JPS642996B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention creates a code by attaching a plurality of ring-shaped marks to the circumference of a pipe or bar, and distinguishes the code two-dimensionally using a two-dimensional sensor, thereby preventing reading errors. The present invention also relates to a method for reading codes for tracking pipes and bars, which allows the codes to be reliably identified without having to take any measures against changes in the diameter of the pipes or bars.

In general, ring-shaped barcode reading devices used on manufacturing lines for steel pipes and bars include devices that use a laser scan method, beam switches, and devices that use a one-dimensional CCD (line sensor). The ring-shaped barcode was also read linearly. For this reason, the barcode may be contaminated with roller bearing related lubricating oil, anti-rust oil, scale, etc., or the barcode itself may be partially damaged due to contact or friction with the roller bearing-related lubricating oil, anti-rust oil, scale, etc. It had the disadvantage of peeling off and causing reading errors.

Conventionally, in order to eliminate this reading error, multiple reading sensors are provided in the circumferential direction to ensure reliable reading, but errors can still occur if the barcode is heavily soiled. However, there were also drawbacks that led to increased costs.

In addition, in the past, when changing the diameter of steel pipes, steel bars, etc., it was necessary to preset the sensor position to keep the object distance constant, or to correct changes in the field of view due to changes in the object distance. had to know this before reading.

The present invention improves and eliminates the above-mentioned drawbacks of the conventional technology by attaching a plurality of ring-shaped marks to the circumference of a pipe or bar to code the code, and using a two-dimensional sensor to encode the code into a two-dimensional image. This invention relates to a method for tracking and reading pipes and bars, which prevents reading errors and reliably identifies codes without having to take any measures against changes in the diameter of the pipe or bar.

The method of the present invention will be explained below based on the case of tracking a pipe material.

FIG. 1 shows a specific embodiment of the present invention. In the figure, 1 is a steel pipe, 2 is a detector for detecting the pipe end 1a of the steel pipe 1, which is composed of emitter/receiver 3 and 4, and 5 is a circular detector at a position a predetermined distance from the pipe end 1a of the steel pipe 1. It is a plurality of ring-shaped barcodes provided around the circumference. The barcode 5 is
As shown in FIG. 2, a reading start position mark 5a,
It has codes 5b to 5m representing the contents and a reading end position mark 5n. 6 is a strobe that emits light at regular intervals according to the signal from the tube end detector 2; 7 is a two-dimensional sensor as an imaging device; 8 is the sensor 7;
9 again on the monitor TV displaying the signal from
is a device that performs image processing on the signal from the two-dimensional sensor 7.

This device 9 stores the still image captured by the strobe 6 and the two-dimensional sensor 7, binarizes it at a predetermined slice level, and marks the reading start position on the binarized image (ring-shaped barcode on one end). and the reading end position mark (ring-shaped barcode on the other end side) are individually counted, and if the counted value is greater than or equal to a predetermined reference value, it is determined that there is a mark, and a predetermined If it is below the standard value, there is no mark.
and determine the field of view. Then, in accordance with this, a window section 11 of a predetermined width is set in a portion corresponding to each constituent bit of the code section indicating the content, and the number of pixels in which the mark on the screen is detected is individually determined. Count. If the number of pixels in each window part 11 is more than a certain number, it is "marked".
If the number is less than a certain number, it is determined that there is no mark. And “1” for “marked”
is given, "0" is given to "no mark", and the code is determined as a binary code in which the reading start position mark side is the most significant bit and the end position mark side is the least significant bit.

The width and spacing of the window section 11 of the image processing device 9, the width and spacing of the barcode 5, and the number of reference pixels are determined based on the distance between the two-dimensional sensor 7 and the steel pipe 1, and the distance between the two-dimensional sensor 7 and the steel pipe 1. It is determined by taking into consideration the field of view, etc.

In a system with such a configuration, the steel pipe 1 is first transported as indicated by the arrow in FIG.
blocks the emitter/receiver 3 and 4 of the tube end detector 2,
The strobe light 6 starts emitting light at regular intervals for a given period of time. Then, in synchronization with this, 2
A still image is projected onto the dimensional sensor 7, monitor television 8, and image processing device 9. The image processing device 9 stores the above-mentioned still image and continues signal processing from the two-dimensional sensor 7 until the reading start position mark 5a and the reading end position mark 5n are captured on the entire screen 10 of the image processing device 9. That is,
The entire code mark 5 is the screen 1 of the two-dimensional sensor 7
Continue until caught within 0. Note that the size of the field of view of the two-dimensional sensor 7 can be set arbitrarily;
By setting this to a large value, it is not only easy to catch the entire code mark 5, but also it is possible to judge changes in the outer diameter of the steel pipe 1 without having to take any measures. On the other hand, the number of pixels corresponding to the width of the mark on the screen decreases and the resolution deteriorates, so the field of view is determined by these considerations.

In the image processing device 9, as shown in FIG. 2, edge detection of the reading start position mark 5a is performed by checking the number of pixels in each vertical column from the end of the binarized image 10 on the side of the reading start position mark. This is the first column in which the number of pixels detecting marks is equal to or greater than a predetermined ratio to the number of pixels in that column. Similarly, check from the other end to find the edge of the reading end position mark. In this way, the reading start position mark 5
Once a and the final position mark 5n are known, the number of pixels detecting the mark in the window section 11 provided corresponding to each constituent bit of the code 5 is counted. And if this is more than a predetermined standard number,
The area of each window portion 11 is given "1" as "marked", and if it is less than a predetermined reference number, "0" is given as "no mark". Perform this operation for all bits from 5b to 5m,
The obtained string of "1" and "0" is read as a binary code in which 5b is the most significant bit and 5m is the least significant bit.

As explained above, in the present invention, a plurality of ring-shaped marks are attached to the circumference of a pipe or a bar to code it, and the code is discriminated two-dimensionally using a two-dimensional sensor. There are no reading errors even if there is dirt etc. In addition, since the field of view is automatically detected each time a reading operation is performed, the field of view can be set arbitrarily.If this field of view is set large in advance, there will be no need to deal with changes in the diameter of the pipe or bar, and the code can be read easily. Discrimination is possible.

[Brief explanation of drawings]

FIG. 1 is an overall system diagram showing one embodiment of the present invention, and FIG. 2 is a drawing showing the relationship between the screen of an image processing device and the code of a steel pipe in the same embodiment. 1... Steel pipe, 5... Cord, 5a to 5n...
Mark, 7...2D sensor.

Claims (1)

[Claims] 1. Put multiple ring-shaped marks on the circumference of the pipe/bar to code it, place a two-dimensional sensor close to the pipe/bar, and check whether the code is within the identification area of the two-dimensional sensor. This is determined based on whether the counts of the number of pixels of the ring-shaped mark on one end and the ring-shaped mark on the other end captured on the screen of the two-dimensional sensor are respectively above or below a predetermined reference value. , the number of pixels detecting the mark on the screen corresponding to each coded mark at the time when all the codes enter the identification area of the two-dimensional sensor is counted, and the counted value is calculated. A code for tracking pipes and bars, characterized in that the presence or absence of each coded mark is determined individually depending on whether it is above or below a predetermined reference value, and the contents of all codes are judged. How to read.