Patent US4792815A successfully refreshed from Google Patents.
Patent EP0361880A2 successfully refreshed from Google Patents.
EP0361880A2
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EP
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Image signal processor
Assignee: Panasonic System Solutions Japan Co Ltd
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Filing: 1989-09-26
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Granted: —
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Expires: 2009-09-26
Abstract
Abstract The power values at fixed frequencies of an input image signal of such as a character, a photograph or a screen halftone show special characteristics depending on each kind of input image signals. In the present invention, there are provided proper image processors for individual kinds of input signals, power detectors for detecting the power at fixed frequencies in the direction of the main scanning and/or subscanning, an image signal identification section which outputs a kind-identification signal of an input image signal based on the detected power, and a selection section for selecting the output of a proper image processor for an input image signal.
Inventors
- 👤 Kazuto Kobayashi
- 👤 Sato Shinichi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 22:00
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/40062; A; A61; A61B; A61B6/00; A61B6/52; A61B6/5258
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
92 words
An image signal processor comprising (a) an error diffusion process means for an input image signal, (b) a binarization process means for an input image signal, (c) an image signal identification means for outputting a kind-identification signal of said input image signal based on a detected power at a fixed frequency at least in a direction of the main scanning or subscanning of said input image signal, (d) a selection means for selecting an output of either said error diffusion process means or said binarization process means based on said kind-identification signal.
Claim 2
Dependent Claim
92 words
An image signal processor comprising (a) an error diffusion process means for an input image signal, (b) a binarization process means for an input image signal, (c) an image signal identification means for outputting a kind-identification signal of said input image signal based on a detected power at a fixed frequency at least in a direction of the main scanning or subscanning of said input image signal, (d) a selection means for selecting an output of either said error diffusion process means or said binarization process means based on said kind-identification signal.
Claim 3
Dependent Claim
119 words
An image signal processor comprising (a) a first process means for executing a quasitone reproduction process by smoothing an input image signal with a low-pass filter, (b) a second process means for executing a quasitone reproduction process of an input image signal, (c) a binarization means for binarizing an input image signal, (d) an image signal identification means for outputting a kind-identification signal of said input image signal based on a detected power at a fixed frequency at least in a direction of either main scanning or subscanning of an input image signal, (e) a selection means for selecting an output from said first process means, said second process means or said binarization means based on said kind-identification signal.
Claim 4
Dependent Claim
119 words
An image signal processor comprising (a) a first process means for executing a quasitone reproduction process by smoothing an input image signal with a low-pass filter, (b) a second process means for executing a quasitone reproduction process of an input image signal, (c) a binarization means for binarizing an input image signal, (d) an image signal identification means for outputting a kind-identification signal of said input image signal based on a detected power at a fixed frequency at least in a direction of either main scanning or subscanning of an input image signal, (e) a selection means for selecting an output from said first process means, said second process means or said binarization means based on said kind-identification signal.
Claim 5
Dependent Claim
19 words
An image signal processor according to claim 2 wherein a dither process is used for said quasi-tone reproduction process.
Claim 6
Dependent Claim
20 words
An image signal processor according to claim 2 wherein an error diffusion process is used for said quasi-tone reproduction process.
Claim 7
Dependent Claim
36 words
An image signal processor according to claim 1, 2, 3 or 4 wherein said image signal identification means outputs a kind-identification signal based on the result of comparison between said power and a prescribed threshold value.
Claim 8
Dependent Claim
130 words
An image signal processor according to claim 5 wherein said power is the power at a frequency or at frequencies as shown below: a frequency f1 in the main scanning direction of said input image signal which is a mesh point pitch frequency (a fundamental frequency) corresponding to a number of lines of a screen halftone, said frequency f1 in the subscanning direction, a frequency f2 in the main scanning direction which is a frequency lower than said frequency f1 and at which the power of a screen halftone becomes a minimum, said frequency f2 in the subscanning direction, a frequency f3 in the main scanning direction which is a maximum picture frequency decided by the reading resolution of said input image signal, said frequency f3 in the subscanning direction.
Claim 9
Dependent Claim
27 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f1 in the main scanning direction and the subscanning direction.
Claim 10
Dependent Claim
33 words
An image signal processor according to claim 7 wherein said image signal identification means comprises power detectors for individual f1 frequencies corresponding to a plurality of prescribed numbers of lines of screen halftones.
Claim 11
Dependent Claim
28 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f2 in the main scanning direction of said input image signal.
Claim 12
Dependent Claim
27 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f2 in the subscanning direction of said input image signal.
Claim 13
Dependent Claim
40 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f2 in the main scanning direction and the power at said frequency f3 in the main scanning direction of said input image signal.
Claim 14
Dependent Claim
38 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f2 in the main direction and the power at said frequency f3 in the subscanning direction of said input image signal.
Claim 15
Dependent Claim
38 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f2 in the subscanning direction and the power at said frequency f3 in the subscanning direction of said input image signal.
Claim 16
Dependent Claim
39 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f2 in the subscanning direction and the power at said frequency f3 in the main scanning direction of said input image signal.
Claim 17
Dependent Claim
56 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f1 in the main scanning direction and in the subscanning direction, the power at said frequency f2 in the main scanning direction and the power at said frequency f3 in the main scanning direction of said input image signal.
Claim 18
Dependent Claim
55 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f1 in the main scanning direction and in the subscanning direction, the power at said frequency f2 in the main scanning direction and the power at said frequency f3 in the subscanning direction of said input image signal.
Claim 19
Dependent Claim
54 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f1 in the main scanning direction and in the subscanning direction, the power at said frequency f2 in the subscanning direction and the power at said frequency f3 in the subscanning direction of said input image signal.
Claim 20
Dependent Claim
55 words
An image signal processor according to claim 6 wherein said power is the power at said frequency f1 in the main scanning direction and in the subscanning direction, the power at said frequency f2 in the subscanning direction and the power at said frequency f3 in the main scanning direction of said input image signal.
Claim 21
Dependent Claim
54 words
An image signal processor according to claim 1, 2, 3 or 4 wherein power value detection sections corresponding to the kinds of resolution of input image signals are provided in said image signal identification means to be able to select the output of said power value detection section matching to the prescribed reading resolution.
Claim 22
Dependent Claim
43 words
An image signal processor according to claim 2, 3 or 4 wherein the cut-off frequency of said low-pass filter is made to be lower than the mesh point pitch frequency f1 (fundamental frequency) corresponding to the number of lines of a screen halftone.
Claim 23
Dependent Claim
43 words
An image signal processor according to claim 2, 3 or 4 wherein said low-pass filter section comprises the filters corresponding to the resolution of an input image signal, and the output of a filter corresponding to a prescribed reading resolution can be selected.
Claim 24
Dependent Claim
78 words
An image signal processor according to claim 2, 3 or 4 wherein said low-pass filter section comprises the filters corresponding to the numbers of lines of screen halftones, and the output of said filter corresponding to a detected frequency from a detection means can be selected, the detection means which is provided in said image signal identification means and detects the mesh point pitch frequency f1 (fundamental frequency) corresponding to the number of lines of a screen halftone.
References Cited (Backward Citations)
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