RU2246743C2 - Method for protecting holograms from forgery and device for automatic control of hologram validity - Google Patents

Abstract

FIELD: holograms protection technologies.

SUBSTANCE: method includes recording a hidden image on hologram in form of two-dimensional matrix of light optical points, wherein individual check code is set in predetermined angles of matrix; also, for positioning protective hologram an image of point object is recorded on it, outside limits of mask aperture, and during reading of hidden image protective hologram is displaced until restored image of point object placed outside mask aperture, fits point aperture in micro-diaphragm, and until an electric signal with maximal amplitude is detected at output of positioning control photo-detector, which shows correctness of positioning of protective hologram.

EFFECT: higher efficiency.

2 cl, 7 dwg

Description

The field of technology.

The invention relates to means of protection and authentication of holograms intended for marking and protection against counterfeiting of goods, products and products.

The level of technology.

The problem of protecting holograms from counterfeiting arose primarily due to the fact that rainbow holograms are widely used as a means of protecting documents and banknotes from counterfeiting. At the first stages, it was assumed that the fake of the rainbow hologram itself is unlikely and can not be carried out without high costs. However, the development of holography technology has led to the fact that at present hundreds of small firms are quite capable of producing almost any hologram. In this regard, there was a need to protect holograms from falsification.

Various options have been proposed for solving this problem. In one of the first options, it was proposed, along with a rainbow hologram, visible to the naked eye when illuminated with natural light, to record another hologram, the image of which can be read only by a laser (see, for example, [1]). An image recorded in this way is usually called a latent image. In practice, this means that the latent image of the additional hologram is located at a sufficiently large distance from the plane of the hologram and, when illuminated with incoherent light, it is smeared due to dispersion and becomes practically invisible. However, such a latent image is easily restored by a laser beam and therefore cannot provide sufficient protection against falsification, since it can be copied and then recorded on a new hologram.

The patent [2] describes a device in which an additional protective hologram is recorded in the form of a thin (several tens of microns) strip, for the formation of which cylindrical optics are used. Due to the small size, such a hologram is difficult to distinguish, and the complexity of manufacturing cylindrical lenses makes it difficult to restore the recorded image and, accordingly, the manufacture of fakes. However, to restore the image in this case, it is not necessary to have exactly the same cylindrical lenses as in the manufacture of the hologram, which allows you to decrypt the hologram with a different set of lenses.

Schemes were also proposed for manufacturing protective holograms using frosted glass as a spatial wavefront modulator with its installation either in the channel of the reference beam [3] or in the channel of the object beam [4, 5, 6]. Such schemes provide a high degree of security for the hologram. However, they require very precise positioning of the hologram during reading (units of microns) to decode the image. In addition, to restore an undistorted latent image, a decoding mask is required, which must be an exact copy of the frosted glass used to record the hologram: making such copies is a difficult problem.

Close to the proposed device in terms of optical design is the device described in the patent [7]. This device uses a microlens raster as a code mask. The hologram authenticity control device comprises a laser sequentially located on the optical axis, a collimating lens, a hologram, a phase mask (lens raster), a Fourier lens and a diffuse screen. Such a device allows the hologram to be displaced relative to the mask by a distance

.

.

Here, δ is the permissible hologram shift value, r is the radius of curvature of the microlenses in the raster, n is the refractive index of the material of the lens raster, d _e is the size of the latent image, f ₀ is the focal length of the Fourier lens. For the case of practically feasible parameters of the device elements, the allowable shift is obtained close to 0.7 mm. Thus, the use of a microlens raster allowed us to reduce the requirements for the accuracy of hologram installation during image restoration.

The disadvantages of this device are: 1) before each raster micro lens when reading from a hologram, a reduced real image of a “hidden object” recorded on the hologram (or part of it) is created, which can be decoded using a microscope, which reduces the degree of security for this type of code mask holograms; 2) the verification of the authenticity of the hologram is carried out visually and not automatically, which leads to a dependence of the quality of the check on the attentiveness of the operator, and also does not allow additional digital processing of the read information.

Closest to the proposed method and device is the method and device described in the patent [8] for reading information from security holograms, adopted as a prototype. In this device, a barcode is recorded on the protective hologram, the actual image of which is restored at a certain (sufficiently large) distance from the surface of the hologram and is read by a photosensitive CCD matrix. Next, the read image is converted into digital binary code, which is entered into the computer for digital processing and comparison with the standard stored in memory. Thus, this device provides automatic authentication of the hologram. An additional feature of the device is that the protective hologram is recorded together with an additional diffraction grating (a hologram of a plane-parallel light wave propagating at an angle different from the angle of propagation of the object wave used to record the barcode), which is used to accurately position the hologram in the reader. For this purpose, an additional photodetector is installed in the reader, onto which light diffracted from the grating is incident, so that the output signal from the photodetector reaches its maximum when the hologram is set to the correct position.

The disadvantages of this device are: 1) the image of the barcode can easily be read using a laser beam - it is not optically encoded; 2) the possibility of additional coding of a digital sequence is not used, which reduces the degree of security of the hologram; 3) when a laser beam is diffracted by a diffraction grating, a parallel light beam is created with a diameter equal to the diameter of the illuminating laser beam (or the diameter of a hologram, if it is less than the diameter of the beam), therefore, the accuracy of the hologram is comparable to the diameter of the laser beam and is several millimeters, which is not enough for using this method to preset a hologram with an encoded optical image.

SUMMARY OF THE INVENTION

The aim of the present invention is to increase the degree of protection against forgery of holograms used for marking products, as well as other types of holograms while maintaining the simplicity of positioning the hologram in the encoded image reader. The goal is achieved by applying to the hologram with a visible image an additional protective hologram with a hidden image, which cannot be read without a special optical encoding-decoding mask. Unlike previously published methods of protection using a hologram with a hidden image, it is proposed:

- use a new type of encoding-decoding mask, which reduces the requirements for the accuracy of positioning of the hologram in the control device without reducing the degree of security;

- it is proposed to record the protective hologram with a laser having a wavelength close to the wavelength of the laser used in the control device, and then copy it in a contact way with the photoresist plate onto which a hologram with a visible image is recorded, which minimizes image distortion arising when the wavelengths of the recording and reading lasers differ;

- in order to increase the degree of security of the hologram and automate the process of checking its authenticity, it is proposed to write in the protective hologram an image in the form of a two-dimensional (for example, rectangular) matrix of light optical dots containing an individual verification digital code, the significant bits of which are located in pre-selected nodes of this matrix, and which is then read and verified by a special algorithm by a computer connected to a control device;

- in order to more accurately process the positioning of the hologram when it is installed in the reader, it is proposed to record the image of a point object located outside the aperture of the encoding mask together with the latent image optically encoded, and when positioning the hologram in the reader, combine the reconstructed image of the point object with a point hole in the micro-diaphragm installed in front of the photodetector of position control, so that the electrical signal with this photodetector reached its maximum; in the second version, positioning is controlled visually by combining the reconstructed image of a point object with a marker (for example, a crosshair) on a frosted glass installed instead of a micro-diaphragm.

Description of the invention and the attached figures.

The basic principles used to solve the problems considered in the present invention are illustrated by the accompanying figures.

Figure 1 presents the recording scheme of the optical code mask.

Figure 2 presents the recording scheme of the protective hologram.

Figure 3 presents the structure of the image recorded on the hologram with a hidden image for the device for automatic control of the authenticity of the hologram.

Figure 4 presents a diagram of an automatic control device with positioning control of the protective hologram by the signal from the output of the photodetector of positioning control.

Figure 5 presents the structure of the read image at the input of the matrix photodetector of the reader.

Figure 6 presents a diagram of the image processing algorithm in the automatic control device.

7 is a diagram of an automatic control device with visual control of the positioning of the protective hologram.

Below is a detailed description of the proposed solutions to the problems and principles of operation of the devices shown in the figures.

The code mask used when recording a security hologram with a hidden image must thus transform the structure of the object wavefront so that it is impossible to restore the image recorded on it without a decoding mask. It was previously shown that this can be achieved using frosted glass as a phase mask. However, when recovering an image from such a hologram, two serious problems arise: firstly, it is necessary to ensure the accuracy of the hologram installation when reading about a few microns, and secondly, it is necessary to use the same mask for reading as when recording, since it is very difficult to produce an exact copy of such a mask.

In accordance with this, one of the problems solved in the present invention is to overcome the above difficulties. To reduce the requirements for the accuracy of the installation of the hologram during its reading, as well as to enable the production of the same code masks in the required quantity, it is proposed to use a bleached photographic plate with a registered speckle structure formed when the frosted glass is illuminated by a laser beam as a code mask.

Figure 1 shows the recording scheme of the code mask, which is a speckle picture photographic plate. The laser beam 1 passes through a positive lens 2 and then hits the frosted glass 3. The light scattered by the frosted glass forms a speckle structure in space, which is recorded on the photographic plate 4. located at a distance R from the frosted glass. The light intensity distribution on the photographic plate is a random two-dimensional function with a correlation radius equal to the speckle size. After exposure, the photographic plate appears and bleaches. As a result, the optical thickness of the photographic plate becomes modulated in accordance with the distribution of illumination during exposure and can be used as a phase mask with a random distribution of the introduced phase shift over the surface, and the correlation radius of the phase modulation function is approximately the average size of the speckles.

. Здесь λ - длина волны лазерного излучения, D - диаметр лазерного пятна на матовом стекле, а R - расстояние от матового стекла до фотопластинки.The sizes of speckles d recorded on the photographic plate are approximately determined by the formula

. Here, λ is the laser wavelength, D is the diameter of the laser spot on the frosted glass, and R is the distance from the frosted glass to the photographic plate.

By changing the distance from the lens to the frosted glass from 0 mm to the focal length of the lens (F), you can change the diameter D of the light spot on the frosted glass from the diameter of the laser beam (2-4 mm) to a value of the order of 10 μm. At R = 20 cm, the speckle size can thus be changed from ~ 10 μm to ~ 3 cm. The speckle size corresponds to the correlation radius of a random picture recorded on a photographic plate, i.e. ultimately, the required accuracy of setting the code mask when restoring the image. Since the depth of phase modulation by such a mask does not exceed several wavelengths, the required hologram installation accuracy during reading is close to the speckle size.

In the circuit shown in FIG. 1, the required number of copies of the code mask can be made. For the manufacture of another series of masks, if necessary, just move the frosted glass a few millimeters.

The advantage of this type of optical mask is that by changing the size of the speckles on the mask, you can adjust the requirements for the accuracy of its installation; in addition, it is not difficult to make a series of identical masks for installing them in control devices located at different control points.

The second version of the mask is a phase glass plate for a code mask with a matrix of pyramids extruded onto it by hot pressing with a size of about 1-2 mm. With a sufficiently small height of the pyramids, the depth of modulation of the phase of the transmitted light wave introduced by them can also be several wavelengths and the required hologram installation accuracy, as in the previous case, is close to the size of the pyramid.

A second problem to be solved by the present invention arises when the hologram is recorded and read by lasers with different wavelengths. It is known that even in ordinary holograms, image distortions are observed when reconstructing an image by radiation with a wavelength different from that used during recording. In the case of holograms recorded with a code mask, these distortions appear even more, given that the phase distortions introduced by the encoding mask can change significantly with a change in the wavelength of light. In a first approximation, we can assume that the refractive index of the material of the phase mask does not depend on the wavelength of the light used. Assuming that the residual phase distribution error after the decoding mask is δ δ = λ / 10, when the phase modulation created by the mask is of the order of the wavelength, the allowable difference in wavelengths during recording and reading of the hologram should not exceed 10%.

It is advisable to use a semiconductor laser in the hologram authentication device, given its small size, low cost and high reliability. The most common type of such lasers are lasers with a wavelength of 0.635-0.650 μm. Accordingly, a protective hologram with a hidden image must be recorded with a laser with a wavelength close to the above. The most suitable type of laser in this case is a He-Ne laser with a wavelength of 0.63 microns.

The most common type of holograms in need of verification is that rainbow holograms are recorded on a photoresist that is insensitive to red light, and therefore cannot be recorded with a helium-neon laser, but with a He-Cd laser with a wavelength of about 0.44 microns. Due to the significant difference in the wavelengths during recording and when playing a hologram, the wavefront distortions are so large that it is not possible to restore the latent image with a red semiconductor laser.

To solve this problem, the present invention proposes to record a protective hologram with a latent image using a He-Ne laser, the wavelength of which is close to the wavelength of semiconductor red lasers, on a holographic photographic plate (for example, type PFG-01 or PFG-03), and then copy it onto the photoresist using a He-Cd laser. It is preferable to record the primary hologram on PFG-03 photographic plates. which have a much lower level of light scattering and, accordingly, create less optical noise when copying a hologram.

The hologram obtained in this way on the photoresist preserves the structure of the hologram recorded using the He-Ne laser; therefore, when reading it with a semiconductor laser, it is possible to restore the latent image.

The recording scheme of the protective hologram He-Ne laser is presented in figure 2. The laser beam 5 passes through the shutter 6 and, using a rotary mirror 7, is directed to a beam splitter 8, with the help of which the beam is split into two channels: the channel of the reference beam and the channel of the object beam. An object beam is split into two beams, one of which is used to record a latent image, and the second to record on a hologram of a point object.

The mirror 9 in the channel of the object beam directs the first beam to the collimator 11, 12, 13, consisting of confocal lenses 11 and 13 and the micro-diaphragm 12. Using the collimator, the diameter of the laser beam is increased to the size necessary to illuminate the input transparency, and using the micro-diaphragm, elimination of scattered light, leading to spurious spatial modulation of the distribution of light intensity over the transparency aperture.

Next, the object beam hits the frosted glass 14 and the transparency with the input image 15. The scattering of light by the frosted glass eliminates the possibility of creating a shadow image of the transparency on the code mask, which would reduce the encoded degree of the recorded latent image. The input image is a logo for the case of recording a hologram with subsequent visual verification of authenticity or a matrix of transparent and opaque openings for the case of automatic authentication. Next, in the channel of the object beam, a code mask 16 is installed (one of the options described above), which introduces distortions into the wave front of the object beam, and a photographic plate 17 onto which a protective hologram is recorded.

The second object beam created with the help of the beam splitter 10 is directed by the mirror 18 to the lens 19, in the rear focal plane of which the micro-diaphragm 20 is installed, and then the beam diverging from the focus of the lens hits the hologram 17. The micro-diaphragm, as in the first object beam, is used to filter out the scattered light .

A rotary mirror 21 is installed in the channel of the reference beam, then a collimator 22, 23, 24, which performs functions similar to those performed by the collimator in the channel of the object beam. During the adjustment of the recording circuit, the output beam of the collimator is reflected by the mirror 25 and the diameter of the reflected beam is controlled on the micro-diaphragm 23 - it must be minimal, which indicates that the micro-diaphragm 23 is installed in the focal plane of the lens 24 and the reference beam has a plane wave front. During hologram shooting, mirror 25 is removed. After exposure and photochemical processing (development, fixation and bleaching), the hologram is set in its place, the channel of the object beam is blocked by an opaque screen 26 and the mirror 25 is set again. If the hologram is recorded qualitatively, an undistorted image appears in the transparency plane.

Next, a protective hologram is copied by the light of a He-Cd laser onto a plate coated with a photoresist layer onto which a hologram with a visible image has been previously recorded. When copying, a photographic plate with a protective hologram recorded on it is set by the emulsion side to the photoresist. Thus, a protective hologram is recorded on a hologram with a visible image by overlay. After recording both holograms, the manifestation of photoresist is performed. Then a metal matrix is made and holograms are replicated using the well-known traditional technology.

The structure of the latent image recorded on the protective hologram for the automatic control device is shown in Fig.3. The image is a matrix of N × N cells with 4 angularly arranged reference frames of high brightness. Reference points are located at the vertices of the rectangle formed by them, inside which there are informative “bits”, (cells), which are circular areas located in nodes of a uniform square grid with the number of nodes N × N.

In order to increase the reliability of hologram authentication, another degree of protection is introduced, namely digital encoding of information in the input image. To this end, from the entire array of cells of the input matrix, cell numbers are preselected in which a predefined code is written. Image processing in a computer is carried out according to a special algorithm, in which the cells in which the identification code is to be written are selected, and the correspondence of the information read from these cells to the specified code is checked. If there is a match, the logo image is displayed on the monitor screen, if there is no match, the image does not appear, but an error message is displayed.

As already noted, in order to simplify the procedure for accurately installing the hologram in the reader, an additional unencoded image of a point object is recorded on the protective hologram.

The device for automatic control of the authenticity of holograms is presented in Fig.4. The collimated beam of the semiconductor laser 27 is directed to the hologram 28. The encoded image reconstructed from the hologram passes through the decoding mask 29 (this is a copy of the mask used during recording) and enters the photodetector 30. As a result of the correction of the wavefront reconstructed from the hologram by the decoding mask, an undistorted image of the matrix recorded on the protective hologram is created at the input of the matrix photodetector. The read image through the interface 31 is entered into the computer 32 for subsequent digital processing.

Simultaneously with the restoration of the latent image, the image of the point is restored, which moves with the hologram when it is moved. The hologram is positioned so that the reconstructed image of the point appears in a pre-calculated place where the hole of the micro-diaphragm 33 is located, as a result of which the photocurrent appears and reaches its maximum at the output of the photodiode 34, which is evidence of the correct installation of the protective hologram.

The read image is a video frame with the number of pixels corresponding to the resolution of the photodetector. The read image may be distorted (tilted or have keystone distortion, as shown in FIG. 5) due to inaccurate installation of the photodetector during image reading. In addition, due to some noise in the image read from the hologram, the brightness of each pixel differs from that which should be with an ideal image.

The read video signal corresponding to the brightness of each pixel in the image is converted to an 8-bit binary code, which corresponds to an image with 256 shades of gray, so that the signal level can vary from 0 to 255.

To restore the image in the form of a binary matrix, an algorithm is used, an enlarged block diagram of which is shown in Fig.6.

At the first step of the algorithm, four frames are distinguished in the image. which are necessary to restore the coordinates of the nodes of the information grid. To do this, the following procedure is implemented.

1) The average brightness of the entire image I _{cp is} determined _. , which is defined as the sum of the video signals from all pixels divided by the total number of pixels.

2) The threshold brightness is selected P _p = I _cf + k _p · (I _cf ) ^0.5 · r · r, where k _p is an a priori coefficient from 1 to 6, chosen empirically; r is the dimension of the square mask corresponding to the number of pixels stacked on the side of the frame (depends on the characteristics of the reader).

3) A search for dimensional objects is carried out and from them a set of M potential benchmarks is formed. To do this, a set of points (pixel coordinates) of the image is formed, the average brightness of the r-neighborhood of each of which exceeds the value of the threshold P _p (summing the brightnesses over a moving square mask of dimension r × r). The next step connects the points closest to each other from the resulting set of individual pixels. Connected points form the desired set M. Points are connected into one object if the distance from each point to the center of gravity of the object does not exceed k ₀ · r, where k ₀ is specified a priori. When connecting another point, the center of gravity is calculated taking into account the coordinates of the last point (the center of gravity is the average value of the coordinates of the connected points with unit weights).

4) In the set M there are two pairs of objects, the distance between which is maximum. These are the required frames with coordinates Xr ₁ , Yr ₁ , Xr ₂ , Yr ₂ , Xr ₃ , Yr ₄ , Xr ₄ , Yr ₄ . Next, the coordinates of the corner elements of the information grid X ₀₁ , Y ₀₁ , X ₀₂ , Y ₀₂ , X ₀₃ , Y ₀₃ , X ₀₄ , Y ₀₄

Here L is the size of the information grid horizontally and vertically (for the case when the grid is square, and the size means the distance between the centers of the extreme nodes horizontally or vertically), and Δ is the distance along one of the coordinates from the center of the reference node to the center of the nearest information node (see figure 3).

Then the coordinates of (i, j) - the grid node are calculated:

X _y = x ₁ + (x ₂ -x ₁ ) * j * h;

Y _y = y ₁ + (y ₂ -y ₁ ) * j * h;

Where

y ₁ = Y ₀₁ + (Y ₀₂ -Y ₀₁ ) * i * h;

y ₂ = Y ₀₄ + (Y ₀₃ -Y ₀₄ ) * i * h;

x ₁ = X ₀₁ + (X ₀₄ -X ₀₁ ) * i * h;

x ₂ = X ₀₂ + (X ₀₃ -X ₀₂ ) * i * h;

h = 1 / (N-1);

N is the number of nodes in one dimension of the square grid.

5) The next step is to calculate for each node the average brightness I _y in its m-neighborhood. The value of m is determined by the formula

m = (Yr ₂ -Yr ₁ ) / ((N-2) * 2).

The average brightness is the average value of all the brightnesses of the points of the m-neighborhood with unit weights. If I _y exceeds the threshold brightness value P _y specified a priori, then the corresponding element of the informative matrix is assigned the value 1, otherwise 0.

6) The informative matrix obtained as a result of the algorithm contains a code for extracting the corresponding reference image from the image database (each database reference image has its own code combination in the matrix).

The procedure for extracting a reference image is as follows. From an informative matrix, a selection is made of elements with predefined numbers from which a binary word is formed. The resulting binary word is compared with the reference word stored in the computer using the algebraic XOR operation. If the words match, a binary address is issued at which the reference image (for example, the logo) is displayed from the database stored on the CD-ROM, which is displayed on the computer screen. This completes the image processing procedure.

Figure 7 presents a diagram of a device for automatic control of the authenticity of holograms with visual control of the positioning of the hologram. Compared to the circuit shown in FIG. 4, the micro-diaphragm 33 and the photodetector 34 are replaced with frosted glass with a reference mark (for example, a crosshair) applied to it, with which the image of the point should be combined when positioning the hologram.

Thus, the proposed method for the manufacture of protective holograms and a device for their control can be used to increase the effectiveness of the system of protection against counterfeiting holograms. Protective holograms made in accordance with the present invention and devices for their control can also be used to protect against counterfeiting a wide range of consumer goods.

List of references

1. John E. Wreede at al. Encoded hologram for producing a machine readable and a human readable image, Patent USA No. 5499116 of Mar. 12, 1996.

2. Halpern A.D. Holographic device for reproducing coding elements. Patent of the Russian Federation No. 2110411 dated 05/10/98.

3. Songcan Lai. Security holograms using an encoded reference wave. Optical Engineering, vol. 35. No. 9, September 1996.

4. Refregier P., Javidi B. Optical image encryption based on input plane and Fourier plane random encoding. Opt. Lett. - 1995. - V.20, N. - P.767-769.

5. Javidi B., Sergent A., Zhang G., Guibert L. Fault tolerance properties of a double phase encoding encryption technique. Opt. Eng. - 1997. - V.36, No. 4. - P.992-998.

6. Javidi B., Zhang G., Li J. Experimental demonstration of the random phase encoding technique for image encryption and security verification. Opt. Eng., 1996, V.35. No. 9, p. 2506-2512.

7. Bondarev L.A., Kurakin S.V., Kurilovich A.V., Odinokov S.B., Smyk A.F. Device for verifying the authenticity of holograms, Patent of the Russian Federation No. 2103741 dated 01/27/98.

8. David J. Pizzanelly, Holograms for security markings, Patent USA No. 5623347 of Apr. 22, 1997 - prototype.

Claims (6)

1. A method of protecting holograms from counterfeiting, in which a protective hologram with a hidden image and an image of a point object located outside the aperture of the encoding mask for positioning the protective hologram are recorded on a recording medium with a hologram with a visible image on it, and the hidden image is restored from a protective hologram, register the latent image with a matrix photodetector, process the received video signal of the latent image in an electronic block ke, and also restore from the protective hologram an image of a point object for positioning a protective hologram, register an image of a point object for positioning a protective hologram with a positioning control photodetector and position the protective hologram according to the maximum electric signal from the positioning control photodetector, characterized in that the latent image is formed in the form of a two-dimensional matrices of light optical dots, specify the individual in the specified matrix of bright optical dots a valid verification code for each type of security hologram at predetermined nodes of this matrix; in addition to the latent image, the image of a point object in the form of a converging spherical wave is recorded on a protective hologram, which, when restored, forms an additional uncoded optical mask image of a point object taken outside the mask aperture to position the protective hologram; when recording a protective hologram between the latent image and the hologram with the visible image in the channel of the object beam, an optical encoding mask is installed; a protective hologram with a hidden image is pre-recorded on a recording medium using a laser with a wavelength different from no more than 10% of the laser wavelength used in the hologram reader as a light source, and then the protective hologram is copied onto the photoresist plate in a contact way on which a hologram with a visible image is also recorded using a laser whose wavelength corresponds to the spectral sensitivity zone of a given photoresist plate; when reading a latent image, the protective hologram is moved until the reconstructed image of a point object located outside the aperture of the coding mask used to control the positioning of the hologram falls into the point hole in the micro-diaphragm and an electric signal with a maximum amplitude is recorded at the output of the position detection photodetector , which determines the correct positioning of the protective hologram; during processing in the electronic unit, predefined elements are selected that contain the identification code, the code read in this way is compared with the standard stored in the memory, and if they coincide, the image of the hologram logo is displayed on the monitor screen. 2. A method of protecting holograms from counterfeiting according to claim 1, wherein a matrix of pyramids extruded onto the phase glass plate for the code mask by hot pressing is used as an optical code mask in the channel of the object beam. 3. A method of protecting holograms from counterfeiting according to claim 1, wherein a speckle structure recorded on a photoemulsion or on a photoresist is used as an optical code mask that occurs when laser radiation is scattered on frosted glass, and the speckle size on the code mask is controlled by changing the laser diameter beam on the frosted glass and changes in the distance from the frosted glass to the photographic plate when recording a code mask. 4. A device for automatic control of the authenticity of a protective hologram, including a laser with a collimating lens sequentially installed along the path of the optical rays, intended for irradiating the protective hologram with a latent image, an array photodetector for converting the reconstructed latent image into a video signal and a photodetector for monitoring the positioning of the protective hologram, electronic processing unit, characterized in that the electronic processing unit is configured to input video signals nal, digitizing the video signal, processing the digitized video signal, as well as storing the standards, comparing the standards with the processed digitized video signal and displaying the comparison results; between the protective hologram and the matrix photodetector, an optical decoding mask is installed to restore the latent image; between the protective hologram and the photodetector of position control, a micro-diaphragm is installed. 5. The device according to claim 4, in which the optical decoding mask is made in the form of a matrix of pyramids extruded onto a glass plate by hot pressing. 6. The device according to claim 4, in which the optical decoding mask is made in the form of a speckle structure recorded on a photoemulsion or on a photoresist.

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