Patent EP0212990A2 successfully refreshed from Google Patents.
EP0212990A2
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Image processing apparatus
Assignee: Canon Inc
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Filing: 1986-08-29
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Granted: —
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Expires: 2006-08-29
Abstract
Abstract In an image processing apparatus, an image signal generator includes a ROM (16) and a D/A converter (2). The ROM consists of gain conversion tables. A PWM signal generator includes a frequency divider (6), a flip-flop (8), an integrator (10, 11), a voltage divider (13), and a comparator (4). The frequency divider is synchronized with the ROM in response to a sync selection signal. An output from the frequency divider is further frequency-divided by the flip-flop and then converted into a triangular wave signal by the integrator. The bias component of the triangular wave signal is adjusted by the voltage divider. The resultant signal (SAW) supplied to one input terminal of the comparator is compared thereby with an output from the D/A converter, thereby obtaining a PWM signal. The peak and bottom values of the triangular wave signal are always matched with the maximum and minimum values of the output from the D/A converter.
Inventors
- 👤 Yoshiyuki Suzuki
- 👤 Naoto Kawamura
- 👤 Hiroaki Ishii
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 10:11
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/409; H04N1/4092; H04N1/405; H04N1/4055; H04N1/4056
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
89 words
An image processing apparatus comprising: image signal generating means for generating an image signal; and pulse width modulated signal generating means for processing the image signal from said image signal generating means by using a pattern signal and outputting a pulse width modulated signal; wherein said pulse width modulated signal generating means comprises pattern signal generating means for generating first and second pattern signals having different periods but an identical amplitude and/or an identical bias level, and selecting means for selecting one of the first and second pattern signals.
Claim 2
Dependent Claim
89 words
An image processing apparatus comprising: image signal generating means for generating an image signal; and pulse width modulated signal generating means for processing the image signal from said image signal generating means by using a pattern signal and outputting a pulse width modulated signal; wherein said pulse width modulated signal generating means comprises pattern signal generating means for generating first and second pattern signals having different periods but an identical amplitude and/or an identical bias level, and selecting means for selecting one of the first and second pattern signals.
Claim 3
Dependent Claim
110 words
An apparatus according to claim 1, wherein said pattern signal generating means comprises clock signal generating means for generating first and second clock signals having different periods so as to form the first and second pattern signals and first and second pattern signal generators for receiving the first and second clock signals and forming the first and second pattern signals, said clock signal generating means being adapted to select one of the first and second clock signals in response to a predetermined designation signal, and said selecting means being adapted to select one of outputs from said first and second pattern signal generators in response to the predetermined designation signal.
Claim 4
Dependent Claim
115 words
An apparatus according to claim 1, wherein said pattern signal generating means comprises clock signal generating means for generating first and second clock signals having different periods so as to form the first and second pattern signals, wherein said clock signal generating means selects and generates one of the first and second clock signals in response to a predetermined designation signal, said pattern signal generating means comprises a plurality of elements for receiving the first and second clock signals and generating the first and second pattern signals, and said selecting means selects said plurality of elements in response to the predetermined designation signal so as to generate one of the first and second pattern signals.
Claim 5
Dependent Claim
21 words
An apparatus according to claim 2 or 3, wherein the predetermined designation signal is a signal representing characteristics of an image.
Claim 6
Dependent Claim
93 words
An image processing apparatus comprising: image signal generating means for generating an image signal; and pulse width modulated signal generating means for processing the image signal from said image signal generating means and outputting a pulse width modulated signal; wherein said pulse width modulated signal generating means comprises means for inputting a-predetermined designation signal representing characteristics of the image signal, and is adapted to switch over a mode for generation of the pulse width modulated signal in response to the designation signal to switch out a mode for image reproduction in one image.
Claim 7
Dependent Claim
93 words
An image processing apparatus comprising: image signal generating means for generating an image signal; and pulse width modulated signal generating means for processing the image signal from said image signal generating means and outputting a pulse width modulated signal; wherein said pulse width modulated signal generating means comprises means for inputting a-predetermined designation signal representing characteristics of the image signal, and is adapted to switch over a mode for generation of the pulse width modulated signal in response to the designation signal to switch out a mode for image reproduction in one image.
Claim 8
Dependent Claim
51 words
An image processing apparatus according to claim 5 wherein said pulse width modulated signal generating means comprises pattern signal generation means for generating first and second pattern signals having respective different periods and selection means for selecting one of the first and second pattern signals in response to the designation signal.
Claim 9
Independent Claim
44 words
An apparatus according to any of claims 1 to 4 and 6, wherein said pulse width modulated signal generating means comprises comparing means for comparing the image signal with the pattern signal selected by said selecting means to form the pulse width modulated signal.
Claim 10
Dependent Claim
43 words
An apparatus according to claim 7, wherein said image signal generating means comprises D/A converting means for converting the digital input image signal into an analog image signal, the analog image signal from said D/A converting means being input to said comparing means.
Claim 11
Dependent Claim
121 words
An image processing apparatus comprising: image signal generating means for generating an image signal; converting means for receiving the image signal generated by said image signal generating means and outputting a converted image signal; and pulse width modulated signal generating means for processing the converted image signal outputted from said converting means by using a pattern signal and outputting a pulse width modulated signal; wherein said pulse width modulated signal generating means comprises pattern signal generating means for generating first and second pattern signals having different periods and selecting means for selecting one of the first and second pattern signals, and said converting means changes a conversion mode of the image signal in association with selection operation of said selecting means.
Claim 12
Dependent Claim
121 words
An image processing apparatus comprising: image signal generating means for generating an image signal; converting means for receiving the image signal generated by said image signal generating means and outputting a converted image signal; and pulse width modulated signal generating means for processing the converted image signal outputted from said converting means by using a pattern signal and outputting a pulse width modulated signal; wherein said pulse width modulated signal generating means comprises pattern signal generating means for generating first and second pattern signals having different periods and selecting means for selecting one of the first and second pattern signals, and said converting means changes a conversion mode of the image signal in association with selection operation of said selecting means.
Claim 13
Dependent Claim
48 words
An apparatus according to claim 9 wherein said converting means comprises a plurality of tables for receiving the image signal as an address signal and outputting the converted digital image signal, said plurality of tables being selected on the basis of the selection operation of said selecting means.
Claim 14
Dependent Claim
59 words
An apparatus according to claim 10 wherein said converting means comprises D/A converting means for converting the converted digital image signal to an analog image signal, and said pulse width modulated signal generating means comprises comparing means for comparing the analog image signal with the pattern signal selected by said selecting means and forming the pulse width modulated signal.
Claim 15
Independent Claim
54 words
An apparatus according to any of claims 9 to 11, wherein said pattern signal generating means comprises clock signal generating means for generating first and second clock signals having different periods so as to form the first and second pattern signals, and said selecting means selects one of the first and second clock signals.
Claim 16
Independent Claim
26 words
An apparatus according to any of claims 1 to 4 and 6 to 12, wherein the first and second pattern signals are triangular wave signals, respectively.
Claim 17
Dependent Claim
85 words
An image processing apparatus comprising: image signal generating means for generating an image signal; pulse width modulated signal generating means for processing the image signal generated by said image signal generating means by using a pattern signal and outputting a pulse width modulated signal; wherein said pulse width modulated signal generating means comprises first and second pattern signal generators, said first and second pattern signal generators being capable of generating first and second pattern signals having different periods but an identical amplitude and/or bias level.
Claim 18
Dependent Claim
85 words
An image processing apparatus comprising: image signal generating means for generating an image signal; pulse width modulated signal generating means for processing the image signal generated by said image signal generating means by using a pattern signal and outputting a pulse width modulated signal; wherein said pulse width modulated signal generating means comprises first and second pattern signal generators, said first and second pattern signal generators being capable of generating first and second pattern signals having different periods but an identical amplitude and/or bias level.
Claim 19
Dependent Claim
22 words
An apparatus according to claim 14, further comprising means for selecting one of outputs from said first and second pattern signal generators.
Claim 20
Dependent Claim
79 words
An image processing apparatus comprising: means for generating an image signal (VD); and means (4;4';21-9) for processing the image signal using a pattern signal (SAW;DSAW) of variable frequency to produce a pulse-width-modulated output signal (PW); characterised by means (16; 9 to 15; 20; 21-6, 21-7; 23-4 to 23-19) responsive to the pattern signal frequency to compensate for variations in the relative amplitudes and/or relative bias levels of the image and pattern signals upon variation of the pattern signal frequency.
Claim 21
Dependent Claim
79 words
An image processing apparatus comprising: means for generating an image signal (VD); and means (4;4';21-9) for processing the image signal using a pattern signal (SAW;DSAW) of variable frequency to produce a pulse-width-modulated output signal (PW); characterised by means (16; 9 to 15; 20; 21-6, 21-7; 23-4 to 23-19) responsive to the pattern signal frequency to compensate for variations in the relative amplitudes and/or relative bias levels of the image and pattern signals upon variation of the pattern signal frequency.
References Cited (Backward Citations)
US4040094A
Cited
EP0216462A2
Cited
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