JP2000293645A - Dot code - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly read dots in a small printing area by arranging the dots at a pitch being about two times as long as their diameter between respective columns and also shifting dots to a column direction from the arrangement positions of dots in a 1st column by almost the diameter of a dot in a 2nd column to arrange them. SOLUTION: A printing part performing printing on a card defines the value of the best resolution pitch as, e.g. P0. Then, in a pixel (dot), its diameter becomes a value being equal to or slightly larger than the value P0. Even though the dot is not a perfect circle but regarded as a circle. Then, the diameter of the dot is defined as equal to the value P0 of the best resolution pitch. When the printing part prints a two-dimensional code on a card, it defines a length being about two times as long as the dot diameter as a printing pitch P in both horizontal and vertical scanning directions. However, when dots are observed in the direction of each column, a dot adjacent to the left or right side is shifted in the column direction for the value P0 of the best resolution pitch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dot code, and more particularly, to a dot code which can be reliably read even if a printing area is small.

[0002]

2. Description of the Related Art FIG. 1 shows an example of a conventional two-dimensional code. As shown in the figure, the two-dimensional code is composed of a group of blocks of a predetermined size. A predetermined code is represented by the presence or absence of a block at each position. Therefore, by printing such a two-dimensional code on a printed material, various kinds of information can be assigned to the printed material.

[0003]

However, since each of the above-mentioned blocks is composed of a plurality of pixels, there is a problem that the printing area of the two-dimensional code becomes large.

[0004] Therefore, for example, one block can be constituted by one dot when printing is performed by a printing device (printer). In this way, as shown in FIG. 2, for example, data can be represented by the presence or absence of pixels in units of a pitch P0 having the highest resolution of the printer.

However, when a pixel is to be printed at a predetermined position by a printer, even if one pixel (dot) is to be printed at a predetermined position, for example, as shown in FIG. Will vary.
As a result, where the outer periphery of the dot should be located at a position of radius r from the center of the original dot position, the radius R1 of the outer periphery C of the offset printed dot is larger than the radius r.

Further, considering the shift in the transport direction of the medium (paper) on which the dot code is printed by the printer, as shown in FIG. The radius R1 in the sub-scanning direction (right direction in the figure) is the same as the radius R1 in FIG.

As shown in FIG. 5, the diameter of each dot of the printer is set to a value equal to or slightly larger than the pitch P0 of the highest resolution of the printer. Therefore, as shown in FIG. 6, dots are printed at adjacent positions in the upper, lower, left, and right directions, and even in a case where dots are not printed at the center, the dots in the respective adjacent regions are printed out. When the two-dimensional code is read, there is a risk that the dot may be erroneously read as a dot also present in the central area. This becomes more remarkable when the displacement of the dot position described with reference to FIG. 3 or FIG. 4 is considered.

The present invention has been made in view of such a situation, and realizes a code which can be correctly read even with a small printing area.

[0009]

According to the dot code of the present invention, the dots are arranged in units of a pitch of about twice the diameter in each row and are adjacent to the first row. In the second row which is separated from the first row by a pitch which is about twice the dot diameter, the position of the dots in the first row is shifted in the direction of the row by about the dot diameter. It is characterized by being arranged.

[0010] In the dot code according to the first aspect, the dots are arranged in units of pitch of about twice the diameter of each row, and the dots are arranged from the first row adjacent to the first row. In the second row which is separated by about twice the pitch of the dot diameter, the dots are arranged in the direction of the row by the dot diameter from the dot arrangement position of the first row.

[0011]

FIG. 7 shows a configuration example of a printing apparatus to which the present invention is applied. In this configuration example,
Data (for example, audio data) corresponding to a two-dimensional code to be printed on the card 3 is input to the data processing unit 1. The data processing unit 1 converts the input data into a two-dimensional code pattern and outputs it to the printing unit 2. The printing unit 2 prints (prints) the print pattern input from the data processing unit 1 on a card 3 made of paper, plastic, or the like.

FIG. 8 shows an example of the card 3 on which the two-dimensional code is printed as described above. In this example, four two-dimensional codes 21-1 to 21-4 (hereinafter, referred to as four-dimensional codes 21-1 to 21-4)
When it is not necessary to distinguish these two-dimensional codes 21-1 to 21-4 individually, they are simply described as two-dimensional code 21. The same applies to other parts). The two-dimensional code 21-1 is divided into a header section 22-1 and a data section 23-1. Header section 22-
1, the type, version, and other information of the data recorded in the data section 23-1 are recorded. In this example, audio data is recorded in the data section 23-1. This means that the two-dimensional code 21-
The same applies to 2 to 21-4.

FIG. 9 shows an example of the configuration of a reading device for reading the card 3 on which the two-dimensional code 21 is printed.
The card 3 is placed on the belt 15 with the surface on which the two-dimensional code 21 is printed facing up. Motor 16 is belt 1
5, the card 3 is conveyed (moved) from left to right in the figure.

The light source 12 generates light in response to a light source control signal output from the image data reading unit control circuit 13,
Irradiate card 3. For example, the reading element 11 such as a CCD image pickup element is controlled by the image data reading unit control circuit 13 to take an image of the surface of the card 3 on which the two-dimensional code 21 is printed, and obtain an image signal obtained as a result of the imaging. Is output to the data processing unit 14.

The data processing unit 14 also receives a synchronization signal synchronized with the image reading operation from the image data reading unit control circuit 13. The data processing unit 14 binarizes the image signal input from the reading element 11 in synchronization with the synchronization signal input from the image data reading unit control circuit 13, performs a recognition process, and executes a binary code based on the recognition result. Generate The data processing unit 14 further converts the binary code into an analog audio signal, and outputs the analog audio signal to the speaker 20 via the amplifier 19.

The CPU 17 includes the data processing unit 14 and the motor 1
6 is controlled. The memory 18 appropriately stores data, programs, and the like necessary for the CPU 17 to execute various processes.

Next, the operation will be described. CPU1
Reference numeral 7 controls the motor 16 to drive the belt 15 when the start of reading is instructed by the user. As a result, the card 3 placed on the belt 15 is conveyed from left to right in the figure.

The CPU 17 controls the image data reading section control circuit 13 so that the light source 12 generates light and irradiates the card 3 with the light. At this time, the reading element 11 is controlled by the image data reading section control circuit 13 and reads the two-dimensional code 21 printed on the card 3. The data processing unit 14 binarizes the image signal input from the reading element 11, converts the image signal into binary data, and then converts the binary data into an analog audio signal. This analog audio signal is output to the speaker 20 via the amplifier 19.

Next, a two-dimensional code printed on the card 3 will be described with reference to FIG. In the printing unit 2 that prints on the card 3, the pitch value of the highest resolution is set to P0. Therefore, the pixel (dot) has a diameter equal to or slightly larger than the value P0. Microscopically, the dots are not perfect circles, but are substantially circular. The dot diameter means the diameter of the circle.
In the present specification, for convenience, the diameter of the dot is
It is assumed that it is equal to the pitch value P0 of the highest resolution.

When printing a two-dimensional code on the card 3, the printing unit 2 has a length approximately twice as large as the dot diameter in both the main scanning direction and the sub-scanning direction, as shown in FIG. Is the printing pitch P. However, when dots are observed in each column direction, dots adjacent to the left or right are shifted in the column direction by the pitch value P0 of the highest resolution.

As a result, for example, as shown in FIG. 11, even if the outer periphery C of the area where dots can be printed protrudes from a cell of size P0 × P0 into an adjacent cell, In the vertical direction, dots are not arranged, so that cells arranged and printed with dots protruding from adjacent cells are less likely to be erroneously determined as those where dots are located. .

For example, in FIG. 11, there is no dot in the cells C14 and C34 vertically adjacent to the cell C24 and in the cell C25 adjacent to the right. Therefore, most of the dot protrusion from the cell C24 is from the cell C23 adjacent to the left side.

The ratio of the protrusion of the cell C23 is larger in the sub-scanning direction (horizontal direction in the drawing) than in the main scanning direction (vertical direction in the drawing).
As described above, of the two cells C23 and C25 adjacent to the cell C24 in the sub-scanning direction, the dot is not arranged in the cell C25, and thus the protrusion of the dot in the cell C24 does not become so large.

In the cell C33, the dots of the two cells C23 and C43 adjacent in the main scanning direction protrude, but the protruding amount in the main scanning direction is smaller than that in the sub-scanning direction. . Therefore, cell C3
The amount of the dot protruding from the adjacent cell with respect to No. 3 is not so large.

Therefore, if the dots are arranged as shown in FIG. 11, the possibility that the dot is erroneously determined to be located in the cell where the dot is not located is reduced.

FIG. 12 shows a dot arrangement for comparison with the dot arrangement shown in FIG. In the example of FIG. 12, the dots are shifted in each row by the pitch P0, but the printing pitch is P0 in both the main scanning direction and the sub-scanning direction. In other words, in this example, the dots are arranged in a dotted pattern. With this arrangement, for example, the cell C23 protrudes from the adjacent cells C22 and C24 in the sub-scanning direction. As a result, there is a possibility that the dot is erroneously determined as being located in the cell C23.
Therefore, such an arrangement is not preferable.

[0027]

As described above, according to the dot code according to the first aspect, the dots are formed in each row by about 2 times the diameter thereof.
In a second row adjacent to the first row and separated from the first row by a pitch of about twice the diameter of the dot, the dots of the first row are arranged in units of double pitches. Since the dots are arranged so as to be shifted from the arrangement position by the dot diameter in the row direction, a dot code that can be read accurately can be realized without increasing the printing area so much.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a conventional two-dimensional code.

FIG. 2 is a diagram illustrating a conventional dot code.

FIG. 3 is a diagram illustrating a shift of a dot printing position.

FIG. 4 is a diagram for explaining a shift of a printing position of a dot.

FIG. 5 is a diagram illustrating a dot diameter and a pitch.

FIG. 6 is a diagram illustrating a state of a dot whose printing position is shifted.

FIG. 7 is a diagram illustrating a configuration example of a printing apparatus to which the present invention has been applied.

FIG. 8 is a diagram illustrating a printing example of the card 3 of FIG. 7;

FIG. 9 is a block diagram illustrating a configuration example of a card reading device to which the present invention has been applied.

FIG. 10 is a diagram illustrating a printing state of dots.

FIG. 11 is a diagram showing a printing state of dots.

FIG. 12 is a diagram illustrating a printing state of dots.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Data processing part 2 Printing part 3 Card 11 Reading element 12 Light source 13 Image data reading part control circuit 14 Data processing part 15 Belt 16 Motor 17 CPU

Claims (1)

[Claims] 1. A dot code composed of a plurality of dots, wherein the dots are arranged in units of a pitch of about twice the diameter of each row, and are adjacent to a first row. In a second row that is separated from the first row by a pitch that is about twice the diameter of the dot, the position of the dot in the first row is equal to the diameter of the dot in the second row. A dot code that is displaced in the direction of.