CA2057479C - Support provided with a security element - Google Patents

Support provided with a security element Download PDF

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Publication number
CA2057479C
CA2057479C CA002057479A CA2057479A CA2057479C CA 2057479 C CA2057479 C CA 2057479C CA 002057479 A CA002057479 A CA 002057479A CA 2057479 A CA2057479 A CA 2057479A CA 2057479 C CA2057479 C CA 2057479C
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CA
Canada
Prior art keywords
image
security element
gradation value
visual system
human visual
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
CA002057479A
Other languages
French (fr)
Other versions
CA2057479A1 (en
Inventor
Sijbrand Spannenburg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Joh Enschede en Zonen Grafische Inrichting BV
Original Assignee
Joh Enschede en Zonen Grafische Inrichting BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Joh Enschede en Zonen Grafische Inrichting BV filed Critical Joh Enschede en Zonen Grafische Inrichting BV
Publication of CA2057479A1 publication Critical patent/CA2057479A1/en
Application granted granted Critical
Publication of CA2057479C publication Critical patent/CA2057479C/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00838Preventing unauthorised reproduction
    • H04N1/00856Preventive measures
    • H04N1/00875Inhibiting reproduction, e.g. by disabling reading or reproduction apparatus
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B42BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42DBOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/20Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose
    • B42D25/29Securities; Bank notes
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00838Preventing unauthorised reproduction
    • H04N1/0084Determining the necessity for prevention
    • H04N1/00843Determining the necessity for prevention based on recognising a copy prohibited original, e.g. a banknote
    • H04N1/00846Determining the necessity for prevention based on recognising a copy prohibited original, e.g. a banknote based on detection of a dedicated indication, e.g. marks or the like
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00838Preventing unauthorised reproduction
    • H04N1/00856Preventive measures
    • H04N1/00859Issuing an alarm or the like
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/32Circuits or arrangements for control or supervision between transmitter and receiver or between image input and image output device, e.g. between a still-image camera and its memory or between a still-image camera and a printer device
    • H04N2201/3201Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
    • H04N2201/3269Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of machine readable codes or marks, e.g. bar codes or glyphs
    • H04N2201/327Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title of machine readable codes or marks, e.g. bar codes or glyphs which are undetectable to the naked eye, e.g. embedded codes
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S283/00Printed matter
    • Y10S283/901Concealed data
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S283/00Printed matter
    • Y10S283/902Anti-photocopy

Abstract

A support provided with a machine-detectable security element, particularly a copying-security element. The security element comprises a first image perceptible to the human visual system, said first image incorporating a second image that is substantially imperceptible to the human visual system.

Description

2Q~'~~'~9 SOPPORT PROVIDED WITH A SECORITY ELEMENT
The invention relates to a support provided with a machine-detectable security element, particularly a copying-security element.
Now sophisticated copiers, such as colour copiers with a matrix laser scanner in particular, and graphic lay-out stati-ons are becoming available for an increasing public, large numbers of photocopies of an original can be produced in an inexpensive and rapid way, the photocopies being not at all or scarcely - distinguishable from the original.
In order to put an end to this technique of copying documents such as valuable documents, e.g. bank notes, or confidential documents, one thought of providing the support with a copy-ing-security element detectable by a copier, so that in the event of detection suitable measures can be taken. In this concept, the copying-security element is formed by an object that is detectable by the copier, e.g. a filament which is incorporated in the support during the manufacturing process of the support, or by a unique type of printing ink having particular optical features. Furthermore, the copier should be provided with suitable detection means.
The invention aims to provide a support with a security ele-ment without any special treatment of the support or the use of special printing inks being required for the provision of the security element.

- X0574.79 In accordance with one aspect of the present invention there is provided an image support carrying a first image perceptible to the human visual system, and a machine-detectable security element, particularly a copying-security element, said first image being composed of line segments arranged in a regular raster pattern, characterized in that line segments have different angular orientations in a plane of the support, said first image incorporates a second image that is substantially imperceptible to the human visual system, said second image being formed by the difference in angular orientation of the line segments, said angular orientation of the line segments being a function of a gradation value of the security element, said first and second images being perceptible to the human visual system after copying.
In accordance with another aspect of the present invention there is provided a method of producing a regular raster pattern for printing a first image perceptible to the human visual system on an image support, and a machine-detectable security element, particularly a copying-security element, said regular raster pattern consisting of raster picture elements each consisting of a line segment, said method being characterized in that line segments are given different angular orientations in a plane of the support, in that a second image is incorporated into the first image by forming said angular orientations of line segments as a function of a gradation value of the security element, said second image being substantially imperceptible to the human visual system, said first and second images being perceptible to the human visual system after copying.
A

- 2a - L057't79 Additional purposes, characteristics and advantages of the support according to the invention will become clear after the following description of a number of preferred embodiments of the support according to the invention, in which references are made to the accompanying drawings, in which:
Fig. la shows an enlargement of an image on a support that is obtained by raster printing techniques;
Fig. lb shows an enlargement of a copy of the image of fig. la;
Fig. 2a shows an enlargement of a substantially uniform image on a support according to the invention that is provided with a first embodiment of a copying-security element;
Fig. 2b shows a partial enlargement of fig. 2a;
Fig. 2c shows an enlargement of a copy of the image of fig. 2a;
Fig. 2d shows a partial enlargement of fig. 2c;
Fig. 3a shows an enlargement of an image on a support according to the invention, in said image the copying-security element of fig. 2a being superposed on the image of fig. la;

~o~~~~~

Fig. 3b shows an enlargement of a copy of the image according to fig. 3a;
Fig. 4a shows an enlargement of the substantially uniform image on a support according to the invention which is provi-ded with a second embodiment of a copying-security element;
Fig. 4b shows a partial enlargement of fig. 4a;
Fig. 4c shows an enlargement of a copy of the image according to fig. 4a;
Fig. 4d shows a partial enlargement according to fig. 4c;
Fig. 5a shows an enlargement of an image on a support accor-ding to the invention, wherein the copying-security element of fig. 4a is superposed on the image of fig. la; and Fig. 5b shows an enlargement of a copy of the image according to fig. 5a.
In order to make the description as clear as possible, all images represented in the figures are shown on a larger scale.
Particularly the images according to figures 2b, 2d, 4b and 4d are represented at six times the full scale, the other images are represented at circa three times the full scale. Whenever a normal distance of assessment is given below, one should take this enlargement into consideration. Furthermore, when assessing the undermentioned visual effects one should realize that the figures accompanying the description are in fact copies, even if they are referred to in the text as originals, which have been obtained by copying the originals once or every so often.
2 ~l 5'~ 4'~ 9 Fig. la shows an image applied onto a support, said image being composed of image elements divided according to a regu-lar raster pattern which consist of circular raster pixels, the surface of which, particularly the diameter, being modula-ted in a way that is common practice in techniques of printing with one or several colours by the use of one or more rasters.
The image is represented at circa three times the full scale.
The density of the raster pixels amounts to circa 100 dpi in reality, which corresponds to a distance of raster pixels of circa 250 ~cm. The support can be made of every material that is suitable for supporting an image perceptible to the human visual system, e.g. paper or synthetic materials.
In the event of a normal distance of assessment, the human visual system will be unable to discern any individual raster pixels, so that the image will be seen as a continuous halfto-ne image.
Fig. lb shows an enlargement of a copy of the image of fig.
la, said copy being obtained by means of a Cannon matrix laser copier having a resolution of 400 dpi and by laser scanning of the original in a matrix. As a result, the distance of the matrix grid of this copier is circa 60 ~,m. As the distance of the grid is smaller than that of the raster pixels, undersam-pling can be avoided, even when the standard model of the copier is provided with a digital filter operating on 3x3 submatrices.
Fig. 2a shows an enlargement of an image of a support accor-ding to the invention, percepted by the human eye as a uniform image at a normal distance of assessment, the image being composed of image elements formed by raster elements or raster "pixels" of a density of 100 dpi, each raster point being shaped as a line segment instead of a circular point as in fig. la. Fig. 2b shows a partial enlargement of fig. 2a. This deformation of circular raster pixels into linear ones will be imperceptible to the human visual system at a normal distance of assessment, due to the high density of the raster pixels.
In other words, a second image is incorporated in the uniform image in the form of a deformation of the image elements of the uniform image into line segments, said second image being imperceptible to the human eye at a normal distance of asses-sment. As the resolution of the copier is nevertheless of an adequate level, this copier will be able to distinguish circu-lar raster pixels from linear ones. Consequently, when this deformation of the raster pattern is detected by the copier, a blocking circuit being part of the copier or connected to it will prevent the copying of the image and/or give an alarm.
Corresponding to a density of raster pixels of 100 dpi is a distance of raster pixels of circa 250 Vim. The width of a line segment is 30 ~cm in this particular example. Such a width is feasible according to raster printing techniques that are currently avaible.
As is shown in fig. 2a, not only the deformation into line segments, in this case the deformation of all the raster pixels although that is not necessary, but also the degree of deformation of the raster pixels differs due to different angular orientations of the line segments in the plane of the support. In that case the angular orientation is a function of a gradation value of a picture corresponding to the mirror image of fig. la. Therefore, the function ~ for the raster point i is represented by:

- 6 - L0574.79 ~t = ~d~x~Y)- dmin~ ~+ ~p ~dmax - dmin) wherein d (x, y) is the gradation value of the picture at the point with the coordinates (x, y), dmin is the minimum gradation value, d",aX is the maximum gradation value, and ~o is an initial angle which equals n/2 in the example.
Therefore, ~i varies continuously within the range rz/2 to 3rr/2.
The copy of the image of fig. 2a, obtained by means of the copier, said copy being represented in fig. 2c, shows clearly that the copy's picture is perceptible indeed or at least considerably more perceptible to the human visual system at a normal distance of assessment. Fig 2d shows a partial enlargement of fig 2c. This visual effect can be explained on account of the fact that the current sophisticated copiers are provided with digital filter circuits such as sharpness-enhancing filters.
Furthermore, changes of colour seemed to occur in the copy, even when the original image was applied in black and white on the support. These changes of colour facilitate the perceptibility of the picture to the human visual system to a further degree.
In addition to that, the orientation of the raster pattern of the support with respect to the matrix of the copier appears to have relevance, e.g. to the angles 0°, 45° and 90°, as well as the mode in which the copier was set , a . g . normal mode or photo mode .
In this way, the support according to the invention is provided with a second image which is imperceptible at a normal '~ ~l 5'~ 4'~ 9 distance of assessment, yet which is perceptible in the copy in the form of a picture to the human visual system at a normal distance of assessment, when the copier allows produ-cing and supplying a copy, which can be the case, for example, when the copier is not provided with a copying-security ele-ment detection circuit and/or a blocking circuit. Therefore, without any additional appliances an original document can be distinguished from a copy. Besides, there are no special requirements with respect to the support and/or applied prin-ting ink. A major advantage is that the copier can be of the currently used type which is not provided with special detec-tion and blocking circuits.
Due to the fact that the deformation of the first image of the support according to the invention is not at all or scarcely perceptible, the second image can be superposed on an image that is modulated in the usual way, e.g. the image according to fig. la, the amplitude of which is modulated. As an exam-ple, reference is made to fig. 3a which shows an enlargement of an image on a support, the second image of fig. 2a being superposed on the image of fig. la. The modulation of the image perceptible to the human visual system is performed by modulating the width of the line segments similarly to the modulation of the diameter of the circular raster pixels in fig. la.
Fig. 3b shows an enlargement of a copy of the image of fig.
3a. At a normal distance of assessment the deformation of the original image is clearly perceptible, so that the mirror image of fig. la is also visible now - this time in negative.
In this case the minimum line width is only 30 ~,m. It is advantageous to select the non-modulated line width as small as possible, as the provision of an out-of-focus filter in the copier may even cause the total absence of the lightest parts from the copy, so that the copy and the original are visibly distinct.

- 8 - 20574.79 A major advantage of the security element according to the invention, in particular the picture concealed in the image whuch represents in this case the mirror image of fig. la, is that it extends over a considerable surface area of the perceptible image, in this case the entire surface. The effect of this is that the copying-security element is fully incorporated in the image of the support to be protected, and moreover, in such a way that the perceptibility of the first image does not - or only scarcely - decrease. The picture concealed in the image as a result of the deformation can also represent a code which is, for example, composed of alphanumeric symbols or a bar code. In that case the copier may be provided with appropriate reading circuits.
Fig. 4a shows an enlargement of a substantially uniform image on a support according to the invention, wherein a second embodiment of the copying-security element is provided which comprises a deformation of raster pixels into line segments which are orientated in accordance with the following function:
. - (d(x,y) - dgem) . 7t + 7t (2) 1 Id(x,y) - dgeml 4 4 wherein ~i is the angle of the image segment i with the horizontal, d(x,y) is the gradation value of the picture at the point with coordinates (x, y) , and deem is an average gradation value. Therefore, each line segment is inclined at an angle of 0 or rr/2, and the function ~ is a binary function. The average value dgem can, for example, equal half of the maximum gradation value of the original picture or which is the limit set by the printing process. Fig. 4b shows a partial enlargement of fig. 4a.

_.. ~~5'~4'?'9 _ g Fig. 4c shows an enlargement of a copy of the image on the support according to fig. 4a, wherein the copy clearly shows the deformation, even at a normal distance of assessment by the human visual system. Fig. 4d shows a partial enlargement of fig. 4c.
In a way similar to that of figures 3a and 3b, figures 5a and 5b show an enlargement of an image and its copy, respectively, wherein the image according to fig. 4a is superposed on the image according to fig. la.
It is noted that the examples with respect to the figures are only meant to illustrate a support provided with a security element according to the invention.
It will be obvious to the expert that many variations of the above-described embodiments of the support according to the invention are feasible within the scope of the invention.
Therefore, other deformations of the image element can be selected than the ones described, including a deformation comprising local translations of the image elements. The foregoing numerical values are only meant to be illustrative and may be adjusted to the specifications of the copiers. The invention also relates to supports provided with an image that is visually perceptible and that is obtained by means of so-called frequency modulation techniques.

Claims (6)

1. An image support carrying a first image perceptible to the human visual system, and a machine-detectable security element, particularly a copying-security element, said first image being composed of line segments arranged in a regular raster pattern, characterized in that line segments have different angular orientations in a plane of the support, said first image incorporates a second image that is substantially imperceptible to the human visual system, said second image being formed by the difference in angular orientation of the line segments, said angular orientation of the line segments being a function of a gradation value of the security element, said first and second images being perceptible to the human visual system after copying.
2. The image support according to claim 1, characterized in that the function of the gradation value is a continuous function of the gradation value of a security element forming an area identical to the area formed by the first image, said first image and said security element being perceptible to the human visual system after copying.
3. The image support according to claim 2, characterized in that said function is:

wherein .PHI.i is the angle formed by line segment i having coordinates (x, y) within the area of the raster pattern, d(x,y) is the gradation value of the security element at the point (x, y) within the area of the security element, d min is the minimum gradation value, d max is the maximum gradation value, and .PHI.0 is an initial angle.
4. A method of producing a regular raster pattern for printing a first image perceptible to the human visual system on an image support, and a machine-detectable security element, particularly a copy-security element, said regular raster pattern consisting of raster picture elements each consisting of a line segment, said method being characterized in that line segments are given different angular orientations in a plane of the support, in that a second image is incorporated into the first image by forming said angular orientations of line segments as a function of a gradation value of the security element, said second image being substantially imperceptible to the human visual system, said first and second images being perceptible by the human visual system after copying.
5. The method according to claim 4, characterized in that as said function a continuous function of the gradation value of the security element forming an area identical to the area formed by the raster pattern is chosen, said first image and said security element being perceptible by the human visual system after copying.
6. The method according to claim 5, characterized in that said function is:

wherein .PHI.i is the angle formed by line segment i having coordinates (x, y) within the area of the raster pattern, d(x,y) is the gradation value of the security element at the point (x,y) within the area of the security element, d min is the minimum gradation value, d maX is the maximum gradation value, and .PHI.o is an initial angle.
CA002057479A 1990-12-13 1991-12-12 Support provided with a security element Expired - Lifetime CA2057479C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL9002740A NL192610C (en) 1990-12-13 1990-12-13 Image carrier and method for printing an image on an image carrier.
NL9002740 1990-12-13

Publications (2)

Publication Number Publication Date
CA2057479A1 CA2057479A1 (en) 1992-06-14
CA2057479C true CA2057479C (en) 2000-11-21

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CA002057479A Expired - Lifetime CA2057479C (en) 1990-12-13 1991-12-12 Support provided with a security element

Country Status (12)

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US (1) US5374976A (en)
EP (1) EP0490457B1 (en)
JP (1) JP3242684B2 (en)
AT (1) ATE136848T1 (en)
CA (1) CA2057479C (en)
DE (1) DE69118837T2 (en)
DK (1) DK0490457T3 (en)
ES (1) ES2089118T3 (en)
GR (1) GR3020558T3 (en)
HK (1) HK1006957A1 (en)
IL (1) IL100352A (en)
NL (1) NL192610C (en)

Families Citing this family (104)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6738491B1 (en) * 1992-06-30 2004-05-18 Minolta Co., Ltd. Image forming apparatus and copy management system
US5721788A (en) 1992-07-31 1998-02-24 Corbis Corporation Method and system for digital image signatures
US6301369B2 (en) 1992-07-31 2001-10-09 Digimarc Corporation Image marking to permit later identification
WO1995027627A1 (en) * 1992-10-01 1995-10-19 Joh. Enschedé En Zonen Grafische Inrichting B.V. Method for making a code image, original comprising such a code image and photocopier for copying such an original
US6757406B2 (en) 1993-11-18 2004-06-29 Digimarc Corporation Steganographic image processing
US5768426A (en) 1993-11-18 1998-06-16 Digimarc Corporation Graphics processing system employing embedded code signals
US6681028B2 (en) 1995-07-27 2004-01-20 Digimarc Corporation Paper-based control of computer systems
US6122403A (en) 1995-07-27 2000-09-19 Digimarc Corporation Computer system linked by using information in data objects
US6944298B1 (en) 1993-11-18 2005-09-13 Digimare Corporation Steganographic encoding and decoding of auxiliary codes in media signals
US6408082B1 (en) 1996-04-25 2002-06-18 Digimarc Corporation Watermark detection using a fourier mellin transform
US6516079B1 (en) 2000-02-14 2003-02-04 Digimarc Corporation Digital watermark screening and detecting strategies
US20020009208A1 (en) * 1995-08-09 2002-01-24 Adnan Alattar Authentication of physical and electronic media objects using digital watermarks
US6611607B1 (en) 1993-11-18 2003-08-26 Digimarc Corporation Integrating digital watermarks in multimedia content
US6574350B1 (en) 1995-05-08 2003-06-03 Digimarc Corporation Digital watermarking employing both frail and robust watermarks
US6424725B1 (en) 1996-05-16 2002-07-23 Digimarc Corporation Determining transformations of media signals with embedded code signals
US6580819B1 (en) 1993-11-18 2003-06-17 Digimarc Corporation Methods of producing security documents having digitally encoded data and documents employing same
US6614914B1 (en) 1995-05-08 2003-09-02 Digimarc Corporation Watermark embedder and reader
US7113615B2 (en) 1993-11-18 2006-09-26 Digimarc Corporation Watermark embedder and reader
US7171016B1 (en) 1993-11-18 2007-01-30 Digimarc Corporation Method for monitoring internet dissemination of image, video and/or audio files
US6449377B1 (en) * 1995-05-08 2002-09-10 Digimarc Corporation Methods and systems for watermark processing of line art images
US6345104B1 (en) * 1994-03-17 2002-02-05 Digimarc Corporation Digital watermarks and methods for security documents
US6983051B1 (en) 1993-11-18 2006-01-03 Digimarc Corporation Methods for audio watermarking and decoding
US5748763A (en) 1993-11-18 1998-05-05 Digimarc Corporation Image steganography system featuring perceptually adaptive and globally scalable signal embedding
US7676059B2 (en) * 1994-10-21 2010-03-09 Digimarc Corporation Video steganography or encoding
DE69521153T2 (en) 1994-01-20 2002-05-02 Omron Tateisi Electronics Co Image processing device and method for detecting a reference pattern
US6522770B1 (en) 1999-05-19 2003-02-18 Digimarc Corporation Management of documents and other objects using optical devices
US7286684B2 (en) * 1994-03-17 2007-10-23 Digimarc Corporation Secure document design carrying auxiliary machine readable information
CA2195682C (en) * 1994-07-26 2007-01-30 Dennis G. Priddy Unalterable self-verifying articles
US6560349B1 (en) * 1994-10-21 2003-05-06 Digimarc Corporation Audio monitoring using steganographic information
US6879701B1 (en) * 1994-10-21 2005-04-12 Digimarc Corporation Tile-based digital watermarking techniques
US6728390B2 (en) 1995-05-08 2004-04-27 Digimarc Corporation Methods and systems using multiple watermarks
US6590996B1 (en) 2000-02-14 2003-07-08 Digimarc Corporation Color adaptive watermarking
US6760463B2 (en) 1995-05-08 2004-07-06 Digimarc Corporation Watermarking methods and media
US6721440B2 (en) 1995-05-08 2004-04-13 Digimarc Corporation Low visibility watermarks using an out-of-phase color
US7555139B2 (en) 1995-05-08 2009-06-30 Digimarc Corporation Secure documents with hidden signals, and related methods and systems
US7224819B2 (en) 1995-05-08 2007-05-29 Digimarc Corporation Integrating digital watermarks in multimedia content
US5710636A (en) * 1995-06-05 1998-01-20 Xerox Corporation Method and apparatus for generating halftone images having human readable patterns formed therein
US6577746B1 (en) 1999-12-28 2003-06-10 Digimarc Corporation Watermark-based object linking and embedding
US6829368B2 (en) 2000-01-26 2004-12-07 Digimarc Corporation Establishing and interacting with on-line media collections using identifiers in media signals
US6788800B1 (en) 2000-07-25 2004-09-07 Digimarc Corporation Authenticating objects using embedded data
BR9601506A (en) * 1995-08-01 1998-03-17 Brugada Jorge Clemen Bernardes Security support printed with micro-pattern preventing document forgery when using high-precision copiers
US6859534B1 (en) * 1995-11-29 2005-02-22 Alfred Alasia Digital anti-counterfeiting software method and apparatus
US6201879B1 (en) * 1996-02-09 2001-03-13 Massachusetts Institute Of Technology Method and apparatus for logo hiding in images
US6381341B1 (en) 1996-05-16 2002-04-30 Digimarc Corporation Watermark encoding method exploiting biases inherent in original signal
US5788285A (en) * 1996-06-13 1998-08-04 Wicker; Thomas M. Document protection methods and products
DE19635761A1 (en) * 1996-09-03 1998-03-05 Giesecke & Devrient Gmbh Document with moirE-generating raster structure
US5722693A (en) * 1996-10-03 1998-03-03 Wicker; Kenneth M. Embossed document protection methods and products
EP0901282B1 (en) 1997-09-03 2006-06-28 Hitachi, Ltd. Method for recording and reproducing electronic watermark information
US5996893A (en) * 1997-10-28 1999-12-07 Eastman Kodak Company Method and apparatus for visually identifying an area on a photograph or image where digital data is stored
DE69835133T8 (en) * 1997-12-03 2007-05-16 Kabushiki Kaisha Toshiba, Kawasaki Image information processing method and method for preventing counterfeiting of certificates and the like
US6804376B2 (en) 1998-01-20 2004-10-12 Digimarc Corporation Equipment employing watermark-based authentication function
US6092732A (en) * 1998-01-29 2000-07-25 Xerox Corporation Selectively accented serpentine halftone patterns for embedding human readable information in images
US6081345A (en) * 1998-01-29 2000-06-27 Xerox Corporation Line screen having extended dynamic tone range for embedding machine readable data in halftone images
US5946103A (en) * 1998-01-29 1999-08-31 Xerox Corporation Halftone patterns for trusted printing
JP3256180B2 (en) * 1998-06-09 2002-02-12 株式会社モノリス Method for encrypting and decrypting three-dimensional shape data
US6320680B1 (en) * 1998-06-18 2001-11-20 Digimarc Corporation Stochastic scanning documents to change moire effects
US6978036B2 (en) * 1998-07-31 2005-12-20 Digimarc Corporation Tamper-resistant authentication techniques for identification documents
US7055034B1 (en) 1998-09-25 2006-05-30 Digimarc Corporation Method and apparatus for robust embedded data
US6351537B1 (en) 1998-10-05 2002-02-26 3M Innovative Properties Company Verifiable holographic article
US6608919B1 (en) 1999-11-10 2003-08-19 Digimarc Corporation Method and apparatus for encoding paper with information
US6625297B1 (en) 2000-02-10 2003-09-23 Digimarc Corporation Self-orienting watermarks
CA2334193A1 (en) 2000-03-23 2001-09-23 Eastman Kodak Company A method for printing and verifying limited edition stamps
AU2001255445A1 (en) 2000-04-17 2001-10-30 Digimarc Corporation Authentication of physical and electronic media objects using digital watermarks
US6804377B2 (en) 2000-04-19 2004-10-12 Digimarc Corporation Detecting information hidden out-of-phase in color channels
NL1016161C2 (en) 2000-09-12 2002-03-26 Joh Enschedu B V Electronic verification device for security markings, converts first scanned image fragment into second fragment in which marking can be made visible
WO2002039714A2 (en) * 2000-11-08 2002-05-16 Digimarc Corporation Content authentication and recovery using digital watermarks
US8543823B2 (en) 2001-04-30 2013-09-24 Digimarc Corporation Digital watermarking for identification documents
DE10127979C1 (en) 2001-06-08 2002-11-07 Ovd Kinegram Ag Zug Diffractive security element for verifying document validity has mosaic of optical structure elements overlaid by individual cell pattern
ATE509326T1 (en) 2001-12-18 2011-05-15 L 1 Secure Credentialing Inc MULTIPLE IMAGE SECURITY FEATURES FOR IDENTIFYING DOCUMENTS AND METHOD FOR PRODUCING THEM
US7728048B2 (en) 2002-12-20 2010-06-01 L-1 Secure Credentialing, Inc. Increasing thermal conductivity of host polymer used with laser engraving methods and compositions
US7321667B2 (en) 2002-01-18 2008-01-22 Digimarc Corporation Data hiding through arrangement of objects
US7824029B2 (en) 2002-05-10 2010-11-02 L-1 Secure Credentialing, Inc. Identification card printer-assembler for over the counter card issuing
US7974495B2 (en) 2002-06-10 2011-07-05 Digimarc Corporation Identification and protection of video
AU2002951963A0 (en) * 2002-10-09 2002-10-24 Commonwealth Scientific And Industrial Research Organisation Method of combining images
US8444181B2 (en) 2002-10-10 2013-05-21 Document Security Systems, Inc. Single-color screen patterns for copy protection
US7307761B2 (en) * 2002-12-12 2007-12-11 Electronics For Imaging, Inc. Methods and apparatus for watermarking digitally printed documents
EP1614064B1 (en) 2003-04-16 2010-12-08 L-1 Secure Credentialing, Inc. Three dimensional data storage
US7906198B2 (en) 2003-05-29 2011-03-15 Wicker Thomas M Document containing security images
AU2003902810A0 (en) * 2003-06-04 2003-06-26 Commonwealth Scientific And Industrial Research Organisation Method of encoding a latent image
AU2003903502A0 (en) * 2003-07-07 2003-07-24 Commonwealth Scientific And Industrial Research Organisation A method of forming a diffractive authentication device
EP1641628B1 (en) * 2003-07-07 2015-04-08 Commonwealth Scientific And Industrial Research Organisation Method of encoding a latent image
AU2003903501A0 (en) * 2003-07-07 2003-07-24 Commonwealth Scientific And Industrial Research Organisation A method of forming a reflective authentication device
US8181884B2 (en) 2003-11-17 2012-05-22 Digimarc Corporation Machine-readable features for objects
US7845572B2 (en) 2005-08-01 2010-12-07 Document Security Systems, Inc. Solid-color embedded security feature
CA2631878A1 (en) * 2005-12-05 2007-06-14 Commonwealth Scientific And Industrial Research Organisation A method of forming a securitized image
US7873237B2 (en) * 2006-02-17 2011-01-18 Dassault Systèmes Degrading 3D information
US20080088621A1 (en) * 2006-10-11 2008-04-17 Jean-Jacques Grimaud Follower method for three dimensional images
DE102007000880A1 (en) 2007-11-12 2009-05-14 Bundesdruckerei Gmbh Document with an integrated display device
DE102007000881A1 (en) 2007-11-12 2009-05-14 Bundesdruckerei Gmbh Document with an integrated display device, method for producing a document and a reader
DE102007000875A1 (en) 2007-11-12 2009-05-14 Bundesdruckerei Gmbh Document with an integrated display device
AU2009230885A1 (en) * 2008-04-03 2009-10-08 Commonwealth Scientific And Industrial Research Organisation A hidden image method and a hidden image apparatus
EP2724331B1 (en) * 2011-06-27 2020-11-11 Canadian Bank Note Company, Limited Encoding hidden information in spatial line frequencies
US8610958B2 (en) 2012-02-21 2013-12-17 Ecole Polytechnique Federale De Lausanne (Epfl) Synthesis of authenticable color multi-halftone images
USD764810S1 (en) * 2015-01-09 2016-08-30 Erika Duparc Textile substrate with surface ornamentation
CN114296175A (en) 2016-07-15 2022-04-08 光场实验室公司 Energy propagation and lateral Anderson localization using two-dimensional, light-field and holographic repeaters
WO2018014045A2 (en) * 2016-07-15 2018-01-18 Light Field Lab, Inc. Method of calibration for holographic energy directing systems
CN112074773B (en) 2018-01-14 2024-02-02 光场实验室公司 Four-dimensional energy field packaging assembly
US11181749B2 (en) 2018-01-14 2021-11-23 Light Field Lab, Inc. Systems and methods for transverse energy localization in energy relays using ordered structures
EP3826741A4 (en) 2018-07-25 2022-08-10 Light Field Lab, Inc. Light field display system based amusement park attraction
US10904479B2 (en) 2019-03-12 2021-01-26 Light Field Lab, Inc. Video communication including holographic content
US11212514B2 (en) 2019-03-25 2021-12-28 Light Field Lab, Inc. Light field display system for cinemas
US11428933B2 (en) 2019-05-13 2022-08-30 Light Field Lab, Inc. Light field display system for performance events
EP4010756A4 (en) 2019-08-09 2023-09-20 Light Field Lab, Inc. Light field display system based digital signage system
CN114270255A (en) 2019-08-26 2022-04-01 光场实验室公司 Light field display system for sports

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4310180A (en) * 1977-05-18 1982-01-12 Burroughs Corporation Protected document and method of making same
US4210346A (en) * 1977-06-23 1980-07-01 Burroughs Corporation Protected document bearing watermark and method of making
US4168088A (en) * 1977-12-15 1979-09-18 Burroughs Corporation Protected document and method of making the same
US4175774A (en) * 1978-03-23 1979-11-27 American Standard Inc. Non-copying printed document and method of printing same
US4227719A (en) * 1978-09-20 1980-10-14 Burroughs Corporation Protection system for documents
US4579370A (en) * 1982-09-10 1986-04-01 Burroughs Corporation Multi-tone cancellation phrase and background
JPS59222398A (en) * 1983-05-31 1984-12-14 株式会社細川活版所 Print suitable for forgery prevention
JPS6017778A (en) * 1983-07-12 1985-01-29 Hosokawa Katsupanshiyo:Kk Copy impossible form and its manufacture
US4891666A (en) * 1988-11-28 1990-01-02 Quebecor Publitech Inc. Copy indicator for a document
FR2667825B1 (en) * 1990-10-12 1996-10-04 Hubert Calvados CODED ENGRAVING PRODUCT, INCLUDING DOCUMENT, MEANS FOR PRODUCING SUCH A PRODUCT AND MEANS FOR READING SUCH A PRODUCT.
US5078428A (en) * 1990-12-03 1992-01-07 Hosokawa Printing Co., Ltd. Copy-proof sheet

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US5374976A (en) 1994-12-20
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