JPH06213624A - Labeled line position measurement method for belt-like member - Google Patents

Abstract

PURPOSE:To measure a labeled line position of a belt-like member highly precisely and quickly and to improve reliability of the measurement at the same time. CONSTITUTION:A top tread 20 is stuck on a belt forming device 10 and a labeled line 22 is drawn in the center of the width direction of the top tread 20. A video camera 28 having a shutter is provided in the position which faces the labeled line 22 of the top tread 20 stuck on the belt forming device 10. The video camera 28 with a shutter is connected to a control device 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a marking line position measuring method for measuring the marking line position of a belt-shaped member such as a tire tread attached to a drum.

[0002]

2. Description of the Related Art Conventionally, as an example of an apparatus for detecting the position of an object, Japanese Patent Application Laid-Open No. 2-44202 discloses an apparatus for detecting the end position of the object. In this apparatus, a threshold is determined from the measured lightness and darkness of the waveform, and the measured waveform data is binarized by this threshold.

However, this apparatus has a problem that it is difficult to determine a correct threshold and the edge position of an object cannot be correctly detected when the contrast of the measured waveform is small.

On the other hand, in a tire manufacturing process, there is a work of winding a belt-shaped top tread into a ring shape on a belt forming drum. This work does not meander the top tread and also in the longitudinal direction. Since it is necessary to prevent both ends from shifting in the width direction, it is extremely difficult,
It was a job that required skill.

An example of a method and apparatus for winding a belt-shaped member for facilitating this work is disclosed in JP-A-3-477.
There is one disclosed in Japanese Patent No. 43.

In this apparatus, the protrusion formed in the center of the top tread is detected by a detector such as a reflection type photoelectric sensor which scans on the screw shaft arranged along the width direction of the top tread to detect the top tread. The position in the width direction is calculated.

However, in this apparatus and method, since it is necessary to provide the top tread with a protrusion,
The manufacture of the top tread becomes complicated, and measurement errors are likely to occur when the projecting shape (height and width) is small.
Further, it is necessary to scan the worm gear with the detector, which causes a problem that the measurement time becomes long.

Further, since a detector such as a reflection type photoelectric sensor is used, it is easily affected by gloss and unevenness of the measured object, the accuracy and reliability are low, and the measured object does not stand still. There is a problem such as being unable to measure.

[0009]

SUMMARY OF THE INVENTION In consideration of the above facts, the present invention can measure the marker line position of the belt-shaped member with high accuracy and high speed and can improve the reliability of the measurement, and the marker line position of the belt-shaped member. The purpose is to obtain a measurement method.

[0010]

The present invention according to claim 1 provides a marker line position measuring method for measuring a marker line position drawn in advance on a belt-shaped member such as a tire tread attached to a drum. A step of drawing a marker line at a center position in the width direction of the belt-shaped member or a position at a constant distance from the center, and a step of imaging the position of the marker line on the circumference of the belt-shaped member with a video camera while rotating the drum. And a step of A / D converting the brightness of each pixel in the image captured by the video camera, and the tread width of the brightness obtained by integrating the brightness of each A / D converted pixel in the length direction of the tread. The method is characterized by including a step of obtaining a histogram of directions and a step of obtaining the position of the marker line at each photographing point from the data of the histogram.

[0011]

According to the marker line position measuring method for a belt-shaped member of the present invention as set forth in claim 1, a marker line is drawn at a center position of a belt-shaped member such as a tire tread or at a certain distance from the center, and the belt-shaped member is attached to a drum. To wear. Next, the position of the marking line on the circumference of the belt-shaped member is photographed by a video camera while rotating the drum. The brightness of each pixel in the image captured by these video cameras is A / D converted, and the brightness of each A / D converted pixel is integrated in the length direction (circumferential direction) of the strip-shaped member to be displayed in the window. A histogram of the luminance of the strip-shaped member in the width direction (axial direction) is obtained. Next, the position of the marker line at each photographing point is obtained from the data of this histogram.

Therefore, even if the contrast of light and darkness of the actually measured image is small, the marker line can be correctly detected by the histogram, and it is not necessary to scan the detector. Since it is less likely to be affected by, it is possible to detect the marker line position of the belt-shaped member with high accuracy, high speed, and high reliability.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a belt forming machine 10 as a cylindrical drum is connected to a drive motor 14 by a rotary shaft 12, and the drive motor 14 moves in the direction of arrow A in FIG. It is designed to be rotated. The drive motor 14 also includes a pulse encoder 15, and the output of the pulse encoder 15 is input to the control device 18.

A belt-shaped top tread 20 is attached along the circumferential direction at the center of the belt forming machine 10 in the width direction, and both longitudinal end portions 20A and 20B of the top tread 20 are connected to each other. ing. Further, the marker line 22 is drawn in red or white at a certain distance from the center of the top tread 20 in the width direction.

A video camera 28 with a shutter is provided at a position near the belt forming machine 10 facing the marking line 22 of the top tread 20, and the output of the video camera 28 with a shutter is input to the control device 18. There is.
An incandescent lamp 30 (which may be a high-frequency light source such as a fluorescent lamp) for illuminating the vicinity of the marker line 22 of the top tread 20 is provided near the video camera with shutter 28, and the marker line of the top tread 20 is provided. 22 areas are constantly illuminated.

The window 34 is set in a rectangular shape across the marker line 36 in the image 32.
The size of 4 is determined by predicting the meandering amount of the top tread 20. For example, when the amount of meandering is about 20 mm,
The width of the window 34 is about 30 mm.

As shown in FIG. 2, the control device 18 includes an arithmetic unit 40, an image memory 42, a set value memory 44,
The input port 46 and the A / D converter 50 are provided, and the image output terminal of the video camera 28 with a shutter is an A / D
It is connected to the input port 46 of the arithmetic unit 40 via the converter 50.

The output of the pulse encoder of the drive motor 14 is connected to the input port 46 of the arithmetic unit 40 to input an image at a predetermined position on the circumference of the belt forming machine 10.

An image of the photographed portion on the circumference of the top tread 20 photographed by the shuttered video camera 28 (in the embodiment, about 8 places including both longitudinal end portions 20A and 20B of the top tread 20) is A / The D converter 50 digitizes the brightness of each pixel 35 (for example, 256 × 256). The digitized data is once recorded in the image memory 42, and thereafter, in each rectangular image 34 in which each pixel 35 is set in an area including the marker line 36 as shown in FIG. Then, the luminance is integrated in the lengthwise direction of the top tread 20 (direction of arrow A in FIG. 1), that is, in the vertical direction in FIG. 4, and as shown in FIG. It is designed to create a histogram of values. The window 34 is set in a rectangular shape across the marker line 36 in the image 32, and the size of the window 34 is determined by predicting the meandering amount of the top tread 20. For example, when the meandering amount is about 20 mm, the width of the window 34 is set to 3
It is about 0 mm.

Further, the control device 18 calculates the position of the marker line 22 of the top tread 20 at each photographing location from the maximum value P of each histogram at each photographing location, and the marker line 22 is calculated.
And the position previously recorded in the setting value memory 44,
The normal sticking reference position of the top tread 20 of the belt forming machine 10 is compared, and the quality of the sticking position of the top tread 20 is judged from the difference, and the judgment result and the deviation amount are displayed on the display panel 51 and the circumference of the top tread 20 is judged. It is designed to be displayed together with each shooting location.

The operation of this embodiment will be described below. In the marker line position measuring method for the belt-shaped member of the present embodiment, the marker line 22 is drawn at a constant distance from the center of the top tread 20 in the width direction, and the top tread 20 is attached to the belt molding machine 10. Next, the drive motor 14 is operated and the belt molding machine 10 is rotated, and the vicinity of the marker line 22 is photographed by the video camera 28 with a shutter at a photographing position on the circumference of the top tread 20.

Next, the image data of the image 32 taken by the video camera 28 is input to the control device 18.

Next, the brightness of each pixel 35 is set to A / D.
A / D conversion is performed by the converter 50 (see FIG. 4) and is temporarily recorded in the image memory 42, and the brightness of each pixel 35 is set in the rectangular window 34 set in the area including the marker line. The top tread 2 of the brightness in the window 34 is integrated in the length direction (vertical direction in FIG. 4).
A histogram (see FIG. 5) in the width direction (axis direction) of 0 is obtained.

Next, the peak value P at each photographing position, that is, the position of the marker line 22 of the top tread 20 is obtained from the data of this histogram. Note that the position in the tread width direction corresponding to the peak value P may be the position of the marker line 22, but as shown in FIG. 5, the position in the width direction X1 of the tread corresponding to the luminance integrated value lower by a predetermined position A than the peak value P. , X
It is better to set the midpoint of 2 to the position of the marker line. The quality of the pasting position of the top tread 20 is determined from the difference between the position of the marker line 22 and the normal pasting reference position of the top tread 20 recorded in the preset value memory 44, and the determination result and the deviation amount are displayed on the display panel. It is displayed at 51 together with the shooting locations on the 20 laps of the top tread.

Therefore, even when the contrast of light and dark in the actually measured image is small, the marker line 22 of the top tread 20 can be correctly detected by the histogram, and it is not necessary to scan the detector, and the object to be measured can be measured. Top tread 2 because it is not easily affected by the gloss and unevenness of
The marker line position of 0 can be detected with high accuracy, high speed, and high reliability, and also the step deviation of the joint portions of the longitudinal end portions 20A and 20B of the top tread 20 can be detected.

In this embodiment, the pulse encoder 1
Although the image is input at a predetermined position on the circumference of the belt molding machine 10 in FIG.
The predetermined position of 2 may be detected by a proximity switch or the like. Further, the video camera with shutter 28 may be a video camera without a shutter as long as the drum rotation speed at the time of image pickup is sufficiently slow.

[0028]

As described above, since the marking line position measuring method of the belt-shaped member of the present invention has the above-mentioned structure, the marking line position of the belt-shaped member can be measured with high accuracy and high speed, and the reliability of the measurement can be improved. It has an excellent effect of being able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing main members used in a marker line position measuring method for a belt-shaped member according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control device used in a method for measuring a marker line position of a belt-shaped member according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a video image of a method for measuring a marker line position of a belt-shaped member according to an embodiment of the present invention.

FIG. 4 is a data table showing a luminance distribution of a video image in the method for measuring the marker line position of the strip-shaped member according to the embodiment of the present invention.

FIG. 5 is a histogram of luminance integrated values in the tread width direction in the marker line position measuring method for a strip-shaped member according to the example of the present invention.

[Explanation of symbols]

 10 Belt Forming Machine (Drum) 14 Drive Motor 18 Control Device 20 Top Tread (Band-shaped Member) 22 Marking Line 28 Video Camera with Shutter 32 Image 34 Window 35 Pixel

Claims (1)

[Claims] 1. A marker line position measuring method for measuring a marker line position drawn in advance on a belt-shaped member such as a tire tread attached to a drum, which comprises a center position or a center in the width direction of the belt-shaped member. Drawing a marker line at a fixed distance position, imaging the position of the marker line on the circumference of the strip-shaped member with a video camera while rotating the drum, and each of the images in the image captured by the video camera. A / D converting the brightness of each pixel,
A step of obtaining the histogram of the brightness in the tread width direction by integrating the converted brightness of each pixel in the length direction of the tread;
And a step of obtaining the position of the marker line at each photographing point from the data of the histogram, the method for measuring the marker line position of a belt-shaped member.