JP4755415B2 - Color two-dimensional code - Google Patents

Description

  The present invention relates to a color two-dimensional code, and in particular, a two-dimensional code that can be read satisfactorily even in a situation where the distance from the reading device is large or the two-dimensional code and the reading device are relatively moving. Concerning structure.

  In recent years, two-dimensional codes that can include a lot of information in an area smaller than a bar code have been used. As a two-dimensional code, for example, QR (Quick Response) code, which is standardized and popularized by JIS in Japan, can store a large amount of information compared to conventional barcodes, and is the same for scanning lines that cross at all angles. By providing a characteristic position detection marker that can obtain a frequency component ratio, high-speed reading is possible, and by providing an error correction function, it is considered to be resistant to dirt and damage (see Patent Document 1 below).

  On the other hand, in order to further increase the amount of information included in one symbol, a color two-dimensional code in which symbols are colored has been proposed (see Patent Documents 2 and 3 below).

Japanese Patent No. 2938338 JP 2001-195536 A JP 2002-163603 A

  By the way, the conventional monochrome two-dimensional code and color two-dimensional code are consciously held by holding the code reading device (code reader / scanner) by hand and holding the two-dimensional code over the reading device. This is based on the premise that an operation for reading a code is performed. Thus, for reliable reading, it is generally necessary to consciously “read” the code under extremely well-organized conditions.

  On the other hand, a utilization mode of a two-dimensional code different from such a conventional utilization method is conceivable.

  For example, in a facility such as a building or factory that requires periodic inspection work, a two-dimensional code can be used to monitor whether the inspection work is being performed reliably. Specifically, for example, a CCD camera is provided as a two-dimensional code reader on a worker's helmet, while a two-dimensional code is attached to an inspection location of each facility to be operated. Workers go around the facility and inspect each piece of equipment, but when the inspection work is performed, the CCD camera automatically captures the two-dimensional code attached to each piece of equipment and acquires the coded information. By doing so, it is detected that the worker has inspected (seen) the equipment. At this time, the worker himself / herself can check and turn around each facility in the same manner as before without paying special attention to the two-dimensional code.

  In another use mode, a two-dimensional code reader (CCD camera) is mounted on a moving body such as an automobile while a two-dimensional code is attached to a signboard such as a road sign or a road surface. According to this, the information obtained by reading with the CCD camera is notified to the driver by voice or vibration, for example, and each device (brake, power unit, etc.) of the moving body is controlled based on the information, etc. Can be acquired immediately and used for the operation of the moving body.

  As described above, various conventional usage modes are conceivable, in which the two-dimensional code is read semi-automatically and the information is used instead of the conventional usage mode in which the two-dimensional code is consciously read.

  However, it is difficult to cope with such a semi-automatic two-dimensional code reading and utilization mode with the conventional two-dimensional code and color code. This is because all of the conventional codes have a symbol structure that is intended to increase the amount of information that can be included in one symbol, and that assumes an extremely well-organized conscious reading situation as described above.

  In the usage mode described above, unlike when reading at a cash register in a store, the distance between the two-dimensional code and the reading device is far away and the two are relatively moving, even if the resolution of the camera is increased. Even so, it is difficult to read with the conventional symbol structure.

  In addition, when used for monitoring the inspection work, it is necessary to force the operator to read the face (camera) toward the two-dimensional code. Therefore, it is desirable to have a system that automatically (unintentionally) reads a code without being conscious of reading the code.

  Therefore, the object of the present invention is good even in a usage mode in which a coded information is acquired by reading a two-dimensional code semi-automatically, or in a situation in which the distance from the reading device is long or relative to the reading device. The point is to obtain a readable two-dimensional code structure.

In order to achieve the object and solve the problem, the color two-dimensional code according to the present invention is arranged in the two-dimensional code and has a specific pattern, thereby enabling detection of the position and orientation of the two-dimensional code. A two-dimensional code comprising a functional pattern and a coding area in which a plurality of cells for displaying encoded target information are two-dimensionally arranged, each of the cells for displaying the target information includes n One of the 2 ⁿ basic colors determined in advance is assigned as an integer of 2 or more, and the basic color used in the coding area is arranged in the functional pattern. To do.

In the color two-dimensional code of the present invention, a functional pattern having a specific pattern that enables detection of the position and orientation of the two-dimensional code is provided, while an encoding area is provided, and target information is encoded in the encoding area. Deploy. The purpose information is desired information (user data) to be included in the two-dimensional code, and includes, for example, characters (English characters, Chinese characters, etc.), numbers, symbols, and the like. The target information is encoded using 2 ⁿ basic colors determined in advance when n is an integer of 2 or more, and arranged in the encoding area as a cell having a color (color cell).

The color (basic color) used for encoding is not limited to a specific color. By using 2 ⁿ colors when n is an integer of 2 or more, 2 ⁿ pieces of information can be displayed in one cell. For example, if 4 colors (n = 2) are used, 2 bits (4 types) of information can be displayed, and if 8 colors (n = 3) are used, 3 bits (8 types) of information can be displayed. As the number of colors increases, the amount of information included in one cell and thus in one symbol increases. However, in the present invention, in order to prevent error detection, it is preferably about several colors (more preferably four colors). To suppress the above basic colors. Further, in the present invention, it is possible to use a gray scale as the basic color, and this is also within the scope of the present invention. However, from the viewpoint of certainty of detection, the basic color is preferably composed of white and primary colors. . For example, there are a total of four colors of three primary colors of white and RGB (red, green and blue), or a total of four colors of white, cyan, magenta and yellow.

  In the present invention, it is preferable that an error correction function is provided by adding an error correction code when encoding target information. The encoding area can further include attached information (information on the type and format of the two-dimensional code). The error correction method and the function pattern shape are the same as those of the QR code and can be compliant with the QR code, but other methods are also possible.

  The functional pattern is not particularly limited as long as it can detect the position and orientation of the two-dimensional code. For example, one or more (for example, one, two, three, or four) that outputs a constant frequency component ratio at the time of scanning by arranging the central figure and the surrounding figure surrounding the central figure concentrically. Position detection markers can be included. Typically, this position detection marker uses a marker having a square overall shape as in the case of the QR code. For example, polygons such as hexagons and octagons, and similar figures such as circles are similarly arranged in a double manner. It is also possible to use a marker.

  Further, a vertex detection marker that enables detection of the vertex of the two-dimensional code may be provided as a function pattern. Further, an L-shaped or cross-shaped pattern may be arranged in the symbol to correct the rotation angle, or an alignment marker having a specific pattern similar to the position detection marker may be provided at an appropriate interval. It can also be provided so as to be embedded in the coding area, so that correction (distortion correction) can be performed when the symbol is read obliquely.

  On the other hand, in the present invention, unlike the QR code, a basic color is arranged in the function pattern. This basic color is used as a reference color that serves as a reference when determining the color assigned to each cell in the coding area. That is, as described in the description of the color two-dimensional code reader according to the present invention, which will be described later, in decoding the two-dimensional code of the present invention, the functional patterns (position detection markers and vertex detection markers) are arranged. The color is taken in, and the color of each cell is determined by comparing this color with the color of each cell in the coding area.

  As a result, in the present invention, even when the light source has a wavelength configuration different from that of natural light (for example, a fluorescent lamp or a sodium lamp), or even if the color of each cell fades or discolors over time, it is compared with the color of the functional pattern. Thus, it is possible to accurately determine the color of each cell and decode the target information. Further, according to the code structure of the present invention, since it is not necessary to separately provide a region in which a reference color serving as a standard for decoding is arranged in the two-dimensional code, the coding region can be widened accordingly. The recognition rate can be improved by enlarging the cell.

  Further, according to the present invention, since the individual cell size can be increased as compared with a conventional two-dimensional code such as a QR code, even a reading device (camera) having a low resolution or a two-dimensional code can be used. Reading can be performed even if the reading apparatus moves relatively and is not in focus. In addition, as a basic color to be encoded, a color that is easier to recognize can be adopted in accordance with an environment in which the color two-dimensional code is used. For example, when used for the above-described inspection of building equipment, the symbol recognizability can be improved by adopting a color different from the background color, such as a wall in a facility or installed equipment, as a basic color.

  The arrangement of the basic colors in the functional pattern can be changed in various ways depending on the number of basic colors and the number and structure of functional patterns (position detection markers and vertex detection markers), and is not particularly limited. For example, when a color two-dimensional code having the position detection marker and the vertex detection marker and having four basic colors is formed, the first color of the basic colors is used as the position detection marker. Place the second color on the center figure, the surrounding figure of the position detection marker, the third color on the vertex detection marker, and the fourth color between the center figure and the surrounding figure (as the ground color). I can do it. Alternatively, when three position detection markers are provided, the first color is used as the first position detection marker, the second color is used as the second position detection marker, and the third color is used as the third position detection marker. In addition, the fourth color may be arranged between the center graphic of each position detection marker and the surrounding graphic. Various other arrangement methods are possible.

  Further, in the color two-dimensional code of the present invention, an error correction function is given as described above. In this case, the encoding area has a plurality of cell groups as error correction units. Among the cell groups, the peripheral cell group (the cell group in which at least one cell is in contact with the peripheral edge of the two-dimensional code) is linearly formed along the peripheral edge of the two-dimensional code. It is preferable to configure so as to be arranged in an L shape.

  Under a usage mode in which a two-dimensional code is read semi-automatically, unlike the conventional mode in which a two-dimensional code is consciously read, various obstacles are interposed between the two-dimensional code and the reading device. It is also assumed that a part (especially the peripheral part) is hidden behind objects. On the other hand, if the arrangement configuration of the cell group as described above is used, the number of blocks for error correction (blocks in which a part of the cells cannot be read because they are hidden behind the object) can be reduced, and decoding can be performed more accurately. Can be done.

The color two-dimensional code creation device according to the present invention is a device that creates a color two-dimensional code by encoding object information, and the color two-dimensional code is arranged in the two-dimensional code and has a specific pattern. A functional pattern that enables detection of the position and orientation of the two-dimensional code, and a coding area in which a plurality of cells that display the encoded target information are two-dimensionally arranged, and the coding The objective information is encoded by allocating one of 2 ⁿ basic colors predetermined when n is an integer of 2 or more to each of the cells in the region, and A basic color used in an encoding area is arranged, and the apparatus includes an objective information input unit capable of inputting objective information to be encoded, a character and code data constituting the objective information, A character code correspondence table storage unit that stores a character code correspondence table that defines a correspondence relationship; a data compression unit that converts the object information into code data in accordance with the character code correspondence table; and a code value for representing the code data; A color code value correspondence table storage unit that stores a color code value correspondence table that defines a correspondence relationship with the basic color, and code data converted by the data compression unit into the basic color according to the color code value correspondence table Are allocated by the basic color allocation unit, a color code conversion unit that converts the code data into color data, a basic color allocation unit that allocates the basic color used in the coding area to the functional pattern, and the basic color allocation unit. A function pattern having a basic color is arranged at a predetermined position and converted by the color code conversion unit. And an image arrangement unit for arranging the color data as color cells in the encoding area.

  The color two-dimensional code creation device of the present invention is a device for creating the color two-dimensional code of the present invention described above. In this apparatus, when target information desired to be encoded is input to the target information input unit, the data compression unit converts this target information into code data. This code data represents object information composed of characters such as letters (English characters, Chinese characters, etc.), numbers, symbols, etc., by code values (for example, binary codes, decimal codes, etc.). The purpose information is converted into code data according to a character code correspondence table that defines the correspondence between characters and code data, and then converted into color data by a color code conversion unit. The color data is generated by dividing the code data into appropriate units and assigning one of the basic colors to the code value of the unit. Allocation of basic colors is performed with reference to the color code value correspondence table stored in the color code value correspondence table storage unit. This color code value correspondence table defines the correspondence between code values and basic colors.

  For example, when a binary code is used as a code value and four colors of white (W), red (R), green (G), and blue (B) are used as basic colors, a color code value is taken as an example. In the correspondence table, for example, “00” can be defined as W (white), “01” as R (red), “10” as G (green), and “11” as B (blue). When a code data string (binary data string) obtained by converting the target information into code values is obtained, any one of the basic colors (W, R, G, B) is assigned bit by bit according to the color code value correspondence table. I'll do it. In this way, color data (for example, “RBWGBBW...”) Can be obtained.

  On the other hand, each basic color is allocated to the function pattern by the basic color allocation unit. Then, the image arrangement unit arranges the functional pattern having the basic color at a predetermined position, and arranges the color data as a color cell in the encoding area. Thereby, a color two-dimensional code is created.

  In addition, a mask processing unit that performs further mask processing after the color data is arranged may be provided so that the same color pattern as the functional pattern does not occur in the encoding region. In this masking process, for example, several types of conversion patterns for changing the cell color according to a predetermined rule are prepared, and color conversion is performed by superimposing these conversion patterns on a range for displaying the target information of the coding area. The cell color is converted by the conversion pattern that provides the best result (there is no or not the same pattern as the functional pattern). In the case of performing mask processing, in order to cancel the mask at the time of decoding, it is necessary to include information for identifying the used conversion pattern (mask) in the two-dimensional code. What is necessary is just to code and arrange as a color cell in a specific area.

A color two-dimensional code reading device according to the present invention is a device that reads and decodes the color two-dimensional code according to the present invention, and the color two-dimensional code is arranged in the two-dimensional code and has a specific pattern. A functional pattern that enables detection of the position and orientation of the two-dimensional code, and a coding area in which a plurality of cells that display the encoded target information are two-dimensionally arranged, and the coding area The target information is encoded by allocating one of 2 ⁿ basic colors predetermined when n is an integer of 2 or more to each of the cells, and the function pattern is encoded with the code The apparatus includes a basic color used in a conversion area, and the device includes an image capturing unit capable of capturing a color image, and the function pattern from image data acquired by the image capturing unit. A function pattern detecting unit for detecting color, a reference color detecting unit for detecting a color arranged in the function pattern detected by the function pattern detecting unit, and a color detected by the reference color detecting unit as a reference color By comparing the reference color storage unit, the reference color stored in the reference color storage unit, and the color of each cell arranged in the encoding area, from the image data acquired by the image capturing unit A color that stores a color code value correspondence table that defines a correspondence relationship between a cell color detection unit that determines the color of each cell arranged in the encoding area, and a code value that represents the basic color and the target information By referring to the code value correspondence table storage unit and the color code value correspondence table, the color of each cell determined by the cell color detection unit is converted into code data which is target information represented by the code value. Convert A color code reverse conversion unit; a character code correspondence table storage unit that stores a character code correspondence table that defines a correspondence relationship between characters and code data constituting the object information; and the color code reverse conversion according to the character code correspondence table. A data expansion unit that converts the code data converted by the unit into target information, and a target information output unit that outputs the target information converted by the data expansion unit.

  In such a reading apparatus, the image capturing unit acquires image data and scans and searches a function pattern from the image data. Since the function pattern outputs a specific frequency component ratio, it is possible to detect the function pattern. Also, as used in conventional QR codes and other two-dimensional codes, the direction of the two-dimensional code (rotation amount and direction) from the positional relationship between a plurality of functional patterns or the shape of the functional pattern itself. The two-dimensional code is rotationally corrected based on these pieces of information, and the coordinates of the coding area are determined to detect each cell position in the coding area.

  On the other hand, in the present invention, in addition to the detection of the function pattern by the same method as the above-described conventional method, the color information arranged in the function pattern is fetched, and this is stored in the reference color storage unit as a reference color when determining the color of each cell. Store. The cell color detection unit compares the color stored in the reference color storage unit with the color detected from each cell and determines which basic color is arranged in the cell. Then, the colors are determined for all the cells to obtain color data. The color data obtained in this way is converted into code data represented by code values by the color code inverse conversion unit according to the color code value correspondence table, and further the character (character, character, character) by the data development unit according to the character code correspondence table. Numbers, symbols, etc.) and the target information is decoded.

  The two-dimensional code includes attached information (information on the type and format of the two-dimensional code, mask information, etc.) in addition to the purpose information. The auxiliary information is encoded as a color cell in the same manner as the objective information and is arranged in the encoding area, and is decoded prior to the decoding of the objective information. The decoding of the auxiliary information is performed in the same manner as the objective information. Can be done.

The color two-dimensional code creation program according to the present invention is a program that captures the invention related to the creation of the color two-dimensional code from the viewpoint of the program, and creates a color two-dimensional code by encoding objective information. The color two-dimensional code is arranged in the two-dimensional code and has a specific pattern, and a plurality of function patterns that enable detection of the position and orientation of the two-dimensional code and encoded target information are displayed. Of the 2 ⁿ basic colors determined in advance when n is an integer of 2 or more. The target information is encoded by allocating one color, and the basic color used in the encoding area is arranged in the function pattern. Data for converting the target information into code data in accordance with a character code correspondence table that defines the correspondence between the characters constituting the purpose information and code data. Compression means, color code conversion means for converting the code data into color data by allocating the basic colors according to a color code value correspondence table that defines a correspondence between code values for representing the code data and basic colors; The basic color assigning means for assigning the basic color used in the coding area to the functional pattern, and the functional pattern having the basic color assigned by the basic color assigning means are arranged at predetermined positions, and the color An image in which the color data converted by the code conversion means is arranged as a color cell in the encoding area. It functions as a message placement means.

A color two-dimensional code reading program according to the present invention is a program that captures the invention relating to reading (decoding) of the color two-dimensional code from the viewpoint of the program, and reads and decodes the color two-dimensional code. The color two-dimensional code has a specific pattern arranged in the two-dimensional code, thereby enabling detection of the position and orientation of the two-dimensional code, and a plurality of pieces of encoded target information for displaying the target information. 1 of 2 ⁿ basic colors predetermined when n is an integer of 2 or more, and each of the cells in the coding area is provided with a coding area in which cells are two-dimensionally arranged. The target information is encoded by assigning a color, and the basic color used in the encoding area is arranged in the function pattern. Image data capturing means capable of capturing a color image, function pattern detecting means for detecting the function pattern from image data acquired by the image capturing means, and function pattern detected by the function pattern detecting means Reference color detection means for detecting colors arranged in the reference color, reference color storage means for storing the color detected by the reference color detection means as a reference color, reference colors stored in the reference color storage means, and the encoding Cell color detection means for determining the color of each cell arranged in the coding area from the image data acquired by the image capturing means by comparing the color of each cell arranged in the area, the object By referring to a color code value correspondence table that defines the correspondence between code values for representing information and basic colors, the color of each cell discriminated by the cell color detection means is determined. Color code reverse conversion means for converting into code data which is the target information represented by the code value, and the color code reverse conversion in accordance with a character code correspondence table which defines the correspondence between the characters constituting the target information and the code data. It functions as data expansion means for converting the code data converted by the conversion section into target information, and purpose information output means for outputting the target information converted by the data expansion means.

Furthermore, a color two-dimensional code creation method according to the present invention is a method for capturing the above-described invention relating to the creation of a color two-dimensional code from the viewpoint of the method, and is a method for creating a color two-dimensional code by encoding objective information. The color two-dimensional code is arranged in the two-dimensional code and has a specific pattern, and a plurality of function patterns that enable detection of the position and orientation of the two-dimensional code and encoded target information are displayed. Of the 2 ⁿ basic colors determined in advance when n is an integer of 2 or more. The target information is encoded by assigning one color, and the function pattern is provided with a basic color used in the encoding area, and the method inputs the target information to be encoded. Converting the object information into code data in accordance with a character code correspondence table that defines a correspondence relationship between characters and code data constituting the object information, a code value representing the code data, and the basic color A step of converting the code data into color data by assigning the basic color to the code data according to a color code value correspondence table that defines a correspondence relationship with the basic color used in the coding area for the functional pattern And a step of arranging the function pattern to which the basic color is assigned at a predetermined position and arranging the target information converted into the color data as a color cell in the coding area.

Further, a color two-dimensional code reading method according to the present invention is a method for reading the color two-dimensional code and decoding the color two-dimensional code. A two-dimensional code has a specific pattern arranged in a two-dimensional code, which enables detection of the position and orientation of the two-dimensional code, and a plurality of cells that display encoded target information. One of the 2 ⁿ basic colors determined in advance when n is an integer equal to or larger than 2, and each of the cells in the coding area is allocated with a dimensionally arranged coding area The target information is encoded, and the function pattern is provided with a basic color used in the encoding region, and the method includes an image capturing step of capturing a color image; A function pattern detecting step for detecting the function pattern from the image data acquired by the image capturing step; and a reference color acquisition for detecting a color arranged in the detected function pattern and storing the color as a reference color A color cell reading step for determining the color of each cell arranged in the coding area by comparing the reference color and the color of each cell arranged in the coding area; and Converting the color data obtained by the reading step into the target information.

  The two-dimensional code can be used for, for example, a traffic sign, and the traffic sign according to the present invention is a traffic sign including the color two-dimensional code of the present invention, Information to be displayed by the traffic sign is encoded and arranged in the encoding area.

  In addition, a color two-dimensional code reading device mounted on a vehicle can be configured as the reading device of the present invention. This reading apparatus includes an imaging device (for example, a CCD camera) as an image capturing unit capable of capturing the color image, and can read the color two-dimensional code displayed on the traffic sign according to the present invention. is there.

  Furthermore, it is possible to configure a vehicle operating system by the traffic sign and the color two-dimensional code reading device mounted on the vehicle. The vehicle operating system according to the present invention installs the traffic sign on the vehicle operating route, and A vehicle on which the color two-dimensional code reader is mounted on the operation route can run.

  According to such a traffic sign, a color two-dimensional code reading device mounted on a vehicle, or a vehicle operation system according to the present invention, the sign information obtained by reading with the imaging device is notified to the driver by voice or vibration, for example. The sign information can be immediately acquired and used for the operation of the vehicle, such as controlling each device (brake, power device, etc.) based on the information.

  In addition, although the said vehicle is a motor vehicle typically, a two-wheeled vehicle, a railroad, a monorail, and other vehicles are also included, and it is possible to apply this invention to these operations.

  According to the color two-dimensional code according to the present invention, under a usage mode in which the coded information is acquired by reading the two-dimensional code semi-automatically, or under a situation where the distance from the reading device is separated or relative to the reading device. The two-dimensional code can be read satisfactorily.

  Other objects, features and advantages of the present invention will become apparent from the following description of embodiments of the present invention.

[Symbol structure]
FIG. 1 shows a color two-dimensional code according to an embodiment of the present invention. As shown in the figure, this two-dimensional code (hereinafter sometimes referred to as “symbol”) detects a coding area 5 in which square cells are arranged in a matrix and the position and rotation angle of the two-dimensional code. Function patterns 1 to 3 that use four basic colors of white (W), red (R), green (G), and blue (B) to encode target information It is. The symbol size is not limited to this example, but has a size of 14 cells in the vertical direction and 14 cells in the horizontal direction (14 × 14 = 196 cells). Of these, the functional patterns 1 to 3 include 66 cells (49 cells for the position detection marker 1 including the boundary 4 with the coding area 5, 4 cells for the vertex detection marker 2, and 13 cells for the cross pattern 3). The area of 130 cells (of which 104 cells are the target information cell including the error correction code and 26 cells are the format information cell) is used for the coding area 5.

  In this embodiment, the function patterns 1 to 3 include one position detection marker 1 arranged at one vertex of the symbol, a vertex detection marker 2 arranged at the other vertex of the position detection marker 1 and the diagonal position, and the vertex A cross-shaped pattern 3 provided between the detection marker 2 and the coding region 5 is provided. Like the QR code, the position detection marker 1 has a square central figure 1a and a double square surrounding figure 1b surrounding the central figure 1a, and has a constant frequency component with scanning lines of every angle across the center. A ratio (in this example, a luminance change pattern of 1: 1: 2: 1: 1) is obtained, whereby the position of the symbol can be detected. Further, based on the positional relationship between the position detection marker 1 and the vertex detection marker 2 and the cross-shaped pattern 3, the direction of the symbol (rotation amount / rotation angle) is calculated, rotation correction is performed, and the coordinates of each cell in the encoding area 5 are calculated. Can be determined. Note that the processing such as the search for the function pattern and the rotation correction can be performed by a method according to the QR code, and thus detailed description thereof is omitted.

  Further, in order to separate the position detection marker 1 from the coding region 5, a gap 4 for one cell is provided between the two. Further, in order to separate the symbols from the surroundings, a gap S having an appropriate width (for example, 3 cells) is provided around the symbols. The symbol size, function pattern structure, type, number of arrangements, etc. can take various forms other than this example depending on the type and amount of target information to be encoded. It is not limited.

  On the other hand, in the present embodiment, unlike the QR code, the basic color used for encoding is arranged in the function pattern (position detection marker 1 and vertex detection marker 2). Specifically, for example, blue (B) is arranged on the central graphic 1a of the position detection marker 1, red (R) is arranged on the surrounding graphic 1b, and green (G) is arranged on the vertex detection marker 2. Further, white (W) is arranged between the center graphic 1a and the surrounding graphic 1b of the position detection marker 1 and the cross pattern 3. The colors arranged in these function patterns 1 to 3 serve as reference colors that serve as a reference when determining the color of each color cell in the encoding area 5. In the drawings, each color is shown by hatching because it cannot be displayed with an actual color.

  Further, the two-dimensional code of this embodiment has an error correction function as will be described later. FIG. 2 shows an arrangement example of a group of cells (cell group) as a unit of error correction. In the illustrated example, the cell groups indicated by numbers 1 to 26 are provided. In the present embodiment, in particular, cell groups (peripheral cell groups) 1, 2, 8, 13, 14, and 24 to be in contact with the periphery of the symbol. 26, the cells constituting the cell group are arranged along the periphery of the symbol (L-shaped at the corner of the symbol and linear at the middle of the symbol).

  As described above, this is different from the conventional mode in which the two-dimensional code is consciously read under the usage mode in which the two-dimensional code is read semi-automatically. This is because a situation in which an obstacle is interposed and a part of the two-dimensional code (particularly the peripheral portion) is hidden behind the object is also assumed. Even in such a situation, if the arrangement configuration of the cell group as described above is used, it is possible to reduce the number of blocks that perform error correction (a cell group that cannot be partially read by being hidden behind the object). Decoding can be performed accurately.

  Further, as shown in the figure, the edge portion facing the position detection marker 1 and the portion along the cross pattern 3 have format information (the type information of the symbol and used for the symbol in mask processing described later). A cell group 6 composed of cells (format information cells) encoded with mask pattern information) is arranged. Since the format information cannot be decoded unless the mask information included therein is obtained, the format information is arranged twice (two sets) in the format information cell arrangement region 6 in the encoding region. In addition, when the data length is short and there is a cell arrangement space in the display area of the format information or the area where the target information is to be displayed, dummy cells are arranged in the surplus part.

[Symbol creation device]
FIG. 3 shows an example of an apparatus for creating the color two-dimensional code. As shown in the figure, the apparatus 11 includes a purpose information input unit 12 that receives target information to be encoded, a data compression unit 13 that converts the input purpose information into code data, and an error correction code added to the code data. An error correction code adding unit 14, a color code converting unit 15 for converting target information converted into code data and added with an error correction code into color data, and a basic color assigning unit 16 for assigning basic colors to function patterns. An image placement unit 17 that places a functional pattern on a symbol and places a color cell in an encoding area according to color data, a mask processing unit 18 that performs mask processing, and mask pattern information and symbol type information applied to the symbol And a format information generating unit 19 for generating. Note that the configuration of each part of these devices (the same applies to the reading device described later) can be realized by software that can be executed on a computer and its peripheral devices.

  The creation device 11 further includes a character code correspondence table storage unit 20, a color code value correspondence table storage unit 21, and a mask pattern storage unit 22. The character code correspondence table storage unit 20 includes characters and code values. A character code correspondence table that defines the correspondence between the color code value correspondence table storage unit 21, a color code value correspondence table that defines the correspondence between code values and basic colors, and the mask pattern storage unit 22 A plurality of types of mask patterns are stored.

  In such a creation device, the purpose information input to the purpose information input unit 12 through the input device 25 such as a keyboard is converted into code data by the data compression unit 13. In the conversion, the data compression unit 13 refers to the character code correspondence table in the character code correspondence table storage unit 20 to convert each character into code data. The code value constituting the code data is not limited to this, but is typically a binary code. The code data can include information on the type of data and information on the number of data at the top. If the data length does not match the predetermined value, padding (so-called padding data addition) may be performed. Further, for example, an error correction code by Reed-Solomon code is added to the code data by the error correction code adding unit 14, and the code data is output from the data compression unit 13 to the color code conversion unit 15.

  The color code conversion unit 15 refers to the color code value correspondence table stored in the color code value correspondence table storage unit 21 and converts the code data into color data based on the color code value correspondence table. This conversion to color data is performed by assigning, for example, basic colors (W, R, G, B) corresponding to 2 bits in order from the top of the code data represented by the code value (binary code). . For example, if “00” is defined as W (white), “01” as R (red), “10” as G (green), and “11” as B (blue) according to the color code value correspondence table, The code data “010010110010...” Is converted into color data “RWGBWG.

  Then, the color data is output to the image arrangement unit 17 and arranged in the symbol coding area 5 (see FIG. 1) as a color cell having the color in a predetermined order. The arrangement order of the color cells is not particularly limited as long as it follows a certain rule. Note that when decoding, which will be described later, the color cell may be read according to the rule.

  The image placement unit 17 places the position detection marker 1 and the vertex detection marker 2 at predetermined positions in the symbol, and forms the cross-shaped pattern 3 in the symbol. At this time, the basic color assignment unit 16 places B (blue) in the center graphic 1a of the position detection marker 1, R (red) in the surrounding graphic 1b, and G (green) in the vertex detection marker 2. W (white) is set between the central figure 1a and the surrounding figure 1b, and between the cross pattern 3 and between the position detection marker 1 and the coding area 5.

  Further, the mask processing unit 18 performs mask processing on the symbols arranged with the function patterns 1 to 3 having the color cell and the basic color in this way. In this mask processing, a plurality of mask patterns for changing the color of the cells according to a predetermined rule are stored in the mask pattern storage unit 22 and these mask patterns are stored in the encoding area 5 (format information cell arrangement area). Cell color conversion is performed by superimposing on the color cells arranged in (Exclude)), and the mask pattern with the best result (there is no or not the same pattern as the functional pattern) is selected and encoded The cell color of area 5 is converted. Thereby, it is suppressed that the same color pattern as a functional pattern arises in the encoding area | region 5. FIG.

  The information (mask pattern number) for specifying the mask pattern used at this time is output to the format information generation unit 19, and the format information generation unit 19 displays the format information including the mask pattern information and the symbol type information. Generate. This format information is converted into color data via the data compression unit 13 and the color code conversion unit 15 and sent to the image arrangement unit 17. The image arrangement unit 17 arranges the format information converted into color data in the format information cell arrangement area 6 (see FIG. 2) in the encoding area 5 as a color cell.

  The format information cell 19 does not perform mask processing, but the format information generation unit 19 pre-formats the format information so that the format information cell does not cause a format information detection error due to consecutive cells of the same color. A process of taking an exclusive OR with predetermined data (for example, “14112543”) is performed. The error correction code adding unit 14 also adds an error correction code to the format information generated by the format information generating unit 19. Further, as described above, since the symbol cannot be decoded unless the mask information is obtained, the image placement unit 17 places the format information in the format information cell placement region 6 in a double manner.

  The created symbol image data is output from the image placement unit 17 to a printing device 26 such as a color printer, and a color two-dimensional code is printed.

[Symbol creation process]
FIG. 4 shows a color two-dimensional code creation process by the creation device 11. As shown in the figure, when purpose information is input to the purpose information input unit 12, the data compression unit 13 converts this purpose information into code data (step S101). An error correction code is added to the converted code data by the error correction code adding unit 14 (step S102), and the code data is assigned a basic color for each unit bit (2 bits) by the color code converting unit 15 and is color-coded. Data is converted (step S103).

  Next, the reference colors are assigned to the function patterns 1 to 3 by the basic color assignment unit 16 (step S104), and the image placement unit 17 places the function patterns 1 to 3 having the basic colors at predetermined positions in the symbol. (Step S105). Further, the image arrangement unit 17 arranges the target information in the predetermined order as color cells in the encoding area 5 based on the color data (step S106).

  In the device 11, the objective information input unit 12 holds a plurality of predetermined symbol patterns (color two-dimensional codes), and in accordance with the input objective information and the specified error correction level. It is also possible to select one symbol from a plurality of types of symbol patterns, and the image placement unit 17 may be configured to place the target information as a color cell in the selected symbol.

  Then, the mask processing unit 18 performs mask processing on the target information arranged as a color cell in the encoding area 5 (step S107), and the format information generation unit 19 includes format information including information for specifying the used mask. Is generated. This format information is converted into code data by the data compression unit 13, converted into color data by the color code conversion unit 15, and then converted into color data by the image arrangement unit 17 in the format information cell arrangement region 6 of the encoding region 5. Arranged (step S107).

[Symbol reader]
FIG. 5 shows an example of a reading device for decoding the color two-dimensional code. As shown in the figure, the reading device 31 is arranged in the function pattern, an image capturing unit 32 that captures image data, a function pattern detection unit 33 that detects the function patterns 1 to 3 from the captured image data, and the function pattern. A reference color detection unit 34 for detecting the color, a reference color storage unit 35 for storing the color information as a reference color, and a cell color detection unit 36 for detecting a color arranged in each cell arranged in the encoding area. A color code reverse conversion unit 38 that converts color data composed of the detected color of each cell into code data, a data development unit 39 that converts code data into character data, and an error correction unit 37 that performs error correction. A color code value correspondence table storage unit 41 that stores a color code value correspondence table that defines a correspondence between code values and basic colors, and a correspondence between characters and code values. And a character code correspondence table storage unit 42 which stores the character code correspondence table that defines the.

  In the reading device 31, when image data is input from the imaging device 45 such as a CCD camera, the image capturing unit 32 outputs the image data to the function pattern detection unit 33 and the cell color detection unit 36. The function pattern detection unit 33 detects the function pattern to calculate the position and orientation (rotation direction / rotation angle) of the color two-dimensional code, and performs rotation correction when the symbol is rotating. The reference color detection unit 34 detects each color arranged in the function pattern and stores it in the reference color storage unit 35 as a reference color.

  The cell color detection unit 36 determines the color of each cell arranged in the encoding area 5 by comparing with the reference color stored in the reference color storage unit 35. The determined color information of each cell is output as color data to the color code inverse conversion unit 38 and converted into code data based on the color code value correspondence table stored in the color code value correspondence table storage unit 41. The error correction unit 37 detects an error in the code data and corrects the error if there is an error. The code data is further output to the data expansion unit 39, converted into character data based on the character code correspondence table stored in the character code correspondence table storage unit 42, and output from the purpose information output unit 40.

[Symbol reading process]
FIG. 6 shows a color two-dimensional code reading process by the reading device 31. As shown in the figure, when the image data is captured by the image capturing unit 32 (step S201), the function pattern detection unit 33 detects the function pattern by scanning the image (step S202). If the function pattern cannot be detected, the image data is captured again (steps S203 to S201). If the function pattern can be detected, the reference color detection unit 34 stores the reference color as the reference color as the reference color. While being stored in the unit 35 (steps S203 to S204), the function pattern detection unit 33 performs symbol size detection, rotation correction, and the like using the function pattern (step S205).

  Next, the color cell arranged in the encoding area 5 is read. First, the format information is decoded (step S206). Specifically, the cell color detection unit 36 determines the color of each cell in the format information cell region 6 to acquire color data, and the color code inverse conversion unit 38 converts this color data into code data. If the converted code data includes an error, the error correction unit 37 corrects this, and the code data is further converted into character data by the data expansion unit 39. As a result, the mask pattern information applied to the target information cell area and the information regarding the error correction level of the target information cell can be obtained. The obtained mask pattern information is sent to the cell color detection unit 36, and the cell color detection unit 36 releases the mask applied to the coding area based on this information (steps S207 to S208). If the format information cannot be decoded, the image is captured again (steps S207 to S201).

  Subsequently, the cell color detection unit 36 determines the color of the target information cell by comparing with the reference color stored in the reference color storage unit 35, and obtains color data (step S209). The color data is converted into code data by the color code reverse conversion unit 38 (step S210), and error correction is performed according to the error correction level information included in the format information, and if there is an error (step S210). S211). If there is no error or the error correction is successful, the data development unit converts it into character data and outputs the target information from the target information output unit (steps S212 to S214). On the other hand, when error correction fails, the image is captured again (steps S212 to S201).

  Note that, in the above-described steps 203, 207, and 212, an appropriate display as a reading error is performed in a usage mode in which an image cannot be captured again.

  The embodiment of the present invention has been described above, but the present invention is not limited to this, and it is obvious to those skilled in the art that various modifications can be made within the scope of the claims. .

  For example, in the embodiment, four colors are used as basic colors for encoding, but the basic colors may be eight colors or 16 colors or more. The symbol of the embodiment outputs (reflects) visible light and detects it, but may output light other than visible light (for example, infrared light or ultraviolet light). Further, instead of using reflected light, it is also possible to configure a two-dimensional code such that the symbol (each cell or function pattern) itself emits light by the light emitting means. The function pattern structure, rotation correction, error correction, and the like can be based on the QR code, but can also be based on various two-dimensional codes other than the QR code.

It is a figure which expands and shows an example of the color two-dimensional code which concerns on this invention. It is a figure which illustrates the example of arrangement | positioning of the format information cell in the color two-dimensional code of FIG. 1, and the arrangement | positioning order of the objective information cell. It is a block diagram which shows one structural example of the color two-dimensional code production apparatus which concerns on this invention. It is a flowchart which shows the preparation process of the color two-dimensional code by the preparation apparatus shown in the said FIG. It is a block diagram which shows one structural example of the color two-dimensional code reader which concerns on this invention. It is a flowchart which shows the reading process of the color two-dimensional code by the reading apparatus shown in the said FIG.

Explanation of symbols

1 Position detection marker (function pattern)
2 Vertex detection marker (function pattern)
3 Cross pattern (functional pattern)
DESCRIPTION OF SYMBOLS 5 Coding area | region 6 Format information cell arrangement | positioning area | region 11 Color two-dimensional code production apparatus 31 Color two-dimensional code reader

Claims (7)

A two-dimensional array of functional patterns that enable detection of the position and orientation of the two-dimensional code by having a specific pattern arranged in the two-dimensional code, and a plurality of cells that display the encoded target information An encoding region ,
assigning one of the 2 ⁿ basic colors predetermined when n is an integer greater than or equal to 2 to each of the cells for encoding and displaying the target information;
A two-dimensional code in which the basic color used in the coding area is arranged in the functional pattern,
The functional pattern includes one or more position detection markers that output a constant frequency component ratio during reading scanning by concentrically arranging a central graphic and an enclosing graphic surrounding the central graphic,
A color two-dimensional code characterized in that a first color of the basic colors is arranged on the central graphic and a second color is arranged on the surrounding graphic . The functional pattern further includes a vertex detection marker that enables detection of the vertex of the two-dimensional code,
One vertex of the basic colors is arranged on the vertex detection marker,
The position detection marker, color two-dimensional code of claim 1, characterized in that arranged the primary colors other than the color that arranged in the vertex detection marker. The color two-dimensional code according to claim 1 or 2 , wherein the basic colors are four colors including white. The color two-dimensional code according to claim 3 , wherein the basic colors are four colors of white, red, green, and blue. The color two-dimensional code according to claim 3 , wherein the basic colors are four colors of white, cyan, magenta, and yellow. The color two-dimensional code has an error correction function,
The coding area has a plurality of cell groups that are units of the error correction,
Among these cell groups, when a cell group in which at least one cell is in contact with the periphery of the two-dimensional code is a peripheral cell group,
Peripheral edge cell group, any one of claims 1 to 5, characterized in that each cell constituting the peripheral cell group are arranged in a straight line or L-shape along the periphery of the two-dimensional code The color two-dimensional code described in the item. A traffic sign comprising the color two-dimensional code according to any one of claims 1 to 6 ,
A traffic sign characterized in that information to be displayed by the traffic sign is encoded and arranged in a coding area of the color two-dimensional code.

Images