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EP0253935A2
Expired / Lapsed
EP
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Weighted-pixel characteristic sensing
Assignee: Light Signatures Inc
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Filing: 1986-10-16
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Granted: —
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Expires: 2006-10-16
Abstract
Abstract A method and system for sensing a characteristic (e.g. translucency) of a document (10) utilises radiation (17) from a specific window area (16) of the document (10). The radiation (17) is sensed by a sensor (18) with pixel dissection (P1 - P3), that affords pixels (P2) of a central location of the window area (16), a greater (x2) weighting so as to attribute enhanced significance to the central portion of the window area (16), whereby tolerance to misalignment with respect to the window area (16) is increased. Data signals in accordance with the weighted pixel signals are compared (62 Fig 3; 120 Fig 6) with stored values (64 Fig 3; 122 Fig 6) for the purpose of document authentication (66 Fig 3; 124 Fig 6). Pixel-weighting techniques used include filtering incident and transmitted light (46, 54 Fig 3, Fig 4), algebraically weighting derived signals (Figs 5, 6), and overlapping the sensed pixels (Fig 7).
Inventors
- 👤 David G. Gold
- 👤 Vahakn K. Gharibian
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 17:24
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/409; H04N1/4092; G; G06; G06K; G06K19/00; G06K19/06; G06K19/08; G06K19/10; G06K19/14; G06K7/00; G06K7/10; G06K7/14; G06V; G06V30/00; G06V30/10; G06V30/14; G06V30/1437; G07; G07D; G07D7/00; G07D7/20; H04N1/024; H04N1/028; H04N1/029
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
66 words
A method of sensing a characteristic of a document or other article in which radiation from a window area of the article is sensed, characterised in that pixel signals are derived from the radiation weighted to enhance pixel signal values centrally located in said window area, and that the weighted pixel signal values are processed to provide data signals representative of the characteristic of the article.
Claim 2
Independent Claim
66 words
A method of sensing a characteristic of a document or other article in which radiation from a window area of the article is sensed, characterised in that pixel signals are derived from the radiation weighted to enhance pixel signal values centrally located in said window area, and that the weighted pixel signal values are processed to provide data signals representative of the characteristic of the article.
Claim 3
Dependent Claim
21 words
A method according to claim 1 further characterised in that said processing step comprises additively combining said weighted pixel signal values.
Claim 4
Dependent Claim
28 words
A method according to claim 1 or claim 2 further characterised in that weighting of said pixel signals is effected utilising filter means for varying the sensed radiation.
Claim 5
Dependent Claim
25 words
A method according to claim 1 or claim 2 further characterised in that weighting of said pixel signals is effected utilising lapping of the pixels.
Claim 6
Dependent Claim
27 words
A method according to claim 1 or claim 2 further characterised in that weighting of said pixel signals is effected utilising algebraic processing of said pixel signals.
Claim 7
Independent Claim
24 words
A method according to any one of claims 1 to 5 further characterised in that the radiation sensed is radiation transmitted through said article.
Claim 8
Independent Claim
27 words
A method according to any one of claims 1 to 6 further characterised in that it includes the step of illuminating said article to provide said radiation.
Claim 9
Independent Claim
28 words
A method according to any one of claims 1 to 7 further characterised in that it includes the step of correlating said characteristic data signals with stored values.
Claim 10
Independent Claim
73 words
A system for sensing a characteristic of a document or other article in which radiation from a window area of the article is sensed, characterised in that apparatus including sensing means is effective to derive pixel signals from the radiation weighted to enhance pixel signal values centrally located in said window area, and that processing means processes the weighted pixel signal values to provide data signals representative of the characteristic of the article.
Claim 11
Independent Claim
73 words
A system for sensing a characteristic of a document or other article in which radiation from a window area of the article is sensed, characterised in that apparatus including sensing means is effective to derive pixel signals from the radiation weighted to enhance pixel signal values centrally located in said window area, and that processing means processes the weighted pixel signal values to provide data signals representative of the characteristic of the article.
Claim 12
Independent Claim
91 words
A system for sensing characteristic data from a document or other article under investigation, in which radiation from a window area of the article is sensed, characterised in that the system comrises sensing means to sense radiation from said article as data indicative of a characteristic of said article, selection means defining the window area of observation, weighted pixel means contolled by said selection means to dissect said window by controlling said sensing means to sense said window by pixels with weighted pixel significance at the central portion of said window.
Claim 13
Independent Claim
91 words
A system for sensing characteristic data from a document or other article under investigation, in which radiation from a window area of the article is sensed, characterised in that the system comrises sensing means to sense radiation from said article as data indicative of a characteristic of said article, selection means defining the window area of observation, weighted pixel means contolled by said selection means to dissect said window by controlling said sensing means to sense said window by pixels with weighted pixel significance at the central portion of said window.
Claim 14
Dependent Claim
31 words
A system according to claim 10 further characterised in that the system includes means to combine the sensed pixels with weighted pixel significance to provide a representation characteristic of said article.
Claim 15
Independent Claim
24 words
A system according to any one of claims 9 to 11 further characterised in that the system includes filter means for weighting said radiation.
Claim 16
Independent Claim
28 words
A system according to any one of claims 9 to 12 further characterised in that the system includes means for lapping said pixels to attain said weighted significance.
Claim 17
Independent Claim
25 words
A system according to any one of claims 9 to 13 further characterised in that the system includes arithmetic means for algebraically varying said pixels.
Claim 18
Independent Claim
28 words
A system according to any one of claims 9 to 14 further characterised in that the system includes adder means to form signals representative of the said characteristic.
Claim 19
Independent Claim
25 words
A system according to any one of claims 9 to 15 further characterised in that the system includes means for testing the characteristic representation derived.
Claim 20
Dependent Claim
21 words
A system according to claim 16 further characterised in that said means for testing includes means for storing a comparison representation.
References Cited (Backward Citations)
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