Patent Application
20160072980
The present invention relates to a method for producing unforgeable printable image information data that can be printed with conventional printers or printing processes, and which are easily decodable or recognizable by means of a camera unit such as a Smartphone, for example.
According to statements by the World Customs Organization (Brussels), the economic impact of counterfeit products placed on the market increases from year-to-year in the global economy. For this reason, and since Smartphones for example are widespread, relatively inexpensive and are well suited for the authentication of codes applied on a package, suitable processes are increasingly developed and used for this purpose.
AlpVision offers a “Varnish Cryptoglyph®” product on the market for example, which introduces micro-holes as a pseudo-random pattern into a varnish coating that are invisible to the human eye. In this context, the invisible micro holes are introduced into cartons, blister packs and labels during a printing process. A corresponding authentication is performed by a software application on the Apple iPhone 4 Smartphone. However, the microholes can be introduced only with relatively great difficulty, which requires a special varnish for this purpose.
Special labels for example such as hologram labels, Guilloche pattern labels, which change the image depending on the viewing angle or become visible only with special screen filters, are expensive to produce and are difficult to handle for the end user. Moreover, forgers meanwhile also increasingly copy standard holograms. Here too, Smartphone based solutions are available for this from InkSure and Jura JSP GmbH, for example.
US 20120243797 A1 discloses a method for applying an image with imperfections onto a package, of which a photograph can be taken with a Smartphone for instantaneous identification. For this purpose the imperfections are so small that they are imperceptible to the human eye. Black-and-white or color imperfections with relatively high contrasts can be photographed easily and can also be correspondingly printed again easily with a printer.
Treméau et. al. publish various methods for watermarking in the paper “Recent Trends in Color Image Watermarking” in the “Journal of Imaging Science and Technology, 2009, Vol. 53(1), 10201 pages 1-15.” For this purpose, it is proposed to use the colors of an image in quantized stages and according to a specified distribution. It is also recommended to use colors with a small color difference for example, although it is difficult to define the quality of recognizing the small color differences. In this context, half-tone coloring is also mentioned.
A method for watermarks or for hiding a message in an image without being able to identify the message with the eye, was published by Thomas et al. in the paper “Image Watermarking based on color quantization process” in the publication “Electronic Imaging 2007, Int. Society for Optics and Photonics, 2007, page 650603.”
In the paper “Watermarking and authentication of color images based on segmentation of the xyY color space” in the Journal “Imaging Science and Technology, 2006, Vol. 50(5): 411-423” Chareyon et al. published a method for hiding a watermark by changing the color in certain areas according to a pattern.
In the paper “Pre-separation clustered-dot color halftone watermarks: Separation estimation based on spatial frequency content” in the “ Journal of Electronic Imaging, 2010, Vol. 19(4), 43007, page 1-12,” Oztan et al. publish a method for capturing CMYK expressions using a RGB scanner.
In the paper “User-friendly random-grid based visual secret sharing” in the publication “IEEE, Trans. on Circuits and Systems for Video Techn., Vol. 21(11), 2011, 1693-1703,” Chen et al. publish a method for hiding one or two secret images or logos in an image.
In the paper “Digital Image Ownership Verification based on spatial Correlation of Colors” in the publication “Image Processing (IPR 2012), IET Conference on IET, 2012, page 1-5,” Surekha et al. publish a method for splitting a watermark into two partial images wherein a first partial image is introduced during printing and a second partial image is used during the recognition of the first partial image, in order to identify the watermark.
In the paper “Revenge of physical—mobile color barcode solutions to security challenges” in the publication “Proc. Optical Document Security, 2010, S.184-197” Simske et al. publish a method for the selection of colors for bar codes.
Likewise, methods for the introduction and recognition of watermarks hidden for the eye are presented in the documents WO2004028140 A1, US20080247002 A1 and U.S. Pat. No. 5,315,098 A.
In addition, solutions exist which offer very large copy protection but require special equipment and varnishes, where the corresponding printing methods are very expensive and are therefore unsuitable for many applications. Numerous copy protection features are frequently introduced on banknotes for identification for example, which make it impossible in particular for end-users to identify all of them. Using smart phones, such features can be stored as patterns and be compared with the respective pattern, however.
An object of the present invention is therefore to eliminate the disadvantages from the prior art by providing a method for producing preferably unforgeable image information data, which can be printed onto paper, carton or suchlike with a standard printing method and which are perceptible to the naked, human eye and that are well identifiable with a camera unit nevertheless, such as a camera-based Smartphone.
The above problems and further problems to be derived from the specification are solved by a method for producing unforgeable printable image information data or by a method for recognizing the image information data according to the features of the independent claim 1 or 18. Further advantageous embodiments of the present invention are stated in the dependent claims.
The advantages accomplished with the present invention in particular consist in that the unforgeable image information data can be applied on paper or carton or suchlike using conventional printing methods or printing devices. The production or the printing of the unforgeable image information data on papers, carton or packaging requires almost no adaptation period, contrary to other methods according to the prior art. The unforgeable image information data can also preferably be very well integrated in a previously specified design or be applied onto existing packaging or labels.
In particular, because information image dots or information pixels in the image information data are preferably printed in the first screen areas encoded preferably only by slightly different color values, these color values or information pixels can no longer be recognized or be distinguished from one another with the naked eye. In this context, the color values or the information color values for encoding are so weakly contrasted that they can almost or at least not be securely distinguished, even under a microscope.
Another aggravating factor for an attempted forgery is that in addition to the information pixels in the image information data, also interference pixels are still arranged in the adjacent interference fields. As a result, a visual perception by a microscope or a camera or scanner-based detection of the information pixels is complicated further. For this purpose, the interference color values assigned to the interference pixels and information color values of the information pixels are defined and printed so that they are only slightly different or contrasted, so that they can be differentiated or distinguished only with great difficulty. A forgery is particularly also significantly complicated in that the difference in color value in adjacent interference pixels compared to the information pixels is so small that it can just be recognized and distinguished by the camera unit with a specific software. Every printing unit moreover produces an equipment specific print as a black-and-white or color print that is slightly different from other printing units.
By initially producing the image information data which are then printed by a printing unit and can be measured subsequently, it is even possible to evaluate the equipment specific printed color values of the image information data for subsequent authentication or decoding. It is therefore also possible to use one or several equipment specific print values of specific approved printing units virtually as fingerprints for the authentication or decoding. In this context, the measured color values or a relative contrast distribution of the printed color values are transmitted to the camera unit or Smartphone for evaluation or authentication via the Internet. For this purpose, the contrasts or color values of the information color values and interference color values are preferably few and just different enough so that they can be reliably distinguished for authentication by the camera units or Smartphones. This makes the authentication even more unforgeable.
During the recognition of the image information data by the camera unit or Smartphone, an Internet connection is not absolutely necessary if the required decoding data for authentication of the respective image information data have been downloaded previously. As a result, authentication is possible in real time, in that the camera unit or Smartphone performs and displays the authentication instantaneously.
A further advantage of the present invention consists in that it can also be used easily and cost-effectively by end-users. Similarly, it can be used in a few bar/QR code applications on Smartphones and the operation requires no special knowledge. The installation and updating of recognition software on the camera units or Smartphones is done by the Apple App Store or Google Play store, or suchlike.
By simple and easily permutable encoding or error encoding and by the simple transmission of the decoding data necessary for the authentication to the camera unit or Smartphone, the creation of unforgeable image information data can be changed very easily at specific time intervals.
A preferred embodiment according to the present invention is illustrated in the subsequent drawings and in a detailed description, but is not intended to limit the present invention thereto.
The drawings show:
The objective of the method according to the present invention is to initially produce unforgeable, printable image information data from specific information data and subsequently recognize and authenticate the corresponding image information data printed on paper, carton or packaging.
For this purpose, the specific information data are put into a form of binary information image dots, which happens in that the information data are transferred into the binary information image dots by a specific encoding rule. In this context, the produced binary information image dots are arranged grid-like in a first screen and respective first screen areas
R1 within an image area. In this context, the first screen can be a unidimensional or two-dimensional screen, such as a standard barcode or a matrix barcode, for example. Three-dimensional screens are also conceivable, although this would require customized printers for printing.
According to the present invention, the first screen or the first screen areas R1 therein is subdivided by a second screen, so that the plurality of second screen areas R2 is arranged in the respective first screen area R1. In this context, a plurality is at least two or more. Preferably, the subdivision in the second screen areas is done in the form of a checkerboard, bar-shaped or like a cake segment, wherein other forms of partitioning are also possible.
Using an information field assignment rule, one of the second screen areas R2 in the respective first screen area R1 is defined as an information field lxy for the respective information image dot, wherein at the same time the remaining second screen areas R2 of the respective first screen area R1 are defined as interference fields Sxy.
According to the binary value 1 or 0 of the information image dot, a first information color value IF1 is assigned to the respective information field lxy at a value 1 and a second information color value IF0 at a value 0. The color value assignment is performed according to an information color value assignment rule. In this context, the second information color value IF0 differs from the first information color value IF1.
According to an interference color value assignment rule, specific interference color values are assigned to the respective interference fields Sxy. This is intended to encumber subsequent recognition and differentiation of the information fields lxy from the interference fields Sxy and accordingly a recognition of the first IF1 and the second information color value IF0.
The color values of the second screen areas with the respective first IF1 and second information color values IF0 and the interference color values will be ultimately stored as the image information data and preferably provided for printing onto the paper, carton or packaging.
The first screen areas R1 are subdivided by the second screen. In the present example, four second screen areas R2 arranged in the form of a checkerboard are produced for each first screen area R1. In
Here, a color value is defined for a color to be printed which includes a specific color or color composition and a specific color density. The colors or color values which are tantamount in this document are mostly produced as color screens onto which dots are applied. For this purpose, the color screen is produced from a composition of primary colors, which are respectively applied or printed with more or less density. For example, the color values are composed of printing inks like red, green, blue, yellow and black, for example. A lighter color is produced by less dense spectral loci, whereas a darker color is produced by denser printing of the spectral loci. In the following, the terms color value or color are to be regarded as being synonymous, wherein the color value is preferably produced by the color screen. It is also conceivable that the different color values are produced by different liquid colorants, however. More preferably, the respective color value is produced as dot matrix or as dot distribution with a specific dot density, however.
Preferably, all color values, such as the first IF1 and the second information color value IF0 and the interference color values can be printed with a conventional printing unit. For this purpose the printers are designed to produce the respective color value from its printing inks, such as for example for a print run or half-tone printing or also for black-and-white print or color laser print or for ink-jet printing.
The first information color value IF1, the second information color value IF0 and size of the information field lxy are preferably defined such that the respective information image dot is no longer perceptible to the naked eye. In that context, the first IF1 and the second information color value IF0 are preferably defined such that the information field lxy is filled with a color less than 25%. For that purpose, the preferred color is yellow for example, which is particularly difficult to detect with the human eye. Preferably, a size of 0.01-0.1 mm2 or a diameter size of 0.11-0.36 mm is defined for the second screen area R2 and in particular for the information field lxy. Consequently, the first screen area R1 is preferably four times the size of the second screen area R2. The information image dots are therefore not simply small, but are also widely distributed and can be recognized with the eye only under a microscope. For this purpose, the color differentiation between the first information color value IF1 and the second information color value IF0 is preferably defined sufficiently small so that this cannot be differentiated with the human eye under a microscope.
Because of the information field assignment rule, preferably the respective information field lxy will always be arranged at the same location in the respective first screen area R1, or in other words always in the same second screen area R2 of the respective first screen area R1. However, according to the information field assignment rule, the information field lxy can also be arranged in alternating second screen areas R2 of adjacent first screen areas R1.
The respective interference color value for the respective interference field Sxy are [sic] preferably defined by the interference color assignment rule such that a specific mean color value in the respective first screen area R1 is produced as an average across the information field lxy and the remaining interference fields Sxy.
The defined mean color values of the first screen areas R1 are preferably produced such that for this purpose either a first for a second defined mean color value is produced. In this context, the defined mean color values are preferably defined such that the defined mean color values are adjacently arranged checkered across adjacent first screen areas R1. To this end, producing a plurality of defined mean color values is also conceivable. In this manner, the adjacent first screen areas R1 can be better distinguished from each other.
The mean color values defined from the first screen areas R1 are preferably defined such that a second encoded information is transmitted by means of them. The second information may be a readable information, for example. The second information may be a print date and/or statement regarding a print batch or a printing unit, for example. Preferably the second information can also be arranged outside of the image area R0 or as part of the logo area R3, however.
Preferably, the defined mean color values of the first screen areas R1 are defined as at least one first or one second defined mean color value such that the defined first mean color value corresponds to the first information color value IF1 and the second defined mean color value corresponds to the second information color value IF0
The respective interference pixel color value is preferably defined such that it has less than 25% contrast difference to the first information color value IF1. In this context, the contrast difference is more preferably below 5%.
Preferably, the plurality of the second screen areas R2 per the first screen area R1 is greater than or equal three to form at least two interference fields Sxy next to the one information field lxy. For that purpose, in the event that the first information color value IF1 is assigned to the information field lxy, a first interference pixel color value SF1 is preferably assigned to a first interference field, said first interference pixel color value SF1 being higher than the first information color value IF1, and a second interference color value SF2 is assigned to a second interference field, said second interference color value SF2 being lower than the first information color value IF1.
Preferably, the first interference pixel color value SF1 is defined at a value that exceeds the first information color value IF1 only to such an extent as to barely permit reliable recognition by the camera unit. Preferably in that context the second interference color value SF2 is defined at a value that falls below the first information color value IF1 only to such an extent as to barely permit reliable recognition by the camera unit.
For that purpose, also a variety of four or nine second screen areas R2 to a first screen area R1 is preferred. Other subdivision varieties are also possible.
Preferably, using the interference color value assignment rule, the second or a further information is transmitted by the corresponding image information data by means of the interference fields.
For this purpose, the second information is also used for encrypted encoding of the information data in the form of the binary information image dots. As a result, the encoding rule can be changed permutationally, for example.
Preferably, a logo, one or multiple graphic characters and/or an image are depicted by the second information. By means of the second information, the print batch, the printing unit and/or the print date can be transmitted. Alternatively, the second information can also be printed on the edge of the image area R0 or in the logo area R3.
For this purpose, the second information includes measured color values originating from a print by the printing unit and that were measured from it. In this manner, printing unit specific color values can be measured and be transmitted to the camera unit or Smartphone for authentication or decoding.
Preferably, the interference color value assignment rule is designed to depict or to transmit the second information by means of the respective interference fields Sxy. In this context, the second information is preferably defined by a function depending on the information data. Preferably, this function can be an algorithm, a function for establishing a checksum, a sign change, a quadrature, or another function from the information data.
Preferably, the encoding of the information data can be performed into the form of the binary information image dots, for example as binary unidimensional or two-dimensional barcode, as alphabetic character text or numerical text.
Preferably, the information data can include a serial number and/or product data.
Preferably, the serial number and/or the product data can also be encoded in the second information.
The image information data can be printed onto all printable materials, such as paper, carton, packaging and suchlike, for example.
Even automatic recognition and differentiation can be performed only with great uncertainties, in that the first information color value IF1 and the second information color value IF0 are defined as a small difference in color or contrast. For this purpose, preferably the first IF1 and the second information color value IF0 are defined as percentile color values of a defined interference color value with sufficiently high color density, in order to be able to measure the defined interference color value securely. For example, in this context, then the first information color value IF1 is defined as 20% of the defined interference color value and the second information color value IF0 is defined as 17% of the defined interference color value, for example. Authentication can be securely performed by knowing these percentages.
The method according to the present invention for recognizing and decoding of the printed image information data in image area R0, which were printed onto paper, carton, packaging boxes, adhesive labels or suchlike as described above, essentially involves the following steps. For this purpose, preferably the recognition and decoding will be performed by a microcontroller supported camera unit, a camera, or a scanner in conjunction with a PC, a Smartphone or suchlike, which will be named camera unit hereafter.
Initially, the camera unit is preferably aligned by using at least one easily visible and recognizable mark located in or on the printed image area. A specific logo with a high-contrast colored bordering can function as a mark, for example. After the camera unit is aligned, an image is recorded with the image area R0 and is stored. Preferably, for the alignment of the camera unit also recognition algorithms are used, which detect and indicate in real time whether and how the camera unit is and/or should be aligned. Preferably, during the automatic detection and a sufficient satisfactory alignment, the image will be triggered and captured automatically. For this purpose, the image includes the image area R0 and the printed image information data located therein.
By using a pattern recognition algorithm on the image, said pattern algorithm being designed to recognize the first screen with the first screen areas R1 and the second screen with the second screen areas R2. Preferably, for this purpose the image will be correctly aligned, rotated, rectified and cropped according to the image area R0, beforehand. Preferably, the pattern recognition algorithm includes a comparison algorithm with a specific pattern. For the recognition of the first R1 and second R2 screen areas, preferably a histogram analysis is performed, which displays the rows and columns.
By using the information field assignment rule, the information fields lxy and the interference fields Sxy are defined from the detected second screen areas R2.
The color values of the respective information fields lxy are subsequently defined by means of their color values, using a further histogram analysis. Preferably, during the histogram analysis two color values with respectively significant accumulation are determined and defined as the first information color value IF1 and the second information color value IF0.
In this context, the histogram analysis for the recognition and differentiation of the color values is preferably designed such that after the first information color value IF1 is approximately recognized, the existing color values with a higher resolution in the area of the first information color value IF1 are analyzed and distinguished. For this purpose, the first IF1 and the second information color value IF0 and the interference color values are then distinguished from one another. In particular, in this manner preferably the first information color value IF1 is distinguished from the two adjacent interference color values SF1 and SF2, as a result of which the first information color value IF1 and the two adjacent interference color values SF1 and SF2 are distinguished as measured color values and can therefore be recognized again.
According to the information color value assignment rule, the value 1 is assigned to the information fields lxy with the first information color value IF1, and the value 0 is assigned to the information fields lxy with the second information color value IF0. As a result, binary information image dots are produced in the information fields lxy.
Thereafter, a decoding rule, which corresponds to the encoding rule is employed on the binary information image dots and the information data printed or recovered therefrom. If the recovered information data correspond with the information data, which were either stored or can be accessed via the Internet, then the authenticity of the recovered information data can be displayed by the camera unit directly or indirectly. Otherwise a forgery can be displayed. Preferably, above a specific degree of correlation, it is assumed that the recovered information data conform with the information data so that individual deviating pixels will not produce a false-negative result.
For this purpose, the pattern recognition algorithm is designed to initially recognize the first screen with its first screen areas R1 as a checkered pattern by low-pass filtering, whereupon edges of a low-pass filtered pattern are defined, and therefore the first screen and the first screen areas R1 can be defined.
Preferably, the mean color values of the first screen areas R1 are defined, wherein at least two significant distinguishable mean color values are recognizable by a further histogram analysis, wherein an evaluation of the mean color values will also be considered for an authentication of the printed information data.
Preferably, for authentication of the information data and, if available, a second information from the interference fields will be compared with a database, whether the information data and, if available, the second information are still admissible or not. Preferably, in this context the database is represented by a memory area or a memory value in the camera unit or by data that are accessible via the Internet, for example.
Preferably, the decoding and recognition algorithms are designed so that they can distinguish the first IF1 and the second information color value IF0 from one another securely, in that according to the information color value assignment rule known to the camera unit the corresponding binary values from both the larger color value and the smaller color value are assigned.
Preferably, the decoding and recognition algorithms are also designed such that they can distinguish the first SF1 and the second interference color value IF0 from one another securely by the histogram analysis, in that the corresponding values are distinguished and assigned according to the information color value assignment rule known to the camera unit.
Preferably, the recognition and decoding of the printed image information includes also the following process steps:
For clarity, it still be pointed out that by interference pixel, an interference field Sxy with an interference color value, and by information pixel, an information field lxy with an information color value, is to be understood.
Further possible embodiments are described in the following claims. In particular, the different features of the embodiments described above can also be combined with one another, unless they conflict in terms of technology.
The reference numbers cited in the claims serve for improved comprehensibility but they do not limit the claims to the forms illustrated in the figures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 103 613.9 | Apr 2013 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/056820 | 4/4/2014 | WO | 00 |
