EP0049359A2
Expired / Lapsed
EP
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Colour separation scanner and method of operation
Assignee: International Business Machines Corp
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Filing: 1981-08-28
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Granted: —
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Expires: 2001-08-28
Abstract
Abstract A colour separation scanner includes a pair of elongated fluorescent tubes (11,12) to illuminate an elemental line of a document (13). An optical lens system (14) focusses an image of the line onto a solid state linear array (15) of photosensors. One tube (1) contains a mixture of two phosphors emitting different colours with different persistence. The other tube (12) contains a phosphor emitting a third colour with a different persistence. The lamps are activated alternately so as to illuminate the line with sequentially different predetermined light and mixtures of light from which colour separated images can be taken.
Inventors
- 👤 James Merrill White
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 18:15
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/48; H04N1/482; H04N1/484
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
150 words
1 A colour separation scanner comprising an optical system (14) for focussing an image of a target region onto a photosensitive transducer (15) for producing an electronic image of the light received thereby, characterised by a fluorescent lamp (11) positioned to illuminate the target region, the lamp having first and second light output modes responding to first and second light output modes responding to-first and second conditions of activation, the first light output mode providing light comprising principally a mixture of first and second colours and the second light output mode comprising principally light of the second colour, activation control means (17) connected to the lamp for cyclically applying the first and second conditions of activation thereto, and computational means (30) responsive to the electronic images produced from light reflected from the target region during the first and second light output modes for producing first and second colour-separated electronic images.
Claim 2
Dependent Claim
150 words
1 A colour separation scanner comprising an optical system (14) for focussing an image of a target region onto a photosensitive transducer (15) for producing an electronic image of the light received thereby, characterised by a fluorescent lamp (11) positioned to illuminate the target region, the lamp having first and second light output modes responding to first and second light output modes responding to-first and second conditions of activation, the first light output mode providing light comprising principally a mixture of first and second colours and the second light output mode comprising principally light of the second colour, activation control means (17) connected to the lamp for cyclically applying the first and second conditions of activation thereto, and computational means (30) responsive to the electronic images produced from light reflected from the target region during the first and second light output modes for producing first and second colour-separated electronic images.
Claim 3
Dependent Claim
102 words
2 A scanner according to claim 1, in which the fluorescent lamp includes at least two essentially different phosphors, the first of which emits, upon excitation, light of the first colour, and the second of which emits, upon excitation, light of the second colour, and wherein the persistence of light emission of the second colour phosphor is substantially greater than the persistence of light emission of the first colour phosphor, the first condition of activation comprising the supply of light driving current to the fluorescent lamp and the second condition of activation comprising the absence of such driving current after its supply.
Claim 4
Dependent Claim
43 words
3 A scanner according to claim 1 or 2, in which the target region comprises an elemental line, the transducer comprises a linear array of photosensors and the fluorescent lamp comprises an elongated tube positioned adjacent to and parallel with the elemental line.
Claim 5
Dependent Claim
37 words
4 A scanner according to claim 1, 2 or 3, in which the computational means subtracts the electronic image produced during the second light output mode from the electronic image produced during the first light output mode.
Claim 6
Dependent Claim
130 words
5 A scanner according to any preceding claim, includig a second fluorescent lamp (12) positioned to illuminate the target region, the second lamp having first and second light output modes responding to alternate conditions of activation, the first light output mode of the second fluorescent lamp providing light comprising a third colour and the second light output mode of the second lamp comprising a substantial absence of the third colour, and further activation control means (18) connected to the second lamp for cyclically applying the alternate conditions of activation thereto, the computational means (30) being further responsive to the electronic images produced from light reflected from the target region during the first and second light output modes of the second lamp for producing first, second and third colour-separated electronic images.
Claim 7
Dependent Claim
36 words
6 A scanner according to claim 5, in which the second lamp includes a phosphor, the persistence of light emission of which is substantially less than the persistence of light emission of the second colour phosphor.
Claim 8
Dependent Claim
27 words
7 A scanner according to claim 5 or 6 in which the first colour is red, the second colour is blue and the third colour is green.
Claim 9
Dependent Claim
38 words
8 A scanner according to claim 5, 6 or 7, as appendant to claim 3 or any claim appendant thereto, in which the fluorescent lamps comprise elongated tubes positioned on either side and parallel with the elemental line.
Claim 10
Dependent Claim
50 words
9 A scanner according to claim 5, 6, 7 or 8, as appendant to claim 4 in which the computational means subtracts the electronic image produced during the second light output mode of the lamp from the electronic image produced during the first light output mode of the second lamp.
Claim 11
Dependent Claim
24 words
10 A method of operating a scanner according to any of claims 1 to 4, comprising alternately activating and de-activating the fluorescent lamp (11).
Claim 12
Dependent Claim
27 words
11 A method of operating a scanner according to any of claims 5 to 9, comprising alternately activating the fluorescent lamp (11) and.the second fluorescent lamp (12).
References Cited (Backward Citations)
No citation records indexed.
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