JPH04100187A - Code reader - Google Patents

Abstract

PURPOSE:To improve reliability by contrasting a character code with a check sum character code, switching a threshold value deciding black-and-white unless the check sum character code to be generated from the character code matches the character code, and reading again. CONSTITUTION:An image recognition device 3 after reading character codes 4a - 4i and check sum character codes 4j and 4k judges whether or not hexadecimal character codes of digits 16<0> and 16<1> of hexadecimal numbers corresponding to the character codes 4a - 4i are equal to the check sum character codes 4k and 4j. When they do not match the check sum character codes, it is considered that a read error is caused and the threshold value 7 is changed; and a read is made again until the check sum character codes 4k and 4j match. Thus, when the character codes are read incorrectly, the threshold value for deciding black-and-white is changed and a read is made again, thereby improving the reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a code reading device that reads character codes through image processing.

[Conventional technology]

An example of a conventional code reading device is shown in FIG. 3 and will be described.

In this Figure 3, 1 is a wafer, 2Fi camera, 3I
i is an image recognition device connected to this camera 2. Further, 41 to 41 indicate character codes marked on the wafer 1.

Figures 4 to 7 are the operating bottom F of Figure 3! This is Ward A.

In FIG. 4, the same reference numerals as in FIG. 3 indicate corresponding parts.

FIG. 5 is an enlarged view of the character codes 41 to 4i in FIG. 4.

FIG. 6 extracts and shows the portion related to the character code 4a in FIG. 5, and 5th to 5f are black and white determination areas within the character code 4a.

Figure 7 is an explanatory diagram of when reading is performed. (-) indicates the case where the reading was performed correctly, and (b) indicates the case where the reading was performed incorrectly. be.

61 to 6f shown in FIG. 7 indicate brightness values corresponding to the black and white determination areas 51 to 5f shown in FIG. 6, and 7 is a threshold value for determining black and white.

Next, the operation will be explained.

First, in FIG. 3, among the character codes 41 to 41 marked on the wafer 1, character codes 41 to 4f are imaged by the camera 2, and the video signals thereof are input to the image recognition device 3.

Next, in the image recognition device 3, the character code 4 shown in FIG.
m, and pre-specified black and white judgment areas 5a to 5
For f (see Fig. 6), the brightness values 6&~6f shown in Fig. 7 (1) are determined, and the brightness values 6&~6f are determined using a threshold value 7 specified in advance to determine the brightness values 6m, 6m, etc. 6e
'er white', and the brightness values less than this are 6b, 6e, 6d,
It is determined that 6f is 1 black.

The character code 4a is read using this black and white information.

Then, character codes 4b to 41 are also read in the same manner.

[Problem to be solved by the invention]

Since the conventional code reading device is configured as described above and operates as described above, if the black/white discrimination is incorrect as shown in FIG. 7(b), the character code may be read incorrectly. , there was a problem that the reading process was completed.

This invention was made to solve this problem, and the object is to obtain a small code reading device that determines erroneous reading, changes the threshold value γ that determines black and white of brightness values 6a to 6f, and performs reading again p. shall be.

[Means to solve the problem]

A code reading device according to the present invention includes a camera that images a plurality of code marks and a code calculated from the code marks, and calculates the brightness value within the code mark from a signal output from the camera, and performs threshold processing. and read the code marks, and the code calculated from the multiple code marks read is calculated from the multiple code marks read! It is determined that the code is a code, detects an increase in erroneous readings, changes the threshold value, and performs reading again.

[Effect]

In this invention, the character code and the checksum character code are compared, and if the checksum character code is not the one that should be generated from the character code, the threshold value for determining black and white is changed and reading is performed again.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing an embodiment of a code reading device according to the present invention.

In FIG. 1, the same reference numerals as in FIG. 3 indicate corresponding parts, and the camera 2 is configured to image a plurality of code marks and codes calculated from the code marks. 4a to 41 are character codes marked on the wafer 1, and 4j and 4 are checksum character codes added on the wafer 1.

Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to FIG. 2.

First, change the black and white pattern of character code 4a marked on wafer 1 to 0616 + the black and white pattern of character code 4b to os.
16. The black and white pattern of character code 4c is 32, , the black and white pattern of character code 4d is 37t6. character code 4e
The black and white pattern of i34+s1 The black and white pattern of character code 4f is 30. ,, the black and white 'も turn of character code 41 is 3
216. The black and white pattern of checksum character code 4j is OA+g+the character pattern of checksum character code 4 is 0616, and hexadecimal numbers corresponding to the character codes are provided. And the total hexadecimal number of this character code 4 凰 ~ 4 quantity is 06+s +05+6+32+6+3716+34+6
+301g+30+g+3018+3218=16AI
It becomes 6. The rAJ that occurred in the 160 and 161 digits
4k checksum character code with 6" in hexadecimal
, 4j.

Next, the image recognition device 3 reads the character codes 4a to 41 and the checksum character codes 4j and 4k, and then reads the hexadecimal total value of 16 corresponding to the character codes 41 to 41.
Determine whether the hexadecimal character code generated in the digits 0 and 161 is the checksum character code 4 or 4j. As shown in FIG. 2, the threshold value 7 is changed and the reading pattern is slightly revised again to obtain a checksum character code of 4k.

Repeat until 4j matches.

As described above, the code reading system fl according to the present invention includes a plurality of code marks and a camera 2 that images a code calculated from the - mark, and the brightness value in the code mark is determined from the signal output from the camera 2. The code mark is read using threshold processing, and misreading is detected by determining that the code calculated from the multiple code marks read is the recruitment code calculated from the multiple code marks read. However, the above threshold value is changed and reading is performed again.

〔Effect of the invention〕

As described above, according to the present invention, the character code and the checksum character code are compared, and if the checksum character code is not the one that should be generated from the character code, the threshold value for determining black and white is changed and reading is performed again. Therefore, when a character code is read after waiting vA, it is possible to change the threshold value for black and white determination and read it again, which has the effect of greatly increasing reliability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the food reading device according to the present invention, FIG. 2 is an explanatory diagram of the operation of FIG. 1, and FIG.
The figure is a block diagram showing an example of a conventional food reading device, and FIGS. 4, 5, 6, and 7 are explanatory diagrams of the operation of FIG. 3. 1...-Wafer, 2--Camera, 38--Image recognition device, 41-41...Character code, 4j, 4--Checksum character code, 5a-5f--・
Black and white judgment area, 6a to 6f... Brightness value, 7...
·threshold.

Claims (1)

[Claims] It is equipped with a camera that captures images of multiple code marks and codes calculated from the code marks, and calculates the brightness value within the code marks from the signal output from this camera, performs threshold processing, and reads the code marks. Misreading is detected by determining that the code calculated from multiple code marks is the code that should be calculated from the multiple code marks read, and reading is performed again by changing the threshold value. A code reading device characterized by: