US6249588B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for authentication of documents by using the intensity profile of moire patterns
Assignee: École Polytechnique Fédérale de Lausanne
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Filing: 1995-08-28
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Granted: 2001-06-19
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Expires: 2015-08-28
Abstract
Abstract The present invention relates to a new method and apparatus for authenticating documents such as banknotes, trust papers, securities, identification cards, passports, etc. The documents may be printed on any support, including transparent synthetic materials and traditional opaque materials such as paper. This invention is based on moire patterns occuring between superposed dot-screens. By using specially designed basic screen and master screen, where at least the basic screen is comprised in the document, a moire intensity profile of a chosen shape becomes visible in their superposition, thereby allowing the authentication of the document. If instead of the master screen a microlens array is used for the authentication purpose, the document comprising the basic screen may be printed on an opaque reflective support, thereby enabling the visualization of the moire intensity profile by reflection. Automatic document authentication is supported by an apparatus comprising a master screen or a microlens array, an image acquisition means such as a CCD camera and a comparing processor whose task is to compare the acquired moire intensity profile with a prestored reference image. Depending on the match, the document handling device connected to the comparing processor accepts or rejects the document. An important advantage of the present invention is that it can be incorporated into the standard document printing process, so that it offers high security at the same cost as standard state of the art document production.
Inventors
- 👤 Isaac Amidror
- 👤 Roger D. Hersch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:32
CPC Classifications
G; G07; G07D; G07D7/00; G07D7/005; G07D7/0053; G07D7/20; G07D7/202; G07D7/207
Claims Analysis
Total Claims: 50
Claim 1
Independent Claim
72 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; b) creating a master screen with a master screen dot shape; c) superposing the master screen and the basic screen, thereby producing a moire intensity profile; and d) comparing said moire intensity profile with a prestored moire intensity profile.
Claim 2
Independent Claim
72 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; b) creating a master screen with a master screen dot shape; c) superposing the master screen and the basic screen, thereby producing a moire intensity profile; and d) comparing said moire intensity profile with a prestored moire intensity profile.
Claim 3
Dependent Claim
28 words
The method of claim 1 , where the prestored moire intensity profile is obtained by image acquisition of the superposition of the basic screen and the master screen.
Claim 4
Dependent Claim
58 words
The method of claim 1 , where the prestored moire intensity profile is obtained by extracting from a convolution of the frequency spectrum of the basic screen and the frequency spectrum of the master screen those impulses describing a (k 1 ,k 2 ,k 3 ,k 4 )-moire, and by applying to said impulses an inverse Fourier transform.
Claim 5
Dependent Claim
26 words
The method of claim 1 , where the prestored moire intensity profile is obtained by a normalized T-convolution of the basic screen and the master screen.
Claim 6
Dependent Claim
37 words
The method of claim 1 , where the basic screen and the master screen are located on a transparent support, and where comparing the moire intensity profile with a prestored moire intensity profile is done by visualization.
Claim 7
Dependent Claim
49 words
The method of claim 5 , where the basic screen and the master screen are located on two different areas of the same document, thereby enabling the visualization of the moire intensity profile to be performed by superposition of the basic screen and the master screen of said document.
Claim 8
Independent Claim
61 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; b) superposing the basic screen and a microlens array, thereby producing a moire intensity profile; and c) comparing said moire intensity profile with a prestored moire intensity profile.
Claim 9
Independent Claim
61 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; b) superposing the basic screen and a microlens array, thereby producing a moire intensity profile; and c) comparing said moire intensity profile with a prestored moire intensity profile.
Claim 10
Dependent Claim
28 words
The method of claim 7 , where the prestored moire intensity profile is obtained by image acquisition of the superposition of the basic screen and the microlens array.
Claim 11
Dependent Claim
58 words
The method of claim 7 , where the prestored moire intensity profile is obtained by extracting from a convolution of the frequency spectrum of the basic screen and the frequency spectrum of the microlens array those impulses describing a (k 1 ,k 2 ,k 3 ,k 4 )-moire, and by applying to said impulses an inverse Fourier transform.
Claim 12
Dependent Claim
37 words
The method of claim 7 , where the basic screen and the microlens array are located on a transparent support, and where comparing the moire intensity profile with a prestored moire intensity profile is done by visualization.
Claim 13
Dependent Claim
49 words
The method of claim 10 , where the basic screen and the microlens array are located on two different areas of the same document, thereby enabling the visualization of the moire intensity profile to be performed by superposition of the basic screen and the microlens array of said document.
Claim 14
Dependent Claim
30 words
The method of claim 7 , where the document comprising the basic screen is printed on an opaque support, thereby allowing the moire intensity profile to be produced by reflection.
Claim 15
Dependent Claim
33 words
The method of claim 7 , where the basic screen is located on an opaque support, and where comparing the moire intensity profile with a prestored moire intensity profile is done by visualization.
Claim 16
Independent Claim
69 words
An apparatus for authentication of documents making use of at least one moire intensity profile, the apparatus comprising: a) a master screen; b) an image acquisition means arranged to acquire a moire intensity profile produced by the superposition of a basic screen located on a document and the master screen; and c) a comparing means operable for comparing the acquired moire intensity profile with a prestored moire intensity profile.
Claim 17
Independent Claim
69 words
An apparatus for authentication of documents making use of at least one moire intensity profile, the apparatus comprising: a) a master screen; b) an image acquisition means arranged to acquire a moire intensity profile produced by the superposition of a basic screen located on a document and the master screen; and c) a comparing means operable for comparing the acquired moire intensity profile with a prestored moire intensity profile.
Claim 18
Dependent Claim
23 words
The apparatus of claim 14 , where the image acquisition means and comparing means are human biosystems, a human eye and brain respectively.
Claim 19
Dependent Claim
36 words
The apparatus of claim 14 , where the comparing means is a comparing processor controlling a document handling device accepting, respectively rejecting a document to be authenticated, according to the comparison operated by the comparing processor.
Claim 20
Dependent Claim
34 words
The apparatus of claim 16 , where the comparing processor is a microcomputer comprising a processor, memory and input-output ports and where the image acquisition means is a CCD camera connected to said microcomputer.
Claim 21
Independent Claim
69 words
An apparatus for authentication of documents making use of at least one moire intensity profile, the apparatus comprising: a) a microlens array; b) an image acquisition means arranged to acquire a moire intensity profile produced by the superposition of a basic screen located on a document and the mnicrolens array; and c) a comparing means operable for comparing the acquired moire intensity profile with a prestored moire intensity profile.
Claim 22
Independent Claim
69 words
An apparatus for authentication of documents making use of at least one moire intensity profile, the apparatus comprising: a) a microlens array; b) an image acquisition means arranged to acquire a moire intensity profile produced by the superposition of a basic screen located on a document and the mnicrolens array; and c) a comparing means operable for comparing the acquired moire intensity profile with a prestored moire intensity profile.
Claim 23
Dependent Claim
23 words
The apparatus of claim 18 , where the image acquisition means and comparing means are human biosystems, a human eye and brain respectively.
Claim 24
Dependent Claim
36 words
The apparatus of claim 18 , where the comparing means is a comparing processor controlling a document handling device accepting, respectively rejecting a document to be authenticated, according to the comparison operated by the comparing processor.
Claim 25
Dependent Claim
34 words
The apparatus of claim 20 , where the comparing processor is a microcomputer comprising a processor, memory and input-output ports and where the image acquisition means is a CCD camera connected to said microcomputer.
Claim 26
Independent Claim
119 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; b) creating a master screen with a master screen dot shape; c) superposing the master screen and the basic screen, thereby producing a moire intensity profile; and d) comparing said moire intensity profile with a prestored moire intensity profile; where the produced moire intensity profile is a normalized T-convolution of the basic screen and of the master screen and where the orientation and period of the produced moire intensity profile are determined by the orientations and periods of the basic screen and of the master screen.
Claim 27
Independent Claim
119 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; b) creating a master screen with a master screen dot shape; c) superposing the master screen and the basic screen, thereby producing a moire intensity profile; and d) comparing said moire intensity profile with a prestored moire intensity profile; where the produced moire intensity profile is a normalized T-convolution of the basic screen and of the master screen and where the orientation and period of the produced moire intensity profile are determined by the orientations and periods of the basic screen and of the master screen.
Claim 28
Dependent Claim
28 words
The method of claim 22 , where the prestored moire intensity profile is obtained by image acquisition of the superposition of the basic screen and the master screen.
Claim 29
Dependent Claim
31 words
The method of claim 22 , where the master screen contains tiny dots and where the moire intensity profile is a magnified and rotated version of the basic screen dot shape.
Claim 30
Dependent Claim
37 words
The method of claim 22 , where the basic screen and the master screen are located on a transparent support, and where comparing the moire intensity profile with a prestored moire intensity profile is done by visualization.
Claim 31
Dependent Claim
49 words
The method of claim 22 , where the basic screen and the master screen are located on two different areas of the same document, thereby enabling the visualization of the moire intensity profile to be performed by superposition of the basic screen and the master screen of said document.
Claim 32
Independent Claim
88 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; b) superposing the basic screen and a microlens array, thereby producing a moire intensity profile; and c) comparing said moire intensity profile with a prestored moire intensity profile; where the orientation and period of the aquired moire intensity profile are determined by the orientations and periods of the basic screen and of the microlens array.
Claim 33
Independent Claim
88 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; b) superposing the basic screen and a microlens array, thereby producing a moire intensity profile; and c) comparing said moire intensity profile with a prestored moire intensity profile; where the orientation and period of the aquired moire intensity profile are determined by the orientations and periods of the basic screen and of the microlens array.
Claim 34
Dependent Claim
28 words
The method of claim 27 , where the prestored moire intensity profile is obtained by image acquisition of the superposition of the basic screen and the microlens array.
Claim 35
Dependent Claim
37 words
The method of claim 27 , where the basic screen and the mnicrolens array are located on a transparent support, and where comparing the moire intensity profile with a prestored moire intensity profile is done by visualization.
Claim 36
Dependent Claim
49 words
The method of claim 29 , where the basic screen and the microlens array are located on two different areas of the same document, thereby enabling the visualization of the moire intensity profile to be performed by superposition of the basic screen and the microlens array of said document.
Claim 37
Dependent Claim
30 words
The method of claim 27 , where the document comprising the basic screen is printed on an opaque support, thereby allowing the moire intensity profile to be produced by reflection.
Claim 38
Dependent Claim
33 words
The method of claim 27 , where the basic screen is located on an opaque support, and where comparing the moire intensity profile with a prestored moire intensity profile is done by visualization.
Claim 39
Independent Claim
116 words
An apparatus for authentication of documents making use of at least one moire intensity profile, the apparatus comprising: a) a master screen; b) an image acquisition means arranged to acquire a moire intensity profile produced by the superposition of a basic screen located on a document and the master screen; and c) a comparing means operable for comparing the acquired moire intensity profile with a prestored moire intensity profile; where the produced moire intensity profile is a normalized T-convolution of the basic screen and of the master screen and where the orientation and period of the produced moire intensity profile are determined by the orientations and periods of the basic screen and of the master screen.
Claim 40
Independent Claim
116 words
An apparatus for authentication of documents making use of at least one moire intensity profile, the apparatus comprising: a) a master screen; b) an image acquisition means arranged to acquire a moire intensity profile produced by the superposition of a basic screen located on a document and the master screen; and c) a comparing means operable for comparing the acquired moire intensity profile with a prestored moire intensity profile; where the produced moire intensity profile is a normalized T-convolution of the basic screen and of the master screen and where the orientation and period of the produced moire intensity profile are determined by the orientations and periods of the basic screen and of the master screen.
Claim 41
Dependent Claim
23 words
The apparatus of claim 33 , where the image acquisition means and comparing means are human biosystems, a human eye and brain respectively.
Claim 42
Dependent Claim
55 words
The apparatus of claim 33 , where the comparing means is a microcomputer comprising a processor, memory and input-output ports, where the image acquisition means is a CCD camera connected to said microcomputer and where said microcomputer controls a document handling device accepting, respectively rejecting a document to be authenticated, according to the operated comparison.
Claim 43
Independent Claim
96 words
An apparatus for authentication of documents making use of at least one moire intensity profile, the apparatus comprising: a) a microlens array; b) an image acquisition means arranged to acquire a moire intensity profile produced by the superposition of a basic screen located on a document and the microlens array; and c) a comparing means operable for comparing the acquired moire intensity profile with a prestored moire intensity profile; where the orientation and period of the aquired moire intensity profile are determined by the orientations and periods of the basic screen and of the microlens array.
Claim 44
Independent Claim
96 words
An apparatus for authentication of documents making use of at least one moire intensity profile, the apparatus comprising: a) a microlens array; b) an image acquisition means arranged to acquire a moire intensity profile produced by the superposition of a basic screen located on a document and the microlens array; and c) a comparing means operable for comparing the acquired moire intensity profile with a prestored moire intensity profile; where the orientation and period of the aquired moire intensity profile are determined by the orientations and periods of the basic screen and of the microlens array.
Claim 45
Dependent Claim
23 words
The apparatus of claim 36 , where the image acquisition means and comparing means are human biosystems, a human eye and brain respectively.
Claim 46
Dependent Claim
55 words
The apparatus of claim 36 , where the comparing means is a microcomputer comprising a processor, memory and input-output ports, where the image acquisition means is a CCD camera connected to said microcomputer and where said microcomputer controls a document handling device accepting, respectively rejecting a document to be authenticated, according to the operated comparison.
Claim 47
Independent Claim
67 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; b) creating a master screen with a master screen dot shape; and c) superposing the master screen and the basic screen, thereby producing a moire intensity profile which is apparent to a human eye.
Claim 48
Independent Claim
67 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; b) creating a master screen with a master screen dot shape; and c) superposing the master screen and the basic screen, thereby producing a moire intensity profile which is apparent to a human eye.
Claim 49
Independent Claim
56 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; and b) superposing the basic screen and a microlens array, thereby producing a moire intensity profile which is apparent to a human eye.
Claim 50
Independent Claim
56 words
A method for authenticating documents by using at least one moire intensity profile, the method comprising the steps of: a) creating on a document a basic screen with a basic screen dot shape; and b) superposing the basic screen and a microlens array, thereby producing a moire intensity profile which is apparent to a human eye.
References Cited (Backward Citations)
GB1138011A
Cited
US4278755A
Cited
GB2224240A
Cited
US5018767A
Cited
US4999006A
Cited
US5275870A
Cited
US5396559A
Cited
US5537486A
Cited
US5487567A
Cited
US5995638A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-06-18 | 2004-12-18 | 2005-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-06-18 | 2008-12-18 | 2009-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-06-18 | 2012-12-18 | 2013-06-19 | $7700.00 | Window Closed / Lapsed |