EP0234809A2
Expired / Lapsed
EP
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Image processing apparatus
Assignee: Canon Inc
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Filing: 1987-02-11
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Granted: —
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Expires: 2007-02-11
Abstract
Abstract An image processing apparatus includes a digital data output device (1, 2) for outputting bi-level image data, a bi-level processor (4) for converting the bi-level image data into multi-level (eg 8-bit) image data, a multi-level processor (4) for performing spatial filter processing with respect to the multi-level image data output from the bi-level processor, and a PWM circuit (5) for processing the multi-level image data output from the multi-level processor using a pattern signal of a predetermined cycle and generating a PWM signal.
Inventors
- 👤 Naoto Kawamura
- 👤 Yuji Nishigaki
- 👤 Hidefumi Ohsawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:41
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4055; H04N1/4056; H04N1/40062; H04N1/40075; H04N1/407; F; F02; F02B; F02B75/00; F02B75/02; F02B2075/022; F02B2075/027
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
57 words
An image processing apparatus comprising: image data generation means for generating m-bit image data; conversion means for converting the m-bit image data generated from said image data generation means into n-bit (n>m) image data; and pulse-width modulation signal generation means for processing the n-bit image data output from said conversion means and generating a pulse-width modulation signal.
Claim 2
Dependent Claim
57 words
An image processing apparatus comprising: image data generation means for generating m-bit image data; conversion means for converting the m-bit image data generated from said image data generation means into n-bit (n>m) image data; and pulse-width modulation signal generation means for processing the n-bit image data output from said conversion means and generating a pulse-width modulation signal.
Claim 3
Dependent Claim
43 words
An apparatus according to claim 1, wherein said image data generation means has halftone processing means for halftone processing input image data and outputting the m-bit image data, and memory means for storing the m-bit image data output from said halftone processing means.
Claim 4
Dependent Claim
51 words
An apparatus according to claim 1 or 2, wherein said conversion means has a converter for converting the m-bit image data generated from said image data generation means into the n-bit image data, and means for performing spatial filter processing with respect to the n-bit image data output from said converter.
Claim 5
Independent Claim
33 words
An apparatus according to any preceding claim, wherein said pulse-width modulation signal generation means processes the n-bit image data using a pattern signal of a predetermined cycle, and generates the pulse-width modulation signal.
Claim 6
Independent Claim
66 words
An apparatus according to any preceding claim, wherein said pulse-width modulation signal generation means has analog pattern signal generation means for generating an analog pattern signal of a predetermined cycle, D/A conversion means for D/A converting the n-bit image data, and comparison means for comparing the analog pattern signal with an analog image signal output from said D/A conversion means and outputting the pulse-width modulation signal.
Claim 7
Dependent Claim
54 words
An image processing apparatus comprising: image data generation means for generating m-bit image data; first conversion means for converting the m-bit image data generated from said image data generation means into n-bit (n>m) image data; and second conversion means for performing density conversion of the n-bit image data output from said first conversion means.
Claim 8
Dependent Claim
54 words
An image processing apparatus comprising: image data generation means for generating m-bit image data; first conversion means for converting the m-bit image data generated from said image data generation means into n-bit (n>m) image data; and second conversion means for performing density conversion of the n-bit image data output from said first conversion means.
Claim 9
Dependent Claim
38 words
An apparatus according to claim 6, wherein said second conversion means has a plurality of tables used for density conversion, and any one of said plurality of tables is selectively used in accordance with a predetermined instruction signal.
Claim 10
Dependent Claim
16 words
An apparatus according to claim 6 or 7, wherein said first conversion means comprises a memory.
Claim 11
Independent Claim
33 words
An apparatus according to any of claims 6 to 8, further comprising pulse-width modulation signal generation means for processing image data output from said second conversion means and generating a pulse-width modulation signal.
Claim 12
Dependent Claim
69 words
An apparatus according to claim 9, wherein said pulse-width modulation signal generation means has analog pattern signal generation means for generating an analog pattern signal of a predetermined cycle, D/A conversion means for D/A converting image data output from said second conversion means, and comparison means for comparing the analog pattern signal and an analog image signal output from said D/A conversion means and outputting the pulse-width modulation signal.
Claim 13
Dependent Claim
56 words
An apparatus according to claim 5 or 10, further comprising means for modulating a beam based on the pulse-width modulation signal and reproducing an image, and means for generating a position signal indicating a scanning position of the beam, said analog pattern signal generation means generating the analog pattern signal in synchronism with the position signal.
Claim 14
Independent Claim
21 words
An apparatus according to any of claims 4, 5, 10 and 11, wherein the pattern signal is a triangular wave signal.
Claim 15
Dependent Claim
48 words
An image processing apparatus comprising: image data generation means; conversion means for converting image data generated from said image data generation means and outputting converted image data having a data volume larger than the image data; and select means for selecting a conversion mode of said conversion mode.
Claim 16
Dependent Claim
48 words
An image processing apparatus comprising: image data generation means; conversion means for converting image data generated from said image data generation means and outputting converted image data having a data volume larger than the image data; and select means for selecting a conversion mode of said conversion mode.
Claim 17
Dependent Claim
57 words
An apparatus according to claim 13, wherein said conversion means has a first converter for converting the image data in a first mode, and a second converter for converting the image data in a second mode different from the first mode, and said select means selects one of the outputs from said first and second conversion means.
Claim 18
Dependent Claim
42 words
An apparatus according to claim 14, wherein said select means has discrimination means for discriminating characteristics of the image data, and a selector for selecting one of the outputs from said first and second conversion means in accordance with the discrimination result.
Claim 19
Dependent Claim
24 words
An apparatus according to claim 15, wherein said discrimination means discriminates using a predetermined filter whether or not the image data is halftone data.
Claim 20
Independent Claim
25 words
An apparatus according to any of claims 14 to 16, wherein said first converter uses surrounding image data when image data of interest is converted.
Claim 21
Independent Claim
21 words
An apparatus according to any of claims 13 to 17, wherein said image data generation means generates halftone processed bi-level data.
Claim 22
Dependent Claim
34 words
An image processing apparatus comprising: image data generation means for generating m-bit image data; and conversion means for converting m-bit image data generated from said image data generation means into n-bit (n>m) image data.
Claim 23
Dependent Claim
34 words
An image processing apparatus comprising: image data generation means for generating m-bit image data; and conversion means for converting m-bit image data generated from said image data generation means into n-bit (n>m) image data.
Claim 24
Independent Claim
17 words
An apparatus according to any preceding claim, wherein said image data generation means generates 1-bit image data.
References Cited (Backward Citations)
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