JPH03126185A - Reading method for bar code - Google Patents

Abstract

PURPOSE:To accurately discriminate a bar code in a short time by finding an irregular waveform by scanning an irregular bar code with an optical range sensor, superimposing the irregular waveform on a waveform delayed by a certain time, comparing the wave with the height and width of the bar code set as reference, and discriminating the pattern of the bar code. CONSTITUTION:The irregular waveform is found by scanning the irregular bar code 1 engraved on the surface of an object with the optical range sensor 2, and the height and width of a bar is detected from an intersection generated when the irregular waveform is superimposed on the waveform delayed by the certain time. And the pattern of the bar code 1 can be judged by comparing those height and width with that of the bar code 1 that becomes reference. Thereby, it is possible to read the bar code 1 at high speed, and to discriminate it in a short time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for reading uneven barcodes engraved, for example, on the side of a tire. This also relates to a method for reading barcodes that can be read with high accuracy.

[Conventional technology]

Conventionally, as a method for sorting tires, etc. of various sizes that are being transported and determining objects to be transported to the next process, for example,
As disclosed in Japanese Unexamined Patent Publication No. 131074/1982, an uneven barcode formed on the surface of an object is scanned by a displacement sensor to determine the area of the uneven waveform, and the obtained area and the reference area are A barcode reading method is known in which the pattern of a barcode is determined by comparing it with the barcode pattern.

Incidentally, in recent years, with the increase in tire production, in order to sort tires at high speed, it has become necessary to read uneven barcodes engraved on the tire side portions at a higher speed than currently available.

[Problem that the invention seeks to solve]

However, in the conventional barcode reading method based on the uneven waveform area, in order to detect thick bars and thin bars from the read waveform of the uneven barcode, upper and lower limits that follow the height displacement of the waveform are set. barcodes were read by comparing the area between them. However, with this method, when scanning a barcode at high speed, the accuracy of thick bars and thin bars is high compared to the collapse of the waveform of thin bars. It cannot be detected well,
Therefore, there is a problem in that barcode reading accuracy is also lowered.

Further, in the case of the conventional method of reading a barcode from the area of the uneven waveform, computer processing is required to calculate the area, which also causes a problem that the processing speed becomes slow.

[Purpose of the invention]

This invention was devised by focusing on such conventional problems, and it is possible to read uneven barcodes engraved on the surface of objects at high speed, and also to identify barcodes in a short time. Its purpose is to provide a method for reading codes.

[Means for Solving the Problems] In order to achieve the above object, the present invention uses an optical distance sensor to scan an uneven barcode engraved on the surface of an object to obtain an uneven waveform. A bar detection and determination device finds the intersection that appears when this uneven waveform is superimposed on a waveform delayed by a certain amount of time, and detects the height and width of the bar from this intersection, allowing high-speed barcode reading. The purpose is to make the determination in a short time.

[Action of the invention]

The present invention is configured as described above, and an uneven barcode engraved on the surface of an object is scanned by an optical distance sensor to obtain an uneven waveform. The barcode can be read at high speed by detecting the height and width of the bar from the intersection that is created when they are overlapped, and comparing this with the height and width of the standard barcode to determine the barcode pattern. It is characterized by being able to make a distinction in a short period of time.

[Embodiments of the invention]

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

FIG. 1 shows a schematic configuration diagram of a barcode reading device embodying the present invention, in which 1 shows an uneven barcode formed on the surface of an object, 2 shows a known laser distance sensor, and this laser The distance sensor 2 is connected via an analog filter circuit 3 to a microcomputer 4 (discrimination control device) that detects and judges barcodes, and the microcomputer 4 is further connected to a host computer 5.

The laser distance sensor 2 scans the uneven barcode 1 formed on the surface of an object at a constant speed to obtain a waveform, which is then passed through the analog filter circuit 3 to detect and determine the barcode. The barcode is detected and determined by inputting it into the microcomputer 4 which performs the following.

Next, a method for reading the uneven barcode 1 will be specifically explained.

FIG. 2 shows a waveform Q when the barcode 1 formed on the surface of an object is detected by the laser distance sensor 2. In the embodiment of the present invention, the waveform Q read by the laser distance sensor 2 is It is shown superimposed on a waveform in which Q is delayed by a small amount of time.

In FIG. 2, M1 to M are the heights of the intersections near the maximum value of the waveform Q, m1 to m are the heights of the intersections near the minimum value of the waveform Q, LI""Lh is the time at that time, L, ~L4 indicate the length (radius) of the detected bar.

In this embodiment, a laser distance sensor 2 scans an uneven barcode 1 formed on the surface of an object to obtain an uneven waveform Q, and this waveform Q is passed through an analog filter circuit 3 to a barcode. 1 and stored in the microcomputer 4, which performs detection and determination, and finds the intersection between the phase-shifted delayed waveform Q and the original waveform Q. Then, the length of the bar LI-L4 is determined from the time between the intersection points near the minimum values of the uneven waveforms Q and Q, and this bar length Ll''''L4 is used as the length of the barcode 1 as a reference. By comparing, the pattern of barcode 1 is determined.

This determination method is specifically shown in the flowchart of the barcode 1 reading method shown in FIG. 3, where H indicates the height of the waveform Q and SN indicates the waveform noise.

Start scanning with laser distance sensor 2 (START)
The height H of the waveform Q is obtained by subtracting the minimum value (X) from the maximum value (Mx) of the waveform Q.

If the height H of this waveform Q is larger than the waveform noise SH, the result is YES and the process proceeds to the inspection of the first barcode l, and if it is smaller, the result is No and the waveform Q is returned again.
Find the height H.

After inspecting the first barcode l, the uneven waveform Q,
Distance from the difference in time t between the intersections near the minimum value of Q! L+-
L4 is determined, and this distance l1lILl~L4 is detected as the width of the bar.

In addition, in Fig. 2, the reason that the value of L is ts-ti instead of t4t is because the value of M, -m4 (height of the bar) is smaller than the noise value SH. .

In this way, the value of L can be determined correctly by comparing it with the noise value SH.

In the embodiment of the present invention, a laser distance sensor 2 is used to detect a barcode 1 having a concavo-convex shape engraved on the surface of an object.
is scanned to obtain the uneven waveform, and the microcomputer-4
The width of the bar is detected from the intersection of the uneven waveform and the delayed waveform near the minimum value, and the barcode can be read at high speed and determined in a short time.

〔Effect of the invention〕

This invention scans the uneven barcode engraved on the surface of an object as described above with an optical distance sensor to obtain an uneven waveform, and superimposes this uneven waveform with a waveform delayed by a certain amount of time. The width of the bar is detected from the time difference between the intersection points near the minimum value when the bar code is detected, and the bar code pattern is determined by comparing this with the height and width of the standard bar code. It is possible to read uneven barcodes engraved on the surface at high speed and accurately identify them in a short time.Also, unlike the conventional discrimination method based on area calculation, no computer processing is required due to area calculation. This has the effect of increasing processing speed and improving work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a barcode reading device embodying the present invention, FIG. 2 is an explanatory diagram showing a waveform detected by a laser distance sensor on a barcode formed on the surface of an object, and FIG. The figure is a flowchart of a barcode reading method. 1...Barcode, 2...Laser distance sensor,
3... Analog filter circuit, 4... Microcomputer (discrimination control device), 5... Host computer,
Q, Q, ... uneven waveform. Figure 3

Claims (1)

[Claims] A bar code that scans an uneven barcode formed on the surface of an object with a sensor to obtain an uneven waveform, and then compares the waveform width of the protrusions of this obtained waveform with a reference width to determine the barcode pattern. In the code reading method, an uneven barcode engraved on the surface of the object is scanned with an optical distance sensor to obtain an uneven waveform, and this uneven waveform is superimposed on a waveform delayed by a certain amount of time. A method for reading a barcode, which is characterized in that the height and width of a bar are detected from the intersection points that occur at the time of the barcode, and the height and width of the barcode are compared with the height and width of the barcode as a reference to determine the pattern of the barcode.