JP2016201061A - Two-dimensional code, and reading method for two-dimensional code - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-dimensional code by which a cell-basis lightness/darkness pattern is easily identified and many dedicated data can be recorded with any other color scheme pattern than the cell-basis lightness/darkness pattern.SOLUTION: At least partial cells are formed from extension cells 2a each formed from a central part 20 that is colored in white or black and a peripheral part 21 that is indicated in one or more colors selected from among three or more kinds of reference colors with different RGB values. At least two kinds of information are recorded for compatible data that are recorded with a color scheme pattern in the central part 20 of the extension cell 2a and dedicated data that are recorded with color scheme patterns in the peripheral part 21 of the extension cell 2a. Regarding such an extension cell 2a, when a light color and a dark color are identified for the unit of a cell, the extension cell 2a with the central part 20a colored in white is easily identified as a light color, and the extension cell 2a with the central part 20a colored in black is easily identified as a dark color.SELECTED DRAWING: Figure 2

Description

  A general two-dimensional code such as a QR code (registered trademark) is formed by arranging bright or dark cells in a matrix, and data is recorded by a light / dark pattern of the cells. Such a two-dimensional code is standardized, and data recorded in the two-dimensional code can be decoded by using a smartphone or the like in which a reading program is installed as a reading device.

  In order to expand the storage capacity of a general two-dimensional code, the inventor divides a two-dimensional code cell into finer subcells, and each subcell has a reflectance or luminance equal to or higher than a predetermined light color threshold. By arranging a plurality of light color reference colors and a color selected from a plurality of dark color reference colors whose reflectance or luminance is equal to or less than a predetermined dark color threshold, compatible data is recorded in a light / dark pattern in units of cells. A two-dimensional code capable of storing additional dedicated data according to a color arrangement pattern of a reference color in units of subcells has been proposed (see Patent Document 1).

  Since the compatible data of the two-dimensional code of Patent Document 1 is recorded by a light / dark pattern in units of cells in the same manner as a general two-dimensional code, the two-dimensional code is read using a general two-dimensional code reader. If read, compatible data can be decoded. On the other hand, since the dedicated data is not recorded in the light / dark pattern in units of cells, it cannot be decoded by a general two-dimensional code reader, but can be decoded by using a dedicated reader.

JP, 2014-154118, A

  Incidentally, the two-dimensional code described in Patent Document 1 has an advantage that a large amount of dedicated data can be recorded. However, since four or more kinds of reference colors are used, the identification rate of the light / dark pattern in units of cells is not high. There is. Since the two-dimensional code generally has an error correction function, compatible data can be read even if the identification of the light / dark pattern of the cell is wrong as long as error correction is possible. However, if the reading device has low light and dark color identification accuracy, if the cell color changes due to changes over time of printing, or if illumination is uneven when reading a two-dimensional code, the light / dark pattern is identified. There may be many errors and reading of compatible data may fail.

  The present invention has been made in view of the present situation, and it is easy to identify cell-by-cell light / dark patterns, and a two-dimensional code capable of recording a large amount of dedicated data by using a color arrangement pattern other than the light / dark pattern in cell units. The purpose is to provide.

  The present invention is a two-dimensional code in which cells identified as light colors and cells identified as dark colors are arranged in a matrix, and at least some of the cells are arranged in white or black. Compatible data recorded by a color arrangement pattern in the center of the extended cell, and an extended cell composed of one or more peripheral colors selected from three or more reference colors having different RGB values And a two-dimensional code characterized in that it includes at least two types of information of dedicated data recorded by a color arrangement pattern in the peripheral part of the extended cell.

  A general two-dimensional code reader extracts a cell area from a captured two-dimensional code image and then focuses on the color near the center of the cell to determine whether the cell is light or dark. Identify. On the other hand, the extended cell according to the present invention has a central portion that is colored with the highest white color with the highest reflectance and brightness, and the lowest black color, so in a general two-dimensional code reader, When light and dark colors are identified on a cell-by-cell basis, an extended cell whose center is white can be easily identified as a light color and an extended cell whose center is black can be easily identified as a dark color. Therefore, the two-dimensional code of the present invention has uneven illumination for illuminating the two-dimensional code when a reading device with low light color and dark color identification accuracy is used, or when the color of the cell fluctuates due to changes in printing over time. Even in such a case, there is an advantage that the identification error of the light / dark pattern does not increase so much and the compatible data can be read reliably.

  On the other hand, in the present invention, dedicated data is recorded by the color arrangement pattern in the peripheral part of the extended cell. Here, as described above, the identification accuracy of the light-dark pattern in the cell unit of the extended cell is ensured by the color arrangement pattern of the central portion of the extended cell, so even when the peripheral portion is colored with many reference colors, Even when the peripheral portion is divided into many subcells, the reading accuracy of compatible data is not impaired. Therefore, according to the present invention, a large amount of dedicated data can be recorded in the expansion cell without impairing the reading accuracy of the compatible data.

  In the present invention, the cell has a square shape, and the expanded cell has a central square portion among the nine squares obtained by dividing the expanded cell into three vertically and horizontally, and the remaining eight squares. A configuration in which the part is a peripheral part is proposed. Generally, the higher the area ratio of the central part in the expansion cell, the lower the color identification accuracy of the peripheral part, and the lower the area ratio of the central part, the lower the color identification accuracy of the central part. According to the inventor's research, in the case of such a configuration, it is possible to secure both the identification accuracy of the light / dark pattern in the central portion and the identification accuracy of the reference color in the peripheral portion with the best balance.

  In the present invention, the reference color includes a plurality of bright color reference colors whose reflectance or luminance is equal to or higher than a predetermined light color threshold value, and a plurality of dark color standards whose reflectance or luminance is equal to or lower than a predetermined dark color threshold value. The extended cell, which is composed of colors and is colored in white in the center, is arranged in one or more colors selected from the plurality of light color reference colors, and is extended in black in the center Is proposed that is arranged in one or more colors selected from the plurality of dark reference colors.

  In such a configuration, even if the color of the peripheral part affects the color of the central part in the image data of the captured two-dimensional code due to the influence of camera shake, out-of-focus, or the averaging filter of the imaging program, The extension cell with white center is surely identified as bright because the periphery is colored with a bright reference color with high reflectivity and brightness, and the extension cell with black center has low reflectivity and brightness. Since the peripheral portion is colored with the dark reference color, it is reliably identified as a dark color. Therefore, according to such a configuration, it is possible to further improve the identification accuracy of the light-dark pattern in the cell unit of the extended cell. In addition, when acquiring color information of the peripheral part, the color information may change due to the influence of the color of the adjacent central part. Since the luminance is approximated, the color information acquired from the peripheral portion is not easily influenced by the color of the central portion, and the color arrangement pattern of the peripheral portion can be identified with higher accuracy.

  Further, in the present invention, it is determined in advance whether each cell is identified as a light color or a dark color, and includes a fixed area that constitutes a pattern that assists optical reading. A sample cell in which a predetermined part is arranged with any one of the reference colors is provided for each reference color, and the sample cell for each reference color is provided at a predetermined position in the fixed area, and the light color reference color The sample cell is a cell that is identified as a light color in the fixed region, and the sample cell for the dark color reference color is a cell that is identified as a dark color in the fixed region.

  Such a configuration has an advantage that the color arrangement pattern of the peripheral portion of each extended cell can be accurately identified by comparing the color information of the sample cell of each reference color with the color information of the peripheral portion of the extended cell. In other words, the color information read from the periphery of the extended cell changes due to changes in printing over time, the effects of printers, display devices, ambient lighting, etc., so the reference color is identified based only on the color information acquired from the extended cell. Then, the reference color identification errors increase, and there is a possibility that the reading of the dedicated data may be hindered. On the other hand, in such a configuration, the reference color of the sample cell changes in the same way as the reference color of the expansion cell due to the influence of the change with time of printing, the printer, the display device, the ambient lighting, etc. By comparing the color information acquired from the periphery of the cell with the color information of the reference color acquired from the sample cell, it is possible to eliminate the time-dependent change of printing and other influences, and to determine which reference color the corresponding part of each expansion cell has. It is possible to accurately identify whether or not the color is arranged. In this configuration, the sample cell for the light reference color is arranged in the cell identified as the light color in the fixed region, and the sample cell for the dark color reference color is the cell identified as the dark color in the fixed region. Therefore, the reference color of the sample cell does not hinder the discrimination of the light / dark pattern of the cell in the fixed region.

  In the above configuration, it is proposed that the fixed region includes a plurality of sets of sample cells for each reference color. In such a configuration, since a plurality of sample cells are provided for each reference color, there is no problem in identifying the color arrangement pattern of the extended cells even when some sample cells are contaminated.

  Further, in the above configuration, the sample cell is composed of a central portion and a peripheral portion, like the expansion cell, and the predetermined portion of the sample cell is the peripheral portion of the sample cell, and the peripheral portion is a light color reference color. A configuration is proposed in which the sample cells that have been colored are arranged in white at the center, and the sample cells that are arranged in the dark reference color at the periphery are arranged in black at the center.

  As described above, in the present invention, since the color information acquired from the peripheral portion of the extended cell may be affected by the color information in the central portion, the sample cell is also extended with this configuration. Like the cell, it consists of the central part and the peripheral part, and like the expansion cell, if the central part is colored with a color according to the reference color of the peripheral part, the color information acquired from the peripheral part of the sample cell is Correction can be performed in the same manner as the color information acquired from the peripheral portion of the extended cell, and the color information acquired from the sample cell and the extended cell can be compared more appropriately. According to the inventor's research, when such a configuration is adopted, it is possible to reduce the frequency of erroneous identification of the reference color in each extended cell, compared to the case where the entire sample cell is arranged with one reference color. It was.

  In the present invention, a configuration is proposed in which the peripheral portion of the extended cell is arranged in one color selected from the three or more reference colors. In such a configuration, since the peripheral portion is colored in a single color, it is possible to improve the identification accuracy of the color arrangement pattern in the peripheral portion.

  In the present invention, the peripheral portion of the extended cell is subdivided into a plurality of subcells, and each subcell is arranged in one color selected from the three or more reference colors. Proposed. In such a configuration, since the peripheral portion is colored with a plurality of types of reference colors, the storage capacity of dedicated data can be increased.

  The present invention further comprises a fixed area comprising cells constituting a pattern for assisting optical reading and an encoding area comprising cells for recording data. A configuration is proposed in which an identification code indicating the recording format of the extended cell is recorded in a remaining area consisting of cells not to be recorded by a light / dark pattern in units of cells.

  The extended cell according to the present invention is assumed to use a plurality of recording formats such as the type and number of reference colors to be used, division / non-division of the peripheral portion, encryption method, error correction method, and the like. For this reason, if the recording format of the extended cell is recorded by the cell-based color scheme as in this configuration, the data recording format of the extended cell can be acquired before identifying the color scheme of the peripheral portion of the extended cell, It is possible to easily identify the color arrangement pattern in the peripheral portion of the extended cell. It should be noted that a general two-dimensional code reader assumes that no data is recorded in the remaining area regardless of the color pattern of the remaining area. When reading the data, the identification code of the remaining area does not hinder reading of the compatible data.

  In the two-dimensional code reading method of the present invention, when identifying the reference color of the extended cell in which the peripheral portion is arranged with a single reference color, the color information is obtained from a plurality of locations in the peripheral portion of the extended cell, Based on the average value of the acquired color information, it is proposed to identify the reference color of the peripheral part of the extended cell. In such a reading method, by averaging the color information acquired from a plurality of locations, fluctuations due to dirt, illumination, and the like are leveled, and the reference color in the peripheral portion can be identified more accurately.

  Further, when a plurality of sample cells are provided for each reference color, in the two-dimensional code reading method of the present invention, the sample color for individually obtaining the color information of the predetermined portion from the plurality of sets of sample cells The predetermined part of the sample cell from which the color information acquired from the specific part of the peripheral part of the expansion process and the expansion cell is individually compared with the color information acquired in the sample color acquisition process, and the closest approximate color information is acquired. It is proposed that the reference color includes a reference color identification process for determining that the reference color is the reference color of the specific part.

  If the two-dimensional code is not illuminated uniformly, even if the color information is obtained from the same reference color part and compared, there may be a large difference in the color information due to the difference in illuminance. Then, since the color information of each extension cell is compared with a plurality of sets of sample cells, it is possible to reduce the identification error of the reference color by comparing the extension cell with a sample cell having a relatively small illuminance difference.

  Further, when reading a two-dimensional code in which the peripheral part of the sample cell is colored with any one of the reference colors and the central part of the sample cell is colored in white or black, the reading of the two-dimensional code of the present invention is performed. In the method, the color information acquired from the specific part in the peripheral part of the expansion cell is compared with the color information acquired from the part corresponding to the specific part in the peripheral part of the sample cell, and the closest color information is acquired. It is proposed that the reference color of the periphery of the sample cell is identified as the reference color of the specific part.

  In such a reading method, for example, when determining the reference color of the lower right portion of the peripheral portion of the extended cell, the color information acquired from the lower right portion of the color cell is acquired from the lower right portion of the peripheral portion of each sample cell. It is determined that the reference color is the same as that of the peripheral portion of the sample cell with the closest color information. In such a reading method, according to such a method, the color information of the peripheral portion of each sample cell to be compared is affected by the color of the central portion, as is the color information acquired from the peripheral portion of the extended cell. Therefore, when comparing the color information of the peripheral part of the extension cell and the sample cell, the reference color can be accurately determined without being influenced by the influence of the color of the central part.

  In addition, when reading a two-dimensional code in which an extension cell having a white central portion is colored with a bright reference color and an extension cell having a black central portion is colored with a dark reference color, the present invention is used. In the two-dimensional code reading method, a compatible data decoding process for identifying a cell-by-cell brightness pattern of each extended cell and decoding the compatible data, and after the compatible data decoding process, from the peripheral part of each extended cell A dedicated data decoding process for identifying the color arrangement pattern of the peripheral part based on the acquired color information and decoding the dedicated data, and in the dedicated data decoding process, the cell unit of the extended cell identified by the compatible data decoding process Based on the light / dark pattern, it is proposed that the reference color in the peripheral portion is narrowed down to either the light color reference color or the dark color reference color.

  In such a configuration, after identifying the color arrangement pattern in the center of the extended cell, in order to identify the color arrangement pattern in the peripheral portion, the color in the peripheral portion is previously narrowed down to one of the light color reference color and the dark color reference color. As a result, the process of identifying the color arrangement pattern in the peripheral portion can be simplified. Further, since the color arrangement pattern at the center can be corrected by using the error correction function provided as standard in the two-dimensional code, the probability of erroneous identification of the color arrangement pattern at the periphery of the extended cell can be reduced.

  In addition, as a two-dimensional code reading method of the present invention, an imaging process for imaging a two-dimensional code is executed a plurality of times, and based on the image data of the two-dimensional code obtained by the imaging process, the periphery of each expansion cell Peripheral part identification process for identifying the color scheme of each part is performed for each imaging process, and then many identification results of multiple peripheral part identification processes performed for each extended cell are never performed in the peripheral part of each extended cell. It is proposed to execute a majority process for specifying a color scheme and a majority decoding process for decoding dedicated data based on the extended cell color pattern specified in the majority process.

  According to the inventor's research, the identification error of the color arrangement pattern in the peripheral part of the extended cell is less likely to occur repeatedly in the same extended cell. Therefore, as in this reading method, the color pattern in the peripheral part of the extended cell is identified. By repeating the above and identifying the color arrangement pattern in the peripheral portion of each extended cell without a large number of multiple identification results, the dedicated data recorded in the two-dimensional data can be more reliably decoded.

  Note that the above-described reading method needs to perform imaging processing a plurality of times and repeat the peripheral part identification processing as many times as the number of imaging processing performed for each extended cell, which requires a relatively large amount of processing. For this reason, based on a piece of image data obtained by imaging the two-dimensional code, the color arrangement pattern of the peripheral portion of the extended cell is identified, and the dedicated data is obtained based on the color arrangement pattern of the peripheral portion of the identified extended cell. It is proposed to execute an initial decoding process for decoding, and to execute the above two-dimensional code reading method when the dedicated data cannot be decoded in the initial decoding process. With such a reading method, processing required for reading the two-dimensional code according to the present invention can be reduced.

  In addition, as a two-dimensional code reading method according to the present invention, a two-dimensional code is imaged under illumination of red light, and color information of the red component in the peripheral portion of the expansion cell is obtained from the obtained two-dimensional code image data. Red identification processing, imaging a two-dimensional code under the illumination of green light, and obtaining green component color information in the periphery of the expansion cell from the obtained two-dimensional code image data, and blue At least two of the three processes including the blue identification process for capturing the two-dimensional code under light illumination and obtaining the color information of the blue component in the peripheral portion of the extended cell from the obtained two-dimensional code image data It is proposed that the reference color of the peripheral portion of the extended cell is identified by combining the color information acquired in at least two of the red identification process, the green identification process, and the blue identification process. .

  Since the image data of the two-dimensional code obtained by imaging under the illumination of red light is free from noise due to blue light or green light, if the color information of the peripheral part of the expansion cell is obtained from such image data, the peripheral part More accurate color information can be obtained for the red component of the color. Similarly, more accurate color information can be obtained for the blue and green components in the periphery from two-dimensional code image data obtained by imaging under blue or green light illumination. Therefore, if the color information of the peripheral part of the expansion cell is acquired for each component from the image data captured under the illumination of red light, green light, and blue light as in this method, and combined, Compared to the case of using the image of the two-dimensional code imaged in step 1, the reference color in the peripheral portion of the expansion cell can be identified more accurately.

  Such a reading method needs to execute imaging of a two-dimensional code a plurality of times, and requires a relatively large amount of processing. For this reason, a two-dimensional code is imaged under illumination of white light, and the color pattern of the peripheral part of the extended cell is identified from the obtained two-dimensional code image data, and the color pattern of the peripheral part of the identified extended cell is identified. Based on this, it is proposed to execute a white light decoding process for decoding dedicated data, and to execute the reading method when the dedicated data cannot be decoded by the white decoding process. With such a reading method, processing required for reading the two-dimensional code according to the present invention can be reduced.

  Further, as in the above-described two-dimensional code reading method, the reference color of the peripheral portion is selected from either the bright color reference color or the dark color reference color based on the cell-by-cell light / dark pattern of the extended cell identified by the compatible data decoding process. In the two-dimensional code reading method of the present invention, the green component of the RGB value is common to all the bright color reference values used in the peripheral part of the extension cell of the two-dimensional code to be read. In addition, when the green color component of the RGB value is common to all the dark color reference values, in the dedicated data decoding process, the two-dimensional code is imaged under illumination of red light, and the obtained two-dimensional code image From the data, red identification processing that acquires the color information of the red component around the expansion cell, and imaging the two-dimensional code under the illumination of blue light, and from the obtained two-dimensional code image data, the periphery of the expansion cell Part blue component color Run the blue identification process of acquiring the broadcast, by combining the color information acquired by the red identification process and the blue identification process, it is proposed to identify the color scheme of the peripheral portion of the auxiliary cell.

  With such a reading method, it is possible to omit the imaging of the two-dimensional code under the illumination of green light, and to suppress the increase in the processing required for reading the two-dimensional code, while accurately adjusting the color arrangement pattern in the peripheral portion of the expansion cell. Can be identified.

  As described above, the two-dimensional code of the present invention can easily identify the light / dark pattern of the light / dark pattern in the cell unit, and can store a large amount of dedicated data by the color arrangement pattern other than the light / dark pattern in the cell unit. .

(A) is the schematic of the two-dimensional code 1 of Example 1, (b) is explanatory drawing which shows each area | region of the two-dimensional code 1 of Example 1 according to the function according to the pattern. It is an enlarged view of the encoding area | region 4. FIG. (A) is explanatory drawing which shows the structure of the extended cell 2a and the sample cell 2b, (b) is explanatory drawing which shows the color scheme of the extended cell 2a and the sample cell 2b. It is a chart which shows a reference color. It is a chart which shows the coding data corresponding to the color scheme of the expansion cell 2a. 3 is a conceptual diagram illustrating a data structure of a two-dimensional code 1 according to Embodiment 1. FIG. It is an enlarged view of the sample area | region 5a. (A) is the schematic of the two-dimensional code 1 of Example 1, (b) is the QR code 1a compatible with the two-dimensional code 1 of Example 1. FIG. 3 is a flowchart illustrating a method for generating the two-dimensional code 1 according to the first embodiment. It is a flowchart which shows the processing content of an encoding process. 3 is a flowchart illustrating a reading process of the two-dimensional code 1 according to the first embodiment. It is a flowchart which shows the processing content of an exclusive data decoding process. It is explanatory drawing which shows the color information acquisition site | part 30. FIG. It is a flowchart which shows the processing content of majority reading processing. It is a flowchart which shows the processing content of a multiple illumination reading process. (A) is explanatory drawing which shows the structure of the extended cell 2c of Example 2, (b), (c) is explanatory drawing which shows the example of the color scheme of the extended cell 2c. It is a graph which shows the coding data corresponding to the color scheme of the expansion cell 2c. FIG. 6 is a conceptual diagram illustrating a data structure of a two-dimensional code 10 according to the second embodiment. (A) is explanatory drawing which shows the color information acquisition site | part 30a-30h of the expansion cell 2c, (b) is explanatory drawing which shows the color information acquisition site | part 31a-31h of the sample cell 2b.

  Embodiments of the present invention are described according to the following examples.

  The two-dimensional code 1 of this embodiment is compatible with the most popular QR code (registered trademark) among the two-dimensional codes. Specifically, as shown in FIG. 1A, the two-dimensional code 1 of the present embodiment is formed by arranging 21 square cells 2 vertically and horizontally in a matrix. Each cell 2 of the two-dimensional code 1 is not limited to only white and black, but can be distinguished from light or dark color in cell units. The basic structure of the two-dimensional code 1 is that of the QR code. Complies with the standard. That is, as shown in FIG. 1B, the two-dimensional code 1 is composed of a functional pattern (fixed area) 3 and an encoding area 4 in the same manner as the QR code. The functional pattern 3 is an area in which whether each cell 2 is identified by light color or dark color is determined in advance, and a position detection pattern 5 that assists optical reading of the two-dimensional code 1, a separation pattern 6, It consists of a timing pattern 7 and the like. The encoding area 4 is an area in which data is recorded by a light / dark pattern in units of cells. A data code area 8 in which data code words and error correction code words are recorded, and a format in which codes indicating format information are arranged. And an information code area 9. Since such a configuration basically conforms to the JIS standard (JIS X 0510: 2004) of the QR code, detailed description thereof is omitted.

  As shown in FIG. 2, the cell 2 in the coding area 4 of the two-dimensional code 1 is composed of an extended cell 2 a composed of a central portion 20 and a peripheral portion 21. More specifically, as shown in FIG. 3A, each extended cell 2a has nine squares obtained by dividing the cell vertically and horizontally into a central square portion 20 and the remaining eight squares around it. The portion is a peripheral portion 21. Although it is a monochrome image, it is not sufficiently shown in FIG. 2 or the like, but the central portion 20 of each expansion cell 2a is colored with one of white and black. Further, the peripheral portion 21 of each expansion cell 2a is arranged in any one color selected from eight types of reference colors.

As shown in FIG. 4, in this embodiment, eight colors of white, yellow, cyan, green, magenta, red, blue, and black having different RGB values are used as reference colors. These reference colors employ colors at the end of a cube in the RGB space so that the colors can be easily identified with each other. Here, among the eight kinds of reference colors, four kinds of white, yellow, cyan, and green having a luminance of 0.7 or more are classified as light reference colors. On the other hand, four types of magenta, red, blue, and black whose luminance is 0.3 or less are classified as dark reference colors. That is, a luminance of 0.7 corresponds to the light color threshold according to the present invention, and a luminance of 0.3 corresponds to the dark color threshold according to the present invention. In addition, the following formula prescribed | regulated by BTA S-001B is used for the conversion formula of RGB value and a brightness | luminance (Y).
Y = (0.2126 × R + 0.7152 × G + 0.0722 × B) / 255

  Here, the extended cell 2a is arranged in any one of the eight color arrangement patterns shown in FIG. In these color arrangement patterns, the extension cell 2a whose white at the central portion 20 is arranged in any one of four bright reference colors in the peripheral portion 21, and the expansion cell 2a whose black at the central portion 20 is arranged at the peripheral portion 21. One of the four dark color reference colors is used.

  When the light and dark pattern of the cell unit is identified by the QR code reader of the extended cell 2a of the two-dimensional code 1 of the present embodiment, the white extended cell 2a is identified as a bright color, and the central portion 20 is The black extended cell 2a is identified as a dark color. The QR code reader attaches importance to color information in the vicinity of the center of each cell, and identifies whether the cell is light or dark. In particular, since the central portion 20 of the extended cell 2a is colored in either the highest color (white) or the lowest color (black), the reflectance and brightness are QR code readers, which are bright in cell units. When the color and the dark color are identified, the extended cell whose center is white can be easily identified as a light color, and the extended cell whose center is black can be easily identified as a dark color. That is, in the present embodiment, the white and black color arrangement pattern of the central portion 20 of the extended cell 2a is identified as a light / dark pattern in cell units of the extended cell 2a. For this reason, in this embodiment, compatible data that can be read by the QR code reader is recorded according to the color arrangement pattern of the central portion 20. The QR code reader is not limited to a dedicated device for reading a QR code, but also includes a smartphone installed with a QR code reading program.

  On the other hand, in this embodiment, the dedicated data is recorded by the color arrangement pattern of the reference color of the peripheral portion 21 of the expansion cell 2a. Since the QR code reader cannot identify the reference color of the peripheral portion 21, a dedicated reader capable of identifying the reference color of the peripheral portion 21 (hereinafter referred to as a dedicated reader) is required to read the dedicated data. is necessary. The dedicated reading device also includes a smartphone or the like in which a program having a reference color identification function or the like of the peripheral portion 21 of the extended cell 2a is installed.

  In the present embodiment, among the nine squares obtained by dividing the expansion cell 2a vertically and horizontally, the central square portion is the central portion 20 and the remaining eight square portions are the peripheral portion 21. According to the inventor's research, when the area ratio between the central portion 20 and the peripheral portion 21 is set to such a ratio (1: 8), the light and dark pattern identification accuracy of the central portion 20 and the reference color of the peripheral portion 21 are identified. Both of the accuracy can be secured in the most balanced manner.

  Further, in the present embodiment, the expansion cell 2a whose center portion 20 is white is arranged with a reference color having a peripheral portion 21 of high luminance (0.7 or more), and the expansion cell 2a whose center portion 20 is black is The peripheral portion 21 is colored with a reference color of low luminance (0.3 or less), and the peripheral portion 21 is colored with a reference color that approximates the color of the central portion 20 with reflectance and luminance. For this reason, in this embodiment, when the two-dimensional code 1 is read, the boundary between the central portion 20 and the peripheral portion 21 becomes ambiguous due to camera shake, out-of-focus blur, an averaging filter of the imaging program, and the like. Even when the color of the peripheral portion 21 affects the acquired color information, the light / dark pattern in units of extended cells can be accurately identified based on the color information acquired from the central portion 20. Further, even when the color information acquired from the peripheral portion 21 affects the color information acquired from the peripheral portion 21, the color arrangement pattern of the peripheral portion 21 can be identified with high accuracy based on the color information acquired from the peripheral portion 21.

  In the present embodiment, as shown in FIG. 5, 3-bit encoded data from “000” to “111” is recorded in one extended cell 2a by eight color patterns of the extended cell 2a. The most significant bit (first bit) of the encoded data is data corresponding to the color arrangement pattern of the central portion 20, and is compatible data that can be read by a QR code reader. On the other hand, the second bit and the third bit are data corresponding to the color arrangement pattern of the peripheral portion 21 and are dedicated data that can be read only by a dedicated reader. In this embodiment, the encoded data of the extension cell 2a is set as a set for each bit at the same position, thereby forming a three-layer data area. Specifically, a first-layer data area is formed by a set of the most significant bits (first bits) of the encoded data, and compatible data is recorded in the data area. Then, a data area of the second layer and the third layer is formed by a set of the second bit and the third bit, respectively, and dedicated data is recorded in the data area.

  In the present embodiment, the three-layer data area has the same data format as that of the QR code encoding area. As shown in FIG. 6, the two-dimensional code 1 of the present embodiment includes QR codes 1a and 1b. , 1c, a data structure in which three data structures are stacked. The QR codes 1a to 1c have the same number of cells as the two-dimensional code 1, and the color of each QR code 1a to 1c is the color arrangement pattern of the extended cell 2a of the two-dimensional code 1 at the same position as the cell. It has become compatible. For example, the cell color of m rows and n columns is “1” (black) for the QR code 1a of the first layer, “0” (white) for the QR code 1b of the second layer, and QR code 1c of the third layer. When it is “0” (white), the color of the extended cell 2a of m rows and n columns of the two-dimensional code 1 is magenta (the encoded data is “100”) (see FIG. 5).

  As shown in FIGS. 1 and 7, the two-dimensional code 1 includes a sample region 5a on the left side of the position detection pattern 5 so that the reference color of the peripheral portion 21 of the extended cell 2a can be accurately identified. ing. The sample region 5a is composed of eight sample cells 2b. Similar to the expansion cell 2a, the sample cell 2b is a cell 2 including a central portion 20 that is colored in one of white and black and a peripheral portion 21 that is colored in any one of the eight kinds of reference colors. It is. The eight sample cells 2b constituting the sample region 5a are arranged in eight color schemes (FIG. 3B) of the expansion cell 2a, and the peripheral portions 21 of the eight sample cells 2b are separated from each other. Colored according to the reference color. Here, in the sample region 5a, it is determined in advance which reference color is used for the peripheral portion 21 of which sample cell 2b. For this reason, in this embodiment, the color information (RGB values) optically acquired from the peripheral portion 21 of the extended cell 2a is compared with the color information acquired from the peripheral portion 21 of each sample cell 2b. The reference color of the peripheral portion 21 of 2a can be identified. When the reference color of the peripheral portion 21 is identified based on the absolute value of the RGB value optically acquired from the peripheral portion 21 of the expansion cell 2a, the change with time of printing, the printer, the display device, and the ambient illumination However, if the reference color is identified with the reference color of the sample cell 2b as a comparison target, the change with time in printing, the printer, and the display Since it is possible to eliminate the influence of the apparatus, ambient lighting, etc., it is possible to reduce identification errors of the reference color.

  In the sample region 5 a, sample cells 2 b in which the central portion 20 is white and the peripheral portion 21 is a bright reference color are arranged in a portion identified by the position detection pattern 5 as a bright color. Since the sample cell 2b in which the central portion 20 is black and the peripheral portion 21 is the dark reference color is arranged in the portion identified as the dark color, the sample region 5a does not hinder the function of the position detection pattern 5. .

  In this embodiment, as shown in FIGS. 1 and 7, one set of sample areas 5a is arranged in the upper left, lower left, and upper right position detection patterns 5, and the peripheral portion 21 has eight reference colors. Three sets of colored sample cells 2b are provided. For this reason, in such a configuration, even when a part of the sample region 5a is soiled, there is no problem in identifying the color arrangement pattern of the extended cell 2a.

  Similarly to the extended cell 2a, the sample cell 2b is obtained by arranging the peripheral portion 21 with a light reference color, the central portion 20 with a white color, and the peripheral portion 21 with a dark reference color. However, since the central portion 20 is colored in black, the color information acquired from the peripheral portion 21 of the expansion cell 2a and the sample cell 2b is similarly affected by the color of the central portion 20. Therefore, according to such a configuration, there is an advantage that the color information acquired from the peripheral portion 21 of the extended cell 2a and the sample cell 2b can be compared without considering the influence of the color of the central portion 20.

  In this embodiment, an identification code 8a indicating the data recording format of the extended cell 2a is recorded in the extended cell 2a of the data code area 8. The recording format of the extended cell 2a includes the type and number of reference colors used in the peripheral portion 21, the number of divisions of the peripheral portion 21, an encryption method, an error correction method, and the like. The identification code 8a is recorded by the color arrangement pattern of the central portion 20, that is, the light / dark pattern of the extended cell 2a. According to the identification code 8a, the dedicated reader can determine the recording format of the extended cell 2a only by identifying the light / dark pattern of the extended cell 2a in units of cells, so the color arrangement pattern of the peripheral portion 21 of the extended cell 2a can be determined. It can be easily identified. The identification code 8 a is provided in the padding area in the data code area 8. The padding area is a remaining area after the compatible data is recorded in the data code area 8, and in the normal QR code, the valid data is not recorded. Since the color arrangement pattern of the padding area is ignored by the QR code reader, the identification code 8a does not hinder the reading of compatible data by the QR code reader.

  As described above, when the QR code reader reads the two-dimensional code 1 of the present embodiment, the reader does not identify the color arrangement pattern of the extended cell 2a in detail, and the color arrangement of the central portion 20 Based on the pattern, each extended cell 2a is identified as light or dark. Then, when the reading device executes a QR code decoding process based on the light / dark pattern, the compatible data recorded in the two-dimensional code 1 is decoded. FIG. 8A shows the two-dimensional code 1 of the present embodiment, and FIG. 8B shows the two-dimensional code 1 of FIG. This is the QR code 1a obtained by making the cells 2b all white and the center portion 20 black and all the sample cells 2b black. This QR code 1a is obtained by recording the same compatible data as the two-dimensional code 1 according to the light / dark binary pattern of the cell. Therefore, when the two-dimensional code 1 and the QR code 1a of FIG. In both cases, the same compatible data is read. That is, the two-dimensional code 1 of the present embodiment can function as an equivalent of the QR code to the QR code reader, and is compatible with the QR code.

  On the other hand, the two-dimensional code 1 of the present embodiment identifies both the compatible data and the dedicated data recorded in the two-dimensional code 1 by identifying the color arrangement pattern of the peripheral portion 21 of each expansion cell 2a if a dedicated reader is used. Can be decrypted.

  FIG. 9 is a flowchart for generating the two-dimensional code 1. First, in step S100, three sets of data to be recorded in the two-dimensional code 1 are captured. The three sets of data are one set of compatible data DS0 and two sets of dedicated data DS1 and DS2.

  In the next step S110, the compatible data DS0 is two-dimensionally encoded in accordance with a normal QR code generation procedure, and the QR code 1a (see FIG. 6) on the data recording the compatible data DS0 is generated. Here, the light / dark pattern of the QR code 1a for recording the compatible data corresponds to the light / dark pattern of the cell unit of the two-dimensional code 1. In step S110, when the QR code 1a is generated, a process for embedding the color arrangement pattern of the identification code 8a in a cell in the padding area of the QR code 1a is performed.

  In the next step S120, each of the dedicated data DS1, DS2 is two-dimensionally encoded in accordance with a normal QR code generation procedure, and the QR codes 1b, 1c on the data for recording the respective data DS1, DS2 (FIG. 6). 2) are generated. The above-described step S110 and the three QR codes 1a to 1c generated in step 120 are generated in the same format (version) as the generated two-dimensional code 1 so that they can be combined with each other. Since the two-dimensional encoding of the respective data DS0, DS1, DS2 can be performed in the same manner as the standardized QR code generation procedure, detailed description thereof is omitted.

In the encoding process of step S130, the QR codes 1a to 1c are combined with each color for each cell at the same position, and converted into the color arrangement pattern of the cell 2 of the two-dimensional code 1. Specifically, when the number of cells one side of the resulting two-dimensional code 1 is N, the entire two-dimensional code 1, N ² pieces of cell 2 is present, even the QR code 1 a to 1 c, N ² pieces of There is a cell color scheme. In the encoding process, the color scheme of the N ² cells 2 is determined one by one. More specifically, when the vertical cell index of the QR code is I and the horizontal cell index is J, all cells can be expressed by combinations of I = 1 to N and J = 1 to N. The color of the cell indicated by I and J is expressed by C (I, J). If each QR code 1a, 1b, 1c is represented by K, it can be represented by C (I, J, K). Here, K is 1 to 3. When the encoding process is executed for all cells, the generation of the two-dimensional code 1 is completed.

  FIG. 10 is a flowchart showing the contents of the encoding process (FIG. 9: S130). In the encoding process, first, in step S210, it is determined whether or not the cell specified by I and J is the cell 2 constituting the function pattern 3. If it is determined that the cell constitutes the functional pattern 3, the color arrangement is determined based on the position of the cell in step S220. On the other hand, if it is determined that the cell 2 is included in the coding area 4, the color arrangement pattern of the cell at the specific position of each QR code 1a to 1c is read in the next step S230. Specifically, the color arrangement data of C (I, J, K) (K is 1 to 3) is read to identify whether each cell is 0 or 1 (light color or dark color). Next, in step S240, 3 bits of encoded data to be recorded in the extended cell 2a are generated by combining the cell color patterns of the QR codes 1a to 1c. At this time, the color arrangement data of the QR code 1a related to the compatible data is combined with the first bit of the encoded data, and the color arrangement data of the QR codes 1b and 1c related to the dedicated data is the second bit and the third bit of the encoded data. Each is associated with a bit. In step S250, the color arrangement of the extended cell 2a is determined from the obtained encoded data. For example, as shown in FIG. 5, when the encoded data is “010”, the central portion 20 is determined to be white and the peripheral portion 21 is determined to be cyan. When the encoded data is “111”, the central portion 20 and the peripheral portion 21 are determined to have a black color scheme. In step S260, it is determined whether or not the above process is completed for all the cells 2. If the processes for all the cells 2 are completed, the encoding process is terminated.

  As described above, in the method of generating the two-dimensional code 1 according to the present embodiment, the compatible data DS0 and the dedicated data DS1 and DS2 are respectively QR-coded, and the QR codes 1a to 1c on the data are synthesized, whereby the two-dimensional code 1 Determine the color scheme. In such a generation method, both the compatible data and the dedicated data are encoded in accordance with the encoding method of the QR code. Therefore, by using a common algorithm for encoding the compatible data and the dedicated data, the two-dimensional code 1 There is an advantage that the generation program can be simplified. Further, since the two-dimensional code 1 generated by such a generation method can use a common algorithm when decoding compatible data and dedicated data, the reading program of the two-dimensional code 1 can be simplified.

Next, a reading method when reading the two-dimensional code 1 of the first embodiment with a dedicated reading device will be described.
FIG. 11 is a flowchart showing the reading process of the two-dimensional code 1 by the dedicated reading device.
In the first step S300, the two-dimensional code 1 is imaged under white light illumination by an imaging device provided in the reading device, and color image data of the two-dimensional code 1 is obtained. Next, in step S301, the two-dimensional code 1 is identified from the captured image according to the QR code image identification procedure, and the cell 2 is cut out. Specifically, for each cell 2, the corresponding pixel data is extracted from the image. Next, in step S302, a normal QR code reading process is performed, and data (compatible data) recorded in the data area of the first layer of the two-dimensional code 1 is read. That is, step S302 corresponds to the compatible data decoding process according to the present invention. At this point, the dedicated reader performs processing without distinguishing the two-dimensional code 1 from the QR code. Since a normal QR code reading process is well known, detailed description thereof is omitted.

  In subsequent step S303, it is determined whether or not the data recorded in the first layer has been successfully decoded. If the decoding has failed, in step S304, a display indicating a reading error is displayed on the display, and the reading is performed. The process ends. On the other hand, if it is determined in step S303 that the decoding is successful, the identification code 8a of the padding area is read in step S305, and it is determined whether or not the identification code 8a is successfully read in step S306. . Here, when reading of the identification code 8a fails, it is determined that the code is a normal QR code without the identification code 8a, and the reading process is terminated. Thus, the two-dimensional code 1 having the extended cell 2a and the normal QR code are identified depending on whether or not the identification code 8a is successfully read, that is, whether or not a valid identification code 8a is recorded. If this is the case, it is possible to easily identify both by simply identifying the light / dark pattern in cell units. On the other hand, if the identification code 8a is successfully read in step S306, it is determined that the data is the two-dimensional code 1 in which the dedicated data is recorded, and the dedicated data decoding process in step S307 is based on the information of the identification code 8a. Dedicated data is decoded and the reading process is terminated. That is, step S307 corresponds to the dedicated data decoding process according to the present invention.

FIG. 12 is a flowchart showing the processing content of the dedicated data decoding process (FIG. 11: S307).
In the dedicated data decoding process, first, in step S401, the color information of the peripheral portion 21 of each sample cell 2b in the sample area 5a is acquired. Specifically, as shown in FIG. 13, the eight values of the peripheral portion 21 of each sample cell 2b are used as the color information acquisition region 30, and the average value of the color information (RGB values) acquired from the eight locations is calculated as the sample. The color information of the peripheral portion of the cell 2b is used. Thus, if the color information of the peripheral portion 21 is obtained by averaging the color information of a plurality of places, the variation in the color information due to dirt or lighting is leveled, and the color information of the peripheral portion 21 is acquired more appropriately. It becomes possible. In this process, the color information of the peripheral portion 21 is acquired for each sample cell 2b for a total of 24 sample cells 2b in the three sets of sample regions 5a. That is, the sample color acquisition process according to the present invention is realized by the process of step S401.

  Next, in step S402, the color information of the peripheral portion 21 of one extended cell 2a is acquired. Specifically, the average value of the color information (RGB values) acquired from the eight locations in the peripheral portion 21 of the extended cell 2a as the color information acquisition portion 30 (see FIG. 13) as in the sample cell 2b. Is the color information of the peripheral portion 21 of the extended cell 2a. As described above, if the average value of the color information acquired from a plurality of locations is used as the color information of the peripheral portion 21, the color information variation due to dirt, illumination, etc. is leveled, and the color information of the peripheral portion 21 is appropriately acquired. Accordingly, the reference color of the peripheral portion 21 can be more accurately identified.

  Subsequently, in step S403, the color information of the peripheral portion 21 of the extended cell 2a acquired in step S402 is individually compared with the color information acquired from the peripheral portion 21 of each sample cell 2b, and the color information is most approximated. The sample cell 2b is determined. Then, it is determined that the determined reference color of the peripheral portion 21 of the sample cell 2b is the reference color of the peripheral portion 21 of the extended cell 2a. That is, the reference color identification process and the peripheral part identification process according to the present invention are realized by the process of step S403. Here, the color information is compared by calculating the Euclidean distance of the RGB values for the color information of the extended cell 2a and each sample cell 2b. Then, it is determined that the sample cell 2b having the shortest Euclidean distance from the color information of the extended cell 2a is closest to the color of the extended cell 2a.

  The color arrangement pattern (bright / dark pattern in cell units) of the central portion 20 of the extended cell 2a has already been identified at the stage of the QR code reading process (FIG. 11: S302). Based on the color of the unit 20, the reference color candidates of the peripheral part 21 of the expansion cell 2a are narrowed down in advance to one of the light color reference color and the dark color reference color, thereby performing comparison processing with the color information of the sample cell 2b. Simplify. Specifically, since the extension cell 2a whose white at the center portion 20 is the peripheral color of the peripheral portion 21 is a light color reference color, the comparison of the color information with the sample cell 2b whose peripheral portion 21 is colored with the dark color reference color is omitted. . Similarly, since the peripheral cell 21 of the extended cell 2a whose central portion 20 is black is a dark reference color, comparison of color information with the sample cell 2b in which the peripheral portion 21 is colored with a light color reference color is omitted. Note that the color pattern (bright / dark pattern in units of cells) in the central portion 20 is corrected by the QR code error correction function at the stage of the QR code reading process (FIG. 11: S302) even if the identification is wrong. The For this reason, accurate information can be obtained for the color arrangement pattern of the central portion 20. Therefore, if the reference color candidates of the peripheral portion 21 are narrowed down based on the color arrangement pattern of the central portion 20 as described above, the color arrangement pattern of the peripheral portion 21 is identified only from the color information of the peripheral portion 21. The identification rate can be improved.

  In step S403, the color information of the peripheral portion 21 of the extended cell 2a is individually compared with the color information of the peripheral portion 21 of the three sets of sample cells 2b. For example, if the central portion 20 is a white extended cell 2a, the color information is individually compared with 12 (4 colors × 3 sets) sample cells 2b in which the peripheral portion 21 is colored with a bright reference color. When the extended cell 2a and the sample cell 2b are not illuminated uniformly, even in color information acquired from a portion arranged with the same reference color, a large difference may occur due to a difference in illuminance. The color information of each extended cell 2a is individually compared with a plurality of sets of sample cells 2b for each reference color, and the extended cell 2a is compared with the sample cell 2b having a relatively small difference in illuminance. Misidentification can be reduced.

  The above steps S402 and S403 are executed for all the cells (extended cells) 2a in the coding area 4 to determine the color scheme of all the extended cells 2a. If it is determined in step S404 that the color arrangement of all the extended cells 2a has been determined, the encoded data recorded in each extended cell 2a is decoded based on the determined color arrangement in step S405. For example, the extended cell 2a determined that the central portion 20 is black and the peripheral portion 21 is red is decoded into encoded data “101” (see FIG. 5). In step S406, the QR code 1a on the data in which the compatible data DS0 is recorded by combining the encoded data of 3 bits decoded for each extended cell 2a for each of the first bit, the second bit, and the third bit; QR codes 1b and 1c in which dedicated data DS1 and DS2 are recorded are obtained. In step S407, the QR codes 1b and 1c for recording the dedicated data are decoded into the dedicated data DS1 and DS2 in accordance with a normal QR code decoding procedure. Since the compatible data DS0 has been decoded at the stage of the QR code reading process (FIG. 11: S302), the QR code 1a for recording the compatible data DS0 is not decoded.

  In step S408, it is determined whether or not the dedicated data DS1 and DS2 have been successfully decrypted. If it is determined that the data has been successfully decrypted, the dedicated data decrypting process is terminated. On the other hand, if it is determined that the decoding of the dedicated data has failed, the majority reading process is executed in step S409, and the dedicated data decoding process is terminated. In the majority reading process, the two-dimensional code 1 is imaged three times, a process for determining the color arrangement of the peripheral portion 21 of the extended cell 2a is performed for each imaged image data, and finally the determination result is determined as a majority. Thus, the final color scheme of each expansion cell 2a is determined. According to the inventor's research, the identification error of the color arrangement pattern in the peripheral portion of the extended cell 2a occurs less frequently in the same extended cell, so that the two-dimensional code 1 is imaged three times as in the majority reading process. Thus, if the reference color of the peripheral portion 21 of the extended cell 2a is never specified for many reference color identification results for each image, the success rate of reading the dedicated data of the two-dimensional code 1 can be remarkably increased. It becomes. The majority reading process has a high reading success rate for dedicated data, but requires a relatively large number of processes and takes a long time to be executed constantly. Therefore, like the reading method, dedicated processing is performed in steps S401 to S407. It is desirable to execute when data decryption fails. That is, the initial decoding process according to the present invention is realized by steps S401 to S407.

FIG. 14 is a flowchart showing the content of the majority reading process (FIG. 12: S409).
In the majority reading process, first, the second imaging of the two-dimensional code 1 is executed in step S500. In steps S501 to S506, the reference color of the peripheral portion 21 of each expansion cell 2a is identified based on the obtained second image data. Since the individual processes of steps S500 to S506 are the same as the processes of steps S300, S301, S305, and S401 to S404 described above, detailed description thereof is omitted. In step S507, steps S500 to S506 are repeated until the specified number of times (here, twice) is reached. As a result, the imaging of the two-dimensional code 1 and the identification of the reference color of the peripheral portion 21 of the expansion cell 2a are repeated a total of three times. Note that the first imaging of the two-dimensional code 1 is executed in step S300, and the first processing for identifying the reference color of the peripheral portion 21 of the extended cell 2a is executed in steps S401 to S404.

  In step S508, the identification result of the reference color that has been repeated three times for each extended cell 2a is never many, and the largest number of identification results are finally specified as the reference color of the extended cell 2a. That is, the majority process according to the present invention is realized by such step S508. If there are two or more identification results as a result of majority decision, one of the identification results is set as the reference color of the extended cell 2a by lottery.

  In steps S509 to S511, the dedicated data DS1 and DS2 are decoded based on the reference color specified for the peripheral portion 21 of each extended cell 2a, as in steps S405 to S407. That is, the majority decoding process according to the present invention is realized by steps S509 to S511. If it is determined in step S512 that the decoding of the dedicated data DS1 and DS2 has been successful, the majority reading process is terminated as it is. If it is determined that the decoding has failed, a display indicating a reading error is displayed in step S513. The majority reading process is completed on the display.

  As can be seen from the above two-dimensional code 1 reading method, in the two-dimensional code 1 of this embodiment, the compatible data is two-dimensionally encoded in accordance with the QR code standard, and each cell 2 is light and dark. Since it is recorded according to the information on which one is compatible, the compatible data can be read by the QR code reader. On the other hand, if a dedicated reader capable of determining the color information of the extended cell 2a and decoding the color information is used, the dedicated data recorded in the peripheral portion 21 of the extended cell 2a can be read.

Next, a modification of the method for reading the two-dimensional code 1 will be described.
The reading method according to the modified example executes the multiple illumination reading process shown in FIG. 15 instead of the above-described majority reading process (FIG. 12: S409). The multiple illumination reading process is a process of identifying the reference color of the peripheral portion 21 of the extended cell 2a based on image data captured under multiple types of illuminations having different colors.

  In the multiple illumination reading process, first, in step S600, the two-dimensional code 1 is imaged under red light illumination. In steps S601 to S603, the color information (RGB values) of the peripheral portion 21 of each expansion cell 2a is acquired based on the captured image data. Next, in step S604, the two-dimensional code 1 is imaged under blue light illumination. In steps S605 to S607, color information (RGB values) of the peripheral portion 21 of each expansion cell 2a is acquired based on the captured image data. That is, the red identification process according to the present invention is realized by steps S600 to S603, and the blue identification process is realized by steps S604 to S607.

  In step S608, the color information (RGB value) of the peripheral portion 21 of each expansion cell 2a is determined by combining the color information acquired from the two images captured under the illumination of red light and blue light. Here, among the RGB values, regarding the red component (R), the color information acquired from the image captured under the illumination of red light is considered to be an accurate value with less noise. For (R), color information acquired from an image taken under illumination of red light is employed. Similarly, regarding the blue component (B) of the RGB values, the color information acquired from the image captured under the illumination of the blue light is considered to be an accurate value with less noise. For (B), color information acquired from an image captured under blue light illumination is employed. In the multiple illumination reading process, color information is not specified for the green component (G) among the RGB values. As shown in FIG. 4, the four light color reference colors share the green component of the RGB value (G = 255), and the four dark color reference colors also share the green component of the RGB value (G This is because the green component (G) of the RGB value hardly contributes to the identification of the reference color.

  In step S609, the reference color of the peripheral portion 21 is identified based on the color information (red component and blue component) of the peripheral portion 21 determined in step S608. In step S609, the color information is not compared with the sample cell 2b, and the reference color is identified based only on the absolute value of the color information of the peripheral portion 21. Specifically, when the numerical value of the red component (R) or the blue component (B) of the color information is 128 or more, it is determined that the value is 255, and the red component (R) or the blue component of the color information is determined. When the numerical value of (B) is 127 or less, it is determined that the value is 0 and compared with the RGB value of the reference value. For example, when the central portion 20 is a white extended cell 2a (G = 255), if the red component of the color information is 200 (R = 150) and the blue component is 50 (B = 50), the peripheral portion The reference color 21 is identified as yellow (RGB value = 255: 255: 0) (see FIG. 4). Then, steps S608 and S609 are repeated for all the extended cells 2a (S610), and the reference color of the peripheral portion 21 of all the extended cells 2a is identified. In step S609, an intermediate value (128) of 0 to 255 is used as a threshold value to determine the RGB value of the reference color of the peripheral part 21, but the threshold value is actually acquired from the peripheral part 21. You may determine based on distribution of color information.

  In steps S611 to S613, the dedicated data DS1 and DS2 are decoded based on the identification result of the reference color of the peripheral portion 21 of each extended cell 2a, as in steps S405 to S407. If it is determined in step S614 that decoding of the dedicated data DS1 and DS2 has succeeded, the multiple illumination reading process is terminated, and if it is determined that decoding has failed, a display indicating a reading error is displayed in step S615. Is displayed on the display, and the multiple illumination reading process is terminated.

  As described above, in the multiple illumination reading process, the red component of the color information acquired from the image data captured under the illumination of red light, and the blue component of the color information acquired from the image data captured under the illumination of blue light, In order to identify the color information of the peripheral portion 21 of the extended cell 2a in combination with the two-dimensional as compared with the case where the color information of the peripheral portion 21 of the extended cell 2a is determined only from an image captured under white light illumination. The success rate of reading the dedicated data of code 1 can be significantly increased. Note that the multiple-illumination reading process has a high reading success rate for dedicated data, but requires a relatively large number of processes and takes a long time to be executed at all times. It is desirable to execute this when the reading of the dedicated data based on the image data captured under the illumination is failed. That is, the white light decoding process according to the present invention is realized by steps S401 to S407.

In the present embodiment, the configuration of the extended cell is changed from the first embodiment.
In addition, since it is the same as that of Example 1 except the structure of an extended cell, about the common structure, the same code | symbol is attached | subjected in the text and drawing, and detailed description is abbreviate | omitted.

  As shown in FIG. 16A, the extended cell 2c of this embodiment has a peripheral portion 21 subdivided into eight subcells 21a to 21h, and eight types of reference colors are provided for each of the subcells 21a to 21h. Any one color is selectively arranged. Specifically, the subcells 21a to 21h are configured by eight squares excluding the square of the central portion 20 among the nine squares obtained by dividing the extended cell 2c into three vertically and horizontally. As shown in FIG. 16B, in the extended cell 2c in which the central portion 20 is white, each of the subcells 21a to 21h is arranged in one of four types of bright color reference colors (see FIG. 4). On the other hand, as shown in FIG. 16C, in the extended cell 2c whose central portion 20 is black, each of the subcells 21a to 21h is arranged in any one of four types of dark color reference colors (see FIG. 4).

Auxiliary cell 2c of this embodiment, the two types of color schemes of the central portion 20, the eight sub-cells 21a~21h and color scheme of four kinds of peripheral portion ^21, are color by color scheme are ^{two 17.} For this reason, in this embodiment, as shown in FIG. 17, 17-bit encoded data is recorded in one extended cell 2c. As in the first embodiment, the encoded data is a set of bits at the same position to form a 17-layer data area, and the data in each layer has the same data format as the QR code, and each extended cell. One bit is recorded in 2c. That is, the two-dimensional code 10 of this embodiment has a data structure in which 17 sets of QR codes 10a to 10h on data are stacked as shown in FIG. The most significant bit (first bit) of the encoded data is data corresponding to the color arrangement pattern of the central portion 20 and is compatible data that can be read by a QR code reader. As described above, the two-dimensional code 10 of the present embodiment divides the peripheral portion 21 into eight subcells 21a to 21h, and colors the reference colors for each of the subcells 21a to 21h. More dedicated data can be stored compared to.

  The two-dimensional code 10 of this embodiment can be generated by the same method as the two-dimensional code 1 of the first embodiment. That is, in the method for generating the two-dimensional code 10 according to the present embodiment, the QR codes 10a to 10h for individually recording the 17 sets of data DS0 to DS16 recorded in the two-dimensional code 10 are generated, and the 17 sets of QR codes are generated. The color arrangement pattern of each cell 2 of the two-dimensional code 10 is determined by synthesizing the colors of the cells at the same position.

  As described above, the extension cell 2c of the present embodiment is arranged in one color of white or black at the central portion 20, and the extension cell 2c in which the central portion 20 is white is the light reference color at the peripheral portion 21. Since the peripheral portion 21 is colored with a dark reference color in the extended cell 2c whose central portion 20 is black, when the light and dark pattern is identified by the QR code reader, as in the extended cell 2a according to the first embodiment, the central portion The expansion cell 2a having a white 20 is identified as a light color, and the expansion cell 2a having a black central portion 20 is identified as a dark color. For this reason, when the QR code reader reads the two-dimensional code 10 of this embodiment, the reader does not identify the reference color of each expansion cell 2c in detail, and the color arrangement pattern of the central portion 20 Based on the above, each extended cell 2c is identified as a light color or a dark color, and the compatible data is decoded according to the QR code decoding process.

  On the other hand, the two-dimensional code 10 of the present embodiment is a 17-layer data recorded in the two-dimensional code 1 if the color arrangement pattern of the peripheral portion 21 of each extended cell 2a is identified in units of subcells using a dedicated reader. All the compatible data DS0 and the dedicated data DS1 to DS16 recorded in the area can be decoded. Since the reading method of the two-dimensional code 10 can be read according to the reading method of the two-dimensional code 1 of the first embodiment, detailed description thereof is omitted. In the reading method of the two-dimensional code 10 according to the present embodiment, as shown in FIG. 19A, the center of the eight subcells 21a to 21h of the expansion cell 2c is used as the color information acquisition part for the subcells 21a to 21h. Further, as shown in FIG. 19 (b), the parts corresponding to the color information acquisition parts 30a to 30h of the subcells 21a to 21h of the sample cell 2b are obtained as the color information of the sample cell 2b. It sets as part 31a-31h. The sample cell 2b has the same configuration as the two-dimensional code 1 of the first embodiment. When identifying the reference colors of the subcells 21a to 21h, the color information acquired from the color information acquisition portions 30a to 30h of the subcells 21a to 21h is used as the color information acquisition portions 31a to 31h of the corresponding portions of the sample cells 2b. Compared with the color information acquired from the above, the reference colors of the subcells 21a to 21h are determined to be the same reference color as that of the peripheral portion 21 of the sample cell 2b with the closest color information. For example, when identifying the reference color of the upper left subcell 21a, the color information acquired from the color information acquisition portion 30a of the upper left subcell 21a is obtained from the color information acquisition portion 31a of the upper left portion of each sample cell 2b. Compare with Thus, if the color information acquired from the subcells 21a to 21h is compared with the color information acquired from the corresponding portions 31a to 31h of the peripheral portion 21 of the sample cell 2b, the color information of the sample cell 2b to be compared is Since the color information acquired from the subcells 21a to 21h is influenced by the color of the central portion 20, when the reference colors of the subcells 21a to 21h of the expansion cell 2c are determined, The reference color can be accurately determined without being influenced by the influence of the color.

  As mentioned above, although embodiment of this invention was described by the Example, this invention can add a various change in the range which is not restricted to the form of the said Example and does not deviate from the summary of this invention.

  For example, although the above embodiment exemplifies a two-dimensional code in which the present invention is applied to the QR code standard, the present invention is also applicable to a two-dimensional code standard other than the QR code. Moreover, in the said Example, although the peripheral part of a cell is colored with 8 types of reference colors, the number of the reference colors which concern on this invention can be changed suitably. In addition, the reference color is not limited to one having a color, and gray of a plurality of gradations can be adopted. In the present invention, the color arrangement of the reference color is not limited to that represented by solid coating of the ink of the reference color, and may be represented by synthesis of fine halftone dots. Further, the two-dimensional code of the present invention is not limited to the one printed on the printed material, but includes one displayed on the display screen.

1, 10 Two-dimensional code 1a, 1b, 1c, 10a to 10h QR code 2 cell 2a, 2c extended cell 2b sample cell 3 function pattern 4 coding area 5 position detection pattern 5a sample area 6 separation pattern 7 timing pattern 8 data code Area 8a Identification code 9 Format information code area 20 Central part 21 Peripheral part 21a-21h Subcell 30, 30a-30h, 31a-31h Color information acquisition part

Claims (18)

A two-dimensional code in which cells identified as light colors and cells identified as dark colors are arranged in a matrix,
At least a part of the cells is an extended cell composed of a central portion arranged in white or black and a peripheral portion arranged in one or more colors selected from three or more reference colors having different RGB values. Yes,
A two-dimensional code comprising at least two types of information: compatible data recorded by a color arrangement pattern at the center of an extended cell and dedicated data recorded by a color arrangement pattern at the periphery of the extended cell. The cell has a square shape,
The extended cell has nine squares obtained by dividing the extended cell vertically and horizontally into a central square portion and a remaining eight square portions as peripheral portions. The described two-dimensional code. The reference color is composed of a plurality of light color reference colors whose reflectance or luminance is equal to or higher than a predetermined light color threshold value, and a plurality of dark color reference colors whose reflectance or luminance is equal to or lower than a predetermined dark color threshold value.
The expansion cell in which the central portion is colored in white is colored in one or a plurality of colors selected from the plurality of bright color reference colors,
3. The two-dimensional image according to claim 1, wherein the extended cells arranged in black at the center are arranged in one or a plurality of colors selected from the plurality of dark reference colors. code. It is determined in advance whether each cell is identified as light or dark, and comprises a fixed area that forms a pattern that assists in optical reading;
The fixed region includes a sample cell in which a predetermined portion is colored with any one of the reference colors, for each reference color,
Sample cells for each reference color are provided at predetermined positions in the fixed area,
The sample cell for the light reference color is a cell in the fixed area that is identified as light,
The two-dimensional code according to claim 3, wherein the sample cell for the dark reference color is a cell of a fixed region that is identified as a dark color.   The two-dimensional code according to claim 4, wherein the fixed region includes a plurality of sets of sample cells for each reference color. Like the expansion cell, the sample cell is composed of a central part and a peripheral part.
The predetermined portion of the sample cell is a peripheral portion of the sample cell;
Sample cells with the lighter reference color at the periphery are colored white at the center, and sample cells with the dark reference color at the periphery are colored black at the center. The two-dimensional code according to claim 4 or 5.   The two-dimensional code according to any one of claims 1 to 6, wherein a peripheral portion of the extended cell is arranged in one color selected from the three or more types of reference colors. .   The peripheral portion of the extended cell is subdivided into a plurality of subcells, and each subcell is arranged in one color selected from the three or more reference colors. Item 7. The two-dimensional code according to any one of items 6. A fixed area consisting of cells constituting a pattern for assisting optical reading, and an encoding area consisting of cells for recording data;
9. An identification code indicating a recording format of an extended cell is recorded in a light / dark pattern in units of cells in a remaining area consisting of cells in which compatible data is not recorded in an encoding area. The two-dimensional code according to any one of the above. A method for reading a two-dimensional code according to claim 7,
A method for reading a two-dimensional code, comprising: obtaining color information from a plurality of locations in a peripheral portion of an extended cell; and identifying a reference color in the peripheral portion of the extended cell based on an average value of the acquired color information. A method for reading a two-dimensional code according to claim 5,
Sample color acquisition processing for individually acquiring the color information of the predetermined part from the plurality of sets of sample cells;
The color information acquired from the specific part of the peripheral part of the expansion cell is individually compared with the color information acquired in the sample color acquisition process, and the reference color of the predetermined part of the sample cell from which the closest color information is acquired is And a reference color identification process for determining a reference color of the specific part. The two-dimensional code reading method according to claim 6,
Compare the color information acquired from the specific part of the peripheral part of the expansion cell with the color information acquired from the part corresponding to the specific part of the peripheral part of the sample cell, and A method for reading a two-dimensional code, characterized in that a reference color of a peripheral part is identified as a reference color of the specific part. A method for reading a two-dimensional code according to claim 3,
A compatible data decoding process for identifying the cell-by-cell brightness pattern of each extended cell and decoding the compatible data;
A dedicated data decoding process for identifying the color arrangement pattern of the peripheral part based on the color information acquired from the peripheral part of each extended cell and decoding the dedicated data after the compatible data decoding process;
The dedicated data decoding process is characterized in that the reference color of the peripheral portion is narrowed down to either a bright color reference color or a dark color reference color based on the light / dark pattern of the extended cell identified by the compatible data decoding process. To read a two-dimensional code. A method for reading a two-dimensional code according to any one of claims 1 to 9,
While performing the imaging process of imaging the two-dimensional code multiple times,
Based on the image data of the two-dimensional code obtained by the imaging process, a peripheral part identifying process for identifying a color arrangement pattern of the peripheral part of each expansion cell is performed for each imaging process,
After that, the majority process that identifies the color arrangement pattern of the peripheral part of each extended cell, never the many identification results of the multiple peripheral part identification process performed for each extended cell,
A two-dimensional code reading method, comprising: executing a majority decision decoding process for decoding dedicated data based on a color arrangement pattern of an extended cell specified by the majority decision process. A method for reading a two-dimensional code according to any one of claims 1 to 9,
First time to identify the color scheme of the peripheral part of the extended cell based on one piece of image data obtained by imaging the two-dimensional code, and to decode the dedicated data based on the color scheme of the peripheral part of the identified extended cell Execute the decryption process,
15. The two-dimensional code reading method according to claim 14, wherein the two-dimensional code reading method according to claim 14 is executed when the dedicated data cannot be decoded in the initial decoding process. A method for reading a two-dimensional code according to any one of claims 1 to 9,
A red identification process for capturing a two-dimensional code under illumination of red light, and obtaining color information of a red component in the peripheral portion of the expansion cell from the obtained two-dimensional code image data;
A green identification process that captures a two-dimensional code under illumination of green light and acquires color information of a green component in the periphery of the expansion cell from the obtained two-dimensional code image data;
At least of three processes including a blue identification process of capturing a two-dimensional code under illumination of blue light and obtaining color information of a blue component in the peripheral part of the extended cell from the obtained two-dimensional code image data Perform two processes,
A method for reading a two-dimensional code, characterized in that the reference color of the peripheral portion of the extended cell is identified by combining the color information acquired in at least two of the red identification process, the green identification process, and the blue identification process . A method for reading a two-dimensional code according to any one of claims 1 to 9,
Based on the image data of the two-dimensional code captured under the illumination of white light, the color arrangement pattern of the peripheral part of the extended cell is identified, and the dedicated data is decoded based on the color arrangement pattern of the peripheral part of the identified extended cell. Process
The two-dimensional code reading method according to claim 16, wherein the two-dimensional code reading method according to claim 16 is executed when the dedicated data cannot be decoded by the white decoding process. A method for reading a two-dimensional code according to claim 13,
The green component of the RGB value is common to all the light color reference values used in the peripheral part of the extension cell of the two-dimensional code to be read, and the green component of the RGB value is common to all the dark color reference values. If you have
In the dedicated data decryption process,
A red identification process for capturing a two-dimensional code under illumination of red light, and obtaining color information of a red component in the peripheral portion of the expansion cell from the obtained two-dimensional code image data;
A blue identification process is performed in which a two-dimensional code is imaged under illumination of blue light, and color information of a blue component in the peripheral portion of the expansion cell is obtained from the obtained two-dimensional code image data,
A method for reading a two-dimensional code, comprising: combining color information acquired in a red identification process and a blue identification process to identify a color arrangement pattern in a peripheral portion of an extended cell.