EP0151353A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Half-tone imaging
Assignee: Crosfield Electronics Ltd
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Filing: 1984-12-20
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Granted: —
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Expires: 2004-12-20
Abstract
Abstract A method and apparatus for generating a representation of a half-tone image including areas of different resolution is described. The apparatus comprises stores (2, 26) for storing digital colour data representing colour density information at low and high resolution respectively. A second store (25) stores the spatial data indicating the type of image data to be used at each position on a record medium (7). A third store (2') is provided for storing half-tone dot information. A group of six light modulators (10) which generate six scanning beams are arranged side-by-side. A support (8) supporting the record medium (7) to be exposed to the scanning beams is provided while drive motors (6', 9') cause relative movement between the support and the scanning beam. Scanning beam control means (25, 27-32) determine the position of the beams relatively to the record medium (7) in use, compare the current position with the stored spatial data and control the beam in response to the previously generated digital colour data and in response to the half-tone dot information. The plurality of beams are controlled together and at a first rate in response to low resolution data and singly or in groups and at a higher, second rate in response to high resolution image data.
Inventors
- 👤 Martin Rosen
- 👤 George Charles Manley
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 22:58
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/52; H04N1/40; H04N1/405; H04N1/4055; H04N1/41; H04N1/4105
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
131 words
A method of generating a representation of a half-tone image including areas of different resolution in which a record medium (7) is exposed to a plurality of scanning beams (B1-B6) arranged side by side, the method comprising controlling the beams in response to previously generated image data and half-tone dot information during relative scanning movement between the beams and the record medium (7), characterised in that the image data comprises both high and low resolution data; and in that the plurality of beams are controlled together and at a first rate in response to low resolution data and singly or in groups and at a higher, second rate in response to high resolution image data, whereby a representation of a half-tone image is generated having areas of high and low resolution.
Claim 2
Independent Claim
131 words
A method of generating a representation of a half-tone image including areas of different resolution in which a record medium (7) is exposed to a plurality of scanning beams (B1-B6) arranged side by side, the method comprising controlling the beams in response to previously generated image data and half-tone dot information during relative scanning movement between the beams and the record medium (7), characterised in that the image data comprises both high and low resolution data; and in that the plurality of beams are controlled together and at a first rate in response to low resolution data and singly or in groups and at a higher, second rate in response to high resolution image data, whereby a representation of a half-tone image is generated having areas of high and low resolution.
Claim 3
Dependent Claim
28 words
A method according to claim 1, wherein at junctions between low and high resolution areas the beams are normally controlled preferentially in response to the high resolution data.
Claim 4
Dependent Claim
44 words
A method according to claim 1 or claim 2, wherein when the beams are controlled in response to high resolution data, the method further comprises overriding that control to control the beams in response to low resolution data for at least one colour separation.
Claim 5
Independent Claim
51 words
A method according to any of claims 1 to 3, comprising comparing each successive discrete position of the beams relative to the record medium (7) with previously generated spatial data, the spatial data indicating whether the beams are to be controlled in response to low resolution or high resolution image data.
Claim 6
Dependent Claim
203 words
Apparatus for generating a representation of a half-tone image including areas of different resolution, the apparatus comprising first storage means (2,26) for storing digital colour data representing colour density information at both low and high resolution; second storage means (25) for storing spatial data indicating the type of image data to be used at each position on a record medium (7); third storage means (2') for storing half-tone dot information; scanning beam generating means (10) for generating a plurality of scanning beams arranged side by side; a support (8) for supporting the record medium (7) to be exposed to the scanning beams; means (6',9 ) for causing relative movement between the support and the scanning beams; and scanning beam control means (25,27-32) for determining the position of the beams relatively to the record medium in use, comparing the current position with the stored spatial data and controlling the beams in response to the previously generated digital colour data and in response to the half-tone dot information, wherein the plurality of beams are controlled together and at a first rate in response to low resolution data and singly or in groups and at a higher, second rate in response to high resolution image data.
Claim 7
Dependent Claim
203 words
Apparatus for generating a representation of a half-tone image including areas of different resolution, the apparatus comprising first storage means (2,26) for storing digital colour data representing colour density information at both low and high resolution; second storage means (25) for storing spatial data indicating the type of image data to be used at each position on a record medium (7); third storage means (2') for storing half-tone dot information; scanning beam generating means (10) for generating a plurality of scanning beams arranged side by side; a support (8) for supporting the record medium (7) to be exposed to the scanning beams; means (6',9 ) for causing relative movement between the support and the scanning beams; and scanning beam control means (25,27-32) for determining the position of the beams relatively to the record medium in use, comparing the current position with the stored spatial data and controlling the beams in response to the previously generated digital colour data and in response to the half-tone dot information, wherein the plurality of beams are controlled together and at a first rate in response to low resolution data and singly or in groups and at a higher, second rate in response to high resolution image data.
Claim 8
Dependent Claim
39 words
Apparatus according to claim 5, wherein the scanning beam generating means (10) generates six scanning beams which may be controlled individually, in one or more pairs, or in one or two triplets in response to high resolution image data.
Claim 9
Dependent Claim
85 words
Apparatus according to claim 5 or claim 6, wherein the spatial data comprises for each high resolution pixel a change portion and for each beam or group of beams which are controlled at the higher, second rate a selection portion, wherein the selection portion indicates whether high or low resolution data is to be used and the change portion indicates whether the previously used high resolution data is to be accessed from the first storage means or new high resolution data is to be accessed.
References Cited (Backward Citations)
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