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US4782398A
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Image processing apparatus
Assignee: Canon Inc
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Filing: 1988-02-18
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Granted: 1988-11-01
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Expires: 2008-02-18
Abstract
Abstract An image processing apparatus having versatility and expandability for obtaining a high-quality reproduced image is provided. The image processing apparatus of the invention has an LUT for generating an image signal, a first pattern signal generator for generating a first pattern signal, a comparator for processing the image signal using the first pattern signal and outputting a first pulse width modulation signal, a second pattern signal generator for generating a second pattern signal different from the first pattern signal, another comparator for processing the image signal using the second pattern signal and outputting a second pulse width modulation signal, and an OR gate for synthesizing the first and second pulse width modulation signals.
Inventors
- 👤 Yoshinobu Mita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:57
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4055; H04N1/4056; H04N1/40062
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
92 words
An image processing apparatus comprising: image signal generating means for generating an image signal; first pattern signal generating means for generating a first pattern signal; means for processing the image signal using the first pattern signal and outputting a first pulse width modulation signal; second pattern signal generating means for generating a second pattern signal different from the first pattern signal; means for processing the image signal using the second pattern signal and outputting a second pulse width modulation signal; and means for synthesizing the first and second pulse width modulation signals.
Claim 2
Dependent Claim
92 words
An image processing apparatus comprising: image signal generating means for generating an image signal; first pattern signal generating means for generating a first pattern signal; means for processing the image signal using the first pattern signal and outputting a first pulse width modulation signal; second pattern signal generating means for generating a second pattern signal different from the first pattern signal; means for processing the image signal using the second pattern signal and outputting a second pulse width modulation signal; and means for synthesizing the first and second pulse width modulation signals.
Claim 3
Dependent Claim
68 words
An apparatus according to claim 1, wherein said first pulse width modulation signal outputting means comprises first comparing means for comparing the first pattern signal with the image signal and outputting the first pulse width modulation signal, and said second pulse width modulation signal outputting means comprises second comparing means for comparing the second pattern signal with the image signal and outputting the second pulse width modulation signal.
Claim 4
Dependent Claim
23 words
An apparatus according to claim 1, wherein said synthesizing means calculates a logical sum of the first and second pulse width modulation signals.
Claim 5
Dependent Claim
22 words
An apparatus according to claim 1, wherein the first and second pattern signals have the same periods and amplitudes and different phases.
Claim 6
Dependent Claim
16 words
An apparatus according to claim 4, wherein the first and second pattern signals are triangular waves.
Claim 7
Dependent Claim
52 words
An apparatus according to claim 1, wherein said image signal generating means comprises converting means for converting input digital image data and outputting converted digital image data, and analog image signal generating means for digital/analog converting the converted digital image data output from said converting means and generating an analog image signal.
Claim 8
Dependent Claim
24 words
An apparatus according to claim 6, wherein said converting means has a function to convert a density level of the input digital image data.
Claim 9
Dependent Claim
112 words
A pulse width modulation signal generating apparatus comprising: signal input means; means for converting the level of a signal input from said input means; first pattern signal generating means for generating a first pattern signal; means for processing a converted signal output from said converting means using the first pattern signal and outputting a first pulse width modulation signal; second pattern signal generating means for generating a second pattern signal different from the first pattern signal; means for processing the converted signal output from said converting means using the second pattern signal and outputting a second pulse width modulation signal; and means for synthesizing the first and second pulse width modulation signals.
Claim 10
Dependent Claim
112 words
A pulse width modulation signal generating apparatus comprising: signal input means; means for converting the level of a signal input from said input means; first pattern signal generating means for generating a first pattern signal; means for processing a converted signal output from said converting means using the first pattern signal and outputting a first pulse width modulation signal; second pattern signal generating means for generating a second pattern signal different from the first pattern signal; means for processing the converted signal output from said converting means using the second pattern signal and outputting a second pulse width modulation signal; and means for synthesizing the first and second pulse width modulation signals.
Claim 11
Dependent Claim
14 words
An apparatus according to claim 8, wherein said input means inputs an image signal.
Claim 12
Dependent Claim
23 words
An apparatus according to claim 8, wherein said synthesizing means calculates a logical sum of the first and second pulse width modulation signals.
Claim 13
Dependent Claim
22 words
An apparatus according to claim 8, wherein the first and second pattern signals have the same periods and amplitudes and different phases.
Claim 14
Dependent Claim
16 words
An apparatus according to claim 11, wherein the first and second pattern signals are triangular waves.
Claim 15
Dependent Claim
89 words
An image processing apparatus comprising: image signal generating means for generating an image signal; means for generating first and second pattern signals; means for processing the image signal using the first pattern signal and outputting a first pulse width modulation signal; means for processing the image signal using the second pattern signal and outputting a second pulse width modulation signal; means for synthesizing the first and second pulse width modulation signals; and selecting means for selecting an output from said synthesizing means in accordance with an input designating signal.
Claim 16
Dependent Claim
89 words
An image processing apparatus comprising: image signal generating means for generating an image signal; means for generating first and second pattern signals; means for processing the image signal using the first pattern signal and outputting a first pulse width modulation signal; means for processing the image signal using the second pattern signal and outputting a second pulse width modulation signal; means for synthesizing the first and second pulse width modulation signals; and selecting means for selecting an output from said synthesizing means in accordance with an input designating signal.
Claim 17
Dependent Claim
40 words
An apparatus according to claim 13, wherein said image signal generating means comprises means for converting the level of the image signal, and said converting means switches a conversion mode of the image signal in accordance with the designating signal.
Claim 18
Dependent Claim
35 words
An apparatus according to claim 13, further comprising means for discriminating an image tonality of the image signal, and wherein the designating signal is output in accordance with a discrimination result of said discriminating means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1991-11-01 | 1992-05-02 | 1992-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-01 | 1996-05-02 | 1996-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-01 | 2000-05-02 | 2000-11-01 | $7700.00 | Window Closed / Lapsed |