rus
Issue #5/2017
A.Y.Betin, M.S.Kovalev, G.K.Krasin, S.B.Odinokov, P.A.Ruchka, N.G.Stsepuro
Printed Graysale Security Elements for Product Labeling
Printed Graysale Security Elements for Product Labeling
The other side of reverse engineering is fast entry of popular production to counterfeit market. The presented security method has several advantages. It uses printed grayscale security elements obtained through digital synthesis. They provide high level of security and resistance to mechanical damage.
The entire process of manufacturing of industrial product, from the beginning to its selling to the consumer, is associated with the need to label products at each stage. This is caused by the operations of identification and recognition in the logistic control of the products movement from its creation to its sale and further repairs. Simultaneously with this movement, there is a flow of counterfeit products. States and producers are coping with the problem of counterfeiting in different ways (trademarks, copyrights etc.), but today there more of these problems because of the more affordable technologies for products to enter the modern market. For example, the technological development of industrial production methods provides ample opportunities for reverse engineering. Therefore, identical copies of products that are in demand by consumers appear on the market almost immediately after going abroad without extra financial expense from the intruders for design and production. As the progress of technology is rapid, everyday work is also rapidly proceeding to create more complex security methods. For example, new label marks are created based on methods of computer synthesis of digital holograms. Analysis of modern achievements and trends in the development of laser-optical and computer technologies shows [1] that the methods of computer synthesis of digital holograms have the following advantages:
• providing a high level resistance to structure damage and security due to redundancy of digital holograms and using of many secret two-dimensional keys based on amplitude and phase coding matrices;
• ability to quickly synthesize and change the encoded information of digital holograms; mass distribution of computer equipment, digital scanners and digital printers made it possible to obtain high-quality reproduction of images with such holograms [2] based on compact and cheap desktop equipment.
Typically, a digital hologram is a grayscale transparency, usually consisting of 256 shades of gray [3] and more [4]. To display such a hologram on a physical medium, special laser image generators [5] are usually used, which today can provide an accurate transmission of only two gradations of the amplitude transmission coefficient.
The calculation of such security elements (without a reference beam) is based on the conjugation of the symmetric expansion of the amplitude-phase representation of the image, the calculation of the discrete Fourier transform (DFT) and the formation of a grayscale image. Thanks to this method, each pixel of the element contains all the information about the original image, which provides stability of such an element to mechanical or other damage. In connection with this, we considered the production of such elements in the form of a grayscale transparency consisting of 256 shades of gray and obtained with a digital printer. Reconstruction of the image was done using smartphone camera and special software.
In this regard, the creation of grayscale security elements on any objects (metal and non-metallic) will include the following technological stages:
• Selecting an encoding object
For example, such objects as shown in Fig. 1 or Fig. 2. The data page is an image (see Fig. 1), coded according to standard ECMA‑377. This kind of data page is used in holographic optical memory [6].
• Computer transformation of the object of coding into the structure of the grayscale picture.
To maintain the smoothness of tonal transitions when encoding images in digital form, it is necessary to ensure the proper number of signal levels for each hardware channel (either RGB-trichromatic, or luminance and color differential, or CMY, or CMYK). To ensure the perceptual uniformity of tonal transitions within the dynamic range of the system 90 levels of brightness are enough and, therefore, 90 levels of sampling of the brightness information.
Depending on the required resolution, coding objects, operating conditions, the method of printing (laser, offset, inkjet, etc.) is selected and printed on any physical media (paper, laser film, plastic).
Reconstruction of encoding objects is possible using a digital scanner or smartphone camera and special software. Examples of reconstructed images are shown below (Fig. 4, Fig. 6–7).
As seen from Fig. 3 the presence of a grayscale security element did not affect the overall perception of the given digital image.
For evaluation the stability of the recovery of encoded information, two types of damage to such structures were accepted: mechanical impact (crumpled paper) and direct impact by a ballpoint pen on paper.
The study was provided as a part of state assignments of The Ministry of education and science of Russian Federation № 3.2236.2017.
• providing a high level resistance to structure damage and security due to redundancy of digital holograms and using of many secret two-dimensional keys based on amplitude and phase coding matrices;
• ability to quickly synthesize and change the encoded information of digital holograms; mass distribution of computer equipment, digital scanners and digital printers made it possible to obtain high-quality reproduction of images with such holograms [2] based on compact and cheap desktop equipment.
Typically, a digital hologram is a grayscale transparency, usually consisting of 256 shades of gray [3] and more [4]. To display such a hologram on a physical medium, special laser image generators [5] are usually used, which today can provide an accurate transmission of only two gradations of the amplitude transmission coefficient.
The calculation of such security elements (without a reference beam) is based on the conjugation of the symmetric expansion of the amplitude-phase representation of the image, the calculation of the discrete Fourier transform (DFT) and the formation of a grayscale image. Thanks to this method, each pixel of the element contains all the information about the original image, which provides stability of such an element to mechanical or other damage. In connection with this, we considered the production of such elements in the form of a grayscale transparency consisting of 256 shades of gray and obtained with a digital printer. Reconstruction of the image was done using smartphone camera and special software.
In this regard, the creation of grayscale security elements on any objects (metal and non-metallic) will include the following technological stages:
• Selecting an encoding object
For example, such objects as shown in Fig. 1 or Fig. 2. The data page is an image (see Fig. 1), coded according to standard ECMA‑377. This kind of data page is used in holographic optical memory [6].
• Computer transformation of the object of coding into the structure of the grayscale picture.
To maintain the smoothness of tonal transitions when encoding images in digital form, it is necessary to ensure the proper number of signal levels for each hardware channel (either RGB-trichromatic, or luminance and color differential, or CMY, or CMYK). To ensure the perceptual uniformity of tonal transitions within the dynamic range of the system 90 levels of brightness are enough and, therefore, 90 levels of sampling of the brightness information.
Depending on the required resolution, coding objects, operating conditions, the method of printing (laser, offset, inkjet, etc.) is selected and printed on any physical media (paper, laser film, plastic).
Reconstruction of encoding objects is possible using a digital scanner or smartphone camera and special software. Examples of reconstructed images are shown below (Fig. 4, Fig. 6–7).
As seen from Fig. 3 the presence of a grayscale security element did not affect the overall perception of the given digital image.
For evaluation the stability of the recovery of encoded information, two types of damage to such structures were accepted: mechanical impact (crumpled paper) and direct impact by a ballpoint pen on paper.
The study was provided as a part of state assignments of The Ministry of education and science of Russian Federation № 3.2236.2017.
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