JP6565786B2 - Optical symbol, display medium, article and generating device - Google Patents

Description

  The present invention relates to an optical symbol, a display medium, an article, and a generation apparatus.

  A two-dimensional code based on binary information such as a QR code (registered trademark) is used in many scenes because information such as an ID can be obtained by imaging with a camera. Further, in order to store more information, for example, a two-dimensional code in which a storage capacity per unit area is improved by using a plurality of colors instead of monochrome binary information has been developed. One of the two-dimensional codes (called color codes) using multiple colors is a color code that improves distortion resistance by coding color transitions between adjacent areas rather than color arrangement. (Patent Document 1).

  However, the color code according to the prior art is resistant to distortion, but it is difficult to execute recognition processing from parallel processing, and it is difficult to improve the processing speed of recognition processing.

  The present invention has been made in view of the above, and an object of the present invention is to provide an optical symbol that can be recognized at higher speed.

  In order to solve the above-described problem, the present invention provides a main code portion having a first cell row in which a plurality of main code cells are connected in one dimension, and a first code in which a plurality of sub code cells are connected in one dimension. And the second cell column includes a plurality of main codes excluding a cell at an end portion of the first cell column among the plurality of main code cells. Connected to any one of the cells.

  According to the present invention, it is possible to provide an optical symbol that can be recognized at higher speed.

FIG. 1 is a diagram schematically illustrating an example of a usage form of an optical symbol according to the first embodiment. FIG. 2 is a diagram illustrating a basic configuration example of the optical symbol according to the first embodiment. FIG. 3 is a diagram illustrating an example of information for encoding into an optical symbol according to the first embodiment. FIG. 4 is a diagram for explaining a coding rule that can be applied to the first embodiment and that can express a binary number. FIG. 5 is a diagram showing an example of the color arrangement in the coded main code portion and sub-code portion according to the first embodiment. FIG. 6 is a diagram illustrating an example of an optical symbol according to the first embodiment. FIG. 7 is a diagram illustrating an example of a coding rule when four colors are used according to the first embodiment. FIG. 8 is a diagram for explaining a more specific example when the number of colors assigned to each cell of the optical symbol according to the first embodiment is four. FIG. 9 is a diagram for explaining a more specific example when the number of colors assigned to each cell of the optical symbol according to the first embodiment is four. FIG. 10 is a block diagram illustrating a configuration of an example of a code generation system applicable to the first embodiment. FIG. 11 is a block diagram illustrating an example of a hardware configuration of the code generation device according to the first embodiment. FIG. 12 is a functional block diagram for explaining functions of the code generation device according to the first embodiment. FIG. 13 is a flowchart illustrating an example of the optical symbol generation method according to the first embodiment. FIG. 14 is a diagram illustrating an example in which the number of cells included in each cell column included in the subcode portion is fixed according to the first embodiment. FIG. 15 is an example of an optical symbol according to the first embodiment in which the size of the cell included in each cell column of the sub-code part is different for each cell column and the length of each cell column is constant. FIG. FIG. 16 is a diagram illustrating an example of an optical symbol using a start cell and an end cell according to the first embodiment. FIG. 17 is a diagram illustrating an example of information for encoding into an optical symbol according to the first embodiment. FIG. 18 is a diagram illustrating an example of an optical symbol and a display medium on which the optical symbol is displayed according to the first embodiment. FIG. 19 is a diagram schematically illustrating a usage example of the display medium on which the optical symbol according to the first embodiment is displayed. FIG. 20 is a block diagram showing a configuration of an example of a code recognition system applicable to the first embodiment. FIG. 21 is a block diagram illustrating an example of a hardware configuration of a code recognition device applicable to the first embodiment. FIG. 22 is a functional block diagram of an example for explaining functions of the code recognition device according to the first embodiment. FIG. 23 is a diagram illustrating an example of a captured image captured by the camera and acquired by the image acquisition unit of the code recognition device according to the first embodiment. FIG. 24 is a flowchart illustrating an example of optical symbol recognition and decoding processing according to the first embodiment. FIG. 25 is a flowchart illustrating an example of recognition processing by the sub code recognition unit according to the first embodiment. FIG. 26 is a diagram for explaining the composition process based on the connection information by the composition unit according to the first embodiment. FIG. 27 is a diagram illustrating an example of a template applicable to the first embodiment. FIG. 28 is a flowchart illustrating an example of a first cutout process according to the first embodiment. FIG. 29 is a diagram illustrating an example of a method for acquiring the color of each cell from the optical symbol image cut out by the first cut-out process according to the first embodiment. FIG. 30 is a flowchart illustrating an example of a second cutout process according to the first embodiment. FIG. 31 is a diagram illustrating a configuration of an example of an optical symbol according to a modification of the first embodiment. FIG. 32 is a diagram schematically illustrating a code management system and a transport system according to the second embodiment.

  Hereinafter, embodiments of an optical symbol, a display medium, an article, and a generation apparatus will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 schematically shows an example of a usage form of an optical symbol according to the first embodiment. In FIG. 1, a display medium 40 on which the optical symbol 30 according to the first embodiment is displayed is attached to each article 50. The display medium 40 is a print medium on which, for example, the optical symbol 30 is printed. However, the display medium 40 may be a display device such as an LCD (Liquid Crystal Display) on which the optical symbol 30 is displayed.

  As will be described in detail later, the optical symbol 30 includes a plurality of small regions each called a cell, and each cell is configured with a color different from that of an adjacent cell. The optical symbol 30 expresses information using a color transition between cells. That is, the optical symbol 30 is a code (color code) obtained by coding information using colors.

  The code recognition device 10 recognizes the optical symbol 30 from a captured image captured by the camera 11 and decodes the recognized optical symbol 30. More specifically, the code recognition device 10 detects a color transition of each cell included in the optical symbol 30 by recognizing the optical symbol 30, and performs decoding based on the detected color transition. The code recognition device 10 outputs information decoded from the optical symbol 30.

(Details of optical symbol according to the first embodiment)
FIG. 2 shows a basic configuration example of the optical symbol 30 according to the first embodiment. As shown in FIG. 2, the optical symbol 30 includes a trunk and a branch having one end connected to the trunk. The trunk is configured by a cell row (first array) in which a plurality of adjacent cells are sequentially arranged in one dimension. That is, the trunk is arranged without a plurality of cells branching and intersecting. A branch is a cell array (second array) in which one or more cells including cells connected to one cell of the trunk are sequentially arranged adjacently in a direction different from the arrangement direction of the trunk. Consists of. When the branch includes a plurality of cells, the plurality of cells are arranged without branching and intersecting like the trunk. Further, the branches do not contact each other.

  Each cell constituting the trunk and branch is assigned a color. At this time, the color assigned to each cell is selected so that adjacent cells do not have the same color. The color assigned to each cell is selected from a plurality of predetermined colors. The plurality of colors to be assigned to the cells are preferably a combination of colors that can be easily identified when two colors arbitrarily selected from the plurality of colors are adjacent to each other.

  The optical symbol 30 according to the first embodiment expresses information based on a color transition between adjacent cells. In other words, the optical symbol 30 encodes information using color transitions. The optical symbol 30 can be expressed by coding different information for each cell of the trunk and each cell of the branch. Information coded by each cell (main code cell) of the trunk is called a main code, and information coded by each cell (subcode cell) of the branch is called a subcode. Hereinafter, unless otherwise specified, the trunk and the branch are referred to as a main code portion 300 and a sub code portion 301, respectively. The sub-code unit 301 can include a plurality of branches.

  In FIG. 2, the main code unit 300 sets a cell at one end as a start cell 302 (also described as “S” in the figure) and a cell at the other end as an end cell 303 (also described as “E” in the figure). It is assumed that the color transition of each cell of the main code unit 300 is detected from the start cell 302 toward the end cell 303 as indicated by an arrow in the drawing. In addition, the transition of the color of each cell of the sub code unit 301 is detected from the end connected to the main code unit 300 toward the other end as indicated by an arrow in the drawing.

  Note that the start cell 302 and the end cell 303 can be omitted. In this case, the cells at the beginning and the rear end of the main code portion 300 can also serve as the start cell 302 and the end cell 303, respectively.

  In the following, it is assumed that the information encoded using the optical symbol 30 is a character string. The character string is, for example, a number “0” to “9”. Not limited to this, the optical symbol 30 may be an alphabetic character string “a” to “z” or an alphabetic character string obtained by adding uppercase letters “A” to “Z” to lowercase letters “a” to “z”, or a symbol. It is also possible to code a character string including.

  FIG. 3 shows an example of information for encoding into the optical symbol 30 according to the first embodiment. In FIG. 3, a main code portion 300 ′ and a sub code portion 301 ′ respectively correspond to the main code portion 300 and the sub code portion 301 in the encoded optical symbol 30. In FIG. 3, each cell included in the main code portion 300 ′ and the sub code portion 301 ′ is called a cell for convenience, following each cell of the optical symbol 30.

  FIG. 3 shows an example in which the character string to be encoded is a number. Each cell “d1”, “d2”, “d3”,... Of the cell string of the main code portion 300 ′ represents each digit of the character string. The leftmost cell “d1” in FIG. 3 represents the first digit of the character string, and the represented digits sequentially move in adjacent cells “d2”, “d3”,... Starting from the cell “d1”. To do. That is, each cell “d1”, “d2”, “d3”,... Of the cell string of the main code portion 300 'corresponds to a position in the character string.

In the example of FIG. 3, each of the cells “d1”, “d2”, “d3”,... Represents each decimal digit. Specifically, the leftmost cell “d1”, which is the leading cell, indicates the digit “10 ⁰ ”, and thereafter, each cell “d2”, “d3”,... Is sequentially “10 ¹ ”, “10 ² ”. ", ... represents the digit.

In the example of FIG. 3, the sub code portion 301 ′ represents the values in the cells “d 1”, “d 2”, “d 3”,... . In the example of FIG. 3, in each cell column of the sub code portion 301 ′, the cell connected to the main code portion 300 ′ is the least significant bit, and the cells “d1”, “d2” and “ Each cell column connected to “d3” has a value “b0010”, a value “b0110”, and a value “b1000”. Therefore, the optical symbol 30 in FIG. 3 is a character string in which the values of “10 ⁰ ”, “10 ¹ ”, and “10 ² ” are decimal numbers “2”, “6”, and “8”, respectively. Represents. In the value notation, the leading “b” indicates that the subsequent number is a binary value.

  In the first embodiment, as described above, the information expressed in the main code portion 300 'and the sub code portion 301' is coded using the color transition between cells. Here, in the main code portion 300 ′, information to be expressed is predetermined. Therefore, the main code portion 300 in the optical symbol 30 in which the main code portion 300 ′ is encoded can be decoded if it is found that the color of each cell is different between adjacent cells. For example, if the number of cells included in the main code unit 300 is known, the main code unit 300 can be decoded by counting the number of color transitions between cells.

  On the other hand, the sub-code portion 301 'needs to express different values depending on the information to be encoded. Therefore, the sub-code unit 301 ′ performs coding using a conversion table in which color transitions and expressible values are associated in advance.

  An encoding rule that can be applied to the first embodiment and that can express a binary number will be described with reference to FIG. In order to express a binary value by a color transition between adjacent cells of different colors, at least three colors are required. FIG. 4 shows an example of a coding rule when a binary is expressed using three colors of red (R), green (G), and blue (B). For example, as illustrated in FIG. 4A, the value “0” is expressed in the clockwise direction, that is, by transition from the R color to the B color, the B color to the G color, and the G color to the R color. . Also, the value “1” is expressed counterclockwise, that is, by transitions from R color to G color, G color to B color, and B color to R color.

  For example, as shown in FIG. 4B, in the cell row in which each cell is sequentially adjacent in the order of G color, B color, G color, and R color, the color of each cell from left to right in the figure. Consider the case of seeing a transition. In this case, the transition from the G color to the B color represents the value “1”, the transition from the B color to the G color represents the value “0”, and the transition from the G color to the R color represents the value “0”. Therefore, the array of FIG. 4B represents the value “b001”, that is, the decimal value “1”.

  Further, for example, as shown in FIG. 4C, consider a case where the color transition is viewed in the direction opposite to that in FIG. 4B with respect to the array of cells in FIG. 4B. In this case, the transition from the R color to the G color represents the value “1”, the transition from the G color to the B color represents the value “1”, and the transition from the B color to the G color represents the value “0”. Accordingly, the array of FIG. 4C represents the value “011”, that is, the decimal value “3”.

  FIG. 4D shows an example of a conversion table that associates color transitions and values according to the coding rule shown in FIG. In the conversion table of FIG. 4D, the leftmost column indicates the color of the immediately preceding cell (transition source cell), and the uppermost row indicates the value to be expressed. For example, when the color of the transition source cell is R color and the value “1” is to be expressed, the color of the transition destination cell adjacent to the transition source cell is G color. Similarly, when the transition source cell color is B color and the value “1” is to be expressed, the transition destination cell color is R color.

  FIG. 5 shows an example of the color arrangement in the coded main code portion 300 and sub-code portion 301 according to the first embodiment. FIG. 5A shows an example of the color arrangement of each cell in the cell row of the main code portion 300. In the example of FIG. 5A, the cell row of the main code portion 300 includes cells of the first color (R color in this example) and cells of the second color (B color in this example) alternately. Arranged and configured. In addition, the cell string of the main code unit 300 is composed of 2N cells (N is an integer of 1 or more). Thus, by fixing the color of the leading cell of the cell row of the main code portion 300 to the first color, the color of the rear end cell is uniquely determined to be the second color. The front and rear ends of the rows can be easily recognized.

  FIG. 5B shows an example of the color arrangement in the cell column of the sub code portion 301. In the cell sequence of the sub-code portion 301, the three colors for expressing the binary values described above are assigned to each cell so that the colors of adjacent cells are different. In addition, the cell string of the sub code unit 301 is coded according to the coding rule described above, with the cell of the main code unit 300 to which the cell string is connected as the first transition source cell.

  Depending on the value to be expressed, an unallocated color among the three colors may occur in the cell string of the sub-code portion 301. On the other hand, the main code unit 300 selects two predetermined colors to be assigned to each cell included in the cell sequence from the three colors used to express the binary values in the sub code unit 301, and selects these two colors. Cell rows are configured by alternately assigning to cells. Therefore, in the cell string of the main code part 300, each color determined to be used for the main code part 300 is necessarily assigned to each cell. Therefore, for example, when the optical symbol 30 is cut out from an image including the optical symbol 30, the optical symbol 30 can be easily cut out by detecting only the color information assigned to each cell of the main code unit 300. Is possible.

  FIG. 6 shows an example of the optical symbol 30 in which the information exemplified in FIG. 3 according to the first embodiment is coded according to the coding rule described with reference to FIG. In this example, the encoded cell string of the main code portion 300 includes an even number of cells, and the tip cell is an R color, and the R color and the B color are alternately arranged.

  In addition, the encoded sub-code unit 301 uses, for example, the R color of the cell of the main code unit 300 to which the cell at the end of the cell column is connected in the leftmost cell column as the first transition source color. The cell color is assigned. In this example, for each cell in the cell row, according to the values “0”, “1”, “0”, “0”, referring to the conversion table in FIG. , B color and G color are assigned respectively.

  As shown in FIG. 6, the optical symbol 30 according to the first embodiment has a plurality of branches (each of the sub-code units 301) with respect to one direction different from the extension direction of the trunk (cell row of the main code unit 300). Cell string) is connected to each cell of the cell string of the main code section 300. In addition, the optical symbol 30 according to the first embodiment is configured so that each cell of the sub-code unit 301 has good recognition accuracy when the optical symbol 30 is recognized from a captured image obtained by capturing the optical symbol 30 with the camera 11. The columns are arranged at predetermined intervals with respect to adjacent cell columns. As described above, the optical symbol 30 according to the first embodiment is configured as a comb shape having a trunk and a plurality of branches.

  By making the optical symbol 30 into a comb shape, for example, in an image including the optical symbol 30, the shape of the optical symbol 30 is distinguished from other shapes included in the image, and the optical symbol 30 in the image is included in the image. The orientation (angle) can be easily recognized. Thereby, for example, the extraction process of the optical symbol 30 using a template, which will be described later, can be executed with high accuracy.

  In the above description, the number of colors assigned to each cell of the optical symbol 30 is three colors, and the information is expressed by binary. However, this is not limited to this example, and the number of colors assigned to each cell may be four or more. By increasing the number of colors assigned to each cell, more information can be expressed with the same number of cells.

  FIG. 7 shows an example of a coding rule when four colors of R color, G color, B color, and K color (black) are used according to the first embodiment. When four colors are used, ternary values, that is, ternary numbers can be expressed. For example, as illustrated in FIG. 7A, the value “0” is generated by clockwise transition, that is, each transition from R color to K color, K color to B color, B color to G color, and G color to R color. ". The value “1” is expressed counterclockwise, that is, each transition from R color to G color, G color to B color, B color to K color, and K color to R color. Furthermore, the value “2” is expressed on the diagonal line, that is, by the bidirectional transition between the R color and the B color and the bidirectional transition between the K color and the G color.

  For example, as shown in FIG. 7B, in a cell column in which cells are sequentially connected in the order of G color, R color, B color, K color, and G color, Consider the case of looking at the color transition of a cell. In this case, the transition from the G color to the R color is the value “0”, the transition from the R color to the B color is the value “2”, the transition from the B color to the K color is the value “1”, and the K color to the G color. Each transition to represents the value “2”. Therefore, the array of FIG. 7B represents the value “3d2120”, that is, the decimal value “69”. In the value notation, the leading “3d” indicates that the subsequent number is a ternary value.

  Further, for example, as shown in FIG. 7C, consider a case where the color transition is viewed in the direction opposite to that in FIG. 7B with respect to the array of cells in FIG. 7B. In this case, the transition from the G color to the K color is the value “2”, the transition from the K color to the B color is the value “0”, the transition from the B color to the R color is the value “2”, and the transition from the R color to the G color. Each transition to represents a value “1”. Accordingly, the array of FIG. 7C represents the value “3d1202”, that is, the decimal value “47”.

  The coding rule using the four color transitions is not limited to the example shown in FIG. FIG. 7D shows another example of a coding rule using four color transitions applicable to the first embodiment. In this other example, the transition between the R color and the K color represents a value “0” in both directions, the transition between the R color and the G color represents a value “1” in each direction, and G The transition between colors B and B represents the value “2” in each direction. The transition from the B color to the R color and the transition from the K color to the G color each represent the value “1”. Further, the transition from the G color to the K color represents the value “0”, and the transition from the R color to the B color represents the value “2”.

  FIG. 7E shows an example of a conversion table that associates color transitions and values according to the coding rule shown in FIG. The meanings of columns and rows in the conversion table in FIG. 7E are the same as those in the conversion table in FIG. In FIG. 7E, for example, when the color of the transition source cell is R color and the value “2” is to be expressed, the color of the transition destination cell adjacent to the transition source cell is B color. Similarly, when the transition source cell color is K color and the value “1” is to be expressed, the transition destination cell color is G color.

  A more specific example of the case where the number of colors assigned to each cell of the optical symbol 30 is four colors according to the first embodiment will be described with reference to FIGS. 8 and 9. As an example, as shown in FIG. 8, each cell column of the sub code portion 301 ′ connected to each cell “d 1”, “d 2”, “d 3”, and “d 4” of the main code portion 300 ′ has a value. “3d0121”, “3d2101”, “3d2212”, and “3d0220”.

  FIG. 9 shows an example of an optical symbol 30 in which the information exemplified in FIG. 8 is coded according to the coding rules described with reference to FIG. In this example, the cell row of the main code portion 300 includes an even number of cells, and the tip cell is an R color, and the R color and the K color are alternately arranged.

  Similarly to FIG. 6, the sub code unit 301 changes the R color of the cell of the main code unit 300 to which the cell at the end of the cell column is connected, for example, in the leftmost cell column, as the first transition source color. The color of each cell is assigned. In this example, for each cell in the cell row, according to the values “1”, “2”, “1”, “0”, referring to the conversion table of FIG. , R color and K color are assigned respectively.

(Apparatus configuration applicable to the first embodiment)
Next, a configuration for generating the optical symbol 30 according to the first embodiment will be described. FIG. 10 shows an example of the configuration of a code generation system applicable to the first embodiment. 10, the code generation system includes a code generation device 20 and a printer 21 connected to the code generation device 20 via, for example, a network 22.

  The code generation device 20 generates the optical symbol 30 by encoding the input information according to the above-described encoding rules. The printer 21 prints the optical symbol 30 generated by the code generation device 20 on a print medium, and creates a display medium 40 on which the optical symbol 30 is displayed. The created display medium 40 is attached to the article 50 as described with reference to FIG.

  FIG. 11 shows an example of the hardware configuration of the code generation device 20 according to the first embodiment. 11, the code generation device 20 includes a CPU (Central Processing Unit) 2000, a ROM (Read Only Memory) 2001, a RAM (Random Access Memory) 2002, a graphics I / F 2003, a storage 2005, and a data I / O. F2006 and communication I / F 2009 are included, and these units are communicably connected to each other via a bus 2010. Thus, the code generation device 20 according to the first embodiment can be realized using a general computer.

  The storage 2005 is a non-volatile storage medium such as a hard disk drive or a flash memory, and stores programs and data. The CPU 2000 controls the overall operation of the code generation device 20 using the RAM 2002 as a work memory in accordance with a program stored in the storage 2005 or the ROM 2001.

  The graphics I / F 2003 is connected to a display 2004 and generates a display signal that can be displayed on the display 2004 based on display control information generated by the CPU 2000 according to a program. The data I / F 2006 is an interface for external data supplied from the outside of the code generation device 20. The data I / F 2006 can be connected to a pointing device 2007 such as a mouse and a keyboard 2008. As the data I / F 2006, for example, USB (Universal Serial Bus) can be applied.

  Data to be encoded is supplied to the data I / F 2006 from the outside. However, the present invention is not limited to this, and the user may input data to be encoded into the code generation device 20 by operating the pointing device 2007 or the keyboard 2008.

  A communication I / F 2009 is connected to the network 22 and performs communication via the network 22. The network 22 may be a LAN (Local Area Network) or the Internet. The network 22 may be connected using either wired communication or wireless communication.

  FIG. 12 is a functional block diagram for explaining functions of the code generation device 20 according to the first embodiment. In FIG. 12, the code generation device 20 includes a data input unit 200, a decomposition unit 201, a conversion unit 202, a color assignment unit 203, a table storage unit 204, and an output unit 205.

  Among these, the data input unit 200, the separation unit 201, the conversion unit 202, the color assignment unit 203, and the output unit 205 are configured by programs that operate on the CPU 2000. However, the present invention is not limited thereto, and some or all of the data input unit 200, the separation unit 201, the conversion unit 202, the color assignment unit 203, and the output unit 205 may be configured by hardware circuits that operate in cooperation with each other. The table storage unit 204 includes a predetermined storage area in the storage 2005 or the RAM 2002.

  The data input unit 200 receives data to be encoded that is input via the data I / F 2006. In this case, as described above, it is assumed that the data to be encoded is a character string. The decomposition unit 201 decomposes the character string received by the data input unit 200 into a value of each digit. The conversion unit 202 converts each digit value decomposed by the decomposition unit 201 into a value corresponding to the number of colors assigned to each cell of the optical symbol 30. For example, if the number of colors assigned to each cell is four, the conversion unit 202 converts the value of each digit into a ternary value.

  The table storage unit 204 stores in advance a conversion table according to the number of colors assigned to each cell, as described with reference to FIGS. 4D and 7D. The color assignment unit 203 assigns a color to each cell of the optical symbol 30 with reference to the conversion table stored in the table storage unit 204 based on the value converted by the conversion unit 202 and the transition source color. It is assumed that the color assignment unit 203 stores in advance information indicating the color arrangement of each cell in the cell row of the main code unit 300.

  The output unit 205 stores the cell to which the color is assigned by the color assigning unit 203 and the color information. When the output unit 205 determines that a color has been assigned to all the cells of the optical symbol 30, the output unit 205 outputs information indicating the color assigned to each cell of the optical symbol 30 in association with the information of each cell. .

  Note that the color assignment unit 203 can obtain the color of the cell coded immediately before from the output unit 205 in the coding of one cell string in the sub-code unit 301.

  A code generation program for realizing each function of the code generation apparatus 20 according to the first embodiment is a file in an installable format or an executable format, which is a CD (Compact Disk), a flexible disk (FD), a DVD ( Provided on a computer-readable recording medium such as Digital Versatile Disk). However, the present invention is not limited to this, and the code generation program may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. Further, the code generation program may be provided or distributed via a network such as the Internet.

  The code generation program has a module configuration including the above-described units (data input unit 200, decomposition unit 201, conversion unit 202, color allocation unit 203, and output unit 205). As actual hardware, the CPU 2000 reads the code generation program from a storage medium such as the storage 2005 and executes the code generation program, whereby the above-described units are loaded on the main storage device such as the RAM 2002, and the data input unit 200, the decomposition unit 201, a conversion unit 202, a color allocation unit 203, and an output unit 205 are generated on the main storage device.

  FIG. 13 is a flowchart illustrating an example of a method for generating the optical symbol 30 according to the first embodiment. In step S100, the data input unit 200 accepts data to be encoded. Here, it is assumed that the data received by the data input unit 200 is a k-digit character string. In the next step S101, the decomposition unit 201 decomposes the k-digit data received by the data input unit 200 into a value v (i) for each digit. The variable i is a loop variable indicating the position in the character string of the digit to be processed, and is an integer (0 ≦ i ≦ k).

  In the next step S102, the variable i is initialized to the value “0”, and in the next step S103, the value “1” is added to the variable i.

  In the next step S104, the conversion unit 202 converts the i-th value v (i) of the k-digit data decomposed by the decomposition unit 201 into an n-ary p-digit value u (q). The value n is a predetermined integer of 2 or more. The variable q is a loop variable indicating the position of the cell in the cell string of the sub code unit 301, and is an integer of (0 ≦ q ≦ p), and the value p is a processing target in the sub code unit 301 Indicates the number of cells included in the cell column.

  In the next step S105, the variable q is initialized to the value “0”, and in the next step S106, the value “1” is added to the variable q.

  In the next step S107, the color assigning unit 203 acquires from the output unit 205 the color of the cell immediately before (transition source) for the cell to which the current color is to be assigned. In step S107, when the value of the variable q is “1”, the color assignment unit 203 acquires the color of the cell corresponding to the i-th digit in the cell string of the main code unit 300.

  In the next step S108, the color assignment unit 203 refers to the conversion table stored in the table storage unit 204 based on the cell color acquired in step S107 and the value u (q), and the subcode unit 301. To obtain the color of the q-th cell in the i-th cell row.

  In the next step S109, the color assignment unit 203 determines whether or not the variable q matches the value p. If it is determined that they do not match (step S109, “No”), the color assignment unit 203 returns the process to step S106. If it is determined that they match (step S109, “Yes”), the color assignment unit 203 shifts the processing to step S110.

  In step S110, the conversion unit 202 determines whether or not the variable i matches the value k. If it is determined that they do not match (step S110, “No”), the conversion unit 202 returns the process to step S103. When it is determined that they match (step S110, “Yes”), the conversion unit 202 performs a series of processes in the flowchart of FIG. 13 assuming that the encoding of the data received in step S100 into the optical symbol 30 is completed. Terminate.

  In the process of the flowchart of FIG. 13, the number of cells included in each cell column included in the subcode unit 301 is not limited. This is not limited to this example, and the number of cells included in each cell column included in the subcode unit 301 may be a fixed number. FIG. 14 shows an example in which the number of cells included in each cell column included in the sub-code unit 301 is fixed to M according to the first embodiment.

  In this way, by making the number of cells included in each cell column included in the sub-code unit 301 a fixed number, it is possible to facilitate decoding processing for the optical symbol 30 described later. Furthermore, it is preferable that the size of each cell is also constant because the optical symbol 30 can be easily cut out using a template, which will be described later.

  In the first embodiment, information is encoded by using color transition between adjacent cells. Therefore, the size of each cell constituting the optical symbol 30 may be different. In this case, it is preferable that the length of each cell column included in the sub-code portion 301 is constant because the optical symbol 30 can be easily cut out using a template, which will be described later.

  FIG. 15 shows an optical symbol 30 according to the first embodiment, in which the size of the cell included in each cell column of the sub-code unit 301 is different for each cell column, and the length of each cell column is constant. An example of In the example of FIG. 15, the leftmost cell column of the subcode portion 301 includes P cells, and the middle cell column includes Q cells that are smaller than P cells than the cells of the leftmost cell column. In addition, the rightmost cell column of the sub-code portion 301 in FIG. In this example, the size of the cell included in each cell column is a size corresponding to the total number of cells (P, Q, R) included in the cell column to which each cell column belongs.

  In the above description, in the optical symbol 30, the start cell 302 and the end cell 303 shown in FIG. 2 are omitted. However, by using the start cell 302 and the end cell 303, the decoding process of the optical symbol 30 described later is performed. In this case, the recognition process of each cell becomes easy, which is preferable.

  FIG. 16 shows an example of the optical symbol 30 using the start cell 302 and the end cell 303 described above according to the first embodiment. As shown in FIG. 16, in the cell string of the main code part 300, the cell string of the sub code part 301 is not connected to the start cell 302 and the end cell 303. The cell string of the main code part 300 is configured such that each cell string of the sub code part 301 is always connected to each cell sandwiched between the start cell 302 and the end cell 303.

  In such a configuration, the main code unit 300 and the sub code unit 301 can be recognized based on the number of connections indicating the number of other cells connected to each cell. That is, the start cell 302, the end cell 303, and the cell at the end of each cell column of the sub code unit 301 (the cell not connected to the cell of the cell column of the main code unit 300) each have a connection number of “1”. Is. On the other hand, the number of connections of each cell other than the end of each cell row of the sub code portion 301 is “2”, whereas each cell other than the start cell 302 and the end cell 303 of the cell row of the main code portion 300 is The number of connections is “3”. Therefore, it can be determined that the cell with the connection number “1” connected to the cell with the connection number “3” is the start cell 302 or the end cell 303.

  By using the start cell 302 and the end cell 303, the cell string of the main code part 300 can be easily recognized at the time of decoding without determining the color of the cell at the tip of the cell string of the main code part 300. Further, since it is not necessary to determine the color of the cell at the tip of the cell row of the main code portion 300, information can be embedded in the cell row of the main code portion 300, and the amount of information included in the optical symbol 30 is increased. Is possible.

(Specific example of optical symbol according to the first embodiment)
Next, a more specific example of the optical symbol 30 according to the first embodiment will be described. Here, the cell color in the optical symbol 30 is assumed to be four colors of R color, G color, B color, and K color, and each digit of the information to be encoded (character string) is represented by a ternary number.

  Here, in the sub-code unit 301, information of each digit can be expressed using a code table in which numerical values and characters are associated with each other. By using the code table, characters and symbols other than numbers can be expressed.

  As an example of such a code table, there is an ASCII (American Standard Code for Information Interchange) code. The ASCII code is expressed as a 7-bit value, the control characters are the codes “0” to “31”, the space is the code “32”, the codes “33” to “47”, “58” to “64”, “91”. ”To“ 96 ”and“ 123 ”to“ 126 ”, symbols“ 48 ”to“ 57 ”, numerals“ 65 ”to“ 90 ”, uppercase letters, codes“ 97 ”to“ 122 ” “Delete” is assigned to the lower case letter “code”.

  For example, when the number of cells included in each cell column of the subcode portion 301 is four, values of “0” to “80” can be expressed in ternary numbers. Therefore, when this value is applied to the ASCII code as it is, it is possible to represent the middle part of the uppercase alphabet. Further, by shifting the 4-digit ternary value expressed by each cell column of the subcode portion 301 by giving an offset value “32”, for example, all characters expressed by the ASCII code, blanks, etc. Symbols excluding some symbols can be expressed.

  The association between numerical values and characters is not limited to the example using the code table based on the ASCII code. That is, in the first embodiment, any form of code table can be applied as long as the characters and symbols can be associated with the numerical values that can be expressed by the cell string of the subcode 301 on a one-to-one basis. In the following, for the sake of explanation, it is assumed that a 4-digit ternary value expressed by each cell string of the subcode portion 301 is applied to the ASCII code as it is.

  FIG. 17 shows an example of information for encoding into the optical symbol 30 according to the first embodiment. Here, it is assumed that the information to be encoded is an 8-digit character string “CBA00283”. In FIG. 17, the eight digits are shown as cells “d1”, “d2”,..., “D8” in order from the smallest digit. In step S100 of the flowchart of FIG. 13, the input of the character string “CBA00283” is accepted by the data input unit 200. In step S101, the decomposition unit 201 decomposes the character string “CBA00283” into values for each digit. At this time, the disassembling unit 201 uses the code table of the ASCII code to change each digit of the character string “CBA00283” to “67”, “66”, “65”, “48”, “48”, “ It is converted into each value of “50”, “56”, and “51”.

  When these values are further converted into ternary numbers, “3d2111”, “3d2110”, “3d2102”, “3d1210”, “3d1210”, “3d1212”, “3d2002”, and “3d1220” are obtained. The value of each digit of these ternary numbers is the value expressed by each cell in the cell string of the subcode portion 301 '. The conversion unit 202 executes this conversion processing for each digit in step S104 of the flowchart of FIG.

  18 shows an optical symbol 30 obtained by coding the information illustrated in FIG. 17 according to the coding rule described with reference to FIG. 7 and a display medium 40 on which the optical symbol 30 is displayed according to the first embodiment. An example of In this example, the cell string of the main code part 300 is composed of 10 cells including a start cell 302 and an end cell 303, and the start cell 302 is set to R color, and R color and K color are alternately arranged. Has been.

  The color assignment unit 203 refers to the conversion table stored in the table storage unit 204 and the color of the transition source cell in steps S106 to S109 in the flowchart of FIG. A color is assigned to each digit of the converted ternary number. For example, the digit corresponding to the cell “d1” in FIG. 17 has the ternary value “3d1220”.

It is assumed that the smallest ternary digit (the digit of “3 ⁰ ”) is assigned to the cell (leading cell) connected to the main code unit 300 in the cell sequence of the sub code unit 301. In this case, the color assignment unit 203 first refers to the conversion table using the K color corresponding to the digit of the cell string of the main code unit 300 as the color of the transition source cell, and assigns the color to the leading cell of the cell string. To get. Thereafter, the color assigning unit 203 assigns a color to each cell in the cell column in sequence, using the cell to which the color is assigned immediately before as the transition source cell.

  In the example of FIG. 18, each cell in the cell row of the sub code portion 301 connected to the cell of the main code portion 300 corresponding to the cell “d1” of FIG. “Color”, “G color”, and “R color” are respectively assigned. When the color assignment to the cell at the end of the cell row ends, the color assignment unit 203 executes a color assignment process to the next cell row in the sub-code portion 301.

  The code generation device 20 displays the optical symbol 30 generated as described above on the display medium 40. For example, the code generation device 20 prints the generated optical symbol 30 on a print medium as the display medium 40 using the printer 21.

  FIG. 19 schematically illustrates an example of use of the display medium 40 on which the optical symbol 30 according to the first embodiment is displayed. In the example of FIG. 19, the display medium 40 on which the optical symbol 30 is displayed is attached to the outer surface of the article 50. As an example, a character string to be encoded to be encoded into the optical symbol 30 can be used as identification information for identifying the article 50. By capturing the display medium 40 with a camera, and recognizing and decoding the optical symbol 30 included in the captured image, the identification information of the article 50 can be acquired without any action from the article 50.

(Optical Symbol Recognition Processing According to First Embodiment)
Next, the recognition process of the optical symbol 30 according to the first embodiment will be described. FIG. 20 shows an example of the configuration of a code recognition system applicable to the first embodiment. In FIG. 20, the code recognition system includes a code recognition device 10, a camera 11, and a code management device 12, and the code recognition device 10 and the code management device 12 are connected to each other via a network 13 so as to communicate with each other. . The camera 11 is connected to the code recognition device 10.

  As described with reference to FIG. 1, the code recognition device 10 recognizes the image of the optical symbol 30 included in the captured image captured by the camera 11 and decodes the optical symbol 30. The code management device 12 manages information obtained by the code recognition device 10 decoding the optical symbol 30.

  FIG. 21 shows an example of the hardware configuration of the code recognition apparatus 10 applicable to the first embodiment. The code recognition apparatus 10 includes a CPU 1000, a ROM 1001, a RAM 1002, a storage 1003, a camera I / F 1004, and a communication I / F 1005, and these units are communicably connected to each other via a bus 1010. Thus, the code recognition apparatus 10 according to the first embodiment can be realized using a general computer. Note that the code recognition apparatus 10 can omit input means such as a keyboard and a pointing device, and display means such as a graphics I / F and a display.

  The storage 1003 is a non-volatile storage medium such as a hard disk drive or a flash memory, and stores programs and data. The CPU 1000 controls the overall operation of the code recognition apparatus 10 using the RAM 1002 as a work memory according to programs stored in the storage 1003 and the ROM 1001.

  The camera 11 is connected to the camera I / F 1004. The CPU 1000 can acquire a captured image captured by the camera 11 via the camera I / F 1004. The CPU 1000 can also control the imaging operation of the camera 11 via the camera I / F 1004.

  The communication I / F 1005 is connected to the network 13 and performs communication via the network 13. The network 13 may be a LAN (Local Area Network) or the Internet. The network 13 may be connected using either wired communication or wireless communication.

  FIG. 22 is a functional block diagram of an example for explaining functions of the code recognition device 10 according to the first embodiment. In FIG. 22, the code recognition device 10 includes an image acquisition unit 100, a cut-out processing unit 101, a recognition unit 102, a decoding unit 103, and a table storage unit 104.

  Among these, the image acquisition unit 100, the cutout processing unit 101, the recognition unit 102, and the decoding unit 103 are configured by programs that operate on the CPU 1000. However, the present invention is not limited to this, and some or all of the image acquisition unit 100, the clipping processing unit 101, the recognition unit 102, and the decoding unit 103 may be configured by hardware circuits that operate in cooperation with each other. The table storage unit 104 is configured by a predetermined storage area in the storage 1003 or the RAM 1002.

  The image acquisition unit 100 acquires a captured image captured by the camera 11. The cutout processing unit 101 cuts out the image of the optical symbol 30 from the captured image acquired by the image acquisition unit 100. The recognition unit 102 performs recognition processing on the image of the optical symbol 30 cut out by the cut-out processing unit 101. That is, the recognition unit 102 detects the image of each cell from the image of the optical symbol 30, and recognizes information obtained from the connection relationship of each cell based on the color information of the detected image or information held by the color information itself. To do. Based on the recognition result, the recognition unit 102 creates symbol information that the optical symbol 30 has.

  More specifically, the recognition unit 102 includes a main code recognition unit 1020, a sub code recognition unit 1021, and a synthesis unit 1022. The main code recognizing unit 1020 recognizes color information indicating the color of the cells constituting the cell row of the main code unit 300 from the image of the optical symbol 30. The sub code recognition unit 1021 recognizes the color information of the cells constituting each cell column included in the sub code unit 301 from the image of the optical symbol 30. At this time, the sub-code recognition unit 1021 executes a recognition process for recognizing the color information of each cell included in the sub-code unit 301 in parallel for each cell. The synthesizing unit 1022 synthesizes information obtained by the recognition by the main code recognizing unit 1020 and the sub code recognizing unit 1021, respectively, and creates the symbol information that the optical symbol 30 has. The symbol information includes, for example, color information of each cell in each cell column included in the main code portion 300 and the sub code portion 301 of the optical symbol 30 and information on connection relations between the cells.

  The table storage unit 104 stores in advance a conversion table corresponding to the number of colors assigned to each cell, as described with reference to FIGS. 4D and 7E. The decoding unit 103 decodes the symbol information created by the recognition unit 102 and restores the information encoded in the optical symbol 30.

  A code recognition program for realizing each function of the code recognition apparatus 10 according to the first embodiment is a file in an installable format or an executable format in a CD (Compact Disk), a flexible disk (FD), a DVD ( Provided on a computer-readable recording medium such as Digital Versatile Disk). However, the present invention is not limited thereto, and the code recognition program may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. The code recognition program may be provided or distributed via a network such as the Internet.

  The code recognition program has a module configuration including the above-described units (image acquisition unit 100, cut-out processing unit 101, recognition unit 102, and decoding unit 103). As actual hardware, the CPU 1000 reads out and executes the code recognition program from a storage medium such as the storage 1003, so that the above-described units are loaded on the main storage device such as the RAM 1002. A processing unit 101, a recognition unit 102, and a decoding unit 103 are generated on the main storage device.

(Details of optical symbol recognition processing according to the first embodiment)
Next, the recognition and decoding process of the optical symbol 30 according to the first embodiment will be described in more detail. In the following description, it is assumed that the optical symbol 30 described with reference to FIG. 18 is used.

  That is, the optical symbol 30 used in the following description includes a start cell 302 and an end cell 303, and includes a main code unit 300 including eight cells sandwiched between the start cell 302 and the end cell 303, and A sub-code unit 301 including eight cell strings connected to eight cells sandwiched between a start cell 302 and an end cell 303, respectively. In the main code part 300, the color of the start cell 302 is R, and the R color and the K color are alternately arranged. In the subcode portion 301, each cell row includes four cells each representing a ternary number using four colors. It is assumed that the code recognition device 10 knows the structure of the optical symbol 30 in advance.

  FIG. 23 shows an example of a captured image 60 captured by the camera 11 and acquired by the image acquisition unit 100 of the code recognition device 10 according to the first embodiment. In the example of FIG. 23, the captured image 60 includes a plurality of sets of images of the display medium 40 and the optical symbol 30 displayed on the display medium 40. The code recognition device 10 cuts out the image of the optical symbol 30 from the captured image 60, and recognizes the color information of each cell included in the optical symbol 30 and the connection relation of each cell based on the cut out image of the optical symbol 30. Then, the optical symbol 30 is decoded based on the recognition result.

  FIG. 24 is a flowchart of an example showing recognition and decoding processing of the optical symbol 30 in the code recognition device 10 according to the first embodiment. In FIG. 24, in step S400, the code recognition apparatus 10 performs a recognition process on the optical symbol 30 by the recognition unit 102, and determines whether or not the cell of the main code unit 300 has been recognized.

  More specifically, in step S <b> 400, the code recognition apparatus 10 cuts out the image of the optical symbol 30 from the captured image 60 by the cutout processing unit 101. The recognizing unit 102 performs the cell recognizing process of the main code unit 300 from the clipped image by the main code recognizing unit 1020, and whether or not cells other than the start cell 302 and the end cell 303 in the main code unit 300 are recognized. Determine. If it is determined that it is not recognized, the recognizing unit 102 returns the process to step S400 (step S400, “No”), and continues the cell recognizing process of the main code unit 300.

  When it is determined in step S400 that the cell of the main code part 300 is recognized (step S400, “Yes”), the recognition unit 102 acquires the color and connection information of the recognized cell, and performs the processing step. The process proceeds to S401 and step S402.

  Note that the connection information includes, for example, information indicating a recognized cell and information indicating a recognized cell adjacent to the recognized cell. The recognition unit 102 uses, for example, identification information (for example, a serial number) corresponding to the order in which cells are recognized by the main code recognition unit 1020 and the sub code recognition unit 1021 as information indicating the cell.

  In step S <b> 401, the main code recognizing unit 1020 in the recognizing unit 102 determines whether or not all cells in the cell row of the main code unit 300 have been recognized. If it is determined that it has not been recognized (step S401, “No”), the recognition unit 102 returns the process to step S400 and continues the cell recognition process of the main code unit 300.

  On the other hand, if it is determined in step S401 that all the cells in the cell string of the main code portion 300 have been recognized (step S401, “Yes”), the recognition unit 102 shifts the processing to step S403.

  For example, it is assumed that the cell string included in the main code unit 300 is configured by alternately arranging cells of two types of color information, and the number of cells included in the cell string is known. In this case, the main code recognizing unit 1020 can determine that all cells in the cell sequence of the main code unit 300 have been recognized by counting the number of transitions of color information between cells in the cell sequence. Further, the main code recognition unit 1020 can recognize the number of transitions of color information between cells in the cell sequence of the main code unit 300 as information expressed by the cell sequence of the main code unit 300.

  Taking FIG. 17 and FIG. 18 as an example, if nine transitions of color information including the start cell 302 and the end cell 303 are counted in the main code unit 300, the cell string of the main code unit 300 is counted. It can be determined that all the cells of have been recognized. Further, it can be recognized that the value obtained by subtracting 1 from the number of transitions of the color information is the information expressed by the cells excluding the start cell 302 and the end cell 303 in the cell string of the main code portion 300, that is, the number of digits.

  In step S <b> 402, the recognition unit 102 performs recognition processing on the cell of the sub code unit 301 by the sub code recognition unit 1021. More specifically, the sub-code recognition unit 1021 sets the cell sequence of the sub-code unit 301 connected to the cell recognized by the main code recognition unit 1020 in step S400 as a processing target, Recognize each cell.

  FIG. 25 is a flowchart of an example showing the recognition processing by the sub-code recognition unit 1021 in step S402 according to the first embodiment. In step S4020, the sub code recognition unit 1021 recognizes, for example, the cell of the sub code unit 301 connected to the cell recognized by the main code unit 300. A cell string including the recognized cell is a cell string to be processed. The sub-code recognition unit 1021 acquires the recognized cell color and connection information. In the next step S4021, the sub-code recognition unit 1021 recognizes a cell adjacent to the cell recognized in the immediately preceding process based on the color transition in the cell row to be processed. The sub-code recognition unit 1021 acquires the recognized cell color and connection information.

  In next step S4022, the sub-code recognition unit 1021 determines whether or not the cell recognized in step S4021 is the terminal cell of the cell string to be processed. If it is determined that the cell is not the terminal cell (step S4022, “No”), the sub-code recognition unit 1021 returns the process to step S4021, and performs a process of recognizing a cell adjacent to the cell recognized in the immediately preceding step S4021. Do. On the other hand, if the sub-code recognition unit 1021 determines that the cell is a terminal cell (step S4022, “Yes”), the series of processing according to the flowchart of FIG. 25 is terminated.

  For example, when the sub-code recognition unit 1021 recognizes a predetermined number of color transitions in step S4021, the sub-code recognition unit 1021 determines in step S4022 that the recognized cell is the terminal cell of the cell string to be processed. To do. However, the sub code recognition unit 1021 may determine the terminal cell in step S4022 based on the number of connected cells adjacent to the cell recognized in step S4021.

  The process according to the flowchart of FIG. 25 is executed in parallel for a plurality of cell strings included in the subcode unit 301. For example, every time a cell is recognized by the main code recognition unit 1020 in step S400 of FIG. 24, the sub code recognition unit 1021 executes the process of step S402, that is, the process of the flowchart of FIG.

  Returning to the description of the flowchart of FIG. 24, the recognition unit 102 determines in step S403 whether or not the processing has been completed for all the cell strings of the sub code unit 301 connected to the cell string of the main code unit 300. . For example, the recognizing unit 102 monitors the processing of steps S400 and S401 in the main code recognizing unit 1020 and the processing of step S402 in the sub code recognizing unit 1021. The recognizing unit 102 determines whether or not the processing in step S402 for the cell string of the sub code unit 301 connected to the cell of the main code unit 300 last recognized in step S400 and step S401 is completed. If it is determined that the process has not been completed (step S403, “No”), the recognition unit 102 returns the process to step S403 and waits for the process to end.

  On the other hand, when the recognition unit 102 determines in step S403 that the processing for all cell strings of the sub code unit 301 connected to the cell string of the main code unit 300 has been completed (step S403, “Yes”). The process proceeds to step S404.

  In step S404, the recognizing unit 102 uses the combining unit 1022 to obtain information obtained by reading the cell sequence of the main code unit 300 and information obtained by reading a plurality of cell sequences included in the sub code unit 301. The information obtained by combining the information is created as symbol information of the optical symbol 30. More specifically, the combining unit 1022 determines whether the information included in the main code unit 300 and the sub code unit 301 are based on the connection information of each cell acquired in step S400 and step S401 and step S402 described above. Performs composition processing with the included information.

  A composition process based on connection information by the composition unit 1022 according to the first embodiment will be described with reference to FIG. Here, for the sake of explanation, the cell string of the main code portion 300 is represented by 3 between the start cell 302 and the end cell 303 and between the start cell 302 and the end cell 303 as shown in FIG. Suppose that it contains cells (each labeled with a circle). In addition, each cell column of the subcode portion 301 includes two cells.

  In FIG. 26D, the numbers given to the cells are identification information (labels) given to the cells according to the order in which the cells are recognized, for example. The labels of the start cell 302 and the end cell 303 are “S” and “E”, respectively.

  FIG. 26A shows connection information between cells using labels. In FIG. 26 (a), it is shown that two cells written in parentheses “()” are connected, and for example, a cell of label # 1 and a cell of label # 2 are connected. Has been. Similarly, each cell of label # 5 and label # 2, each cell of label # 3 and label # 9, each cell of label # 1 and label # 3, each cell of label # 1 and label #S, label # 8 And each cell of label # 4, each cell of label # 3 and label # 6, each cell of label # 6 and label # 7, each cell of label # 9 and label # 4, each of label # 9 and label #E It is shown that the cells are each connected.

  The combining unit 1022 obtains the number of connections, which is the number of other cells connected to each cell, based on the connection information between the cells illustrated in FIG. FIG. 26B shows the number of connected cells of labels # 1 to # 9. Each cell of labels # 1, # 3 and # 9 has a connection number “3”, each cell of labels # 2, # 4 and # 6 has a connection number “2”, and labels # 5, # 7 and # 9 Each of the eight cells has the number of connections “1”.

  The combining unit 1022 obtains a connection set of each cell based on the connection information of each cell shown in FIG. 26A and the number of connections of each cell shown in FIG. That is, as described with reference to FIG. 16, the cell with the number of connections “3” is a cell in the cell row of the main code unit 300. A cell with the number of connections “2” is a cell other than the end of each cell string in the sub-code unit 301. Further, the cell with the number of connections “1” is a cell at the end of each cell column in the sub code unit 301. Note that the start cell 302 and the end cell 303 also have the number of connections “1”, but the start cell 302 and the end cell 303 are distinguished from other cells as labels #S and #E, and are considered here. There is no need.

  The synthesizer 1022 uses the cells of labels # 1, # 3, and # 9 based on these pieces of information and the connection information of the cells shown in FIG. 26 (a), as shown in FIG. 26 (c). The connection relationship of each cell in the cell row of the trunk, that is, the main code unit 300 is created by the connection set. In addition, the connection relationship of each cell in each cell column of the branch, that is, the subcode section 301 is created by each connection set of labels # 2 and # 5, labels # 4 and # 8, and labels # 6 and # 7. To do. Furthermore, the combining unit 1022 connects each cell string of the sub code unit 301 to each cell in the cell string of the main code unit 300 based on the connection relationship of each cell of the trunk and the connection relationship of each cell of the branch. .

  Based on the configuration in which each cell string of the sub code unit 301 is connected to each cell in the cell string of the main code unit 300, the combining unit 1022 includes information included in the cell string of the main code unit 300, and the sub code unit 301. Each information included in each cell column is acquired. The combining unit 1022 combines the acquired pieces of information and creates the combined information as symbol information that the optical symbol 30 has. As described above, the symbol information includes the color information of each cell in each cell column included in the main code portion 300 and the sub code portion 301 of the optical symbol 30 and information on the connection relationship between the cells.

  Returning to the flowchart of FIG. 24, symbol information held by the optical symbol 30 by combining the information based on the cell sequence of the main code unit 300 and the information based on each cell sequence of the sub code unit 301 by the combining unit 1022 in step S404. Is created, the process proceeds to step S405. In step S405, the decoding unit 103 decodes the symbol information created in step S404 and restores the original information.

  More specifically, the decoding unit 103 refers to the conversion table stored in the table storage unit 104 based on the symbol information created by the synthesis unit 1022 in step S404. Based on the symbol information, the decoding unit 103 uses the cells closer to the cell column of the main code unit 300 as adjacent cells in each cell column of the sub code unit 301 of the optical symbol 30 as the transition source cells. The value is obtained by referring to the conversion table according to the cell color information.

  When a value is acquired for each cell of one cell string of the sub-code part 301, the decoding unit 103 adds the acquired values according to ternary digits to obtain the value of the cell string. . Based on the obtained value of the cell string, the decoding unit 103 restores the original character with reference to, for example, a code table. This process is executed for all the cell strings in the sub-code unit 301, and the original character string encoded in the optical symbol 30 is decoded.

  When the decoding process in step S405 ends, a series of processes according to the flowchart of FIG. 24 ends.

  As described above, in the optical symbol 30 according to the first embodiment, a plurality of cell strings of the sub code part 301 are connected to a cell string of the main code part 300. Therefore, the decoding process for a plurality of cell strings in the subcode unit 301 can be executed in parallel, and the decoding process can be speeded up.

(Optical Symbol Cutout Processing According to First Embodiment)
Next, a clipping process for clipping the optical symbol 30 according to the first embodiment from the captured image will be described. In the first embodiment, as the cut-out process, (1) a first cut-out process based on template matching using a template and (2) a second cut-out process using continuity of pixel colors, Apply either one.

(First cutout process)
First, the first cutout process (1) will be described. In the first cutout process, the shape of the optical symbol 30 is known, and a template having a shape corresponding to the shape of the optical symbol 30 is prepared. FIG. 27 shows an example of a template applicable to the first embodiment. FIG. 27A shows an example of the optical symbol 30 whose shape is known.

  FIG. 27B shows an example of a template 70a using a binarized image. For example, the template 70a is created by binarizing the optical symbol 30 shown in FIG. 27A based on a predetermined threshold value for the luminance value. FIG. 27C shows an example of a template 70b created by edge detection. For example, the template 70b converts the optical symbol 30 shown in FIG. 27A into a grayscale image, performs edge detection processing on the grayscale image by a known method, and detects the detected edge information. Use to create.

  The first cut-out process may be executed using any of these templates 70a and 70b. In the following description, it is assumed that a template 70a using a binarized image is used.

  FIG. 28 is a flowchart illustrating an example of a first cutout process according to the first embodiment. The process according to the flowchart of FIG. 28 corresponds to the process of step S400 in the flowchart of FIG.

  In step S <b> 200, the code recognition device 10 causes the cutout processing unit 101 to perform edge detection processing on the captured image 60 (see FIG. 23) using a known technique. In the next step S201, the cutout processing unit 101 selects the size and shape of the template 70a to be used. That is, the orientation and size of the image of the optical symbol 30 included in the captured image 60 changes depending on the distance between the camera 11 and the optical symbol 30 at the time of imaging, the angle of view of the camera 11, the imaging angle, and the like. Therefore, the cutout processing unit 101 prepares templates 70a having a plurality of sizes.

  In the next step S202, the cutout processing unit 101 performs template matching processing on the captured image 60 using a known technique using the template 70a selected in step S201, and obtains a similarity. For example, the cutout processing unit 101 scans the template 70a selected in step S201 in the captured image 60, and obtains the similarity at each position.

  In the next step S203, the cut-out processing unit 101 determines the presence or absence of a similarity equal to or greater than a threshold based on the similarity obtained in step S202. At this time, as described above, since the optical symbol 30 has a comb shape, the image of the optical symbol 30 and the image other than the optical symbol 30 included in the captured image 60 can be easily distinguished from each other. The determination based on the degree can be executed with high accuracy. If it is determined that there is no similarity equal to or greater than the threshold (step S203, “No”), the cut-out processing unit 101 returns the process to step S201, selects a template 70a having a different size and shape, and again performs template matching processing. I do.

  If it is determined in step S203 that there is a similarity equal to or higher than the threshold (step S203, “Yes”), the extraction processing unit 101 shifts the processing to step S204. In step S204, the cut-out processing unit 101 cuts out an image of the area of the template 70a at the position on the picked-up image 60 where the similarity is determined to be greater than or equal to the threshold value from the picked-up image 60. In the next step S205, the code recognition device 10 recognizes the color information of the cells constituting the cell string of the main code unit 300 from the image cut out in step S204 by the main code recognition unit 1020 of the recognition unit 102.

  When the color information of the cells constituting the cell row of the main code unit 300 is recognized, a series of processes according to the flowchart of FIG.

  FIG. 29 shows an example of a method for acquiring the color information of each cell from the image of the optical symbol 30 cut out by the first cut-out process according to the first embodiment. FIG. 29A shows an example in which color information is acquired from a pixel at a predetermined position in each cell. FIG. 29B illustrates an example in which color information is acquired from a plurality of pixels whose positions are continuous by scanning a cell row in the cell connection direction.

  The acquisition method shown in FIG. 29A enables high-speed color acquisition when each cell in the optical symbol 30 has a certain size and the captured image 60 has little distortion. . On the other hand, the acquisition method shown in FIG. 29B requires more processing time than the acquisition method shown in FIG. 29A, but the size of each cell is not constant or the captured image 60 is distorted. Even when there are many cases, it is possible to acquire colors with high accuracy. In addition, the acquisition method illustrated in FIG. 29B has an advantage of being resistant to color unevenness in the captured image 60.

  It is preferable that the acquisition method shown in FIG. 29A and the acquisition method shown in FIG. 29B can be appropriately selected according to the imaging conditions of the captured image 60 and the like.

(Second cutout process)
Next, the second cutout process (2) will be described. In the second cut-out process, the color is recognized for each pixel of the captured image 60, and when the adjacent pixel adjacent to the target pixel and the target pixel are the same color, the target pixel and the adjacent pixel are collectively labeled. To do.

  FIG. 30 is a flowchart illustrating an example of a second cutout process according to the first embodiment. The process according to the flowchart of FIG. 30 can correspond to the process of step S400 in the flowchart of FIG. 24 described above.

  In step S300, the code recognition device 10 causes the cutout processing unit 101 to randomly select a pixel from the captured image 60 as a target pixel. In step S300, a predetermined pixel of the captured image 60 may be selected as a target pixel.

  In the next step S301, the cutout processing unit 101 recognizes the color of the target pixel. In the next step S302, the clipping processing unit 101 determines whether the color information of the target pixel corresponds to the color information of the constituent color of the optical symbol 30 (for example, any one of R color, G color, B color, and K color). Determine whether or not. As an example, when the value indicating the color related to certain color information is within a predetermined range with respect to the value indicating the color related to other color information, the clipping processing unit 101 stores the certain color information. It is determined that it corresponds to the other color information. When it is determined that the color information of the pixel of interest does not correspond to the color information of the constituent color of the optical symbol 30 (step S302, “No”), the cutout processing unit 101 returns the process to step S300 and adds another pixel. Selected as a target pixel.

  On the other hand, when it is determined in step S302 that the color information of the target pixel corresponds to the color information of the constituent color of the optical symbol 30 (step S302, “Yes”), the extraction processing unit 101 proceeds to step S303. . Step S303 is a process of labeling each pixel based on the color information of the target pixel and the color information of the adjacent pixel adjacent to the target pixel. In other words, step S303 is a process for specifying a cell included in the optical symbol 30. Step S303 includes a series of processes of steps S3030 to S3037.

  In step S <b> 303, in step S <b> 3030, the extraction processing unit 101 performs labeling that assigns a unique label to the target pixel. The labeling is performed by associating coordinate information on the captured image 60 of the pixel to be labeled (target pixel), color information of the target pixel, and a predetermined label. The cutout processing unit 101 stores information on the labeled pixels in, for example, the RAM 1002.

  In the next step S3031, the extraction processing unit 101 adjusts parameters used for color information recognition. For example, the cut-out processing unit 101 adjusts threshold values for recognizing each of R color, G color, B color, and K color in step S3031.

  In the next step S3032, the cutout processing unit 101 determines whether there is an unprocessed adjacent pixel among the adjacent pixels adjacent to the target pixel. The cutout processing unit 101 checks whether or not a label is assigned to the adjacent pixel based on the coordinates of the adjacent pixel to be determined, and if the label is not attached, the adjacent pixel is an unprocessed pixel. judge. When it is determined that there is no unprocessed adjacent pixel (step S <b> 3032, “No”), the cut-out processing unit 101 proceeds to step S <b> 3034 described later.

  On the other hand, if it is determined in step S3032 that there is an unprocessed adjacent pixel (step S3032, "Yes"), the cutout processing unit 101 proceeds to step S3033. In step S3033, the extraction processing unit 101 stores the coordinates of unprocessed adjacent pixels in the coordinate storage unit. For example, a predetermined area of the RAM 1002 or the storage 1003 is used as the coordinate storage unit. In the process of step S3033, unprocessed adjacent pixels of color information that does not correspond to the color information of the constituent colors of the optical symbol 30 are also stored in the coordinate storage unit.

  In the next step S3034, the extraction processing unit 101 determines whether or not the coordinates of unprocessed adjacent pixels are stored in the coordinate storage unit. When it is determined that the coordinates of the unprocessed adjacent pixels are stored in the coordinate storage unit (step S3034, “Yes”), the cut-out processing unit 101 shifts the processing to step S3035. In step S3035, the cutout processing unit 101 selects one pixel from unprocessed adjacent pixels. At this time, the extraction processing unit 101 preferentially selects a pixel having the same color as the target pixel.

  In the next step S3036, the cutout processing unit 101 recognizes the color information of the unprocessed adjacent pixels selected in step S3035. In the next step S3037, the extraction processing unit 101 determines whether or not the color information recognized in step S3036 corresponds to the color information of the constituent colors of the optical symbol 30.

  When it is determined that the recognized color information corresponds to the color information of the constituent color of the optical symbol 30 (step S3037, “Yes”), the cutout processing unit 101 returns the process to step S3030, and the unprocessed adjacent pixel Is labeled as a new pixel of interest.

  In this labeling, when the color information of the new pixel of interest corresponds to the color information of the pixel of interest in the immediately preceding process, the extraction processing unit 101 adds the pixel of interest in the immediately preceding process to the pixel of interest in the immediately preceding process. Give the same label. On the other hand, when the color information of the new pixel of interest is different from the color information of the pixel of interest in the immediately preceding process, the cutout processing unit 101 adds the pixel of interest in the immediately previous process to the new pixel of interest. Give a different label. In other words, the cutout processing unit 101 assigns a unique label to a group of pixels having coordinate information and corresponding color information by the labeling process in step S3030.

  On the other hand, if it is determined in step S3037 that the color information recognized in step S3036 does not correspond to the color information of the constituent colors of the optical symbol 30 (step S3037, “No”), the process is performed. It returns to step S3034. When it is determined in step S3034 that the coordinates of the unprocessed adjacent pixels are stored in the coordinate storage unit (step S3034, “Yes”), the cut-out processing unit 101 selects the previous process in step S3035. An unprocessed adjacent pixel that is different from the unprocessed adjacent pixel is selected.

  If it is determined in step S3034 described above that the coordinates of the unprocessed adjacent pixels are not stored in the coordinate storage unit (step S3034, “No”), the series of processing in step S303 is terminated, and the processing proceeds to step S304. Is done. That is, when there is no unprocessed adjacent pixel in step S3032, and the coordinates of the unprocessed adjacent pixel are not stored in the coordinate storage unit in step S3034, the series of processing in step S303 is terminated.

  In step S304, in the code recognition apparatus 10, the main code recognition unit 1020 determines whether the configuration of each pixel group to which a unique label is assigned by the labeling in step S303 matches the cell connection information of the main code unit 300. Determine whether or not.

  That is, in this step S304, there are a plurality of pixel groups to which unique labels are assigned by the labeling process in step S303, and the connection relationship between the plurality of pixel groups is determined by each cell in the cell column of the main code section 300. It is determined whether or not a connection relationship that completely matches the connection information is included. The connection relationship between the pixel groups can be known based on, for example, the coordinates and color of each labeled pixel.

  When the main code recognition unit 1020 determines in step S304 that the configuration of each pixel group to which a unique label is assigned does not match the cell connection information of the main code unit 300 (step S304, “No”). The process returns to step S300. That is, in this case, the pixel selected in step S300 is not a pixel constituting the optical symbol 30.

  On the other hand, when the main code recognition unit 1020 determines in step S304 that the configuration of each pixel group to which a unique label is assigned matches the cell connection information of the main code unit 300 (step S304, “Yes”). ), A series of processes according to the flowchart of FIG. 30 is terminated. In this case, at least the extraction process of the main code portion 300 of the optical symbol 30 has been completed.

  The main code recognizing unit 1020 determines the pixel group based on the connection relationship between the pixel group to which the unique label is assigned and the other pixel group connected to the pixel group in the labeling process in step S303 described above. Can be recognized as a cell of the main code part 300. When the pixel group is recognized as a cell of the main code unit 300, the process proceeds to step S402 according to the determination in step S400 of FIG. 24 (step S400, “Yes”), and the cell process of the sub code unit 301 is performed. Run.

  In this case, for example, the code recognition apparatus 10 can execute the cell string cut-out process of the sub-code unit 301 by separately executing the process of the flowchart of FIG. As an example, the extraction processing unit 101 performs pixel selection in step S300 on pixels adjacent to the pixel group that is recognized as a cell of the main code unit 300. In the determination process in step S304, for example, the sub code recognition unit 1021 determines whether or not the cell connection information of the sub code unit 301 matches.

  The code recognition device 10 can separately execute the processing of the flowchart of FIG. 30 in parallel each time the main code recognition unit 1020 recognizes a cell of the main code unit 300. As a result, the processing speed can be increased.

  In step S303 in the flowchart of FIG. 30, when the color execution of the adjacent pixel adjacent to the target pixel corresponds to the color information of the constituent color of the optical symbol 30, the adjacent pixel is processed as a new target pixel, and sequentially The area to which the label is attached will be expanded. At this time, the area is not expanded to adjacent pixels of colors other than the constituent colors of the optical symbol 30. In this way, by limiting the area where the labeling process is performed, it is possible to execute the labeling process at a higher speed.

(Modification of the first embodiment)
Next, a modification of the first embodiment will be described. In the first embodiment, the optical symbol 30 is connected to each cell except the main code part 300 by a cell row in which cells are arranged in a straight line, and the start cell 302 and the end cell 303 of the main code part 300. The sub-code unit 301 is composed of a plurality of cell rows in which cells are arranged in a straight line. The shape of the optical symbol 30 is not limited to this example, and a shape in which the cell columns of the main code portion 300 and the sub code portion 301 are not arranged linearly is also possible.

  FIG. 31 shows an exemplary configuration of an optical symbol 30 ′ according to a modification of the first embodiment. In the modification of the first embodiment, as illustrated in FIG. 31 (a), the optical symbol 30 ′ is made different in size of each cell, and the connection between the cells is arbitrarily set in each cell. This is performed so that three or more cells are not arranged in a straight line. In addition, the alphabet in the cell of Fig.31 (a) has shown the label provided to the cell.

  FIG. 31B shows the configuration of the optical symbol 30 ′ in FIG. In FIG. 31B, a cell is shown by enclosing the label in a circle. In FIG. 31B, cells “a”, “b”, “g”, “k”, “p”, and “q” are the cell strings of the main code portion 300. In this example, cells “a” and “q” are a start cell 302 and an end cell 303, respectively, and each cell “b”, “g”, “k” and “ In “p”, three or more cells are connected.

  Also, cells “c”, “d” and “e”, cells “i” and “j”, cells “l”, “m”, “n” and “o”, and cells “r” and “s” "Is a cell string of the sub code unit 301 connected to the cells" b "," g "," k ", and" p "of the main code unit 300, respectively. In the example of FIG. 31B, the cells “f” and “h” are also configured as cell strings of the sub-code portion 301, respectively. In this case, for example, the cell “f” is connected to the cell “b” of the main code unit 300 in a direction different from the cell row by the cells “c”, “d”, and “e”. The same applies to the cell “h”. Further, these cells “f” and “h” are also terminal cells of the cell string in the sub-code portion 301.

  Even in such a configuration, each cell string of the sub code unit 301 is connected to each cell of the main code unit 300, so that the processing for each cell string of the sub code unit 301 can be executed in parallel. The processing speed can be increased.

(Second Embodiment)
Next, a second embodiment will be described. The second embodiment is an example in which the optical symbol 30 according to the first embodiment is applied to a code management system and a transport system. FIG. 32 schematically shows a code management system and a transport system according to the second embodiment. Note that, in FIG. 32, the same reference numerals are given to portions common to FIGS. 1, 10 and 20 described above, and detailed description thereof is omitted.

  In FIG. 32, the code management system includes a code recognition device 10, a code management device 12, a code generation device 20, and a printer 21 that are connected to each other via a network 13. The transport system further includes a transport control device 14 in addition to the configuration of the code management system. The transport control device 14 can perform drive control of the transport device 51. For example, the conveyance control device 14 can drive and control the conveyance device 51 at a position corresponding to the input position information by inputting the position information.

  In the example of FIG. 32, the articles 50 are loaded on the respective conveyance devices 51. A display medium 40 on which the optical symbol 30 according to the first embodiment is displayed is attached to the article 50 on the outer surface (the upper surface in this example). Each optical symbol 30 displayed on the display medium 40 attached to each article 50 is obtained by encoding identification information for identifying each article 50.

  Each identification information for identifying each article 50 is input to the code generation device 20. The code generation device 20 encodes each input identification information according to the procedure shown in FIG. 13, for example, and generates each optical symbol 30 corresponding to each article 50. The code generation device 20 prints the generated optical symbols 30 on the display medium 40, respectively. Each display medium 40 on which the optical symbol 30 is printed is attached to an article 50 corresponding to the identification information encoded in the optical symbol 30.

  The code recognition device 10 cuts out each optical symbol 30 from the captured image 60 captured by the camera 11 according to the method described with reference to FIGS. That is, the code recognition device 10 functions as an image acquisition unit that acquires the captured image 60 including the optical symbol 30. The code recognition apparatus 10 further decodes each cut-out optical symbol 30 to restore the identification information encoded in the optical symbol 30. That is, the code recognition device 10 also functions as an identification information acquisition unit that acquires identification information encoded in the optical symbol 30. Further, the code recognition device 10 acquires the position of each optical symbol 30 in the captured image 60 based on, for example, the coordinates of the pixel acquired during the cutting process of the optical symbol 30. That is, the code recognition device 10 also functions as a position acquisition unit that acquires the position of the optical symbol 30.

  The code recognition device 10 transmits the identification information restored by decoding each optical symbol 30 and the position information indicating the position of each optical symbol 30 to the code management device 12. The code management device 12 manages each identification information transmitted from the code recognition device 10 in association with each position information. Here, it is assumed that the imaging range of the captured image 60 and the coordinates of the region where each article 50 is arranged are associated in advance.

  For example, the conveyance control device 14 receives, from the outside, identification information of a specific article 50 and a movement instruction for moving the article 50. The transport control device 14 transmits the input identification information to the code management device 12 and requests the code management device 12 for position information associated with the identification device. In response to this request, the code management device 12 acquires position information associated with the identification information from the managed information and transmits it to the transport control device 14. The transport control device 14 controls the operation of the transport device 51 corresponding to the position information transmitted from the code management device 12 and moves the transport device 51.

  As described above, the code management system and the transport system according to the second embodiment captures each optical symbol 30 displayed on the display medium 40 attached to each article 50 with the camera 11, and sets each optical symbol 30. Each encoded identification information can be acquired and managed collectively. Therefore, it is possible to easily execute the delivery management of each article 50.

  The above-described embodiment is a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Code recognition apparatus 11 Camera 12 Code management apparatus 14 Conveyance control apparatus 20 Code generation apparatus 21 Printer 30, 30 'Optical symbol 40 Display medium 50 Article 51 Conveyance apparatus 60 Captured image 70a, 70b Template 100 Image acquisition part 101 Extraction process part 102 Recognition unit 103 Decoding unit 104, 204 Table storage unit 201 Decomposition unit 202 Conversion unit 203 Color allocation unit 300, 300 ′ Main code unit 301, 301 ′ Sub code unit 302 Start cell 303 End cell 1020 Main code recognition unit 1021 Sub code Recognition unit 1022 Compositing unit

Japanese Patent No. 4404224

Claims (14)

A main code portion having a first cell row in which a plurality of main code cells are connected in one dimension;
An optical symbol including a subcode portion having a second cell row in which a plurality of subcode cells are connected in one dimension,
The second cell column is an optical symbol connected to any one of the plurality of main code cells excluding a cell at an end of the first cell column among the plurality of main code cells. The optical symbol according to claim 1, wherein the sub-code portion includes a plurality of the second cell columns. The optical symbol according to claim 2, wherein the second cell columns are connected to different main code cells, and the second cell columns have a predetermined interval or more. The optical symbol according to any one of claims 1 to 3, wherein the main code cell and the sub code cell are assigned different colors from the cells connected adjacently. The main code cell and the sub code cell are:
The optical symbol according to any one of claims 1 to 4, wherein a color selected from a plurality of colors is assigned. The first cell column is:
The main code cells of two kinds of colors are alternately arranged, and the colors of the main code cells at one end and the other end of the first cell row are different from each other. 6. The optical symbol according to any one of items 5. The second cell column is:
The optical symbol according to any one of claims 1 to 6, wherein the optical code has a predetermined size, and the sub code cell has a size corresponding to a total number of sub code cells included in a cell column to which the sub code cell belongs. The second cell column is:
The optical symbol according to claim 1, wherein the optical symbol has a predetermined size and includes a predetermined number of the sub code cells. The sub-code part is
The optical symbol according to any one of claims 1 to 8, wherein a value is expressed using a color transition between the sub-code cells connected adjacently. The main code portion is
The optical symbol according to claim 9, wherein a position of the value expressed in the sub code portion including the sub code cell connected to the main code cell is expressed. The optical symbol according to claim 1, wherein a direction in which the main code cells are connected is different from a direction in which the sub code cells are connected.   A display medium on which the optical symbol according to any one of claims 1 to 11 is displayed.   An article having the display medium according to claim 12 attached to an outer surface.   12. A generating device for generating an optical symbol according to claim 1.

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