HOLOGRAPHIC SECURITY CODE AND RELATED VERIFICATION METHOD

Description

HOLOGRAPHIC SECURITY CODE AND RELATED METHOD OF VERIFY DESCRIPTION OF THE PRIOR ART Automatic identification of anti-counterfeiting elements has become increasingly important in order to recognize hidden information and make document authentication independent of human inspection. In the field of holographic security elements, new technologies have been developed numerous solutions for encoding optical information in such a way as to allow automatic verification. Patent EP0644508A1 describes a linear sequence of diffractive gratings, oriented at different angles, capable of containing encoded information. One specific reader composed of a laser beam and multiple sensors arranged in a way such as to collect the diffracted beams, allowing the message to be reconstructed encoded. In patent CN1399764A a phase pattern generated by a Fourier transformation is associated with a label: a second phase pattern is recorded on a mask which acts as an element Detector of a dedicated reader. During the label verification operation Authenticity is proven by optical correlation of signals coming from the first and second phase patterns. Patent US200208099 proposes an authentication code associated with a “digital watermark” type hologram, i.e. a graphic form consisting of a matrix of dots present in the hologram, containing information that can be decoded using a special reader. The disadvantage of all the solutions described above is that to carry out the check it is necessary to use dedicated readers which are not available on the market but must be developed ad hoc with non-development costs always suitable for the areas of application. In patents US20190220718 and WO2019 / 211422 a method is described to create variable coded information by associating a QR code and / or serial code to a HSF holographic product, hot applied on the support paper. The verification of the authenticity of the label is carried out by means of a smartphone device: after acquiring the image via camera, the authentication SW (SoftWare) verifies the congruity of the holographic code with printed codes. The solution described above represents a valid anti-photocopying tool. The authentication SW is able to detect a silver shape and detect the authenticity of the code among a data set of possible codes. However, the size of the code is such that it can be reproduced by inkjet printing on a silver support: this reproduction is in able to deceive the authentication SW, which is not able to discriminate a possible label reproduced in its entirety using inkjet printing. In order to overcome the above mentioned problems, a particular holographic code detectable by the camera of a smartphone phone. It consists of a two-dimensional sequence of elementary cells, detectable by a smartphone camera only under specific conditions observation angles, which cells are small enough to prevent any kind of reproduction without introducing errors or alterations that compromise their recognisability. This size is also chosen so that it can be acquired by the camera of a smartphone. The elementary cells are distributed in in such a way as to form a code which, when acquired by a camera, can be verified with a dedicated algorithm. The specific pattern allows to store a non-binding information viewable with perpendicular lighting and therefore not photocopiable. Furthermore, the shape and size of the elementary cells is chosen in such a way to prevent reproduction by printing technologies. DESCRIPTION OF THE INVENTION The object of the present invention is the realization of a holographic code security consisting of a pattern of cells of alternating diffractive structures “empty” elementary cells, suitable for being associated with an image holographic as an element for authenticity verification. The elementary cells “empty”, black in colour, they are clearly distinguishable from the holographic image iridescence of diffractive structures. From a first, more general point of view, the present invention has for subject a holographic security code comprising: a pattern of elementary cells having a predetermined shape and a predetermined relative position, the said pattern comprising a two-dimensional sequence of said elementary cells; the said pattern comprising a predetermined number of cells so-called "empty" elementary ones, that is, ones that appear to be a pre-established color dark, especially black, and the said pattern including a pre-established number of elementary cells that generate a diffractive effect, so-called iridescent cells, each comprising at least one diffractive grating having a predetermined orientation, preferably a combination of at least two diffractive gratings that differ from each other with respect to their orientation; the said diffractive gratings being made in such a way that the The emitted light radiation is visible only with observation according to different angles of view included in a pre-established range, the said pattern generating when observed according to the above mentioned angles of view, a image consisting of the combination of the said pre-established number of cells, so-called empty ones, having a pre-established dark colour, preferably black, and of so-called iridescent cells and in particular of different colors contrasting with the dark color of the so-called empty cells; while with viewing and / or illumination angles outside the said range of viewing angles, especially perpendicular to the surface along which you are viewing extends the said two-dimensional sequence of elementary cells, the said cells empty elementary cells and the said iridescent elementary cells do not present a different appearance from each other; the said elementary cells presenting lengths of the sides and / or diagonals or of the larger diameters included in the range from 50 to 300 microns. Dependent claims 2 to 10 relate to specific shapes and executive variants of the said holographic code. The present invention also relates to a holographic product of security characterized by the fact that it comprises a substrate on which is applied the holographic code according to one or more of the forms and variants executive provisions provided for above and in dependent claims 2 to 10. Dependent claims 12 to 15 further define improvements or variations of the holographic product. The present invention also relates to a verification system anti-counterfeiting, which system includes: - a variety of anti-counterfeit labels made according to one or more of claims 11 to 15. Dependent claims 17 to 20 relate to possible variants executive and / or improvements of the said system. According to a still further aspect, the present invention has for object a method of verifying the authenticity of security verification codes which involves the use of a holographic code according to one or more of the forms and of the executive variants described in claims 1 to 10 and of a holographic product according to one or more of the forms and executive variants described in claims 11 to 15. This method can be implemented by a system according to one or more of the executive variants of claims 16 to 20. In particular, according to a first executive form, the method provides the following steps: a) define a first element of information; b) generate a second piece of information by processing of transformation of the said first piece of information c) represent the said second piece of information below map shape of cells having two different aspects according to two colors between them contrasting; reproduce on a holographic product such as a label or similar one or more pre-established parts of the said map by means of sequences two-dimensional models of so-called empty and so-called iridescent elementary cells, that is, by means of one or more holographic codes according to one or more of the claims 1 to 10; apply the said holographic product to an object subject to verification of authenticity; store the information and / or characteristics of the map encoding of the said second piece of information; read the said two-dimensional coding sequence(s) of the said coding map of the second information element from the product holographic and reconstruct from them the parts of the said coding map from said two-dimensional sequences and / or extract the features from them relating to the size, shape and position of the said cells of the map of coding; compare the said reconstructed or extracted information and characteristics with the information and / or characteristics relating to the said map and / or the said first and / or to the said second element of information previously memorized; define the holographic product as authentic, i.e. the label when between the reconstructed and stored information and / or characteristics there is a correspondence within pre-established tolerances. In this description and in the claims, with the definition of contrasting colors are colors that correspond to different intensities of reflection or refraction of light energy, such as and in in particular the black color for the so-called empty cells and other colors for the iridescent cells. Furthermore, in the present invention, the term viewing angle refers to to a direction of view with a predetermined orientation which is referred to the two-dimensional plane on which the sequence of elementary cells extends two-dimensional. The term plan is not to be understood in a limited sense but also includes slightly curved surfaces. According to one embodiment, the said reader may consist of a device comprising a reading unit and a control unit transmission and reception communication and optionally a unit of visualization and / or acoustic diffusion, while the processing of the codes acquired by the reader is performed only by one unit of processing of a remote unit, which remote unit comprises a communication unit with the said reader for receiving signals generated by the reader itself and for the transmission of the signals to the said reader confirmation or denial of the correctness of the code. In an alternative embodiment, the said reader is associated with or integrated with a processing unit, such as a smartphone, a PDA, tablet, or similar device that has software loaded containing the instructions for performing the steps according to the preceding claims, which steps include reading the codes and transmitting them to the remote unit and the reception and display or acoustic diffusion of confirmation signals or of denial of the authenticity of the code and which software can optionally also include instructions for performing at least part of the of the functions provided for the processing unit of the said remote unit. Brief description of the figures The features and advantages of the invention will become more evident from the The following description of its embodiments is given by way of example and not limiting with reference to the attached drawings where: • Figure 1 represents a multiplicity of diffractive gratings; • Figure 2 shows the hologram observation mode iridescent; • Figure 3 shows a schematic of the cell pattern elementary school; • Figure 4 shows the ways of observing the holographic code; • Figure 5 represents an amplitude spectrum calculated using FFT algorithm; • Figure 6 shows the extraction of n portions from the amplitude spectrum of Fig. 5a; • Figure 7 shows two examples of codes; • Figure 8 shows a schematic of a sequence of holographic labels with encoded information; • Figure 9 shows a schematic of a sequence of labels with coded holographic stripe; • Figure 10 represents a flow chart of the process of stand-alone verification; • Figure 11 represents information encoded by stochastic algorithm; • Figure 12 represents a preferred label configuration with holographic stripe coded with the pattern illustrated in Fig. 10; • Figure 13 shows the sequence of operations of the process of stand-alone verification; • Figure 14 shows a sequence of codes generated with a stochastic algorithm; • Figure 15 represents a preferred label configuration with holographic stripe encoded with the sequence of codes illustrated in Fig, 13; • Figure 16 shows the sequence of operations of the process of check for example form 1; • Figure 17 shows the sequence of operations of the process of check for example form 2; • Figure 18 shows the sequence of operations of the process of verification carried out partially in offline mode and partially in online mode. Detailed Description of the Invention A holographic master is generally composed of a multiplicity of gratings diffractive with pitch in the range 0.4 - 1.5 µm, depth of the order of 200-400 nm and oriented differently according to a pre-established array, such as in the example shown in Fig.1. By means of a thermo-pressure process (known technique) it is possible reproduce the 100 diffractive grating array on a plastic material thermoformable which, when metallized, reproduces the sequence of colors of the rainbow as the observation angle varies. Fig. 2 shows an element 101 of the array 100 and the observation at different angles, in the range indicated 200. It is also possible to obtain holographic or pseudo-holographic reticles through a deep drawing process on formable plastic materials UV drying. The holographic code which is the object of the present invention is made up of patterns of 110 cells filled with orthogonal diffractive gratings, alternating with the cells 120 “empty” elementary (see Fig. 3), suitable to be associated with an image iridescent holographic and to act as an element of authenticity (or "imprint") of the hologram itself. The specific array of 110 structures represented in Fig. 3 will be visible both at an observation in the angular range 250, shown in Fig. 4a, both at an observation in the angular range 251 (rotating the sample by 90°) shown in Fig. 4b: since the grating pitch of the cell 110 is included in the range 0.4 - 1.5 µm, the angular range 250 (and 251) is included in the 200 range of Fig. 2. The combination of iridescent holographic cells alternating with “empty” cells generates a succession of colored pixels alternating with black pixels, when it is acquired by a camera with non-perpendicular illumination. In order to obtain an image suitable for processing by a black pixel recognition algorithm, it is appropriate to use cells of size in the range 50-200 microns. It is also appropriate to use square or rectangular cells or other shapes shape with sharp edges to prevent counterfeiting attempts using printing techniques. The holographic security code which is the subject of the present invention is generated, in a first preferred configuration, by means of a function mathematics that calculates the spatial distribution of frequencies of a graphic pattern (FFT algorithms) in order to connect the holographic code of security to a graphic element printed on a label or product. The verification process involves the acquisition of both elements using the camera of a smartphone device and authentication of the code in “stand-alone” mode via an app based on FFT algorithms, such as better specified below. Fig. 5 shows an example of a graphic element A and its relative Fourier transform of 1024x1024 pixels (amplitude spectrum). In Fig. 6 it is represented (220) the extraction of “N” portions of Fig. 5b of size 40x40 pixels each, which will constitute the codes 1, 2,… N. In Fig. 7 they are Enlarged images of codes 1 and 2 are shown. By extracting “N” different portions from Fig. 5b, one can obtain multiple series of codes that can be used, in a preferred configuration, on a plurality of labels. Each code, for example 1, 2,… N in Fig. 7, can be transformed into the cell pattern of Fig. 3 by filling the white pixels with 110 grids and the black pixels with the “empty” elementary cells 120; this pattern can also be inserted, as part of the graphic layout, within a iridescent holographic image. This pattern is suitable for use for the production of holographic products in self-adhesive label format (as a product authentication element) or in strip format holographic applied on paper or plastic support (as an anti- photocopy of securities). Figure 8 shows a schematic of a holographic product in label format. self-adhesive, in particular two self-adhesive holographic labels 300 (on silicone support 301), containing respectively the holographic code of security 320 (code 1) and 321 (code 2). Each code is provided, on the left side and on the top side, of a “position code” consisting of two sequences of black and white cells, 310 and 311 respectively, which encode in binary form, respectively the coordinates of the top left vertex 210 of the holographic code 320 and 321 compared to the distribution of Fig. 5b and the its size. The 300 label also contains a graphic element or logo 330 printed by inkjet. Fig. 9 shows a schematic of a holographic product in paper label format. 350 with 360 holographic stripe containing a sequence of “N” codes holographic with their respective position codes: in this case some codes of the sequence 1, 2, …, N positioned along the edge of the holographic strip will be contained within the paper label 350 (preferably 2 or 3). The paper label, similarly to what is described above for the self-adhesive label also contains a graphic element or logo 330 printed by inkjet, useful for the verification process below detailed. The verification of the congruity of the elements present in the label is carried out by acquiring the position code 310 (or 311), of the holographic code 320 (or 321) and the graphic element or logo 330 by means of the smartphone camera. Fig. 10 shows the sequence of operations of the verification process. which involves acquiring the photo of the label (350) using the smartphone camera, with a shooting angle that allows it to view the pattern of black and iridescent elementary cells that form the code holographic (with non-perpendicular illumination). The Logo image acquired by camera is searched in the set of predefined images contained in a Database (355). If the search has successful, the image contained in the database is transformed using the FFT algorithm in a matrix containing the distribution in the Logo frequency space (360). The information extracted from the code of position (365) allows you to obtain the portion relating to the matrix holographic security code (370). The authenticity verification of the holographic code (375) will be positive if of congruence between the pattern extracted by the authentication algorithm and the code acquired by camera. To take into account the wear of the label and any defects of the elements being verified, a summary may be inserted into the information redundancy for error correction or a redundancy may be established acceptance threshold in the range 85%-95% (percentage of congruence between the Images). In case of offline verification, all activities are delegated to the App, which also contains the default information set. In case of online verification, the database and the necessary functions for the verification of congruity they are placed on a remote server while the activity of image acquisition and interface between the server and the operator are delegated to the App. Other preferred configurations may include the use of algebraic functions, trigonometric, Laplace transforms, stochastic functions, etc. In a second preferred configuration the holographic security code is consisting of a non-uniform sequence of black elementary cells 410 alternating with iridescent elementary cells 420, as shown in the executive simplification of Fig. 11. For the generation of sequences pseudorandom, with elementary cells of discrete and predefined dimensions, a stochastic algorithm is used. Referring to Fig. 11, the black elementary cells 410 are alternated with the 420 iridescent cells, both of variable size in the range 80-300 micron. Pattern 400 is used in the holographic stripe product 520 of Fig. 12, applied on the paper support 500. According to one embodiment, in order to produce labels with code holographic security with maximum variability, a development of the die-cut layout not commensurate with distance 530 so that, by die-cutting the paper support into the final 510 format of the labels, get different elementary cell patterns on individual labels. This preferred configuration is suitable for insertion into the strips holographic foils are widely used as an anti-counterfeiting element for cards values ​​such as product authentication labels, tobacco tags, brands stamp, banknotes, etc… The verification process is carried out by acquiring and processing, with a dedicated App, of the image of the holographic strip, acquired with a smartphone camera: from the image are extracted the geometric characteristics of the elementary cells and of the sequence of cells. The authenticity check will be positive in case of congruence between the detected values ​​and those expected from a data set or from a pre-established function both in terms of size and sequence of the dimensions of the elementary cells. Fig. 13 shows the sequence of operations in the process of verify: - acquisition of the photo of the holographic strip (650) by means of the smartphone camera, with a shooting angle such as visualize the pattern of black and iridescent elementary cells that form the holographic code (with non-perpendicular illumination); - image processing to check the size and distance of black elementary cells (655); - comparison with the information stored in the verification app (data specific set or functions) (660); - congruence of the information extracted from the photo with the data set or with the values ​​of the specific function (665), within an acceptance value in the range 85%-95% (percentage of congruence between images). The above mentioned verification operations can be performed directly from the app in offline mode or in a more secure way, they can be performed on a remote server, while the data acquisition activity images and interface between the server and the operator are delegated to the App. In another preferred configuration, the holographic security code is made up of multiple patterns of elementary cells, black and iridescent, positioned with a random step inside a holographic strip. In Fig. 14 the elementary cell patterns 601, 602, 603 and 604 which are added at random in the holographic strips 410 of Fig. 15. The 510 labels, obtained by die-cutting the 500 paper support, will contain pattern of elementary cells located in different positions within the portion of the holographic strip present on the label itself. This positioning information, combined with the recognition of the code allows you to proceed with the verification in the ways illustrated below. The verification is carried out with a dedicated App, which acquires and processes the label image: information is extracted from the image encoded in the patterns and the relative distances between the patterns in the strip holographic of the single label. In a first exemplary representation of this configuration, all elementary cells have the same size and are positioned uniformly in a checkerboard pattern to form a pattern. The information contained in the patterns are binary codes obtained using a generator of pseudo-random numbers: the codes are represented in the patterns, attributing the logical value 1 to the black elementary cells and the logical value 0 to the cells iridescent elements. Patterns may also contain information coming, for example, from logical or mathematical operations performed on the binary codes represented in the patterns, to be used in the phase to verify the holographic security code as detailed below. Redundancy systems (control and / or correction) to correct reading errors or slight wear of the cells elementary school. Below are some examples and are not exhaustive: Examples of types of information encoded in patterns: • In each pattern there is information that follows a rule of sequentiality established by a specific function; • In each pattern 3 pieces of information are encoded: two are binary codes obtained through the pseudo-random number generator and the third is obtained through an operation performed on the two codes (for example an XOR operation) • In each pattern a binary code is represented in the first half obtained through the pseudo-random number generator and in the second half the same code but encrypted. Fig. 16 shows the sequence of operations of the process. verify: - acquisition of the photo of the holographic strip (750) by means of the smartphone camera, with a shooting angle such as visualize the pattern of black and iridescent elementary cells that form the holographic code (with non-perpendicular illumination); - extraction of elementary cell patterns (755); - extraction of distances between patterns (760); - logical / mathematical operations on the information extracted from the patterns (765); The authenticity check (770) will be positive if it is consistent with the pre-established rules in coding information in patterns, namely: • if the information (binary codes) encoded in the patterns present on each label respects a sequencing rule established by the specific function used; • if the third piece of information encoded in the pattern is the correct result of the pre-established logical / mathematical operation; • if the decrypted code is present in the second half of the pattern coincides with the code present in the first half. In all 3 cases above the verification will be completed with the congruity of the distance between patterns predetermined by the data set or specific function. In a second exemplary representation of this configuration, Deformations are introduced into the chessboard that forms the pattern by modifying one or more elementary cells (for example the size or the shape, for example trapezoidal instead of square). The position of the cell elementary “deformed and / or translated” or the type of deformation / translation is established by the information encoded in the pattern itself. This correlation will be used in the verification phase of the holographic code of safety. The patterns, as mentioned, are distributed within the label with a step random. This conformation, together with the previous correlation will be used during the verification phase. By way of example and not limited to, the following will be consider the following two situations: • the values ​​of the relative distances between the patterns are stored in a dataset • the values ​​of the relative distances between the patterns respect some rules of sequences established by a specific function. Figure 17 shows the sequence of operations of the process. verify: - acquisition of the photo of the holographic strip (850) by means of the smartphone camera, with a shooting angle such as visualize the pattern of black and iridescent elementary cells that form the holographic code (with non-perpendicular illumination); - extraction of elementary cell patterns (855); - extraction of distances between patterns (860); - processing of deformations and translations of elementary cells according to the information encoded in the pattern (865); The authenticity check (870) will be positive if it is consistent with the pre-established rules, namely: • if the position of the elementary cell is “deformed and / or translated” agrees with the information encoded in the pattern • If the values ​​of the relative distances between the patterns correspond with those default (dataset present in the app) • If the sequence regarding the distance values ​​is respected relative between patterns according to the specific function used. The verification processes described above can be performed in off-line mode. online, in online mode or in mixed mode. In case of offline verification, all activities are delegated to the App, which also contains the default information set. In the case of remote verification, the App performs the acquisition function of images and interfacing between user and remote server, which It performs the functions of recognition and congruence. In case of mixed mode part of the comparison and verification operations will be performed with the set of information stored in the remote server and the rest directly from the App. Reference is made to the first executive representation of Fig. 16, for describe, in an exemplary and non-exhaustive manner, a verification process in mixed mode where, in off-line mode, the values ​​of the positions of pattern elements and sequences of predetermined values, allowing an initial check even in the absence of a network signal, while the control of logical-mathematical operations is carried out remotely. The sequence of operations of the verification process, as outlined in Fig. 18, is reported below: - The photo of the holographic strip is acquired by the App, in off-mode line, using a smartphone camera; - The verification of congruence between the values ​​of the positions of the elements of the patterns and sequences of pre-set values ​​are performed by the App, in offline mode; - If the offline verification is successful, the App performs the connection to the remote server; - The remote server performs the operations verification logical / mathematical on the information extracted from the patterns and produces a positive or negative outcome in case of congruence or incongruence with the expected values.

Claims

1. Holographic security code comprising: a pattern of elementary cells having a predetermined shape and a predetermined relative position, said pattern comprising a two-dimensional sequence of said elementary cells; said pattern comprising a predetermined number of elementary cells which are so-called “empty” or which appear to be of a predetermined dark colour, in particular black, and said pattern comprising a predetermined number of elementary cells which generate a diffractive effect, so-called iridescent cells, and which each comprise at least one diffractive grating having a predetermined orientation, preferably a combination of at least two diffractive gratings which differ from each other with respect to their orientation;the said diffractive gratings being made in such a way that the emitted light radiation is visible only when observed according to different viewing angles included in a predetermined range, the said pattern generating, when observed according to the aforementioned viewing angles, an image consisting of the combination of the said predetermined number of cells, so-called empty, having a predetermined dark color, preferably black, and of so-called iridescent cells and in particular of different colors contrasting with the said dark color of the so-called empty cells; while with viewing and / or illumination angles outside the said range of viewing angles, in particular perpendicular to the surface along which the said two-dimensional sequence of elementary cells extends, the said empty elementary cells and the said iridescent elementary cells do not present a different appearance from each other;the said elementary cells having side lengths and / or diagonals or major diameters in the range from 50 to 300 microns; 2. Holographic code according to claim 1, wherein two types of diffractive gratings are provided in the so-called iridescent cells which have orientations perpendicular to each other.

3. Holographic code according to claims 1 or 2, wherein said cells have a polygonal shape with accentuated edges, preferably a quadrangular shape, i.e. square or rectangular.

4. Holographic code according to one or more of the preceding claims, wherein said two-dimensional sequence of elementary cells is in the form of a chessboard having a predetermined extension along two mutually orthogonal directions and said distribution of the so-called empty cells with respect to the so-called iridescent cells within said two-dimensional sequence is defined by means of a transformation function of a first information element into a second information element encoded in the form of a graphic coding map comprising cells having two mutually different aspects according to two types of contrasting colours and in which the cells of one type are represented by so-called empty elementary cells while the cells of the other type are represented by said so-called iridescent cells.

5. Holographic code according to claim 4, wherein said graphic coding map has a number of cells greater than the elementary cells provided for in said two-dimensional sequence, the elementary cells of said two-dimensional sequence being defined corresponding to the cells of a predetermined region of said graphic coding map of said second information element, said two-dimensional sequence of elementary cells being associated with an identification code of the position of a starting elementary cell of said two-dimensional sequence with reference to said graphic coding map,which identification code is of the binary type and is constituted by at least one further position coding distribution comprising a predetermined number of empty cells and iridescent cells having a predetermined position within the said two-dimensional sequence of elementary cells and a dimension smaller than the said two-dimensional sequence, the said position coding distribution being optionally a linear distribution and / or a combination of at least two linear distributions along two different directions.

6. Holographic code according to claim 5, wherein said code comprises two or more different two-dimensional sequences of elementary cells, which two or more two-dimensional sequences differ from each other in that said two-dimensional sequences are defined by said two different aspects of the cells of said graphic coding map of respectively different parts of said graphic coding map, each two-dimensional sequence being associated with the binary graphic coding code of the position of the part of said coding map represented by said two-dimensional sequence.

7. Holographic code according to one or more of the preceding claims, wherein the elementary cells of a two-dimensional sequence alternatively have: a) all substantially the same dimensions, said second information element being encoded solely by the distribution pattern of the so-called empty cells and the so-called iridescent cells within said two-dimensional sequence; b) dimensions which are different from each other and which dimensions constitute a further coding function of said second information element or of a predetermined part thereof in combination with the coding by means of said pattern of said so-called empty cells and said so-called iridescent cells;c) alternatively or in combination with points a) or b) a two-dimensional distribution of two or more different two-dimensional sequences according to claim 6 which is characterized by a specific selection of said two or more different two-dimensional sequences and / or by their relative arrangement within the two-dimensional extension of said two-dimensional distribution with respect to a predetermined order of succession and / or their distance. d) alternatively or in combination with points a) to c) predetermined variations in the perimeter shape of a predetermined number of elementary cells of the so-called empty type and / or the so-called iridescent type.

8. Holographic code according to one or more of the preceding claims, wherein the transformation function of said first information element into said second information element can be constituted alternatively or in combination by one or more of the following functions: - a mathematical function such as one or more transforms, preferably a Fourier transform, a Laplace transform, one or more trigonometric functions, one or more algebraic functions, one or more stochastic functions.

9. Holographic code according to one or more of the preceding claims, characterised in that it is provided in combination with an additional optionally holographic information element in a form superimposed and / or adjacent to the same.

10. Holographic code according to one or more of the preceding claims, wherein one or more of said two-dimensional sequences comprises a combination of so-called empty elementary cells and so-called iridescent elementary cells configured so as to encode strings verifying the correctness of the encoded information.

11. Holographic security product characterised in that it comprises a substrate on which the holographic code according to one or more of the preceding claims is applied.

12. Holographic security product according to claim 11, wherein said holographic code is provided in combination with a graphic and / or alphanumeric information element, optionally represented by a hologram, and wherein said information element constitutes said first information element, while said second information element is constituted by a processing of said first information element by one or a combination of said transformation functions.

13. Holographic product according to claim 12, wherein, said holographic code is constituted by a holographic code according to one or more of claims 5 to 7.

14. Holographic product according to claim 11, wherein the holographic code is applied to said substrate in the form of a continuous holographic band on which are represented in a predetermined sequence alternatively: a) a cyclic repetition of one, two or more of said different two-dimensional sequences; b) a random repetition of two or more of said different two-dimensional sequences; c) a repetition according to point a) or point b) wherein in said band the relative position of said one or two or more two-dimensional sequences is different along the longitudinal extension thereof and is defined by a function, preferably a random function.

15. Holographic product according to one or more of claims 11 to 14, characterised in that it is in the form of a label comprising one, two or more of said two-dimensional sequences or at least one said two-dimensional sequence and at least a part of one, two or more of said two-dimensional sequences.

16. Anti-counterfeiting verification system, which system comprises: - a plurality of anti-counterfeiting labels made according to one or more of claims 11 to 15; - at least one reader of codes applied to said labels, said codes being constituted by at least one holographic code according to one or more of claims 1 to 10; - at least one processing unit comprising a memory in which said codes are stored and at least one program for comparing the codes transmitted by the reader and the codes contained in said database, at least one visual and / or acoustic reception and reproduction unit associated with said reader;the said processing unit generating a confirmation or denial signal of the authenticity of the code based on the outcome of the said comparison, said signal being transmitted to the said visual and / or acoustic reproduction unit for the emission of visual and / or acoustic information on the confirmation or denial of the authenticity of the said code.; 17. Anti-counterfeiting verification system according to claim 16, wherein - said codes further consist of at least one graphic and / or alphanumeric information element preferably applied in such a way as to be visible on said labels; - said first information elements and the functions for generating the corresponding said second information elements and the functions for encoding said second information elements in a holographic code according to one or more of claims 1 to 10 are stored in the memory of said processing unit, or in said database, which is constituted by at least one or two or more of said two-dimensional sequences of elementary cells;- the said at least one code reader being connected to an input of the said processing unit and in the said processing unit there is or can be loaded a software comprising the instructions for receiving the reading data from the said reader corresponding to a holographic code and verifying the congruence of the said first information element(s) with the corresponding second information element(s) reconstructed by decoding the said holographic code.; 18. System according to claim 16 or 17, wherein: - said first information element consists of a graphic and / or alphanumeric logo; - said second information element consists of an algorithmic processing of said first information element, which algorithm is of the type according to claim 8; - said holographic code consists of a holographic code according to one or more of claims 5 to 10; - said processing software comprising instructions for performing the following operations: i) processing the image acquired by said reader of said first information element by applying thereto the transformation function used for generating the second information element; ii) generation of the coding map of said second information element reconstructed from said image of said first information element;iii) determination of the position of the two-dimensional sequence or sequences of elementary cells, from the position codes of the same with reference to the areas of the coding map of the second information element represented by the said one or more two-dimensional sequences; iv) comparison between the said one or more two-dimensional sequences reconstructed from the acquired image of the first information element with the said one or more two-dimensional sequences acquired by the reader, with labels being considered authentic for which the result of the said comparison indicates an identity within pre-established tolerances.

19. System according to claim 16 or 17, wherein - said first information element consists of a deterministic or random combination of dimensions and / or distances of cells having aspects according to two typologies with contrasting colors, in particular black and white; - said second information element consists of a representation of said first information element by means of one, two or more two-dimensional sequences of so-called empty and so-called iridescent elementary cells; - said processing software comprising instructions for performing the following operations: i) acquisition of said one or more two-dimensional sequences of so-called empty cells and so-called iridescent cells by the reader;ii) determination of the distance and / or size of the cells of the first information element, of the distances and / or size of the cells of the said one or more two-dimensional sequences of so-called empty cells and so-called iridescent cells; iii) comparison between the information on the distance and size of the cells of the first information element stored in the memory of the said processing unit with the corresponding values ​​obtained from the processing of the said one or more two-dimensional sequences, labels being considered authentic for which the result of the said comparison indicates an identity within pre-established tolerances.

20. System according to one or more of claims 16 to 18, wherein - said first information element is constituted by a deterministic or random combination of one, two or more of said two-dimensional sequences of so-called empty cells and so-called iridescent cells, said deterministic or random distribution being related to the dimensions and / or distances of the cells having aspects according to two typologies with contrasting colors, in particular black and white and / or related to the order of succession of said different two-dimensional sequences with respect to each other and / or related to the variation of the perimeter shape of a predetermined number of so-called empty elementary cells and / or so-called iridescent elementary cells; - said second information element is constituted by a representation of said first information element by means of one, two or more two-dimensional sequences of so-called empty elementary cells and so-called iridescent elementary cells;- the said processing software comprising instructions for performing the following operations: i) acquisition of the said one or more two-dimensional sequences of so-called empty cells and so-called iridescent cells by the reader; ii) determination of the distance and / or size and / or perimeter shape of the cells of the first information element, the distances and / or size and / or perimeter shapes of the cells of the said one or more two-dimensional sequences of so-called empty cells and so-called iridescent cells and / or determination of the distance of the said two-dimensional sequences from each other and / or determination of the order of succession of the said two-dimensional sequences from each other;ili) comparison between the information on distance and size and / or perimeter shape of the cells of the first information element and / or the distance and / or the order of succession of the two-dimensional sequences stored between them in the memory of the said processing unit with the corresponding values ​​obtained from the processing of the said one or more two-dimensional sequences, the labels for which the result of the said comparison indicates an identity within pre-established tolerances being considered authentic.;