JP2003091697A - Two-dimensional code system and method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-dimensional code that is larger in data capacity than a two-dimensional code of two black and white colors. SOLUTION: The standard of a mean optical density C of each cell has four-level multiple gradations C (0) to C (3) as exemplified in Fig. 3 (c), and a cell 1 of the lowest mean optical density, a cell 3 of the next low level, a cell 4 of the next low level and a cell 2 of the highest mean optical density correspond to two-bit data 00, two-bit data 01, two-bit data 10 and two-bit data 11 respectively. The two-dimensional code can express six-bit data with three multiple-gradation cells as exemplified in Fig. 3 (d). The two-dimensional code can thus realize twice as high an information density as a monochrome two-dimensional code.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional code system and method for converting data into a two-dimensional code and decoding the data from the two-dimensional code.

[0002]

2. Description of the Related Art For example, in a POS system or the like, data is converted into a one-dimensional pattern (one-dimensional code) called a bar code, which is attached to a management target, and the code attached to the management target is optically read. Therefore, the method of managing is used. Further, in order to increase the amount of data expressed by a code expressing data, a method of converting the data into a two-dimensional black and white code has been used. For example, Japanese Patent Laid-Open No. 2000-123132 (Reference 1) discloses a method for converting data into a two-dimensional color code.

However, if the amount of data to be expressed is increased by using a two-dimensional code of two colors of black and white, it is necessary to print the two-dimensional code and increase the resolution for reading the printed two-dimensional pattern. . In addition, reference 1
The method disclosed in requires a color printer and a color scanner capable of printing and reading an image in color,
For example, it cannot be applied to a system having only a monochrome printer and a monochrome scanner. Further, even if the method disclosed in Document 1 is used, the color scanner separates the color image into the three primary colors (R, G, B) and reads it, so that the data capacity cannot be increased more than three times. .

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is a two-dimensional code capable of greatly increasing the data capacity as compared with a two-dimensional code of two colors of black and white. It is an object to provide a system and a method thereof. Further, according to the present invention, a two-dimensional code system capable of creating a two-dimensional code having a large data capacity and restoring the original data from the two-dimensional code even when a color printer / color scanner is not used. The purpose is to provide the method.

[0005]

[Two-dimensional code system] In order to achieve the above object, a two-dimensional code system according to the present invention converts data into a two-dimensional code including a plurality of cells in a two-dimensional array. A two-dimensional code system for converting and restoring the data from the converted code, wherein the data is converted into color densities of a plurality of cells included in the two-dimensional code to create the two-dimensional code. It has a two-dimensional code creation means and a two-dimensional code output means for outputting the created two-dimensional code as an image.

Preferably, the two-dimensional code is represented by one color, and the shade of the color of the cell included in the two-dimensional code is represented by a plurality of gradations of the one color.
The dimension code creating means creates the two-dimensional code by converting the data into the gradation of the one color of each of the plurality of cells included in the two-dimensional code.

[0007] Preferably, there is further provided a data decompressor for decompressing the data based on the gradation of one color of each of a plurality of cells included in the output two-dimensional code.

Preferably, the two-dimensional code is represented by a plurality of colors, and the shade of each color of cells included in the two-dimensional code is represented by superimposing gradations of each of the plurality of colors, The two-dimensional code creating means creates the two-dimensional code by converting the data into a superposition of gradations of each of the plurality of colors of each of the plurality of cells included in the two-dimensional code.

Preferably, it further comprises a data restoring means for restoring the data based on the gradation of each of the plurality of colors of each of the plurality of cells included in the output two-dimensional code.

Preferably, the output means further outputs, in addition to the two-dimensional code, an image of a pattern showing gradations of colors expressing the shades of colors of a plurality of cells included in the two-dimensional code.

[Method] The method according to the present invention is a method of converting data into a two-dimensional code including a plurality of cells in a two-dimensional array, and restoring the data from the converted code. The data is converted into color densities of a plurality of cells included in the two-dimensional code to create the two-dimensional code, and the created two-dimensional code is output as an image.

[Program] A program according to the present invention is a program for converting data into a two-dimensional code including a plurality of cells in a two-dimensional array, and restoring the data from the converted code. The data is
The computer is caused to execute the steps of converting the color density of a plurality of cells included in the dimension code to create the two-dimensional code and the step of outputting the created two-dimensional code as an image.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Background of the Invention] Before describing the embodiments of the present invention, the background thereof will be described in order to help understanding of the present invention. FIG. 1 is a diagram of a two-dimensional code 101 shown as the background art of the present invention. The two-dimensional code 101 shown in FIG. 1 is configured with a rectangular unit, called a cell 102, printed in white or black as a minimum unit. Two-dimensional codes other than the two-dimensional code shown in FIG. 1 are also composed of cells, but the shape of the cells is not necessarily square. In the types of two-dimensional codes other than those shown in FIG. 1, shapes other than squares, such as rectangles, circles, ellipses, or lines,
Various shaped cells may also be used.

In a two-dimensional code, not all cells are used to represent data, for example:
The two-dimensional code 101 is a data area 105 that represents data.
Position detection pattern 102 and timing pattern 104 that provide a reference for accurate reading
Contains cells. Two-dimensional code 101 shown in FIG.
Can represent data of about 1000 bytes.

In order to further increase the amount of information, a method of creating a plurality of two-dimensional codes or a method of miniaturizing the minimum size of cells forming the two-dimensional code can be considered. However, when a plurality of two-dimensional codes are created, the arrangement area becomes large and it takes time to read each of the plurality of two-dimensional codes. Also, when the minimum cell size is reduced,
A reading error is likely to occur due to minute dust or dirt, and it becomes necessary to use a high-resolution optical system for reading.

FIG. 2 is a diagram for explaining colorization of a two-dimensional code. In addition to these, there is a method of increasing the amount of information up to three times by colorizing a two-dimensional code. For example, as shown in FIG. 2, in the two-dimensional code 106 on the white surface, the cells on the left side and the lower side of the two-dimensional code 106 are colored black, and the cells on the other two sides are alternated between white and black. The guide cell 107 created by attaching to the
It is composed of a data cell 108 which represents data by a combination of green, blue and black.

In light color combination, three colors of red, green and blue are combined into white, and red, green and black are combined into yellow,
Combining green, blue, and black produces cyan, and combining blue, red, and black produces magenta. The two-dimensional code 106 expresses an information amount three times as large as that of the two-dimensional code expressed in monochrome by adding white (same as the background color) yellow, cyan, and magenta to each cell inside the guide cell 107. be able to. In order to restore the data from the two-dimensional code 106, the two-dimensional code 106 may be read and the color of each cell may be separated into RGB.

Since an ordinary color scanner performs color separation into three colors of RGB, even if colorization is attempted as in the two-dimensional code 106, the amount of data that can be expressed cannot be tripled or more. Also, the two-dimensional code 106
Of course, a color printer is required for printing, and the two-dimensional code 106 cannot be printed by a system having only a monochrome printer. Therefore, if it is possible to represent a larger amount of data than the colorized two-dimensional code 106 (FIG. 2) in the same area as the monochrome two-dimensional code 101 (FIG. 1), it is very convenient and wide range. Applications can be expected.

The two-dimensional code according to the present invention stores a basic area composed of two-dimensionally arranged cells used for position detection and the like at the time of reading and input data represented by binary data. In a two-dimensional code formed of a data area composed of cells arranged in a dimension, a cell in the data area corresponds to a value representing two or more binary data in one cell. It is characterized by comprising a plurality of optical densities.

Preferably, in a color two-dimensional code formed by cells of a plurality of colors, the cells of the same color in the data area consist of the plurality of optical densities according to data, and the cells of each color Are integrated by being superposed.

Preferably, a cell in the data area has a pattern in which the optical density is defined at a predetermined position other than the data area in the two-dimensional code having the plurality of optical densities according to the data.

[First Embodiment] The first embodiment of the present invention will be described below. FIG. 3 is a diagram for explaining a cell of a color two-dimensional code according to the present invention, in which (a) shows an optical density C of a cell included in a monochrome two-dimensional code,
(B) exemplifies a cell pattern included in a monochrome two-dimensional code, (c) is a diagram showing an optical density C of a cell of a two-dimensional code according to the present invention, and (d) relates to the present invention. The pattern of the cells included in the two-dimensional code is shown.

The cell of the monochrome two-dimensional code is shown in FIG.
As shown in (a), C having a high average optical density of the cell
It is divided into a black cell 2 of (1) and a white cell 1 of C (0) having a low average optical density. For example. White cell 1 has a bit value of 0
The black cell 2 represents the bit value 1, and as shown in FIG. 3B, the monochrome two-dimensional code represents the data by the pattern arrangement of the white cell 1 and the black cell 2.

On the other hand, in the two-dimensional code according to the present invention, the standard of the average optical density C of each cell is C (0), C (1), C (as shown in FIG. 3C. 2), C
The cell 1 having the lowest average optical density is the 2-bit data 00, the cell 3 having the second lowest is the 2-bit data 01, and the cell 4 having the second lowest is the 2-bit data 1 in (3).
The cell 2 having the highest average optical density is associated with 0 to the 2-bit data 11. By doing so, in the two-dimensional code according to the present invention, 6-bit data is converted into the data shown in FIG.
As illustrated in (d), it can be represented by three multi-tone cells. Therefore, the two-dimensional code according to the present invention can realize twice the information density as compared with the monochrome two-dimensional code.

In FIGS. 3 (c) and 3 (d), the gradation of the cell is 4
Although the case where the number of steps is set as an example is illustrated, if the gradation of the cell is further increased and, for example, the average optical density is set to eight, the information density can be three times that of the monochrome two-dimensional code. When 16 is a value, the information density can be quadrupled. That is, if the average high-price density of one cell is set to the nth power of 2 (n is an integer), the amount of data that can be stored in one cell is such that the average optical density of the cell is binary (white.
It will be n times that of black).

A cell which expresses in such a multi-gradation in which the average optical density is changed is a PDF 41 which is generally known.
7, Micro PDF417, Code49, Code16K, Cod
ablock, SuperCode, UltraCode, QR code, Micr
o Qr code, VeriCode, CPCode, DataMatrix,
Code1, MaxiCode, AztecCode, DataMatrix E
It can be applied to two-dimensional codes such as CC200, scan talk code, SP code, DD code, Intacta Code, and Cyber Code, and can also be used for general barcodes.

[Method for Creating Two-Dimensional Code According to the Present Invention] The method for creating a two-dimensional code according to the present invention will be described below. The value of the input 24-bit data is, for example,
[0111 0010 1000 1000 0001 0001
1101], each of these 24-bit data is associated with three colors of RGB, eight each, R [0111 0010] as R data, and G [1 as G data.
000 0001], and B [0001 as the data of B
1101]. R for each color data
[01 | 11 | 00 | 10], G [10 | 00 | 00 | 0
1], B [00 | 01 | 11 | 01], and divide [00], [01], [10], [11] into R
In the case of, the average optical densities R (0), R (1),
By converting into four values of R (2) and R (3), R
4 like [R (1) | R (3) | R (0) | R (2)]
Individual data are formed.

FIG. 4 is a diagram illustrating a cell pattern included in the two-dimensional code according to the present invention. (A) shows R data, (b) shows G data, and (c). )
Shows data of B, and (d) is a diagram showing a state in which the data shown in (a) to (c) are superimposed. The data thus converted into the value of the average optical density is arranged according to a predetermined format to form a two-dimensional matrix.

As shown in FIG. 4A, in the case of a 2 × 2 matrix M (2,2) 5, M (1,1) 6, M (1,
2) If data is arranged in the order of 7, M (2,1) 8, M (2,2) 9, the data of the value of the average optical density is R
(1) → M (1,1) 6, R (3) → M (1,2) 7,
R (0) → M (2,1) 8, R (2) → M (2,2) 9
Are stored in the matrix 5 as follows. Furthermore, FIG.
As shown in (b) and (c), similar processing is performed for G and B. The RGB matrices thus formed are overlaid as shown in FIG. 4D, and the respective colors of the RGB cells of each matrix are combined at the specified average optical density in the cells located in the same matrix, and data cell 1
Create 0.

Although the example in which the data is composed of a 2 × 2 matrix has been described above, the same operation is actually performed in all cells in the data area of the two-dimensional code. As shown in FIG. 5, the two-dimensional code 11 generally includes position detection patterns 13 to 15 for detecting the position of each cell, in addition to the data area 12 for storing data. Here, the first position detection pattern 13 is set to R
(3), G (3), and B (3) having the average optical density colors, and the second position detection pattern 14 is formed by R (2), G (3).
(2), B (2) are formed with a color having an average optical density, and the third position detection pattern 15 is formed by R (1), G (1), B
By forming the color having the average optical density of (1), it is possible to easily set the average optical density as a reference during reading.

The pattern used as the reference of the average optical density does not necessarily have to match the position detection pattern, and like the position detection pattern, it is arranged in the two-dimensional code 11 as a reference pattern containing no data. Good.
In this way, the image of the color two-dimensional code expressed in multiple gradations is output by the printing device.

Although the number of elements of the matrix of each color and the size of the cell are the same here, the size of the matrix and the cell may be different for each of RGB. This is because when the data is separated into RGB after reading, they are independently decoded, and there is no correlation in handling the data. The multi-gradation cell shown in the embodiment of the present invention is not limited to the pattern of the two-dimensional code shown in FIG. 5, but the two-dimensional one expressed in monochrome or color which has been conventionally used. It can also be applied to code.

Next, a method of restoring data from the created two-dimensional code will be described with reference to FIG. After setting the medium with the two-dimensional code written in the scanner, start the scanner. In a general scanner, light passing through a lens is color-separated through a color filter and is incident on CCD sensors corresponding to RGB. The signal converted into an electric signal by the CCD sensor is converted from analog / digital (A / D) and stored in the memory for each color.

After detecting the position detection pattern for each color,
The position of the optical density reference pattern is specified based on this information, the density of the reference pattern is read, and the reference density is set. Next, the optical density of each cell in the data area is divided into four values by comparing with the reference density, and from the four values to 2 according to the predetermined format based on the information of the position detection pattern.
The data is expanded into value data to perform decoding and error correction. After each of the RGB data is decoded, the input data is restored by synthesizing the data, and is output by a predetermined method.

Although a commonly used scanner is given as an example here, a general camera may be used. In that case, the two-dimensional code read by the camera lens is color-separated and
The processing after storing in the memory after D conversion is the same. Although a filter is used here for color separation, a monochrome scanner or camera can be used by applying RGB monochromatic light when performing color separation into RGB. Further, here, the value of the average optical density of each cell is determined by comparison with the reference pattern of optical density, but if the reference pattern of optical density is not used to secure a wide data area, it is set in the data area. The reference value may be calculated by analyzing the distribution of the optical density read from a certain cell.

As described above, in the first embodiment of the present invention, the description has been made by using the color two-dimensional code of RGB three colors. However, a material which is transparent to visible light and absorbs infrared light, or When a material that is transparent to visible light and absorbs ultraviolet light is used, and if the material forming RGB is sufficiently transparent to infrared light or ultraviolet light as compared with the absorbing material, these are used in the present invention. By applying the two-dimensional code, it is possible to increase the capacity.

[Second Embodiment] The second embodiment of the present invention will be described below. FIG. 7 is a diagram illustrating a two-dimensional code according to the present invention to which density gradation is applied. In a silver salt photograph or a sublimation printer, since it is possible to directly modulate the density of the smallest dot forming an image, the density gradation is usually used. Also in realizing the two-dimensional code according to the present invention, when one cell is composed of a plurality of dots, the optical density of each dot depends on the exposure intensity and the exposure time in a silver salt photograph, and in the sublimation type printer, a resistor. By controlling the heat generation amount of C (0) 16a, C (1) 16b,
It can be changed like C (2) 16c and C (3) 16d. The optical density at this time is almost equal to the average optical density. Here, the case of 4 gradations is taken as an example, but when accurate density modulation is performed, gradations up to about 256 gradations can be taken, and in that case, one cell corresponds to 8 bits per color. It is possible to store the data of.

[Third Embodiment] A third embodiment of the present invention will be described below in which area gradation used in printing using a printing plate, an electrophotographic printer, a thermal transfer printer, or an inkjet printer is applied. In the case of printing, electrophotographic printers, thermal transfer printers, or inkjet printers, it is generally difficult to directly control the density of the smallest dot that forms an image. A method is used in which gradation is obtained by the average density within one pixel depending on the area occupied by the dots inside. In the two-dimensional code, a cell can be associated with this pixel and the average density in the cell can be used for gradation.

FIG. 8 is a diagram schematically showing a two-dimensional code according to the present invention to which surface gradation is applied. In FIG. 8, one cell 16 is formed of four minimum dots, and the case where the minimum dots are read by a CCD having a resolution in which four photoelectric conversion elements 17 are read is schematically shown. Here, a (1,1) to a (2,2) are the smallest dots at the time of printing that form the cell 16, and b (1,1) to b
(5, 5) shows the arrangement of the photoelectric conversion elements 17 of the CCD.

As shown in FIG. 8A, when the cell 16 composed of 2 × 2 dots corresponds to the 4 × 4 photoelectric conversion element, data from the position detection pattern is obtained. The photoelectric conversion element most suitable for reading the cell is selected based on the above, and the optical density of a (1,1) is B (1,1), B.
It is read by the photoelectric conversion elements of (2,1), B (1,2), and B (2,2). If the optical density of the printed cells is 1 when printed and 0 when not printed, then a (1,
If 1) is printed, b (1,1), b
A light amount having an optical density of 1 is incident on each of (2,1), b (1,2), and b (2,2). In such a case, an error does not occur and an accurate gradation can be read.

However, it is usually difficult for the cell 16 and the photoelectric conversion element 17 to completely overlap each other.
As shown in (b), when the positions of the cells 16 are displaced by half the pitch of the photoelectric conversion elements 17, the photoelectric conversion elements B
From (1,1) to B (5,5), B (1 to 4,1 to 1)
Combination A of 4) or combination B of B (1 to 4, 2 to 5)
Or a combination C of B (2, 5, 1 to 4) or B (2
~ 5, 2 to 5) any one of the four combinations D
16 photoelectric conversion elements of a set are selected.

In a cell composed of four dots, ideally, a maximum of five gradations can be expressed by setting how many of the four dots have an optical density of 1. Therefore, a method of expressing gradation will be described below. Here, it is defined that when the reflected light from the printing surface having the optical density of 1 is incident on the entire surface of one photoelectric conversion element, the optical value is 1, and it is proportional to the area of the incident photoelectric conversion element. As a result, the sum of the optical values of all photoelectric conversion elements corresponding to one cell is calculated, and the value obtained by dividing this by the number of photoelectric conversion elements becomes the gradation (average optical density) of the cell.

[For dot 1] Of the dots in the cell,
Assuming that one has an optical density of 1, if the dot of a (1,1) has an optical density of 1, in the combination A of photoelectric conversion elements reading this cell, B (1,1) has a quarter Since light with an optical density of 1 is incident on the area, the optical value at B (1,1) is 0.25, and similarly at B (2,1) is 0.5, B (3,
1) is 0.25, B (2,1) is 0.5, B (2,2)
2) is 1, B (2,3) is 0.5, B (3,1) is 0.25, B (3,2) is 0.5, and B (3,3) is 0.25. The total sum is an optical value of 4. In the same way, the optical values for combinations B, C, and D are 3, 3, 2.2, respectively.
5, the optical value obtained when one dot has an optical density of 1 is in the range of 2.25 to 4. This is 4 in the cell
It is the same regardless of which dot is selected from the two dots.

[Dot 2] Of the dots in the cell,
When two have an optical density of 1, and when a (1,1) and a (2,1) have an optical density of 1 as a vertically and horizontally adjacent combination, the optical value of the photoelectric conversion element combination A is 7, The combinations B, C, and D are 5.25, 7, and 5.25, respectively. On the other hand, as diagonal combinations a (1,1) and a (2,
When the optical density of 1 is 2), the optical values of the combinations A, B, C, and D are 6.25, 6, 6, and 6.25, respectively.

The expected value of the optical value in both the vertical and horizontal directions and the diagonal value (total sum ÷
The number of combinations is the same at 6.125, but the variation (difference between maximum and minimum ÷ expected value × 100) is about 29 in the vertical and horizontal directions.
%, The diagonal is about 4%, so when selecting 2 dots in a cell consisting of 4 dots, it is preferable to select diagonally.
Then, the optical value of two dots is in the range of 6 to 6.25.

[For dot 3] Of the dots in the cell,
Assuming that three have an optical density of 1, selecting three dots having an optical density of 1 in a cell is equivalent to selecting one dot having an optical density of 0, so this is the same as the case of one dot. Similarly, it does not depend on the choice. a (1,1), a
If (2,1) and a (1,2) are assumed to have an optical density of 1, the optical values of the combinations A, B, C, and D are 10, 925, and
It becomes 9.25 and 8.25, and the range of the optical value is 8.25 to 1.
It is 0.

[In case of dot 4] Optical density is 1 in all cells
In the case of, the optical value is 12.25. In the above description, all the peripheral cells other than the cell of interest have an optical density of 0, but actually, there are various patterns. In that case, B (1,1-5), B, which corresponds to the edge of the cell
(2,1), B (2,5), B (3,1), B (3,
5), B (4,1), B (4,5), B (5,1)
Since the reflected light from another cell adjacent to the cell is incident on the photoelectric conversion element of 5), an error occurs.
When all of the surrounding cells have an optical density of 0, the optical value of the photoelectric conversion element at the edge of the cell is 0, but when all of the surrounding cells have an optical density of 1, the photoelectric conversion elements B (1,
1), B (1,5), B (5,1), B (5,5) have a maximum optical value fluctuation of 0.75, and the photoelectric conversion elements at the other ends have a maximum optical value of 0. There is a fluctuation of .5.

Then, even when any one of the four combinations of the optical conversion elements is selected, the maximum fluctuation of the optical value is 3.75 (for example, B (1,1-4), B (2,2). 1 to
4), B (3,1-4), and B (4,1-4) are selected, B (1,2-4), B (2-4,1)
6 photoelectric conversion elements each have an optical value of 0.5, so a total of 3.0, and B (1,1) photoelectric conversion elements have an optical value of 0.5.
75). Now, as shown above, there are two cells
FIG. 9 shows the optical values obtained in the case where one dot is detected by four photoelectric conversion elements, which are formed from × 2 dots, in a tabular form.

In order to detect the gradation, it is necessary to set the optical density of the dots so that the variation amount of the optical value is larger than the variation amount of the optical value. In the above example,
Since the optical values of the dot 0, the dot 2, and the dot 4 are farther than the fluctuation amount, three values can be taken. In the above, an example in which one dot is detected by four photoelectric conversion elements has been described, but the optical value in the case of detecting one dot other than the number of four photoelectric conversion elements is shown in FIG. Indicate.

As can be seen from FIG. 10, if the number of photoelectric conversion elements per dot is 9 or more, the optical value at each dot number can be separated into five values even if the optical value varies. Is. Therefore, when a cell is formed by four dots and is divided into four or more values, one dot is detected by at least 9 and preferably 16 or more photoelectric conversion elements. Here, the number of photoelectric conversion elements is set to an integral multiple with respect to one side of one dot, but the number of photoelectric conversion elements may be other than an integral multiple, and the configuration of the cell is not limited to a square, and an optical obtained in a rectangle, a triangle, etc. Similar considerations can be applied for values and variations.

[Fourth Embodiment] Hereinafter, as a fourth embodiment of the present invention, an example in which there are more than four dots forming cells will be described. FIG. 11 shows a schematic diagram when a cell 16 is formed from a minimum dot of 9 dots and is read by a CCD in which photoelectric conversion elements 17 having a resolution twice the minimum dot are arranged. Here, a (1,1) to a (3,3) are cells 16
Is the smallest dot when printed that makes up B (1,1) ~
B (7, 7) indicates the arrangement of the CCD photoelectric conversion elements 17.

Here, when the position of the cell is shifted by a half of the pitch of the photoelectric conversion element 17, the photoelectric conversion element B
From (1,1) to B (7,7), B (1 to 6,1)
6), combination A or B (1-6, 2-7) combination B
Or a combination C of B (2-7, 1-6) or B (2
~ 7, 2-7) Any one of the four combinations D
A set of 36 photoelectric conversion elements is selected.

[Dot 1] Of the dots in the cell,
The method of selecting one is basically a (1,1), a (1,
2) and a (2,2), and the rest are equivalent to any of these three. If a (1,1) is the optical density 1, the optical values of the combined ABCD are 4, 3, 3, respectively.
At 2.25, the optical values of the dots at the four corners of the cell are 2.25 to 4. If a (1,2) is the optical density 1, then the optical values of the combined ABCD are 4, 4, respectively.
Three and three. When a (2,2) is the optical density 1, the optical value of the combination ABCD is 1 in all cases.

Therefore, when one dot has an optical density of 1, it is desirable that the dot of a (2,2) has an optical density of 1. Further, even when the number of dots forming a cell increases, it is possible to suppress the fluctuation of the optical value by changing the optical density from the central dot where the cell does not contact other cells.

[For dot 2] Of the dots in the cell,
The two selection methods are basically a (1,1) + a (1,
2), a (1,1) + a (1,3), a (1,1) + a
(2,2), a (1,1) + a (2,3), a (1,
1) + a (3,3), a (1,2) + a (2,1), a
(1,2) + a (2,2), a (1,2) + a (3,
There are 8 ways in 2), and the rest are equivalent to any of these 8. These eight optical values are a (1,1) + a
(1,2) is 5.25 to 8, a (1,1) + a (1,
3) is 5.25 to 7, a (1,1) + a (2,2) is 6.
25-8, a (1,1) + a (2,3) is 6.25 ~
7, a (1,1) + a (3,3) is 6.25, a (1,
2) + a (2,1) is 6 to 8, a (1,2) + a (2,
2) is 7 to 8, and a (1,2) + a (3,2) is 7.

As a result, when the pixels are arranged vertically or horizontally or diagonally with a (2,2) as the center, the variation of the optical value is small and a
When (2, 2) is included, the upper limit of the optical value becomes high,
If a (1,1) is included, the lower limit tends to be low. Here, a (1,
2) Select the pattern of + a (3,2).

[For dot 3] Of the dots in the cell,
Although there are many ways to select three, here, the case of dot 1 and the case of dot 2 are taken into consideration. By selecting a (2,2) selected by dot 1 and a (1,2) + a (3,2) selected by dot 2 from the point that the fluctuation of the optical value is small,
An optical value of 11 is obtained.

[Case of Dot 4] Optical values 14 to 15 can be obtained by adding a (2,1) from the dots at the ends excluding the four corners of the cell to the dot selected as the dot 3.

[Dot 5] The optical value is obtained by adding a (2,3) at a position symmetrical to a (2,1) with respect to a (2,2) to the dot selected by dot 4. 18 is obtained.

[In the case of dot 6] In the dot selected in dot 5, a (1,1) is set as one of the four corners of the remaining cells.
The optical values of 20.25-22 are obtained by adding.

[Case of Dot 7] By adding a (3,3) at a diagonal position of a (1,1) to a (2,2) to the dot selected by dot 6, Value 24-2
4.25 is obtained.

[In the case of dot 8] By adding a (1,3) as one of the remaining cells to the dot selected in dot 7, optical values of 26.25 to 28 are obtained.

[Case of Dot 9] When the optical density of all dots is 1, the optical value is 30.25.

Next, considering the influence from cells other than the cell of interest, when the photoelectric conversion elements of B (1-6, 1-6) are selected, B (2-6, 1) and B (1, 2 to 6) each have an optical value variation of 0.5, and B (1,1) has an optical value variation of 0.75, so that the maximum optical value variation is 5.75 at maximum. Here, as described above, FIG. 12 shows optical values obtained when cells are formed from 3 × 3 dots and one dot is detected by four photoelectric conversion elements in a table format. .

As can be seen from FIG. 12, in the example shown here, dot 0, dot 3, dot 6, and dot 9 are selected for gradation expression to obtain a difference in optical value larger than fluctuation. You can The fluctuations shown here and the optical values when all the dots have an optical density of 1 are the same as when the number of photoelectric conversion elements per dot is 9, as shown in Table 2 in Example 1. is there. This is because the total number of photoelectric conversion elements for detecting cells is the same, 36 in each case. Therefore, it can be seen that the fluctuation and the upper limit of the optical value are determined by the number of photoelectric conversion elements detecting cells. On the other hand, as the number of dots forming a cell increases, the optical value can be separated into a large number, and a large number of gradations can be expressed.

As can be seen from the fourth embodiment, the smaller the central area of a cell or the contact area with an adjacent cell, the smaller the contribution of fluctuations to the optical value. Therefore, when the number of dots forming a cell further increases, first change the optical density from the dot in the center of the cell, and then change the optical density of the dot with a small contact area with the adjacent cell at the edge of the cell. Change. Further, when the optical density of dots other than the central portion of the cell is changed, it is possible to suppress the fluctuation by simultaneously setting the optical density of the dots symmetrical with respect to the center of the cell. In the present embodiment, the vertical and horizontal directions of the cells are the same in the vertical and horizontal directions of the photoelectric conversion elements, but the vertical and horizontal directions of the cells are different from the vertical and horizontal directions of the photoelectric conversion elements. Also, the optical density is first changed from the dot in the center of the cell, then the optical density of the dot where the contact area with the adjacent cell is small is changed at the edge of the cell, and the optical density of dots other than the center of the cell is changed. When changing, the dots at positions symmetrical with respect to the center of the cell are effective to have the same optical density at the same time.

Further, when an image of a cell is formed on the photoelectric conversion element by an optical system having a high resolution capable of resolving each dot, each dot can be regarded as a cell. However, in that case, the fluctuation due to the influence of the peripheral dots is determined by the number of photoelectric conversion elements to be detected, and therefore the fluctuation of one dot is larger than that of the entire cell. Further, since the high resolution optical system has a shallow depth of focus, the error due to defocus is large. On the other hand, in the multi-gradation method, since one cell is formed by a plurality of dots, defocus at the center of the cell does not cause a detection error.

According to the two-dimensional code of the present invention, in a two-dimensional code represented in monochrome, a general-purpose printing device / printer / scanner / camera can be used in the same area compared to the conventional one without using a dedicated device. It is possible to store a large amount of data. Further, the two-dimensional code according to the present invention can be applied as it is to a two-dimensional code that has been colorized.

[Image Processing Apparatus] The two-dimensional code creation and data restoration according to the present invention described above are
For example, it can be realized by the image processing device 50 shown in FIGS. 13 to 15 and a program executed by the image processing device 50. As shown in FIG. 13, the image processing device 50 includes a main body including a CPU 500 and a memory 502, a recording device 510, a display / input device 520 such as a CRT display device and a keyboard, a digital camera 522, and the like.
It is composed of a scanner 524 and a printer 526.
That is, the image processing device 50 includes a component as a computer capable of reading and printing an image.

[Code Creation Program 60] FIG.
It is a figure which shows the structure of the code production | generation program 60 which produces | generates the two-dimensional code concerning this invention. The code creating program 60 includes a data receiving unit 600, a code creating unit 602, and a print control unit 604. The code creation program 60 is loaded into the memory of the image processing apparatus 50 via the recording medium 512 and executed, for example. The code creation program 60 converts the data received from the display / input device into a two-dimensional code by these components and prints it by the printer 526.

[Data Decoding Program 70] FIG.
It is a figure which shows the structure of the data decoding program 70 which decodes data from the two-dimensional code concerning this invention. As shown in FIG. 15, the data decoding program 70 includes a code reading unit 700, a code decoding unit 702, and a display control unit 704. The data decoding program 70 is also loaded into the memory of the image processing apparatus 50 via the recording medium 512 and executed. The data decoding program 70 decodes the original data from the two-dimensional code according to the present invention read from the digital camera 522, the scanner 524, etc., and displays it on the display / input device 524.

[0072]

As described above, according to the present invention,
According to the dimensional code system and the method thereof, the data capacity can be greatly increased as compared with the two-dimensional code of monochrome two colors. Further, according to the two-dimensional code system and the method thereof according to the present invention, even if the color printer / color scanner is not used, the data capacity is large.
A dimension code can be created and recorded, and the original data can be restored from this two-dimensional code.

[Brief description of drawings]

FIG. 1 is a diagram of a two-dimensional code shown as the background art of the present invention.

FIG. 2 is a diagram illustrating colorization of a two-dimensional code.

FIG. 3 is a diagram illustrating a cell of a color two-dimensional code according to the present invention.

FIG. 4 is a diagram exemplifying a pattern of cells included in a two-dimensional code according to the present invention.

FIG. 5 is a diagram showing a data area for storing data in a two-dimensional code and generally a position detection pattern for detecting the position of each cell.

FIG. 6 is a diagram showing a method of restoring data from a two-dimensional code.

FIG. 7 is a diagram illustrating a two-dimensional code according to the present invention to which density gradation is applied.

FIG. 8 is a diagram schematically showing a two-dimensional code according to the present invention to which surface gradation is applied.

FIG. 9 is a diagram showing, in a tabular form, optical values obtained when cells are formed from 2 × 2 dots and one dot is detected by four photoelectric conversion elements.

FIG. 10 is a diagram showing optical values in a table format when one dot is detected with a number other than four photoelectric conversion elements.

FIG. 11 is a schematic diagram when a cell is formed by a minimum dot of nine dots and is read by a CCD in which photoelectric conversion elements having a resolution twice that of the minimum dot are arranged.

FIG. 12 is a diagram showing, in a tabular form, optical values obtained when cells are formed from 3 × 3 dots and one dot is detected by four photoelectric conversion elements.

FIG. 13 is a diagram showing a configuration of an image processing apparatus.

FIG. 14 is a diagram showing a configuration of a code creating program for creating a two-dimensional code according to the present invention.

FIG. 15 is a diagram showing a data decoding program configuration for decoding data from a two-dimensional code according to the present invention.

[Explanation of symbols]

50 ... Image processing device 60 ... Code creation program 70 ... Data decryption program

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shoji Yamaguchi             430 Sakai, Nakai-cho, Ashigarakami-gun, Kanagawa Prefecture             Kunakai Fuji Xerox Co., Ltd. (72) Inventor Tetsuya Kimura             430 Sakai, Nakai-cho, Ashigarakami-gun, Kanagawa Prefecture             Kunakai Fuji Xerox Co., Ltd. (72) Inventor Hideaki Ashikaga             430 Sakai, Nakai-cho, Ashigarakami-gun, Kanagawa Prefecture             Kunakai Fuji Xerox Co., Ltd. F-term (reference) 2C055 JJ00 JJ07 JJ12                 5B035 BA01 BB03                 5B072 CC21 CC32 DD01 DD21

Claims (8)

[Claims] 1. A two-dimensional code system for converting data into a two-dimensional code including a plurality of cells in a two-dimensional array and restoring the data from the converted code, wherein the data is the two-dimensional code. Create the two-dimensional code by converting the color density of a plurality of cells included in
A two-dimensional code system having a two-dimensional code creating means and a two-dimensional code output means for outputting the created two-dimensional code as an image. 2. The two-dimensional code is represented by one color,
The light and shade of the color of the cell included in the two-dimensional code is 1
Expressed by a plurality of gradations of one color, the two-dimensional code creating means converts the data into the one-color gradation of each of a plurality of cells included in the two-dimensional code to generate the two-dimensional code The two-dimensional code system according to claim 1, which is created. 3. A data restoring means for restoring the data based on the gradation of one color of each of a plurality of cells included in the output two-dimensional code.
The two-dimensional code system described in 1. 4. The two-dimensional code is represented by a plurality of colors, and the shade of each cell included in the two-dimensional code is represented by superimposing gradations of each of the plurality of colors. The dimensional code creating means creates the two-dimensional code by converting the data into a superposition of gradations of each of the plurality of colors of each of the plurality of cells included in the two-dimensional code. Two-dimensional code system. 5. The data reconstructing unit according to claim 4, further comprising a data reconstructing unit that reconstructs the data based on gradations of the respective colors of the plurality of cells included in the output two-dimensional code. Dimensional code system. 6. The output means further outputs, in addition to the two-dimensional code, an image of a pattern showing gradations of colors expressing the shades of colors of a plurality of cells included in the two-dimensional code. The two-dimensional code system according to any one of 1 to 5. 7. A method of converting data into a two-dimensional code including a plurality of cells in a two-dimensional array and restoring the data from the converted code, wherein the data is included in the two-dimensional code. A method of converting the color densities of a plurality of cells to create the two-dimensional code and outputting the created two-dimensional code as an image. 8. A program for converting data into a two-dimensional code including a plurality of cells in a two-dimensional array and restoring the data from the converted code, wherein the data is included in the two-dimensional code. A program for causing a computer to execute a step of converting the color density of a plurality of cells to create the two-dimensional code and a step of outputting the created two-dimensional code as an image.