to claim 8, wherein a maximum threshold level of said first dither pattern is lower than a minimum threshold level of said second dither pattern.
Claim 17
Dependent Claim
106 words
An intermediate tone image forming method comprising the steps of: forming a plurality of micro-pixels, each of which is of small area and has either low density, intermediate density or high density, in response to an electric signal representative of an image density; forming a plurality of pixels each being formed by said plurality of micro-pixels; and forming an image by a set of pixels; wherein each pixel is a combination of micro-pixels of low and intermediate density or a combination of micro-pixels of intermediate and high density such that there does not exist in a pixel a combination of low density and high density micro-pixels.
Claim 18
Dependent Claim
106 words
An intermediate tone image forming method comprising the steps of: forming a plurality of micro-pixels, each of which is of small area and has either low density, intermediate density or high density, in response to an electric signal representative of an image density; forming a plurality of pixels each being formed by said plurality of micro-pixels; and forming an image by a set of pixels; wherein each pixel is a combination of micro-pixels of low and intermediate density or a combination of micro-pixels of intermediate and high density such that there does not exist in a pixel a combination of low density and high density micro-pixels.
Claim 19
Dependent Claim
18 words
The method according to claim 12, wherein the micro-pixels of low density are formed without a dot therein.
Claim 20
Dependent Claim
34 words
The method according to claim 12, wherein the micro-pixels of intermediate and high densities are each formed with a dot therein, the dot for the intermediate and high density pixel being different in size.
Claim 21
Dependent Claim
127 words
An intermediate tone image forming apparatus in which the image is formed by a set of pixels each of which is formed by a plurality of small areas, which comprises: means for representing the pixels with a plurality of gradation levels by different combinations of micro-pixels each of which comprises a small area, each of the small areas having one of low density, intermediate density and high density, in response to an image density signal; means for detecting respective differences between adjacent ones of the gradation levels of at least three pixels represented by said representing means; and control means for variably controlling the density of the small areas having the intermediate density when the magnitudes of the respective differences of the gradation levels are not uniform.
Claim 22
Dependent Claim
127 words
An intermediate tone image forming apparatus in which the image is formed by a set of pixels each of which is formed by a plurality of small areas, which comprises: means for representing the pixels with a plurality of gradation levels by different combinations of micro-pixels each of which comprises a small area, each of the small areas having one of low density, intermediate density and high density, in response to an image density signal; means for detecting respective differences between adjacent ones of the gradation levels of at least three pixels represented by said representing means; and control means for variably controlling the density of the small areas having the intermediate density when the magnitudes of the respective differences of the gradation levels are not uniform.
Claim 23
Dependent Claim
54 words
The apparatus according to claim 15, wherein said detecting means detects both of the difference in a high gradation region and the difference in a low gradation region, and said control means variably controls the density level of said small areas of the intermediate density in accordance with the difference between the differences detected.
Claim 24
Dependent Claim
32 words
The apparatus according to claim 15, wherein said representing means forms dots for the micro-pixels of high and intermediate densities, and does not form a dot for a micro-pixel of low density.
Claim 25
Dependent Claim
34 words
The apparatus according to claim 15, wherein said representing means forms a pattern having a plurality of gradation levels prior to an actual image formation, said detecting means reading the density of the pattern.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-01-01 | 1988-07-02 | 1989-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-01 | 1992-07-02 | 1993-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-01 | 1996-07-02 | 1997-01-01 | $7700.00 | Window Closed / Lapsed |