JP2000337819A - Wall thickness measuring device for glass bottle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of wall thickness measurement of glass bottles by constituting an optical pedestal, where both of an irradiating means for irradiating with laser beam and an image pick-up means are placed movable in a direction to the glass bottles and freely swingable in a vertical plane corresponding to deflection of the glass bottles at rotation. SOLUTION: The wall thickness measuring device for glass bottles, where the wall thickness of a glass bottle 1 is calculated based on a beam trace picture-taken of an excitation beam between an external surface and internal surfaces of the glass bottle 1 produced by a laser beam entered into the bottle 1, comprises a rotorplatform 3 rotating the glass bottle 1 about a bottle axis, an optical pedestal 25 placed so as to be movable in a direction to the glass bottle and freely swingable in a vertical plane, a plurality of contact members (27), 28 fixed to the pedestal 25 and placed so as to be in contact with the body of the glass bottle 1 rotating on the rotorplatform 3, an optical picture- taking means 35 that is fixed to the pedestal 25 and photographs the beam trace of the excitation beam produced by the laser beam entering the bottle 1 with the contact members (27), 28 in contact with the body of the glass bottle 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass bottle thickness measuring apparatus for optically measuring, for example, a wall thickness of a glass bottle using a laser beam.

[0002]

2. Description of the Related Art Conventionally, laser light is incident on a glass bottle using a semiconductor laser, and the light trace of the excitation light from the outer surface to the inner surface of the glass bottle generated by the laser light is photographed by a CCD camera. A glass bottle thickness measuring device that calculates the thickness of the glass bottle based on the photographed light traces has been proposed.

[0003]

In this type of conventional apparatus, when the position of the glass bottle is shifted with respect to the semiconductor laser and the CCD camera, the glass bottle and the laser incident point,
Alternatively, there is a problem in that the relationship between the glass bottle and the focal position of the CCD camera changes, the target to be measured deviates from the screen, the target to be measured is blurred, and the thickness measurement value has an error.

[0004] Further, in the conventional configuration, dirt or dust attached to the surface of the glass bottle, or a joint of the glass bottle,
When laser light is applied to bubbles, scratches, stones, and the like, there is a problem that the length of the light trace changes and an error occurs in the measured wall thickness.

Accordingly, an object of the present invention is to provide an apparatus for measuring the thickness of a glass bottle with improved accuracy in measuring the thickness of the glass bottle.

[0006]

According to the first aspect of the present invention,
Laser light is incident on the outer surface of the glass bottle while rotating the glass bottle in the circumferential direction of the body, and the light trace of the excitation light from the outer surface to the inner surface of the glass bottle caused by the laser light is photographed. In the glass bottle thickness measuring device to calculate the thickness of the glass bottle based on the captured light trace, the irradiation means for irradiating the laser beam, and the imaging means is installed on the same optical bench, The optical table is configured to be movable in the direction of the glass bottle and swingable in a substantially horizontal plane in accordance with the shake of the glass bottle during rotation.

According to a second aspect of the present invention, a laser beam is incident on the outer surface of the glass bottle while rotating the glass bottle in the circumferential direction of the body, and the laser beam generated by the laser beam is applied from the outer surface to the inner surface of the glass bottle. In a glass bottle thickness measuring device that photographs the light trace of the excitation light up to and calculates the thickness of the glass bottle based on this photographed light trace, it is movable in the glass bottle direction and in a substantially horizontal plane. An optical bench that is swingably installed, a plurality of abutting members fixed to the optical bench and configured to be able to abut on a barrel of a rotating glass bottle, and an abutting member fixed to the optical bench. An optical imaging means for emitting a laser beam to the glass bottle in a state in which the laser beam is brought into contact with the body of the glass bottle, and capturing a light trace of excitation light generated by the laser beam.

According to a third aspect of the present invention, in the second aspect, the optical table is biased in the direction of the glass bottle so that the contact member always comes into contact with the body of the glass bottle. Means.

According to a fourth aspect of the present invention, a laser beam is made incident on a glass bottle, and the light trace of the excitation light from the outer surface to the inner surface of the glass bottle generated by the laser beam is photographed. In a glass bottle thickness measuring device that calculates the thickness of the glass bottle based on the trace, the device includes means for measuring the thickness of the glass bottle based on the captured light trace, and this means converts the light trace into a binary value. It is characterized in that the largest connected component is selected by imaging and labeling, and the thickness is measured based on the length of the selected connected component.

[0010]

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

In FIG. 1, reference numeral 1 denotes a glass bottle. The glass bottle 1 is mounted on a turntable 3 and is configured to be rotatable in the circumferential direction of the body. The turntable 3 is fixed to a rotation shaft 5, which is connected to a rotation mechanism 7, and a rotation drive motor 11 is connected to the rotation mechanism 7 via a belt 9. Therefore, the turntable 3 is rotationally driven by the rotational drive motor 11.

The rotation mechanism 7 and the rotation drive motor 11 are connected to an elevating mechanism 13, and the elevating mechanism 13 is connected to an elevating drive motor 15. Therefore, the turntable 3 is driven up and down by the lift drive motor 15.

The turntable 3 descends to a position A, receives a glass bottle conveyed by a conveyor (not shown), and then stops at a position B shown in the figure.

In this position B, the head 1 a of the glass bottle 1 on the turntable 3 is rotatably supported by the top 17. The frame 17 is supported by an arm 18, and the arm 18 is supported by a column 19 so as to be vertically movable.

The means for holding the glass bottle 1 on the turntable 3 may be a vacuum means for adsorbing the bottom of the bottle.

A base 21 is provided next to the turntable 3. On this base 21, a linear bearing 22,
An optical table 25 is provided via a swing bearing 23. Therefore, the optical table 25 is movable in the direction of the glass bottle 1 via the linear bearing 22 and is swingable in a substantially horizontal plane via the swing bearing 23.

The linear bearing 22 comprises an upper member 22a and a lower member 22b. The lower member 22b is fixed to a base 21, and the upper member 22a carries a swing bearing 23 and an optical table 25, and It is movable in the direction of. A wire 24 is fixed to a front end of the upper member 22a, the wire 24 is suspended via a pulley 26, and a weight 30 is fixed to a lower end thereof. This weight 3
Due to the zero weight, the optical bench 25 is always biased in the direction of the vial 1.

As shown in FIG. 2, on the optical table 25, two contact rollers (contact members) 27 and 28 for setting the body 1b of the glass bottle 1 are provided. , 28 are supported by roller support members 31, 32, and the roller support members 31, 32 are attached to the optical table 25 so that their positions can be adjusted in the direction of arrow A.

On the optical table 25, two abutting rollers 2 are attached to the body 1b of the glass bottle 1 rotating on the rotating table 3.
An optical photographing means 35 is provided for irradiating a laser beam into a glass bottle with the 7, 28 in contact with the glass bottle and photographing a light trace of excitation light generated by the laser beam. The optical photographing means 35 comprises a semiconductor laser 37 and a CCD camera 39.
It is composed of

The laser light from the semiconductor laser 37 is shown in FIG.
As shown in (1), after being converged by the converging lens 41, it reaches the outer surface A of the body 1b of the glass bottle 1. After reaching the outer surface A, the light is refracted by the outer surface A, travels straight through the body 1b of the glass bottle 1, reaches the inner surface B, and is refracted by the inner surface B. Enter the interior space. The light trace K of the light traveling straight between the outer surface A and the inner surface B of the glass bottle 1 is photographed by a CCD camera (“photographing means”) 39.

The light trace K of light captured by the CCD camera 39 is excitation light generated by the absorption of laser light by impurity ions (transition metal ions or rare earth ions) in the glass. Light is a semiconductor laser 3
7 has a wavelength on the longer wavelength side than the wavelength of the laser light output from the laser beam 7.

Therefore, only this excitation light is applied to the CCD camera 3
9, a filter 42 is disposed between the CCD camera 39 and the glass bottle 1 to exclude light (for example, laser light) having a wavelength other than the wavelength of the light that represents the light trail K.

In this embodiment, a laser having a wavelength in the visible light region and having a large optical power, for example, having a wavelength of 68
A semiconductor laser having a power of 5 nm and an optical power of 30 mW is used. According to this, a light intensity of 20 mW is obtained on the outer surface A.

As shown in FIG. 1, an image processing device 45 is connected to the CCD camera 39 via a communication line 44.

In this image processing device 45, a light trace K of light photographed by the CCD camera 39 is input, and, for example, as shown in FIG. 4A to FIG. The thickness (length of light trace K) of the glass bottle 1 is measured.

Here, for example, when dust or the like is attached to the surface of the glass bottle 1, FIGS.
As shown in c, a light spot K1 serving as disturbance light is generated in addition to the light trace K. In this case, as shown in FIG. 4C, when measuring the length of the light trail K by a conventionally known edge detection method, the light spot K1 is detected, and the length L10 including the light spot K1 is measured. Therefore, a measurement error occurs due to the influence of disturbance light.

In this embodiment, the image processing device 45
The light trace K including the disturbance light input from the CCD camera 39 is converted into a binary image (black and white image), and the connected components of the binary image are labeled and assigned different numbers, as shown in FIG. Label images K10 and K20 containing disturbance light are formed.

Since the light spot K1 due to the disturbance light appears as a small light spot and the appearance time is also instantaneous, in the image processing device 45, the light spot K1 due to the disturbance light is longer than the longer one of the label images K10 and K20. Short label image K20 of length L1
, And the light trace K becomes the label image K
10, the label image K10 having the longest length L among K20
Is recognized as equivalent to

As shown in FIG. 1, a computer 47 is connected to the image processing device 45 via a communication line 46. The computer 47 calculates and measures the thickness of the glass bottle 1 based on the length L of the label image K10 representing the light trail K.

According to this embodiment, the light trail K is converted into a binary image, and the maximum connected component is selected by labeling.
Since the length L of the selected connected component is measured, and the thickness of the glass bottle 1 is measured based on the length L, a small light spot K1 or the like due to disturbance is ignored, and the thickness measurement without measurement errors can be performed. Will be possible.

FIG. 5 shows that the glass bottle 1 is located at the point of incidence of the laser beam.
7 shows a measurement example in the case where the joint is located and the trajectory of the laser beam is bent by the unevenness of the joint. FIG. 6 is a diagram in which the inner surface edge of the excitation light excited by the incidence of the laser light is viewed through the seam of the glass bottle 1, and the unevenness of the seam is disturbed, and the end portion of the light trace appears cut off. A measurement example will be described. FIG. 7 shows that 2 mm before and after the seam of the glass bottle 1 is 0.2 mm.
FIG. 3 is a diagram in which light trace images are stuck at a pitch of mm.

When measured according to the example of FIG. 5, a light trail K extends to the left in the figure as shown by an arrow A in FIG. 7, and when measured according to the example of FIG. 6, it is shown by an arrow B in FIG. Thus, the length of the light trace K appears short. In any case, the light trace K does not represent the actual thickness. Therefore, a measurement value error occurs.

In this embodiment, continuously measured values are subjected to difference processing and interpolation processing in the following procedure.

As shown in FIG. 8, when the measured thickness is on the vertical axis and the circumferential position of the body of the glass bottle 1 is on the horizontal axis, the thickness values are plotted as shown. Here, the data suddenly changed is defined as an, and the data before and after that are an-1, an + 1.
Then, (an-1) -an> 0.1 (an + 1) -an> 0.1 {(an-1) -an} + {(an + 1) -an}>
If all of 0.2 are satisfied, the data an is deleted (difference processing). However, an error of 0.1 mm or more is excluded.

Then, as shown in FIG. 9, instead of the deleted data an, data an 'obtained according to the following interpolation formula (1) is interpolated.

An ′ = {(an−1) + (an + 1)} / 2 + {(an−1) − (an−2)} / 4 + {(an + 1) − (an + 2)} / 4 (1 In this embodiment, even if a change occurs in the measurement length due to a change in the length of the light trace K due to seams, bubbles, scratches, stones, and the like of the glass bottle at a position around the body of the glass bottle 1, Since the data an is subjected to the difference processing and the interpolation processing as described above, it is possible to perform the thickness measurement with high accuracy.

The operation contents of the computer 47 are summarized as follows.

The light trail K is converted into a binary image by image processing.
The largest connected component is selected by labeling, and the number of dots in the horizontal direction of the selected connected component is obtained.

The actual length of the number of dots is obtained based on the magnification of the lens of the CCD camera 39. At this stage, a method may be adopted in which the length of each dot is determined in advance by placing a scale on the surface of the glass bottle 1.

The wall thickness is calculated from the length of the light trace K measured by the CCD camera 39 by geometrical optics calculation in consideration of the curvature of the glass bottle 1.

A regression equation of the measured thickness with respect to the actually measured thickness is prepared in advance, and a slight deviation from the actually measured value is calculated and corrected by the regression equation.

Sudden errors are removed by the above-described difference processing and interpolation processing.

That is, by the image processing described in the above, the influence of small light spots caused by dust and bottle defects is removed.
The data processing described in (1) removes sudden errors that occur rarely at joints and the like, and this method enables stable thickness measurement with few measurement errors.

In this embodiment, only the wavelength of the light trail K is incident on the CCD camera 39 very efficiently to measure the thickness of the glass bottle 1, so that flint (transparent), amber, dark smoke, emerald green, etc. It is possible to measure the thickness of the glass bottle 1 of most colors.

However, since the brightness of the light trail K slightly changes due to the difference in the color of the glass bottle 1, it is necessary to adjust the sensitivity of the CCD camera 39 and the like.

In this embodiment, the thickness of the glass bottle 1 can be measured with high accuracy, high stability, simpleness, and high speed. And this increases the number of measurement points, improves the reliability of the measured values, and increases the frequency of periodic measurement,
Since the thickness information fed back from this measuring device is more substantial than that of the conventional one, the thickness management and control of the glass bottle 1 can be easily performed.

As described above, the present invention has been described based on one embodiment, but the present invention is not limited to this. For example, the contact rollers 27 and 28 are not limited to this, and may be contact bars that contact the glass bottle 1.

In the configuration shown in FIG. 2, the contact rollers 27 and 28 on the optical bench 25 are pressed against the body of the glass bottle 1, thereby positioning the optical bench 25. However, the present invention is not limited to this. Instead, for example, the contact rollers 27 and 28 are replaced with non-contact sensors, and the shake during rotation of the glass bottle 1 is detected by this sensor, and the optical table 25 is positioned with respect to the glass bottle 1 according to the shake amount. May be performed.

In this case, it is needless to say that an actuator for moving the optical bench 25 in the direction of the glass bottle and an actuator for swinging the optical bench 25 in a substantially horizontal plane are required.

[0050]

According to these inventions, the position of the glass bottle does not shift with respect to the semiconductor laser and the CCD camera. Therefore, the depth of focus of the CCD camera is maintained, the object to be measured is not blurred, and the accuracy of thickness measurement is improved. In addition, even if the laser light is irradiated on dust, dust, or seams of the glass bottle, bubbles, scratches, stones, etc., and the length of the light trace changes, No error occurs in the measured thickness. Then, the thickness of the glass bottle can be measured with extremely high precision using laser light.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a plan view showing an optical photographing means.

FIG. 3 is a diagram illustrating a principle of photographing a light trace.

FIGS. 4A to 4C are diagrams illustrating captured light traces.

FIG. 5 is a diagram illustrating a principle of photographing a light trace.

FIG. 6 is a diagram illustrating the principle of photographing a light trace.

FIG. 7 is a diagram in which light trace images before and after a seam of a glass bottle are stuck.

FIG. 8 is a diagram illustrating a difference processing of a measured thickness.

FIG. 9 is a diagram showing an interpolation process of a measured thickness.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 glass bottle 3 rotating table 7 rotating mechanism 11 rotating drive motor 13 lifting mechanism 15 lifting drive motor 21 base 25 optical table 27, 28 contact roller (contact member) 30 weight 35 optical imaging means 37 semiconductor laser 39 CCD Camera 45 Image processing device 47 Computer

Claims (4)

[Claims] 1. A laser beam is incident on an outer surface of a glass bottle while rotating the glass bottle in a circumferential direction of a body, and excitation light generated by the laser light from the outer surface to the inner surface of the glass bottle is generated. In a glass bottle thickness measuring device for photographing a light trace with a photographing means and calculating the thickness of the glass bottle based on the photographed light trace, the irradiation means for irradiating the laser beam, and the photographing means are the same. A glass characterized by being arranged on an optical table, and configured such that the optical table can be moved in the direction of the glass bottle and swingable in a substantially horizontal plane in accordance with a shake at the time of rotation of the glass bottle. Bottle thickness measuring device. 2. A laser light is incident on the outer surface of the glass bottle while rotating the glass bottle in the circumferential direction of the body, and excitation light generated by the laser light from the outer surface to the inner surface of the glass bottle is generated. An apparatus for measuring the thickness of a glass bottle based on an image of a light trace and calculating the thickness of the glass bottle based on the photographed light trace. Optical bench, a plurality of abutting members fixed to the optical bench and configured to be able to abut on a rotating glass bottle barrel, and a plurality of abutting members fixed to the optical bench and the abutting member being a glass bottle barrel. A laser light incident on the glass bottle in a state where the laser light is in contact with the portion, and an optical photographing means for photographing a light trace of the excitation light generated by the laser light. Thickness measuring device. 3. The optical table according to claim 2, further comprising: urging means for urging the optical table in the direction of the glass bottle so that the contact member always comes into contact with the body of the glass bottle. Glass bottle thickness measuring device. 4. A laser beam is made incident on a glass bottle, a light trace of excitation light from the outer surface to the inner surface of the glass bottle generated by the laser light is photographed, and the glass trace is formed based on the photographed light trace. A glass bottle thickness measuring device for calculating the thickness of a bottle, comprising means for measuring the thickness of the glass bottle based on a photographed light trace, and this means converts the light trace into a binary image and labels the most. A thickness measuring apparatus for a glass bottle, wherein a large connected component is selected, and the thickness is measured based on the length of the selected connected component.