JP2006330930A - Method and device for preparing and reading color code - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for preparing a color code with high reading precision. <P>SOLUTION: This color code reading device is provided with a mapping part 12 for assigning inputted code data to each of cells as the configuring units of a color code, a bit inversion pattern storing part 14 for storing a bit inversion pattern for defining the inversion or non-inversion of each data, an inversion processing part 13 for converting the code data assigned to the cells based on the bit inversion pattern and a color code preparing part 15 for displaying each cell in a color corresponding to the converted code data of the cell. It is possible to convert the color of each cell of the color code based on the bit inversion pattern, and to solve the deviation of the color in the color code. Thus, it is possible to increase reading precision in the case of reading. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for creating a color code, a method for reading the color code, and an apparatus for performing the method, and particularly aims to improve reading accuracy.

  In recent years, mobile phones with cameras that can read a two-dimensional code have become widespread. However, in the currently popular two-dimensional code, information is expressed by binary values of white and black, so that the amount of information that can be embedded in the two-dimensional code is limited.

  This amount of information can be increased using a color barcode as described in Patent Document 1 below. For example, information density can be increased by recording barcodes printed on white paper with colors selected from cyan, magenta, yellow, and their combined colors red, green, blue, and black. .

  When reading this color barcode, the red, green, and blue wavelength signals are detected from the reflected light, and compared with the red, green, and blue data determination thresholds, the red, green, and blue components. The presence or absence of color is determined, and the color is identified.

  For color barcodes, color reading accuracy is very important. However, in general, image data captured by a camera varies greatly depending on a shooting environment such as ambient brightness, and it is difficult to read an accurate color.

Patent Document 2 below proposes a method of printing a red bar for RGB correction, a green bar, and a blue bar at the head of a color barcode to be printed in order to improve the reading accuracy of the color barcode. In this method, when the color barcode is read, the three bars are photographed by the camera, and the data determination threshold values of the R component, the G component, and the B component are optimized.
JP-A-8-96097 JP 2004-199203 A

  However, even if RGB correction is performed as in Patent Document 2, there are still colors with low reading accuracy due to the surrounding environment, brightness, camera performance, and the like. In particular, when there are many such colors with low reading accuracy biased to the color code, or when many such colors are adjacent to the color code, the reading accuracy of the color code is degraded. Become.

  The present invention was devised in view of these circumstances, and provides a method for creating a color code with high reading accuracy, a method for reading the color code, and an apparatus for performing those methods. It is an object.

  The color code creation method of the present invention includes a mapping step for assigning code data to each cell which is a constituent unit of a color code, and a bit inversion pattern in which the code data assigned to the cell is defined as inversion or non-inversion of each data. And a colorizing step for displaying each of the cells in a color corresponding to the converted code data of the cell.

  Therefore, the color of each cell of the color code can be converted based on the bit inversion pattern to eliminate the color deviation in the color code.

  In the color code creating method of the present invention, in the mapping step, code data is assigned to cells other than the identification cell for displaying the type of bit inversion pattern, and in the conversion step, the identification cell is used for conversion. Set identification code of bit inversion pattern.

  Therefore, when reading the color code, the bit inversion pattern used at the time of creating the color code can be known from the identification code set in the identification cell.

  In the color code creation method of the present invention, in the conversion step, the code data assigned to the cell is converted in a plurality of ways based on a plurality of bit inversion patterns, and a plurality of color codes are created through the colorization step. .

  Therefore, when reading a color code, it is possible to select and read a color code having an optimal color arrangement from a plurality of color codes according to the performance of the reading device and the situation at the time of reading.

  In the color code creation method of the present invention, in the mapping step, bits selected from the code data corresponding to the character code of the character represented by the color code are allocated to the same cell, and the character code is supported. Each bit of the code data is set to be distributed in a plurality of cells.

  By doing so, even when a “burst error” occurs in which an error occurs in a large number of bits in a cell, errors related to one character code are reduced, and correction using an error correction code becomes possible.

  In the color code creating method of the present invention, in the mapping step, all the bits of the code data corresponding to the character code of the character expressed by the color code may be assigned to the same cell. it can. In this case, bit interleaving of the code data is performed before the mapping step.

  In this way, “burst errors” can be dealt with.

  Further, the color code reading method of the present invention is a step of reading code data assigned to each of the cells that are the constituent units of the color code from the color code, and the code data assigned to the cell is used when creating the color code. In addition, a conversion step for converting based on a bit inversion pattern defining inversion or non-inversion of each data, and a code analysis step for restoring information represented by a color code from the converted code data are provided.

  Therefore, data can be accurately read from a color code with no color deviation.

  In addition, the color code generating apparatus of the present invention holds a mapping unit that assigns input code data to each cell that is a unit of color code, and a bit inversion pattern that defines inversion or non-inversion of each data. A bit inversion pattern holding unit, an inversion processing unit for converting the code data assigned to the cell based on the bit inversion pattern, and each of the cells is displayed in a color corresponding to the code data after conversion of the cell A color code creating unit.

  With this apparatus, it is possible to create a color code with no color deviation regardless of the information to be color coded.

  Further, the color code reading device of the present invention includes a code data reading unit that reads code data assigned to each cell constituting the color code from the color code, and a bit that defines inversion or non-inversion of each data. A bit inversion pattern holding unit for holding an inversion pattern, an inversion processing unit for converting code data assigned to the cell based on the bit inversion pattern used when creating the color code, and a color code from the converted code data And a code analysis unit that restores the information represented by.

  In this apparatus, the original data represented by the color code can be restored from the code data read out by selecting a color code having no color deviation.

  The present invention makes it possible to improve the reading accuracy of a color code. In addition, since a color code can be created by error correction coding with little redundancy, the actual amount of data embedded in the color code can be increased.

  Here, in order to simplify the description, a colorized 4 × 4 two-dimensional code such as R10 in FIG. 1 will be described. The coordinates of each cell are defined as Z10 in FIG.

  First, in this color code, binary data such as a character string and image data is assigned to each cell as shown in FIG. In this example, the character string “http” is represented as “01101000 01110100 01110100 01110000” by an 8-bit ASCII code, and this bit string is assigned to one cell by 3 bits (mapped). That is, in mapping, a bit selected from code data corresponding to a character code of a character expressed by a color code is assigned to the same cell. As a result, each bit of code data corresponding to the character code is distributed to a plurality of cells. In this example, the bits “01101000” constituting “h” are distributed in three cells.

  In the color code, the color of each cell is displayed in a color corresponding to 3 bits assigned to the cell. For example, when a color code conversion table that defines the correspondence between 3 bits and colors is defined as shown in FIG. 3, cell (1,2) is cyan (C) and cell (1,3) is green The cell (1, 4) is displayed in black, the cell (2, 1) is displayed in white,.

  In the color code creating method of the present invention, the bit mapped to each cell of the color code is converted in accordance with a preset inversion pattern, and the color of each cell is set to a color corresponding to the converted 3 bits. In the color code reading method, the bit corresponding to the color of each identified cell is obtained and then converted based on the inversion pattern to restore the 3 bits initially assigned to each cell. .

  FIG. 4 is a block diagram showing a configuration of the color code creating apparatus 10 according to the embodiment of the present invention.

  The apparatus 10 includes a data input unit 11, a mapping unit 12 that maps data to each cell, an inversion pattern holding unit 14, an inversion processing unit 13 that performs inversion processing of the mapped data, and a color code conversion table holding A unit 16 and a color code creating unit 15 for creating a color code are provided.

  Data to be displayed with a color code is input to the data input unit 11, and the data input unit 11 outputs a bit string of the data to the mapping unit 12. The mapping unit 12 maps this data to each cell of the color code. C20 in FIG. 5 shows bits of each cell mapped by the mapping unit 12. Note that the cell at the coordinates (1, 1) is used as an inversion pattern identification cell, so no mapping is performed here.

  The inversion pattern holding unit 14 holds the inversion pattern A (P01), the inversion pattern B (P10), and the inversion pattern C (P11) shown in FIG.

  The inversion processing unit 13 converts the bits of each cell mapped by the mapping unit 12 into three types using each of the inversion pattern A (P01), the inversion pattern B (P10), and the inversion pattern C (P11). In this conversion process, when the bit of the cell mapped by the mapping unit 12 is 0, the bit is converted to 0 if the bit at the same position in the inversion pattern is 0, and to 1 if the bit is 1, and the mapping unit 12 performs mapping. When the bit is 1, it is converted to 1 if the bit at the same position in the inversion pattern is 0, and converted to 0 if it is 1. That is, the exclusive OR of the bit mapped by the mapping unit 12 and the bit at the same position of the inversion pattern is calculated.

  FIG. 5 shows a case where no inversion process is performed on C20 mapped by the mapping unit 12 (no inversion) in C00, and each cell when inverted using the inversion pattern A (P01) of FIG. The bit is indicated by C01, the bit of each cell when inverted using the inverted pattern B (P10) of FIG. 6 is indicated by C10, and each bit when inverted using the inverted pattern C (P11) of FIG. The bit of the cell is shown at C11.

  At this time, when there is no inversion, “000” representing “no inversion” is embedded in the cell of the coordinates (1, 1) of C20. Further, when the reverse pattern A is used, “001” representing the “reverse pattern A” is embedded in the cell of the coordinates (1, 1) of C20, and then the reverse process is performed using the reverse pattern A. Similarly, when using the inversion pattern B, after embedding “010” representing the “inversion pattern B” in the cell of the coordinates (1, 1) of C20, the inversion process is performed using the inversion pattern B, and the inversion pattern B When C is used, “011” representing “inverted pattern C” is embedded in a cell at coordinates (1, 1) of C20, and then inversion processing is performed using the inverted pattern C.

  For example, when the inversion pattern A is used, the value of the inversion pattern A is “000” for the cell at the coordinates (1, 1), so that no bits are inverted and “001”. For the cell at coordinates (1, 2), since the value of the inversion pattern A is “100”, only the third bit of “111” of C20 is inverted to become “011”. For the cell at coordinates (2, 1), since the value of the inversion pattern A is “001”, only the first bit of “111” of C20 is inverted to become “110”.

  The color code creation unit 15 obtains a color corresponding to the bit of each cell of C00, C01, C10, and C11 mapped by the inversion processing unit 13 from the color code conversion table 16, and creates a color code. FIG. 7 shows color codes C00, C01, C10, and C11 in which the color of each cell is set based on the color code conversion table of FIG. 3 together with C20.

  It should be noted here that in the case of the color code of C20, since it is created without considering the color balance and arrangement, the color code is biased to a specific color, but inversion processing was performed. In C01, C10, and C11, the color of a cell changes moderately, and the bias | inclination to a specific color is not seen. Therefore, reading accuracy can be improved by reading the color code that has been subjected to inversion processing.

  FIG. 8 is a block diagram showing the configuration of the color code reader 20 in the embodiment of the present invention.

  The apparatus 20 includes a color code conversion table holding unit 26, a code data reading unit 21 that reads code data represented by a color code, an inversion pattern holding unit 24, and an inversion pattern identification unit that identifies a used inversion pattern. 22, an inversion processing unit 23 that performs inversion processing of the read code data, and a code analysis unit 25. These configurations are added to provide a camera-equipped mobile phone or the like with a color code reading function.

  The code data reading unit 21 identifies the color of each cell of the color code selected by the user, and converts the color into code data based on the color code conversion table. For example, when the color code C01 in FIG. 7 is selected, the bit data C01 in FIG. 5 is generated using the color code conversion table in FIG.

  The reversal pattern identification unit 22 identifies the reversal pattern used by the color code creation side for reversing the color code from the code data of the (1, 1) cell. For example, if the code data of the (1, 1) cell is “001”, it is identified that the inversion pattern A (P01) in FIG. 6 is used.

  The inversion processing unit 23 performs inversion processing of the code data using the inversion pattern identified by the inversion pattern identification unit 22. This inversion processing is the same as the processing in the inversion processing unit 13 of the color code creating apparatus 10. When the bit of the code data is 0, if the bit at the same position of the inversion pattern is 0, it is 0 or 1. If the bit of the code data is 1, it is converted to 1 if the bit at the same position of the inversion pattern is 0, and converted to 0 if it is 1.

  Therefore, “011” of the cell at coordinates (1, 2) is converted to “111” by “100” of the inverted pattern A, and “111” of the cell at coordinates (1, 3) is converted to “ 000 ”is converted to“ 111 ”, and“ 010 ”of the cell at the coordinates (1, 4) is converted to“ 110 ”by“ 100 ”of the inversion pattern A, thus restoring the original C20 code data. .

  The code analysis unit 25 converts the bit string data into original character string data, image data, or the like.

  As described above, this color code reader can read data with high reading accuracy from a color code having no color deviation.

The flowchart of FIG. 9 shows the processing procedure of the color code creation device.
Data of a bit string to be displayed with a color code is input (F11), and this data is mapped to each cell other than the color code inversion pattern identifying cell (F12).

  Next, a code indicating “no inversion” is embedded in the inversion pattern identification cell to create a color code of “no inversion” (F20). Further, a code indicating “inverted pattern A” is embedded in the inversion pattern identification cell (F21), and an inversion process using the inversion pattern A is performed to create a color code (F31). Further, a code indicating “inverted pattern B” is embedded in the inverted pattern identification cell (F22), and an inversion process using the inverted pattern B is performed to create a color code (F32). Further, a code indicating “inverted pattern C” is embedded in the inversion pattern identification cell (F23), and an inversion process using the inverted pattern C is performed to create a color code (F33).

  Further, the flowchart of FIG. 10 shows a processing procedure of the color code reader.

  Code data is read from the color code (S11), and the inverted pattern used is identified (S12). When the inversion is not performed (No in S21), the code data acquired in S11 is analyzed to obtain the original data (S31). When the inversion is performed (Yes in S21), it is identified whether or not the “inversion pattern A” is used (S22). When the result is Yes, the inversion process by the inversion pattern A is performed to perform the original code. The data is restored (S25), and the code data is analyzed to obtain the original data (S31). When S22 is No, it is identified whether or not the “inverted pattern B” is used (S23). When Yes, the inversion process using the inverted pattern B is performed to restore the original code data (S26). The code data is analyzed to obtain the original data (S31). When S23 is No, it is identified whether or not the “inverted pattern C” is used (S24). When Yes, the inversion process using the inverted pattern C is performed to restore the original code data (S27). The code data is analyzed to obtain the original data (S31).

  Here, the case where the color code creation side creates a plurality of color codes that have been subjected to inversion processing, and the color code reading side reads one color code selected from them, but the color code creation side One reversal color code that seems to be optimal may be created, and the color code reader may read it.

  Here, the cell at the coordinates (1, 1) is the pattern identification cell, but the pattern identification cell may be a cell other than the coordinates (1, 1). However, the color code reader needs to know where the pattern identification cell is located, and the bit inversion pattern of the pattern identification cell does not invert the bit. Must be known.

  Further, here, a color code composed of 4 × 4 cells has been described, but the same processing can be performed even if the number of cells increases. Further, a color barcode composed of n × 1 cells can be processed in the same manner.

  In addition, here, an example in which the inversion patterns are three patterns A, B, and C is shown, but the number of inversion patterns to be used may be more or less. When the inversion pattern is identified by 3 bits, 8 (2 to the 3rd power) inversion patterns can be used.

  Here, 3 bits are assigned to one cell of the color code, but other numbers of bits may be assigned. FIG. 11 shows an example in which one character ASCII code (8 bits) is assigned to one cell. Further, error correction coding may be performed in the middle, but even in that case, the same processing can be performed.

  Note that one character may be assigned to one cell as shown in FIG. That is, in mapping, all bits of code data corresponding to the character code of the character expressed by the color code are assigned to the same cell. In this case, there is a case where the character cannot be restored due to the occurrence of a burst error in which an error reaches a large number of bits of one cell. This is because it is difficult to correct burst errors with an error correction code. Such a situation can be avoided by performing bit interleaving at random before mapping, reducing the allocation of the same character to the same cell, and distributing different character codes in the same cell. By doing so, the burst error is converted into a random error, and correction using an error correction code becomes possible.

  Although various embodiments of the present invention have been described above, the present invention is not limited to the matters shown in the above-described embodiments, and those skilled in the art can make modifications and applications based on the description and well-known techniques. This is also the scope of the present invention, and is included in the scope of seeking protection.

  The present invention can be widely used in each field where a two-dimensional color code, a color barcode, and the like are used in order to improve the reading accuracy of those color codes.

Example of color code coordinate assignment in the embodiment of the present invention Example of character string mapping in the embodiment of the present invention (3 bits / cell) Color code conversion table according to an embodiment of the present invention The block diagram which shows the structure of the color code production apparatus in embodiment of this invention. Example of randomization in the embodiment of the present invention The figure which shows the inversion pattern in embodiment of this invention The figure which shows the color code randomized in embodiment of this invention The block diagram which shows the structure of the color code reader in embodiment of this invention The flowchart which shows the color coding processing procedure in the embodiment of the present invention The flowchart which shows the process sequence at the time of reading in embodiment of this invention Example of character string mapping in an embodiment of the present invention (8 bits / cell)

Explanation of symbols

C00 4 × 4 color code C01 without inversion 4 × 4 color code C10 with inversion pattern A 4 × 4 color code C11 with inversion pattern B 4 × 4 color code C20 with inversion pattern C 4 before conversion × 4 color code 10 color code creation device 11 data input unit 12 mapping unit 13 inversion processing unit 14 inversion pattern holding unit 15 color code creation unit 16 color code conversion table holding unit 20 color code reading device 21 code data reading unit 22 inversion pattern Identification unit 23 Inversion processing unit 24 Inversion pattern holding unit 25 Code analysis unit 26 Color code conversion table holding unit

Claims (10)

A mapping step for assigning code data to each of the cells that are the constituent units of the color code;
A conversion step of converting the code data assigned to the cell based on a bit inversion pattern defining inversion or non-inversion of each data;
A colorizing step of displaying each of the cells in a color corresponding to the code data after conversion of the cell;
A method for creating a color code. The color code creating method according to claim 1,
In the mapping step, the code data is assigned to the cells other than the identification cell that displays the type of the bit inversion pattern,
A color code generation method in which, in the conversion step, an identification code of the bit inversion pattern used for conversion is set in the identification cell. The color code creating method according to claim 1 or 2,
In the conversion step, the code data assigned to the cell is converted in a plurality of ways based on the plurality of bit inversion patterns, and a plurality of color codes are generated through the colorization step. The color code creating method according to any one of claims 1 to 3,
In the mapping step, a bit selected from the code data corresponding to a character code of a character represented by a color code is assigned to the same cell, and each bit of the code data corresponding to the character code is assigned to a plurality of cells. Color code creation method set to be distributed. The color code creating method according to any one of claims 1 to 3,
In the mapping step, a color code creation method in which all bits of the code data corresponding to a character code of a character expressed by a color code are assigned to the same cell. The color code creating method according to claim 5,
A color code generation method for performing bit interleaving of the code data before the mapping step. The color code creation method according to any one of claims 1 to 6,
A color code generation method for calculating an exclusive OR of a bit of the code data and a bit of the bit inversion pattern in the conversion step. Reading from the color code code data assigned to each of the cells that are the constituent units of the color code;
A conversion step for converting the code data assigned to the cell based on a bit inversion pattern that defines the inversion or non-inversion of each data used when creating the color code;
A code analysis step for restoring information represented by a color code from the converted code data;
A color code reading method comprising: A mapping unit that assigns the input code data to each of the cells that are the constituent units of the color code;
A bit inversion pattern holding unit for holding a bit inversion pattern defining inversion or non-inversion of each data;
An inversion processing unit for converting the code data assigned to the cell based on the bit inversion pattern;
A color code creating unit for displaying each of the cells in a color corresponding to the code data after the conversion of the cell;
A color code creation device comprising: A code data reading unit that reads code data assigned to each cell that is a unit of color code from a color code;
A bit inversion pattern holding unit for holding a bit inversion pattern defining inversion or non-inversion of each data;
An inversion processing unit that converts code data assigned to the cell based on the bit inversion pattern used when creating a color code;
A code analysis unit that restores the information represented by the color code from the converted code data;
A color code reader comprising:

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