RU2823438C1 - Method of generating and decoding two-dimensional code of data medium - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to formation of information carriers. Technical result is achieved by the fact that it provides for the possibility of decoding the aggregating two-dimensional code, wherein for the formation of the aggregating two-dimensional code of the information medium, the steps are performed at which: selecting the format of the QR code; set of information to be placed in the aggregating two-dimensional code is converted into a bit data array; breaking down each generated bit array of data, which exceeds the allowable volume for the selected QR code format, into a set of blocks; generating a QR code for each block; obtained QR codes are placed in a matrix of aggregated values; for each single data element of the used format of the QR code, layer-by-layer bitwise aggregation is carried out; dimension of identifier parts responsible for encoding information in cells of the aggregating two-dimensional code, which determine the colour of the symbol and the symbol in the cell, is determined, and a control code table used for encoding is formed.

EFFECT: increase in the amount of information placed in the aggregating two-dimensional code of the information medium while maintaining the possibility of recognition by the built-in cameras of smartphones and subsequent decoding.

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Description

Field of technology to which the invention relates

The proposed inventions relate to the field of forming information media containing an aggregating two-dimensional code, such as identification documents or information media containing technological instructions or information materials, as well as for use for marketing purposes.

State of the art

The main problems faced by consumers of the market for systems for working with identification documents using solutions based on QR codes are determined by the limitation on the amount of information that can be placed in a QR code and the requirement to maintain the stability of reading QR codes at a given level.

In an attempt to increase the amount of data that can be stored using a QR code, the following types of solutions can be distinguished.

Using two or more QR codes in one document or using, in addition to the main QR code, an additional two-dimensional barcode made using “invisible barcode” technology. Obviously, this way of increasing the volume of information placed on an identification document by using several smaller QR codes has the following disadvantages:

1) limiting the number of available models of QR code scanners due to the lack of functionality in a number of models for simultaneous reading of several QR codes with subsequent merging of the received information into a single block, and the functionality for reading “invisible QR codes”;

2) standard applications for mobile devices do not have the functionality for simultaneous reading of several QR codes with subsequent integration of the received information into a single block, which may require the development of additional software modules for systems that work with QR codes;

3) the total area, taking into account the mandatory separating fields between QR codes, occupied by several QR codes on a document exceeds the area occupied by a higher-level QR code, which increases the likelihood of mechanical damage to the entire information field occupied by QR codes on a document.

4) placement on an identification document of 2 or more QR codes of less than the 30th version instead of one QR code of the 40th version will lead to a forced reduction in the size of the entire field of each of the available QR codes, and, taking into account the number of elements by version , and each individual QR code module, will lead to a significant reduction in the readability of the entire QR code by scanners, control terminals and mobile devices.

A second way to increase the amount of data that can be stored using a QR code is to use grayscale or color cells instead of black and white cells. Increasing the number of colors, on the one hand, leads to an increase in the amount of information that can be stored using a QR code, but, on the other hand, it imposes restrictions on the minimum cell size, and, therefore, increases the size of the QR code, while the number of used colors is limited by both the capabilities of printing devices and the capabilities of reading devices.

For example, DataMatrix codes proposed in US 2022/0327302 A1, publ. 10/13/2022, formed on the basis of colored rectangular elements with 3-bit color coding, can be used for marking labels of containers and test tubes with materials for biochemical research, but only for a small number of colors in the code palette and only for codes with a low density of elements. Images. With an increase in the number of colors in the code and the use of densely spaced and boundary unseparated rectangular elements to form the image, as well as in the absence of a control color code table in the image, this solution will be very dependent (when used for contactless reading of the code image) on the conditions external lighting. The presence of color components in external light sources can lead to a significant shift in the color palette of the scanned image, thereby causing decoding errors.

In US 7032823 B2, publ. 04/25/2006 describes the process of forming a bit stream to form a 5-layer array (RGB layers, brightness and scale layers), which provides for the use of a distributed control color palette in the QR code. This technology does not take into account color features when printing images of documents and the features of the process of scanning documents with mobile devices when conducting checks in different lighting conditions. In conditions of mass use with currently available printing/reading devices, the use of such technology is difficult and will lead to a large number of errors during decoding.

There are also known attempts to create two-dimensional codes containing colored figures in the form of triangles as the main elements of data encoding (US 7936901 B2, published 05/03/2011 and CN 111723890 A, published 09/29/2020). The use of this technology is not applicable when creating information media, since the regular structures of halftone figures make it almost impossible to use mobile devices that use contrast or phase autofocus technologies to read them. In addition, in different lighting conditions when scanning identification documents with mobile devices, it is almost impossible to obtain an image in which it is possible to reliably identify figures with similar halftones of the same color.

In CN 107895187 A, publ. 04/10/2018 shows a method for generating a two-dimensional character code, but its applicability is positioned only for the exchange of short messages, without application in the field of identification documents. An example of a simple non-standard matrix code of unspecified format is given. The declared goal of reducing the volume of code is to combat the possibility of using codes as carriers of computer viruses.

The closest to the claimed invention is patent US 9805296 B2, publ. 10/31/2017, disclosing a method for generating a multi-layer color QR code from data to be encoded, including:

dividing the data to be encoded into a plurality of data blocks according to the number of layers and the error correction level of each layer specified by the user;

splitting the data in all data blocks into bits;

independently encoding separated blocks of data into multiple monochrome QR codes, with each monochrome QR code having the same dimension;

shuffling the data blocks in each monochrome QR code randomly or based on the sizes of each monochrome QR code;

combining all monochrome QR codes to create a multi-layer color QR code using a predefined color code table; And

adding color restrictions to spatial patterns,

while adding color constraints to spatial patterns includes: coloring all search patterns and alignment patterns with a set of colors to reduce false positives during the localization process.

The disadvantages of this method of generating a multilayer color QR code include the use of standard forms of QR code elements to form the resulting image of a multilayer color QR code, completely filled with color from the code palette, and having a common border - this solution is not applicable for the use of high-quality QR codes density (version 20 and higher) in identification documents, since when printing borderline non-separated multi-colored elements, borderline color mixing will occur, which will cause the appearance of colors that are not in the palette and will lead to a significant distortion of the boundaries of the QR code elements.

This patent also discloses a method for decoding a multi-layer color QR code, including:

capturing an image of one or more two-dimensional multi-layer color QR codes having multiple layers of encoded data;

detecting coarse locations of color QR codes using a sliding window based QR code detector trained offline;

generating within each detected bump location a corrected color QR code that is generated using a robust geometric transformation algorithm;

performing color restoration from a corrected color QR code by restoring the original color of each color pixel of the corrected color QR code using an offline-trained color classifier and further decomposing the reconstructed color QR code into multiple monochrome QR codes using a predefined table color codes used in the encoding process; And

extracting encoded data from monochrome QR codes layer by layer and combining monochrome QR codes to output data encoded in the captured color QR code.

The disadvantages of this method of decoding a multilayer color QR code include the inapplicability of this method for use in verification processes of identification documents, since image capture of two-dimensional multilayer color QR codes formed from boundary unseparated multi-colored elements, when read from a detecting device, is highly dependent on the conditions illumination (in particular from the intensity of light sources and the color spectrum of light sources), and color interference at the interfaces of QR code elements, especially for density QR codes (version 21 and higher).

The claimed invention is aimed at eliminating the shortcomings of known technical solutions.

Disclosure of the invention

The technical result of the claimed invention is to increase the volume of information placed in the aggregating two-dimensional code of the information carrier while maintaining the possibility of recognition by the built-in cameras of smartphones and subsequent decoding.

The technical result is achieved through a method for generating an aggregating two-dimensional code of an information carrier, which includes the following actions:

a) select a format that includes the version and noise immunity of the QR code used for further aggregation;

b) forming at least one set of information to be placed in the aggregating two-dimensional code;

c) each generated set of information is converted into a bit array of data;

d) splitting each generated bit array of data that exceeds the volume permissible for the selected QR code format into a set of blocks corresponding to the permissible data volume of the selected QR code format;

e) for each data block from the received at least one set of data blocks, a QR code is generated according to the selected format;

f) the resulting QR codes are placed in at least one matrix of aggregated values with dimension [n, n, m+1], where n is the dimension of the two-dimensional matrix of the selected QR code format, m is the number of aggregated QR codes;

g) for each single data element of the used QR code format, a layer-by-layer bitwise aggregation is carried out onto the (m+1)th aggregation layer of each matrix to obtain an identifier for each cell of the (m+1)th aggregation layer;

h) determine the dimension of the parts of the identifier responsible for encoding information in the cells of the aggregating two-dimensional code, determining the color of the symbol and the symbol in the cell, and form a control code table used for encoding;

i) carry out the formation of an image of the markup elements of the aggregating two-dimensional code;

j) using the identifier values from each cell of the (m+1)-th aggregation layer of each matrix of aggregated values, in accordance with the control code table, an image of the resulting aggregating two-dimensional code is formed, while the number of symbols in one cell of the aggregating two-dimensional code corresponds to the number of matrices of aggregated values ;

k) fields with a control code table are added to the generated image of the aggregating two-dimensional code;

l) the generated image of the aggregating two-dimensional code is applied to the information carrier.

In particular, in addition to action h) the part of the identifier responsible for the color of the cell border is determined.

In particular, in addition, according to action h) the part of the identifier responsible for the color or optical density of the cell background is determined.

In particular, fields with a control code table are placed in the form of a distributed set of elements of the aggregating two-dimensional code in the selected fields of data elements or markup elements of the aggregating two-dimensional code.

In particular, at least one of the generated QR codes contains means for restricting access to the information contained therein.

In particular, additional information about the number and/or order of placement of matrices in the assembly is added to the control code table.

In particular, additional information about the version of the aggregated QR codes is added to the control code table.

Also, the technical result is achieved through a method for decoding an image of an aggregating two-dimensional code of an information carrier, including the following actions:

a) scan the image of the aggregating two-dimensional code from the storage medium;

b) detect images of markup elements of the aggregating two-dimensional code;

c) the resulting image is positioned using the selected marking elements;

d) using the black-and-white fields of the markup elements of the search template, determine the boundaries of the dynamic range and adjust the white balance in the image of the aggregating two-dimensional code;

e) decompose the image of the aggregating two-dimensional code and form a set of images of its elements with indexing corresponding to the numbering of the QR code data modules;

f) extract the aggregating two-dimensional code of the control code table from the image;

g) using the control code table, they determine the coding elements that determine the color of the symbol and the symbol in the cell, and also determine the dimensions of the parts of the identifier used to encode information that determine the color of the symbol and the symbol in the cell, determine the number and method of isolating QR codes from the aggregating two-dimensional code;

h) determine the parameters of the necessary color correction based on the analysis of the parameters of control images of coded color marks for the color of the characters;

i) carry out color correction of a set of images of data elements of the aggregating two-dimensional code;

j) perform recognition of the entire set of images of the aggregating two-dimensional code and form at least one matrix of identifiers of its elements, wherein the number of generated matrices corresponds to the number of characters in one cell of the aggregating two-dimensional code specified in the control code table;

k) from each matrix of identifiers, the layers of the constituent QR codes are restored;

l) carry out layer-by-layer decoding of information from the components of QR codes with its subsequent distribution among sets of information;

m) the decoded information is displayed on the screen of the control device.

In particular, in addition to action g) the part of the identifier responsible for the color of the cell border is determined.

In particular, in addition to action g) the part of the identifier responsible for the color or optical density of the cell background is determined.

Brief description of drawings

Fig. 1 - structure of markup elements of QR code version 7.

1 - free zone, 2 - search pattern, 3 - separator, 4 - synchronization pattern, 5 - guide pattern, 6 - format information, 7 - version information, 8 - data and error correction codewords, 9 - function patterns, 10 - coding area.

Fig. 2 - structure of data blocks and error correction blocks of a QR code using version 21 as an example. Number of data modules in a QR code: 1 - 101 modules, 2 - 85 modules.

Fig. 3 - carrying out layer-by-layer bitwise aggregation of QR codes into an aggregating two-dimensional code.

Fig. 4 - structure of data blocks and error correction blocks (with block numbering) using the example of QR code version 7.

Purpose of blocks: D1-D13 - data block 1, D14-D26 - data block 2, D27-D39 - data block 3, D40-D52 - data block 4, D53-D66 - data block 5, E1-E26 - error correction block 1, E27-E52 - error correction unit 2, E53-E78 - error correction unit 3, E79-E104 - error correction unit 4, E105-E130 - error correction unit 5.

Fig. 5 - view of a single data cell of an aggregating two-dimensional code for single-stream aggregation. The cell size when using the basic 21st version of the QR code is 0.5 x 0.5 mm.

Fig. 6 - view of a single data cell of an aggregating two-dimensional code with 4-stream aggregation. The cell size when using the basic 21st version of the QR code is 1 x 1 mm.

Fig. 7 - comparison of cards with QR code version 40 placed on them and an aggregating two-dimensional code based on QR codes of version 21. While maintaining the dimensions, the volume of data in the aggregating two-dimensional code is increased by more than 4 times.

Fig. 8 is an example image of a test prototype of an aggregating two-dimensional code.

Carrying out the invention

The proposed technology for encoding and presenting information in aggregating two-dimensional codes can be used to optimize the presentation of volumes of information when placing personal identification, biometric and departmental information about the owner in identification documents, as well as in the formation of information media for advertising and technological purposes, containing general information and additional information machine readable documents.

The technology is based on the use of a set of sequentially applied methods (including neural network methods) that make it possible to generate an image of a high-capacity aggregating two-dimensional code and use it when placed both on identification documents of limited size and on large-sized information media for various purposes. The generated image can be read using both standard cameras of mobile devices and specialized QR code readers that allow you to save the resulting image in raster format.

A feature of the proposed method is the ability to pre-select the QR code format used for further aggregation. Thus, an aggregating two-dimensional code can be created depending on the version and noise immunity requirements placed on it.

In the case of limited space for placing a two-dimensional code, for example, on identification documents, an aggregating two-dimensional code is formed according to the size of the area allocated for its placement, taking into account the minimum allowable cell size.

For example, to place aggregating two-dimensional codes, inserts on passport pages in the ID-3 format of the ICAO standard or identification plastic cards in the ID-1 format of the ICAO standard can be used, which will determine the maximum permissible geometric size.

On the contrary, in the absence of strict requirements for the size of a two-dimensional code, for example, when placed on information posters or stands, it is possible, without increasing the series of the QR code, to place a larger amount of information in the aggregating two-dimensional code by increasing the number of characters in one cell. The most advantageous from the point of view of the capacity of the aggregating two-dimensional code is to place characters in a cell in an amount equal to the square of the integer, i.e. 4, 9, 16, etc.

The amount of data contained in a QR code is determined by the version of the code used. Moreover, the higher the correction level (the permissible level of damage to the QR code), the less information is available for placement in the QR code (for versions 20 to 40 are presented in Table 1, in bits).

Table 1

QR code version Number of modules Correction level (acceptable level of damage) 7% (L) 15% (M) 25% (Q) 30% (H) 20 97x97 6888 5352 3880 3080 21 101x101 7456 5712 4096 3248 22 105x105 8048 6256 4544 3536 23 109x109 8752 6880 4912 3712 24 113x113 9392 7312 5312 4112 25 117x117 10208 8000 5744 4304 26 121x121 10960 8496 6032 4768 27 125x125 11744 9024 6464 5024 28 129x129 12248 9544 6968 5288 29 133x133 13048 10136 7288 5608 thirty 137x137 13880 10984 7880 5960 31 141x141 14744 11640 8264 6344 32 145x145 15640 12328 8920 6760 33 149x149 16568 13048 9368 7208 34 153x153 17528 13800 9848 7688 35 157x157 18448 14496 10288 7888 36 161x161 19472 15312 10832 8432 37 165x165 20528 15936 11408 8768 38 169x169 21616 16816 12016 9136 39 173x173 22496 17728 12656 9776 40 177x177 23648 18672 13328 10208

The following are examples of the formation and decoding of an aggregating two-dimensional code for an identification document and for an information stand.

An example of using an aggregating two-dimensional code in an identification document.

A feature of the use of an aggregating two-dimensional code in an identification document is the limited field on the document for placing a QR code. This example presents an option for generating, placing and decoding a two-dimensional code on an identification document for registering citizens’ weapons (permit to store and carry weapons) with a dedicated field for a QR code measuring 40 x 40 mm.

The generation of an aggregating two-dimensional code for an identification document is carried out in the following order:

a) a format is selected, including the version and noise immunity of the QR code used for further aggregation:

For placement on an area of 40 x 40 mm, it is most optimal to use the QR code version 21, containing 9252 data modules. The volume of data placed in the QR code version 21, taking into account the correction level “M” (15%), is 5712 bytes or 5.578 KB (see Table 1, Figs. 2 and 4).

b) one set of information is generated to be placed in an aggregating two-dimensional code:

It is expected to place in a two-dimensional code a set of the following documents and information:

1) Identification data of the weapon owner (2 KB);

2) Biometric profile of the weapon owner (total before vector quantization - 24 Kbytes: 2 iris vectors of 3 Kbytes, 1 face vector of 2 Kbytes, 2 fingerprint vectors of 8 Kbytes, in total after vector quantization - 6 Kbytes);

3) Cards of weapons owned by the owner (15 x 2 KB);

4) Data on the purchase of cartridges (10 x 2 KB);

5) Electronic digital signature data (1 KB).

Total total size of data placed in the two-dimensional code: 59 KB.

c) the generated set of information is converted into a single bit array of data. If significant information is not present in all sections of the information, for example, if the owner of the weapon has less than 15 units, then the data in the empty pieces of information is filled in with the additional padding symbol “#”.

d) the generated bit array of data is divided, in proportion to the data volume of the previously selected QR code, into the number of data blocks (bit arrays), as a result of which the number of QR codes required to accommodate the given amount of data is determined. To accommodate 59 KB in the version 21 QR code set, 11 QR codes will be required. The redundant data set of the last QR code is filled with the extra padding symbol "#".

e) for each block of data from the set of blocks obtained after division into blocks, a QR code is generated according to the selected format.

f) the resulting QR codes are sequentially placed on layers 1 to 11 in a matrix of aggregated values of dimension [101, 101, 12].

g) for each single data element of the used QR code format, a layer-by-layer bitwise aggregation is carried out onto the 12th aggregation layer of the matrix of aggregated values (see Fig. 3), resulting in an identifier for each cell of the 12th aggregation layer.

h) the dimension and composition of the parts of the identifier responsible for encoding information in the cells of the aggregating two-dimensional code, determining the color of the symbol and the symbol in the cell, are determined. An 11-bit identifier is used (with the number of bits corresponding to the number of QR codes being aggregated), in which 4 bits are reserved for the symbol color code, 4 bits for the symbol code, 3 bits for the color of the frame around the symbol).

Next, a control code table is generated, used for coding, containing:

- the number of aggregated QR codes (in this example 11);

- number of groups of aggregated QR codes (in this example 1);

- the number of identifier bits reserved for the color code;

- the number of identifier bits reserved for the character code;

- the number of identifier bits reserved for the frame color code;

- 4 control images of code color marks (each control image contains 4 color squares separated by white fields) - a total of 16 color control marks that determine the character encoding.

Symbol table. To encode a 4-bit table in this example, 16 uppercase characters of the English alphabet are used, in bold Calibri font:

Table 2. Symbols used for coding and cell numbers for placing control samples in them (triple redundancy).

No. Symbol QR code data module numbers 1 A D101, D301, D501 2 B D107, D307, D507 3 C D114, D314, D514 4 D D121, D321, D521 5 E D128, D328, D528 6 F D135, D335, D535 7 G D142, D342, D542 8 H D149, D349, D549 9 I D156, D356, D556 10 K D163, D363, D563 eleven L D170, D370, D570 12 M D177, D377, D577 13 N D184, D384, D584 14 O D191, D391, D591 15 P D198, D398, D598 16 Q D713, D743, D777

The data from the elements of the QR codes is temporarily replaced by the data of the control code table of the aggregating two-dimensional code, and when decoding will be restored through the use of a QR code format with a correction level.

The first seven colors from the character code table are used to color control the color of character frames.

The colors used are 4 basic colors of the CMYK palette + 3 additional colors obtained by pairwise mixing of 3 basic CMY colors + the same 7 colors with 60% saturation + 2 colors with 30% saturation (black and blue).

i) an image of the markup elements of the aggregating two-dimensional code is formed.

j) using the identifier values from each cell of the aggregation layer of the matrix of aggregated values, in accordance with the control code table, an image of the resulting two-dimensional aggregation code is formed (see Fig. 5).

k) fields with a control code table are added to the generated image of the aggregating two-dimensional code:

Table 3. Distribution of control table data by QR code data modules version 21 (triple redundancy).

No. Indicator name QR code data module numbers 1 Number of aggregated QR codes D1, D201, D401 2 Number of groups of aggregated QR codes D22, D222, D422 3 Number of identifier bits reserved for color code D43, D243, D443 4 Number of identifier bits reserved for the character code D64, D264, D464 5 Reference images of coded color marks for character color D85, D285, D485

l) the generated image of the aggregating two-dimensional code is applied to the information carrier. The image can be applied directly to the information carrier (in this case, if it is necessary to make changes to the contents of the document, the information carrier is re-issued) or the image can be applied to stickers glued to the information carrier. In the first case, sublimation color printing can be used to apply the QR code image, in the second - thermal inkjet or piezoelectric inkjet color printing.

The use of aggregating two-dimensional codes on identification documents allows you to solve the following problems:

a) ensure the possibility of using large volumes of data, especially in the production of identification documents in conditions of a significant shortage of electronic chips used to store information in identification documents (see Fig. 7);

b) significantly (by several times) reduce the cost of producing identification documents using two-dimensional code technology, compared to the cost of producing identification documents with electronic storage media;

c) when two-dimensional code technologies are used together with electronic storage media technology, the level of security of the identification document is significantly increased.

Decoding of the aggregating two-dimensional code is carried out in the following order:

a) scanning an image of an aggregating two-dimensional code from a storage medium - scanning is carried out using a mobile application using a smartphone camera, followed by correction of geometric distortions of the resulting image of an aggregating two-dimensional code. To minimize geometric distortions, when scanning an image, it is recommended to position the optical axis of the smartphone camera lens normal to the center of the scanned code;

b) detection of marking elements of an aggregating two-dimensional code on the received image;

c) positioning the resulting image according to the selected marking elements;

d) using the black-and-white fields of the markup elements of the search pattern, the boundaries of the dynamic range are determined and the white balance in the image of the aggregating two-dimensional code is adjusted;

e) carrying out, using a pre-trained neural network, decomposition of an image of an aggregating two-dimensional code, forming a set of images of its elements, with indexing corresponding to the numbering of QR code data modules;

f) carrying out recognition of images of data elements containing elements of the code table of the aggregating two-dimensional code, with the subsequent formation of a control code table;

g) using the control code table, determine the size of the identifier parts used to encode information, the number of aggregated QR codes, the number of groups of aggregated QR codes, the number of identifier bits reserved for the symbol color code, the number of identifier bits reserved for the symbol code, the number identifier bits reserved for frame color code, code colors and code character set;

h) determining the parameters of the necessary color correction based on the analysis of the parameters of control images of coded color marks for the color of characters;

i) carrying out color correction of a set of images of data elements of a two-dimensional aggregation code;

j) performing recognition of the entire set of images of data elements of the aggregating two-dimensional code and forming the 12th aggregation layer of the identifier matrix;

k) from the 12th aggregation layer of the matrix of aggregated values, the layers 1 to 11 of the QR code matrix are restored;

l) carry out layer-by-layer decoding of information from the components of QR codes with its subsequent distribution among sets of information, in which, for each QR code, the information of data elements temporarily occupied by the code table of the aggregating two-dimensional code is restored, followed by combining the sets of information into a single result set information;

m) the decoded information is displayed on the screen of the control device.

An example of using an aggregating two-dimensional code for an information stand.

A special feature of using an aggregating two-dimensional code for information stands is that there are no restrictions on the size of the QR code, which allows not only the use of QR codes version 40, but also the use of multi-stream aggregation of QR codes.

This example presents the option of generating, placing and decoding a two-dimensional code on an information stand located next to the equipment, or directly on the equipment body, in the production workshop of the enterprise. It is assumed that production features do not allow the use of wireless communication technologies, and technical personnel servicing the equipment need prompt access to instructions for servicing this equipment. Using a mobile application on a smartphone or tablet, the technician scans a two-dimensional code from an information stand containing instructions for servicing this equipment or its individual component, and performs the actions described in it.

In this example, we will consider the formation of an aggregating two-dimensional code measuring 50 x 50 cm using data aggregation into several streams.

The generation of an aggregating two-dimensional code is carried out in the following order:

a) a format is selected, including the version and noise immunity of the QR code used for further aggregation.

For placement on an area of 50 x 50 cm, it is most optimal to use the QR code version 40, containing 29648 data modules. The volume of data placed in the QR code version 40, taking into account the correction level “M” (15%), is 18672 bytes or 18.234 KB (see Table 1).

b) one set of information is generated to be placed in an aggregating two-dimensional code:

It is supposed to be placed in the aggregating two-dimensional code:

1) technological instructions in pdf format with a total volume of 290 KB;

2) electronic digital signature data (1 KB).

Total total size of data placed in the two-dimensional code: 291 KB.

c) the generated set of information is converted into a single bit array of data.

d) the generated bit array of data is divided in proportion to the data volume of the previously selected QR code into the number of data blocks (bit arrays), as a result of which the number of QR codes required to accommodate the given amount of data is determined. To accommodate 291 KB in the version 40 QR code set, 16 QR codes will be required. To generate an aggregating two-dimensional code, we will generate 4 streams of 4 aggregated QR codes. When using 4 aggregation streams, the total volume for storing data will be 298,752 bytes or 291,744 KB. The redundant data set of the last QR code is filled with the extra padding symbol "#".

f) for each block of data from the set of blocks obtained after division into blocks, a QR code is generated according to the selected format.

f) the resulting QR codes are sequentially placed on layers 1 to 4 in 4 matrices of aggregated values of dimension [177, 177, 5].

g) for each single data element of the QR code format used, layer-by-layer bitwise aggregation is carried out to the 5th aggregation layer of the matrix of aggregated values. The operation is performed sequentially for each of the 4 matrices. As a result, an identifier is obtained for each cell of the 5th aggregation layer of each of the 4 matrices.

h) the dimension and composition of the parts of the identifier responsible for encoding information in the cells of the aggregating two-dimensional code, determining the color of the symbol and the symbol in the cell, are determined. Each of the 4 matrices uses a four-bit identifier (with the number of bits corresponding to the number of aggregated QR codes), in which 2 bits are reserved for the symbol color code, 2 bits for the symbol code. No color is reserved for the frame, since the frame color is not used for coding in this example (all frames will be black).

Next, a control code table is generated, used for coding, containing:

- the number of aggregated QR codes in one stream (in this example 4);

- the number of groups (aggregation streams) of aggregated QR codes (in this example 4);

- the number of identifier bits reserved for the color code;

- the number of identifier bits reserved for the character code;

- 1 control image of code color marks (contains 4 colored squares each, separated by white fields) - a total of 4 color control marks that determine the character encoding.

Symbol table. To encode a 2-bit table in this example, 4 uppercase characters of the English alphabet are used, in bold Calibri font:

Table 4. Symbols used for coding and cell numbers for placing control samples in them (triple redundancy).

No. Symbol QR code data module numbers 1 A D101, D301, D501 2 B D107, D307, D507 3 C D114, D314, D514 4 D D121, D321, D521

The data from the elements of the QR codes is temporarily replaced by the data of the control code table of the aggregating two-dimensional code, and when decoding will be restored through the use of a QR code format with a correction level.

The colors used are 4 basic colors of the CMYK palette.

i) an image of the markup elements of the aggregating two-dimensional code is formed (see Fig. 6).

j) using the identifier values from each cell of the aggregation layer of the matrix of aggregated values, in accordance with the control code table, an image of the resulting aggregating two-dimensional code is formed, while each data module of the aggregating two-dimensional code contains one set of 4 characters (in format 2 x2). Each of the sets is formed from cells of 4 matrices with the same indices.

k) fields with a control code table are added to the generated image of the aggregating two-dimensional code:

Table 5. Distribution of control table data by QR code version 40 data modules (triple redundancy).

No. Indicator name QR code data module numbers 1 Number of aggregated QR codes in one stream D1, D201, D401 2 Number of groups of aggregated QR codes (aggregation streams) D22, D222, D422 3 Number of identifier bits reserved for color code D43, D243, D443 4 Number of identifier bits reserved for the character code D64, D264, D464 5 Reference image of coded color marks for character color D85, D285, D485

l) the generated image of the aggregating two-dimensional code is applied to the information carrier. Thermal inkjet or piezoelectric color inkjet printing can be used to apply the two-dimensional code image.

The use of two-dimensional aggregation codes on information stands makes it possible to use large volumes of data, especially when placing storage media with two-dimensional aggregation codes in areas where for some reason the use of wireless communications is impossible or prohibited.

Decoding of the aggregating two-dimensional code for the information stand is carried out in the following order:

a) scanning an image of an aggregating two-dimensional code from a storage medium - scanning is carried out using a mobile application using a smartphone camera, followed by correction of geometric distortions of the resulting image of an aggregating two-dimensional code. To minimize geometric distortions, it is recommended that when scanning an image, place the optical axis of the smartphone camera lens at the normal to the center of the scanned code;

b) detection of marking elements of an aggregating two-dimensional code on the received image;

c) positioning the resulting image according to the selected marking elements;

d) using the black-and-white fields of the markup elements of the search pattern, the boundaries of the dynamic range are determined and the white balance in the image of the aggregating two-dimensional code is adjusted;

e) carrying out, using a pre-trained neural network, decomposition of an image of an aggregating two-dimensional code and generating a set of images of its elements with indexing corresponding to the numbering of QR code data modules;

f) carrying out recognition of images of data elements containing elements of the code table of the aggregating two-dimensional code, with the subsequent formation of a control code table;

g) using the control code table, determine the size of the identifier parts used to encode information, the number of aggregated QR codes, the number of groups of aggregated QR codes (aggregation streams), the number of identifier bits reserved for the symbol color code, the number of identifier bits reserved for character code, code colors and code character set;

h) determining the parameters of the necessary color correction based on the analysis of the parameters of control images of coded color marks for the color of characters;

i) carrying out color correction of a set of images of data elements of a two-dimensional aggregation code;

j) performing recognition of the entire set of images of data elements of the aggregating two-dimensional code and forming the 5th aggregation layer for each of the 4 identifier matrices;

k) from the 5th aggregation layer of each of the 4 matrices of aggregated values, the layers 1 to 4 of the QR code matrix are restored;

l) carry out layer-by-layer decoding of information from the components of QR codes with its subsequent distribution among sets of information, in which, for each QR code from each stream, the information of data elements temporarily occupied by the code table of the aggregating two-dimensional code is restored, followed by combining the sets of information into a single result set of information;

m) the decoded information is displayed on the screen of the control device.

Addition to examples

There may be a case when it is desirable to place the generated information in the form of several sets of information. Then each set of information is separately converted into a bit array of data, and then for each bit array the same set of actions is performed to generate QR codes. In the future, during decoding, the information presented in the form of separate sets will also be presented separately, which allows, if necessary, to set restrictions on access to certain sets of information.

It is possible that there is already a generated set of information recorded in the QR code. If you do not have access to the contents of this QR code, it can be used when generating an aggregating two-dimensional code by including it in one of the layers in the existing format. In this case, it is advisable to select the format of the aggregated codes according to the format of the existing QR code. If this approach is not possible, aggregation of QR codes of different versions is possible.

When aggregating QR codes of different versions, the basic template for placing modules from the QR code of the older version from the entire aggregated set of codes is used. Aggregation of bit cells is carried out not according to the principle of geometric coincidence of cells in QR code templates, but according to their serial numbering. To do this, a conversion table of layers is generated, on the basis of which the [n, n, m+1] matrix is then constructed. For smaller version QR codes, cells from the larger version template for which no corresponding cells are found in the minor version are filled with arbitrary values and ignored when the aggregated 2D code is converted back to the original QR code. The versions of the aggregated codes and the order in which they are assembled are indicated in the control table of the two-dimensional aggregation code.

It is possible to use different versions of QR codes for aggregation, both for single-stream and multi-stream aggregation. With multi-stream aggregation, it is possible to use an option when QR codes are divided into streams, taking into account the same versions.

If the identifier is long, then in addition to the parts of the identifier responsible for the color of the symbol in the cell and the symbol in the cell, as well as the color of the cell frame, it is possible for part of the identifier to be responsible for the color or optical density of the background of the cell.

The control code table can be formed either in a dedicated field in the center or at the edge of the image of the aggregating two-dimensional code, or in the form of a distributed set of elements of the aggregating two-dimensional code placed in the dedicated fields of data elements or markup elements of the aggregating two-dimensional code.

Thus, the proposed technical solution makes it possible to increase the amount of information placed in the aggregating two-dimensional code of the information carrier, followed by its decoding, while maintaining the ability to be recognized by the built-in cameras of smartphones.

Limitations when using aggregating two-dimensional codes

When using aggregating two-dimensional codes, the following restrictions must be taken into account:

a) restrictions on the number of colors in the color palette are determined by:

a. the size of the media or the area allocated to accommodate the aggregating two-dimensional code;

b. optical resolution of devices used to read the aggregating two-dimensional code;

b) restrictions on the colors used in the palette - it is undesirable to use colors from the Pantone palette and similar ones, which may fall outside the boundaries of the color space of printers and scanners used for applying and reading QR codes;

c) restrictions on light colors used in the palette - it is recommended, in order to increase the readability of the aggregating two-dimensional code, not to use the light area of the color gamut of devices used for applying and reading the aggregating two-dimensional code;

d) restrictions on the composition of the equipment used for reading aggregating two-dimensional codes:

a. to read aggregating two-dimensional codes, it is recommended to use mobile phones, tablets or terminals equipped with high-resolution color cameras (at least 12 MP);

b. it is possible to use specialized hardware QR code scanners, which allow, after reading the structure of the QR code, to transfer a color image of the QR code to an image processing device for its further software processing;

e) restrictions on the composition of the character code table: it is advisable to avoid including in the code table characters that differ in style (overlap in image area) by less than 30%;

f) when generating an image of an aggregating two-dimensional code, symbols that collectively form geometric patterns (triangles, squares, completely filled with color or halftone cells) should not be included in the code table and used for encoding, since such images interfere with the correct operation of the autofocus systems of reading devices , using contrast or phase detection autofocus technologies;

g) restrictions on the maximum size of the aggregating two-dimensional code are determined by the optical capabilities of the lenses and the characteristics of the matrices of the reading devices.

Development prospects

A further increase in the density of information placed in aggregating two-dimensional codes can be achieved by partially changing the forms of the basic elements of the two-dimensional code: in addition to standard alphanumeric characters, it is possible to use sets of various geometric elements placed in standard familiarity spaces of the matrix of the aggregating two-dimensional code to encode information. In addition, it is possible to use both black and white and halftone symbolic elements, both separately and in various combinations (subject to restrictions). The emergence of new mobile devices with hundreds of megapixel cameras over the past 5 years gives reason to believe that in the coming years, with further improvements in image acquisition technologies, some of the above restrictions will be lifted.

Using the method described above is possible to create not only information media, but also information materials of a much larger size, while a significant increase in the volume of information placed as part of an aggregating two-dimensional code is possible due to an increase in the number of colors and symbols used in coding.

Claims (35)

1. A method for generating an aggregating two-dimensional code of an information carrier, including the following steps: a) select a format that includes the version and noise immunity of the QR code used for further aggregation; b) forming at least one set of information to be placed in the aggregating two-dimensional code; c) each generated set of information is converted into a bit array of data; d) splitting each generated bit array of data that exceeds the volume permissible for the selected QR code format into a set of blocks corresponding to the permissible data volume of the selected QR code format; e) for each data block from the received at least one set of data blocks, a QR code is generated according to the selected format; f) the resulting QR codes are placed in at least one matrix of aggregated values with dimension [n, n, m+1], where n is the dimension of the two-dimensional matrix of the selected QR code format, m is the number of aggregated QR codes; g) for each single data element of the used QR code format, a layer-by-layer bitwise aggregation is carried out onto the (m+1)th aggregation layer of each matrix to obtain an identifier for each cell of the (m+1)th aggregation layer; h) determine the dimension of the parts of the identifier responsible for encoding information in the cells of the aggregating two-dimensional code, determining the color of the symbol and the symbol in the cell, and form a control code table used for encoding; i) carry out the formation of an image of the markup elements of the aggregating two-dimensional code; j) using the identifier values from each cell of the (m+1)-th aggregation layer of each matrix of aggregated values, in accordance with the control code table, an image of the resulting aggregating two-dimensional code is formed, while the number of symbols in one cell of the aggregating two-dimensional code corresponds to the number of matrices of aggregated values ; k) fields with a control code table are added to the generated image of the aggregating two-dimensional code; l) the generated image of the aggregating two-dimensional code is applied to the information carrier. 2. The method according to claim 1, characterized in that additionally, by action h) the part of the identifier responsible for the color of the cell frame is determined. 3. The method according to claim 1 or 2, characterized in that additionally, according to action h), the part of the identifier responsible for the color or optical density of the cell background is determined. 4. Method according to any one of paragraphs. 1-3, characterized in that the fields with the control code table are placed in the form of a distributed set of elements of the aggregating two-dimensional code in the selected fields of data elements or markup elements of the aggregating two-dimensional code. 5. Method according to any one of paragraphs. 1-4, characterized in that at least one of the generated QR codes contains means for restricting access to the information contained in it. 6. Method according to any one of paragraphs. 1-5, characterized in that additional information about the number and/or order of placement in the assembly of matrices is added to the control code table. 7. Method according to any one of paragraphs. 1-6, characterized in that additional information about the version of the aggregated QR codes is added to the control code table. 8. A method for decoding an image of an aggregating two-dimensional code of an information carrier, including the following steps: a) scan the image of the aggregating two-dimensional code from the storage medium; b) detect images of markup elements of the aggregating two-dimensional code; c) the resulting image is positioned using the selected marking elements; d) using the black-and-white fields of the markup elements of the search template, determine the boundaries of the dynamic range and adjust the white balance in the image of the aggregating two-dimensional code; e) decompose the image of the aggregating two-dimensional code and form a set of images of its elements with indexing corresponding to the numbering of the QR code data modules; f) extract the aggregating two-dimensional code of the control code table from the image; g) using the control code table, they determine the coding elements that determine the color of the symbol and the symbol in the cell, and also determine the dimensions of the parts of the identifier used to encode information that determine the color of the symbol and the symbol in the cell, determine the number and method of isolating QR codes from the aggregating two-dimensional code; h) determine the parameters of the necessary color correction based on the analysis of the parameters of control images of coded color marks for the color of the characters; i) carry out color correction of a set of images of data elements of the aggregating two-dimensional code; j) perform recognition of the entire set of images of the aggregating two-dimensional code and form at least one matrix of identifiers of its elements, wherein the number of generated matrices corresponds to the number of characters in one cell of the aggregating two-dimensional code specified in the control code table; k) from each matrix of identifiers, the layers of the constituent QR codes are restored; l) carry out layer-by-layer decoding of information from the components of QR codes with its subsequent distribution among sets of information; m) the decoded information is displayed on the screen of the control device. 9. The method according to claim 8, characterized in that additionally, by action g) the part of the identifier responsible for the color of the cell frame is determined. 10. The method according to claim 8 or 9, characterized in that in addition to action g) the part of the identifier responsible for the color or optical density of the cell background is determined.