JPH0413752B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of reading a Tagata code that can represent several bits of information with one code.

[Prior art and its problems]

Conventionally, this Taneda type code has meshes arranged in a matrix, so when reading the position information of the meshes, that is, the code, it is not only necessary to align the meshes, but also takes a considerable amount of time. , This has the disadvantage that the code cannot be fully utilized.

[Purpose of the invention]

This invention takes into consideration these conventional drawbacks,
The purpose is to accurately know the position of the Tagata code and to read the data accurately.

[Summary of the invention]

In order to achieve the object, the present invention provides a reference line having a predetermined dimension in parallel with a plurality of tag-shaped cords arranged along a first direction, and scans this reference line within a predetermined angle. By this, the relative angle between the reference line and the scanning direction is determined, and from this relative angle, the scanning start point corresponding to each mesh of the taga code is determined using one end of the reference line as a reference, and from this scanning start point, each of the taga code is It is designed to read mesh data, which allows the scanning direction of the Tagata code to be allowed over a relatively wide range of angles.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In other words, in Fig. 2, reference numeral 1 indicates the basic configuration of the well-known Tagata cord. For example, four square meshes each having a side of 2 mm are combined in a square shape to form a Tagata cord having a side of 4 mm as a whole. be done. This field code can represent information of a predetermined number of bits by filling each mesh with a dark color, for example, black. For example, if four meshes are used, there will be 4 bits of information, and the number will be 16. If we assume that if none of the meshes are filled in, that is, in the case of light colors including white, it will be 0, then when all the meshes are filled in, it will be 15, and if the upper left mesh is filled in, it will be 1, and in the upper right corner. You can get 2 by filling out the area, 4 by filling out the bottom left, and 8 by filling out the bottom right.

In addition, a plurality of these T-shaped cords are arranged at predetermined intervals along the first direction, that is, the horizontal direction in FIG. In the second direction intersecting the direction, that is, in FIG. 1, the vertical direction is aligned. In FIG. 1, the Tagata code lines 1 and 1 are further provided with a second Tagata code line at an interval of 1 mm from the first Tagata code line. On one side of the first Tagata code row, a reference line 3 having a predetermined length is arranged at a predetermined interval from each Tagata code, that is, an interval of 1 mm, in the first direction, that is, parallel to the Tagata code row. be done. Further, in this first direction, one end, that is, the left end of the Tagata cords 1a ₁ and 1a ₂ located at the left end in FIG. The other end, that is, the right end of the Tagata code 1j ₁ and 1j ₂ located at the end, that is, the right end, coincides with the other end, that is, the right end of the reference line 3, respectively.

Next, the principle of the code reading method in the above configuration will be explained.

First, the reference line 3 and the taga codes 1, 1 are scanned in a first direction, that is, approximately along the first direction within a predetermined angle with respect to the reference line 3, and the direction of the scanning line in this scan is It progresses from the reference line 3 side toward the field code 1, 1 side along the direction intersecting the scanning direction.

The scanning direction for the reference line 3 and the Tagata codes 1, 1 is generally performed in an inclined state, so the coordinates are as shown in Figure 3A, with the direction in which the reference line 3 extends, that is, the horizontal direction, as the x-axis, and the reference line The direction intersecting with , that is, the vertical direction, is the y-axis.

When scanning is performed in this state, and if dark color, i.e., black pixels continue to a certain value or more, the x coordinates x ₀₀ , x ₀₁ and y coordinates y ₀₀ of both ends are set as the initial value of the reference line 3.
Find (Figure 3 B).

Next, the process moves on to the next scan, and similarly finds a line in which black pixels are continuous at a certain value or more. Then, the x coordinates x ₁₀ and x ₁₁ of both ends of the newly found line are calculated, and the x coordinate x ₁₁ of the other end point, that is, the right end point, is the x coordinate of one end of the line, that is, the left end point, found by the previous scanning line. If and only if the coordinate x is greater than ₀₀ and the x coordinate x ₁₀ of the left end point of the new line is smaller than the x coordinate x ₀₁ of the right end point of the line found by the previous scan line,
The area of the line that has been scanned up to that point and the new line are continuous in the axial direction. At the same time, update the coordinates of that line. To update the coordinates of this line, compare the x coordinate of the left end point of the line obtained by the previous scanning line, for example x ₁₀ , with the x coordinate of the left end point of the new line x ₂₀ , and if the x coordinate of the new line is If ₂₀ is small, update the left end point of reference line 3 and at the same time change the y value at that time.
Also update the coordinates. And when the x-coordinate of the left end of the new line is larger, its x-coordinate, for example x ₃₀
is not updated. Also, for the coordinates of various right end points, compare the x coordinate of the right end point found in the previous scan, for example x ₁₁ , with the x coordinate of the right end point of the new line x ₂₁ , and if the x coordinate of the right end point of the new line is If _x21 is large, the right end point of the reference line 3 is updated, and at the same time, the y coordinate is also updated. and x at the right end point of the new line
When the coordinate, for example x ₉₁ , becomes smaller than the x coordinate, for example x ₈₁ , of the right end point of the line found in the previous scan, that x coordinate is not updated.

From the above results, the right end point x shown in Figure 3 A and B,
The y coordinate and the x, y coordinates of the left end point are determined, and from these coordinates, the approximate inclination of the input image, that is, the reference line 3 and the Tagata codes 1 and 1 is determined.

Once the reference line 3 has been determined, the scanning start point corresponding to each mesh of each Tagata code is determined using the left end point as a reference. The positional relationship between the mesh of each field code 1 and the reference line 3 is known in advance as shown in Figure 1, so using this, we can move from the left end point of the reference line 3 in the y-axis direction as shown in Figure 4. 2.5
The points at mm, 4.5 mm, 7.5 mm, and 9.5 mm are the starting points for scanning the mesh of the leftmost field code 1a. As is clear from FIG. 4, the y-coordinate of the left end point of the reference line 3 correctly corresponds to each mesh of the field code 1 no matter where the position is within the reference line 3.

The slope of the input image is also calculated from the x and y coordinates of the left and right end points of the reference line 3, as shown in Figure 5, and the scanning start point of each mesh is corrected in the x and y directions from the left end point. The distance is proportional to the distance in the axial direction.

Once the scanning start point is determined, scanning is performed for 1 mm from that point, and if the number of pixels equivalent to 0.8 mm are continuously black, that mesh is determined to be black.

Furthermore, this code is converted and the value of each code is calculated.

As described above, this method allows recognition of a tag code that allows not only deviations in the x-axis and y-axis directions but also deviations in the rotational direction.

Note that if the angle between the input image and the scanning direction of the scanning line is extremely small, the reference line 3 is
location information can be obtained.

The code reading device 5 is composed of a reading section 7 and a controller section 8, as shown in FIG. This field code is attached to the two-dimensional image sensor 1 along with the reference line.
The images are input by making the second scanning direction and the first direction substantially coincide with each other. In this figure, reference numeral 11 denotes a light source consisting of a light emitting diode, which illuminates the object 6. lens 1
Reference numeral 6 guides reflected light from the object 6, that is, an image on the surface thereof, onto a two-dimensional image sensor 12, and this image sensor further photographs the image. The image sensor driver 13 reads out an image based on the output signal from the synchronization generation circuit 14 and outputs it to the signal processing circuit 15 . Binarization circuit 1
8 binarizes the input image signal that has undergone processing such as amplification and filtering by the signal processing circuit 15, and its threshold value is determined by the ratio of the average density value or maximum density value of one cycle before, etc. It is possible to set it automatically by

Further, in the controller section 8, a timing generation circuit 21 generates a clock signal.
The frame memory 23 receives a binarized image signal using a clock signal. The microprocessor 24 processes the contents of the information in the line memory 23 using the timing generation circuit 21 and obtains the mesh information of each field code 1. The code conversion circuit 25 converts the mesh information of the Tagata code 1 into a code value. The serial converter 26 converts the code value into serial data, and also converts the code value into serial data.
The 32C port 27 outputs serially converted data to the outside.

Next, the operation in the above configuration will be explained.

First, the tag code 1 printed on the object 6 is illuminated by the light source 11 in the scanning section 7, and is imaged by the two-dimensional image sensor 12 through the lens 16. On the other hand, the timing generation circuit 21 in the controller section 8
The clock signal generated by the image sensor driver is used to drive the synchronization generation circuit 14 in the scanning section 7, and the readout signal generated by this synchronization generation circuit is input to the image sensor driver 13. The image signal from the dimensional image sensor 12 is read out to the signal processing circuit 15. The image signal input to this signal processing circuit is then amplified and
After processing such as filtering, the binarization circuit 1
8 is input. Further, the binarized image signal is sent to the controller section 8, and inputted to the frame memory 23 by the clock generated by the timing generation circuit 21. Microprocessor 24 utilizes the clock signal from timing generation circuit 21 to implement the read method or algorithm described above. Next, code conversion circuit 25 receives each mesh signal from microprocessor 24 and converts it into a code value. When outputting this value to the outside in serial form, the code value is input to the serial conversion circuit 26 for serial conversion, and further outputted to the outside through the RS232C port 27.

FIG. 7 is a flowchart for determining the reference line 3, and finally the x and y coordinates of both ends of the reference line 3 are determined.

Further, FIG. 8 is a flowchart showing an algorithm for determining the mesh value of Tagata code 1.

〔Effect of the invention〕

As mentioned above, this invention is in parallel with the Tagata code.
A reference line is provided, and these are scanned within a predetermined angle with respect to the reference line, thereby determining the relative angle between the reference line and the scanning direction, and from this relative angle, one end of the reference line is set as the reference line. The scanning start point corresponding to each grid of the tag pattern code is determined by Of course, even if the scanning direction is slightly tilted with respect to the reference line, the data of the Tagata code can be read accurately. This has the effect of drastically reducing the burden on

[Brief explanation of drawings]

Fig. 1 shows an example of the method for reading the Tagata code according to the present invention, and is a layout diagram of its patterns, Fig. 2 is a configuration diagram of the Tagata code, and Fig. 3 is an explanatory diagram of the method for reading the reference line. Figures 4 and 5 are explanatory diagrams showing how to read the Tagata code, Figure 6 is a block diagram of the code reading device, Figure 7 is a flowchart for determining the reference line, and Figure 8 is for determining the mesh value of the Tagata code. This is a flowchart. 1...Tagata code, 3...Reference line, 5...Code reading device, 6...Object, 7...Reading section, 8
...Controller section, 11...Light source, 12...2
Dimensional image sensor, 13... Image sensor driver, 14... Synchronization generation circuit, 15... Signal processing circuit, 18... Binarization circuit, 21... Timing generation circuit, 23... Frame memory, 24...
Microprocessor, 25... code conversion circuit,
26...Serial conversion circuit, 27...RS232
C port.

Claims (1)

[Claims] 1 A plurality of grid-shaped codes, which are constructed by combining four rectangular meshes in a grid pattern and display codes by the shade of the color of each grid, are arranged in a predetermined manner along the first direction. They are arranged at intervals and with their respective axes aligned with a second direction intersecting the first direction, and a reference line having a predetermined dimension is placed at a predetermined interval from the above-mentioned Tagata code. , and disposed in a first direction, and further in this first direction.
In the direction of match each end of the
Scanning the reference line within a predetermined angle with respect to the reference line, and advancing the scanning line in this scanning from the reference line side toward the Tagata code side along a direction intersecting the scanning direction, And find the relative angle between the two from the reference line and the scanning direction,
Furthermore, from this relative angle, a scanning start point corresponding to each mesh of the above-mentioned Tagata code is determined using one end of the above-mentioned reference line as a reference, and data of each mesh of the above-mentioned Tagata code is read from this scanning start point. Features: How to read tagata codes.