DE102004022976A1 - Steganographic printing and verification system uses transparent overlay with apparently random pattern placed on apparently random printed pattern to make picture or text visible - Google Patents

Abstract

Coded information on packaging may be printed in monochrome with an apparently random raster pattern giving a grey field. An initial printed region (1) may have an L-shape and a small square defining corners of the printed region and the coded message may be printed in the space between the L-shape and small square. A frequency or stochastic modulation system may be used. A transparent overlay with a frequency or stochastic modulation pattern is used to visualize the coded information as a black-and-white pattern. An offset or flexographic printing process may be used.

Description

object The invention is a steganographic printing method for attachment hidden messages, such as a sequential number and / or a date and the like by means of conventional Printing method, in particular by means of offset, flexo and gravure printing methods in preferably monocolorer design.

at forgery critical Products, such as packaging, a leaflet, a Blister packaging and the like printed products in the pharmaceutical sector, in the food industry, cosmetics and similar areas is often a cost effective possibility the installation of a hidden information desired.

Of the Incorporation of digital secret watermarks would be counterfeit-proof increase significantly but leads due to the need to use a security feature substance additional Production costs and does moreover a correspondingly selective and expensive verification system is required.

In the EP00877998B1 a method is performed, such as by a software program on a computer system, for digitally producing tamper-blended encoded indicia for application to printed matter by (i) digitizing and dividing an input image into elementary input segments in accordance with a basic code factor specifying the number of segments; (ii) mixing the input segments by translation in accordance with a lens density factor of a lens used for decoding, the mixing process creating mixed elementary output segments; (iii) digitizing and screening a source image into segments depending on the number of merged elementary output segments generated; (iv) merging the rasterized source image segments with the merged elementary output segments to obtain an output image; and (v) printing the output image with a resolution such that the decrypting lens can be used to obtain the input image. The disadvantage is the expense associated with the method.

In WO03105111A1 a method is called, which for the verification Lens systems needed. The preparation of such transparent verification elements with Lens structures is expensive and expensive and will therefore only for some few products realized, for example in stamps.

In the EP01003324B1 For example, a document having a support with printed text and graphics thereon, which graphic provides a visual impression to human viewers of the graphics and secretly transmits multiple bits of digital data retrievable by computer analysis of that graphic, wherein at least a portion the digital data is correlated to at least part of the text ..

Reached This is due to the fact that the graphic has pixels which are replaced by corresponding ones Digital original values are defined, which depend on the multiple bits of digital data have been changed to the digital ones Embedding data in the graph steganographically, the so embedded digital data from the data are recoverable which by scanning the graphics with visible light.

In WO03086759A1 discloses a halftone image encryption carried out.

In the DE19812826C1 A method is described for securing against forgery of documents with an image, preferably with a passport image, in which the image is converted into a digital image file or exists as a digital image file, in which a binary secret image is incorporated in such a way that the digital image file of the image in Parquet cells is divided, the number of which is equal to the number of pixels of the secret image.

It a parameter function is formed, each parquet cell on the base of parameter values describing each pixel assigns a bivalent result value such that the bivalent result values all parquet cells give a bivalent position matrix, so that with help of an optimization method, the parameter values of the pixels of the individual parquet cells are modified so that, on the one hand the changes made to the digital image file of the image of the document no visually perceivable changes on the other hand, the result of the application of the parameter function on the individual parquet cells to a bivalent position matrix leads, the the binary values corresponds to the secret image, and that the information of the secret image containing image applied to the document or together with the document is printed.

In the DE19900856C2 and the EP01048168B1 coded screening systems are proposed, namely a coded screening, while in the present invention frequency-modulated or stochastic screening systems are used.

• a) Bereitstellen einer von einem Benutzer ausgewählten Basis-Rasterung (basic screen);
• b) Zusammenfügen (merging) der Sekundärinformation und der vom Benutzer ausgewählten Basis-Rasterung, die auf einem vom Benutzer ausgewählten Kodierungsprinzip basiert, um eine kodierte Rasterung zu erzeugen;
• c) Kompensieren des kodierten Rasters, um a) jedwede Verzerrungen in der kodierten Rasterung zu kompensieren, die beim Schritt b) des Zusammenfügens entstanden sind, und b) eine kompensierte Rasterung zu erzeugen, welche die Sekundärinformation, verborgen in der kompensierten Rasterung, enthält;
• d) Rastern des Primärbildes mit der kompensierten Rasterung, um ein kombiniertes Ausgabebild herzustellen, und zwar gemäß einer Wiedergabebzw. Reproduktionstechnik, die dem vom Benutzer gewählten Kodierungsprinzip entspricht.

In the DE19900856C2 is a method for a computerized or computerized digital Raster technique proposed to generate coded rasters for inserting secondary information as an anti-counterfeiting security feature into a visible primary image, the method comprising the steps of:

• a) providing a user-selected basic screen;
• b) merging the secondary information and the user-selected basic rasterization based on a user-selected encoding scheme to produce a coded rasterization;
• c) compensating the coded raster to a) compensate for any distortions in the coded rasterization produced in step b) of the fusing, and b) produce a compensated raster containing the secondary information hidden in the compensated rasterization;
• d) screening the primary image with the compensated halftone to produce a combined output image, according to a reproducing or recording. Reproduction technique that conforms to the encoding principle chosen by the user.

The known method uses a complex compensation method, that's the implementation severely hampered.

• a) Bereitstellen eines vom Benutzer ausgewählten Basisrasters;
• b) Fusionieren der Sekundärinformation und des vom Benutzer ausgewählten Basisrasters, basierend auf einem vom Benutzer gewählten Codierungsprinzip, um ein codiertes Raster zu erzeugen;
• c) Kompensieren des codierten Rasters, um i) jedwede Störungen im codierten Raster zu kompensieren, die im Fusionierungsschritt (b) erzeugt wurden und ii) ein kompensiertes Raster zu erstellen, welches die Sekundärinformation, versteckt im kompensierten Raster, enthält,
• d) Rastern des Primärbildes mit dem kompensierten Raster, um ein kombiniertes Ausgabebild gemäß einer Reproduktionstechnologie herzustellen, welche dem vom Benutzer ausgewählten Codierungsprinzip entspricht, und
• e) Reproduzieren des Dokuments unter Verwendung der Reproduktionstechnologie, wobei das Dokument das kombinierte Ausgabebild mit umfasst.

With the EP01048168B1 there is provided a method performed on a computer system for digitally producing coded lattices for incorporating secondary information as an anti-counterfeiting security feature into a visible primary image for use on a document, the method comprising the steps of:

• a) providing a user-selected basic grid;
• b) merging the secondary information and the user-selected basic raster based on a user-selected encoding principle to produce a coded raster;
• c) compensating the coded raster to i) compensate for any perturbation in the coded raster generated in the fusing step (b) and ii) create a compensated raster containing the secondary information hidden in the compensated raster;
• d) screening the primary image with the compensated raster to produce a combined output image according to a reproduction technology that conforms to the user-selected encoding principle, and
• e) reproducing the document using the reproduction technology, wherein the document comprises the combined output image.

task the invention is in contrast the cost-effective Producing hidden news on products such as packaging, Leaflets, blister packs and similar products in the Pharmaceutical industry, the cosmetics industry, the food industry, the sanitary industry, the tool industry, the fashion industry, for high quality toys, with original spare parts for the automotive and aerospace industries and the like industries and the fast and cost-effective visual verification of these hidden messages using simple, economical and custom-made verification agent.

The solution This object is achieved by the features of the independent claims.

According to the invention was found that by using frequency modulated or Stochastic screening of a printed image and a hidden graphic message and their merging into a common printed image, the hidden message for the human eye is imperceptible.

The Visual visualization can be very easy due to the pressure for example, the rasterized message on a transparent film and thinking about it printed picture done.

The The present invention is based on being able to quickly and cost effectively individual Verification elements can be produced.

All essential for the function of this novel method is visual randomness the distribution of grid points or that no fixed Angle and no fixed screen widths of the dot structure are given. In reality they use However, various methods involve exact mathematical algorithms the goal, coarse-grained Structures as well as disturbing Avoid effects and patterns. The preferred according to the invention Barco Monet Screen procedure allows Brilliant print results, as relatively large dots are used can.

Of the Assembly of the at least two rastered printed images takes place first at the printing plate exposure.

The simple verification method for visual visualization of the hidden message preferably takes place with a transparent Foil that is printed with only one of the two information and about the Printed image is placed. The hidden information thus becomes visual visible, noticeable.

This Verification agent can only on presentation of one of the two print images can be created and above all very easily and inexpensively manufactured become. in principle The hidden information can also be visualized with a scanner and in this case it becomes one of the rasterized print image information superimposed on this scanned image in an additive or subtractive way.

Some embodiments The invention will be described below with reference to the drawing figures.

there shows:

1 the exemplary Screen 1 (printed image 1 )

2 Screen 2 (hidden message = printed image 2 )

3 Screen 1 + 2 (= printing plate = overlaid printed image),

4 the verification movie with Screen 1 or 2

5 the overlaid print image plus the verification film over it.

In 1 is an example of the printed image 1 shown. An unspecified printed image was frequency modulated or modulated stochastically or with a commercially available frequency-modulated screening method to a rasterized printed image 1 guided. The rastered print image 1 is visible to a viewer, but not decodable without further aids.

In 2 is an example of the hidden message as a print image 2 shown. A message not shown was frequency modulated or modulated stochastically or with a commercially available frequency-modulated screening method to a rasterized printed image 2 guided. The rastered message 2 is visible to a viewer, but not decodable without further aids.

In 3 is an example of the overlay of the printed image 1 with the message as a print image 2 shown. The rastered print image 1 of the 1 and the rasterized message 2 of the 2 became a merged print image by exposure to a printing plate 3 brought. The message 2 in the assembled print image 3 is neither visible nor decodable to a viewer without further aids. The exposure of the printing plate for the printed image 3 conventionally takes place via individual films or digitally or by means of a computer-to-plate method outside the printing press and / or inside the printing press. The print of the print image 3 takes place in particular on products such as packaging, leaflets or blister packs in the field of the pharmaceutical industry, the cosmetics industry, the food industry and similar industries.

In 4 is an example of the verification film 4 (Decoder) shown in the form of a transparent film. The message 2 or the rasterized print image 1 is on the verifier 4 printed. In particular, the offset printing method, the flexographic printing method and the gravure printing method are used as the printing method. As a verification agent 4 in particular commercially available transparent films are used, which by means of conventional laser printer or ink-jet printer or transfer printer or thermal sublimation printer with the necessary for the visual verification rasterized message 2 or the screened print image 1 be provided.

If next to a rasterized message 2 additional rasterized messages 2 with the rastered printed image 1 to a stitched print image 3 can be mounted, either a verification agent 4 per hidden message 2 be provided or a single verification means 4 for all hidden news 2 ,

In 5 is an example of the superimposed print image 3 plus the verification movie 4 above lying as a visualized message 5 shown, causing the hidden message 2 visually visible and thus decoded.

The hidden message 2 In addition, it may also be detectable by machine (not shown) by means of a scanner and thereby the assembled printed image 3 be recorded electronically with the scanner. Subsequently, computer assisted by comparison of this scanned assembled print image 3 with the at least one rastered message 2 a statement about the presence of the hidden message 2 be taken or made accessible to the user of the scanner, for example by display or voice output.

The hidden message 2 is a consecutive number or a date and is comparable to a barcode stored in a database.

In summary, the present invention describes a steganographic printing method for attaching hidden messages 2 using offset, flexo and gravure printing in preferably monochrome embodiment based on the superposition of at least two in particular frequency-modulated printed images 3 , where a printed image 1 the hidden message 2 includes. Furthermore, the present invention describes a simple verification method for visually visualizing the hidden message 2 in the form of the decoded message 5 , based on a transparent foil 4 with one of the two print images 1 or 2 , Furthermore, the present invention describes the application of this method and system for mounting and simple visual verification of covert messages 2 in packaging and leaflets and blister packs, especially in the pharmaceutical, food, cosmetics and such counterfeit sensitive products.

1

rasterized print image

2

screened message

3

Merged print image with the message (= printed image = printing plate)

4

verification means = transparent foil with rastered printed image or message

5

visualization the message (the verification device is placed over the printed image)

Claims (10)

Steganographic printing method for applying hidden messages by means of conventional monochrome printing methods on graphically designed product surfaces and visual verification method, characterized in that a printed image modulated frequency modulated or stochastically or with a commercial frequency-modulated raster method to a rasterized printed image ( 1 ) and a message about a rasterized message ( 2 ) and the rasterized print image ( 1 ) and the rastered message ( 2 ) by exposure on a printing plate to a joined printed image ( 3 ) to be brought. Steganographic printing method according to claim 1, characterized in that the rastered message ( 2 ) is not visually recognizable and on a product a printed image ( 3 ) and that for visualization on a verification means ( 4 ) in the form of a transparent foil the rastered message ( 2 ) or the rasterized print image ( 1 ) and the verification agent ( 4 ) about the printed image ( 3 ) and visually the hidden message becomes visible. Steganographic printing method claim 1 or 2, characterized in that as a printing method in particular the offset printing process, the flexographic printing process and the gravure printing process is applied. Steganographic printing method according to one of claims 1 to 3, characterized in that the exposure of the printing plate conventionally over individual films are made or done digitally or by means of a computer-to-plate Procedure outside the printing machine and / or within the printing machine. Steganographic according to one of claims 1 to 4, characterized in that the pressure on products such as packaging, Leaflets or blister packs in the pharmaceutical industry, the cosmetics industry, the food industry and the like Industries. Steganographic printing method according to one of claims 1 to 5, characterized in that as a verification means ( 4 ) commercially available transparent films are used, which are processed by means of conventional laser printers and / or inkjet printers and / or transfer printers and / or thermal sublimation printers and the like digital printers with the rastered message necessary for the visual verification ( 2 ) or the rastered printed image ( 1 ). Steganographic printing method according to one of claims 1 to 6, characterized in that, in addition to the rastered message ( 2 ) one more or more rasterized messages ( 2 ) with the rastered printed image ( 1 ) to a merged print image ( 3 ) and in each case a verification means ( 4 ) per hidden message ( 2 ) and a verification means ( 4 ) for all hidden messages ( 2 ) can be generated. Steganographic printing method according to one of claims 1 to 7, characterized in that the at least one hidden message ( 2 ) is also mechanically detectable by means of a scanner and thereby the assembled print image ( 3 ) is recorded electronically with the scanner and then computer-aided by comparing this scanned print image ( 3 ) with the at least one rastered message ( 2 ) a statement about the presence of the at least one hidden message ( 2 ) receives. Steganographic printing method according to one of claims 1 to 8, characterized in that the at least one hidden message ( 2 ) is a consecutive number, a date or the like and with a further information of the printed image ( 1 ), for example with a barcode and the like machine-readable information, is in a certain context and at at least parts of this information are stored in a database and can be queried during the verification. Application of the steganographic printing method for attaching hidden messages by means of usual Printing process in monocolorer design on graphically designed product surfaces and visual verification method according to any one of claims 1 to 9 for the Protection against imitation and forgery of printed products such as packaging, leaflets or blister packs in the field of the pharmaceutical industry, the cosmetics industry, the food industry and the like industries.