JP2003097929A - Method and device for shape inspection of curved platy structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for shape inspection of a curved platy structure achieving a simpler configuration than ever before and an enhanced accuracy in measurement. SOLUTION: The method comprises a step projecting lights from a zonal light source 2 onto a curved platy structure (e.g. a glass plate 1), a step imaging a picture of the curved platy structure, a step extracting both an edge 1a on the curved platy structure and an edge 1b on the reflected figure of the zonal light source 2 from the imaged picture, and a step determining the quality level in bending shape of the curved platy structure based on tilt of these edges.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for inspecting the shape of a curved plate-like body, and more particularly to a method and an apparatus for inspecting the shape of a glass plate used for automobile windows.

[0002]

2. Description of the Related Art Conventionally, a glass sheet used for an automobile window is heated to a predetermined forming temperature while being conveyed on a conveying means such as a roller in a heat forming furnace or a gas conveying bed, and has a curvature of a conveying surface. It is formed into a shape having the same curvature in the conveying direction along the line. That is, the generatrix forming the curved surface is formed so as to face a predetermined direction.

FIG. 4 (a) shows a non-defective molded glass plate, and FIG. 4 (b) shows a defective product. As shown in FIG. 3A, the glass plate 1 is formed so as to be convex downward with a predetermined radius of curvature, and this curved shape has a reference line parallel to the conveying direction in the heating furnace, that is, a generatrix 20. It has a curved shape.

If the glass sheet 1 is conveyed in an inclined state during the heat forming, as shown in FIG.
Is molded into a shape having a bus bar 21 inclined from the regular bus bar 20. Glass plate 1 having such a curved shape
Is treated as a defective product because of its poor appearance and difficulty in mounting to windows.

Therefore, in order to prevent the occurrence of such defective products, it has been conventionally inspected whether or not the glass sheet 1 is bent and formed with a predetermined radius of curvature after the bending. In this inspection, the operator visually inspected whether the bus bar 21 of the glass plate 1 was in the correct position.

However, in the visual inspection, the inspection result varies due to individual differences of operators and physical conditions.
In order to solve such a problem, Japanese Patent Publication No. 7-26833 discloses an apparatus for automatically inspecting the bus bar of a glass plate. That is, the glass plate to be inspected is conveyed by the belt conveyer, and the side conveyer is used to adjust the glass plate to be conveyed at a predetermined position on the belt conveyer. A band-shaped light source and a shutter camera are installed above the glass plate, and the glass plate that has been conveyed is irradiated with light from the band-shaped light source, and the reflected image is captured by the shutter camera to determine the quality of the bus bar of the glass plate. judge.

[0007]

However, in the inspection device of the above publication, since the side conveyor is used as a positioning device for the glass plate, a motor and a gear box for driving the side conveyor are also required, and the device is thus required. There is a problem that the configuration is complicated and large-scale. Further, there has been a problem that the device cost increases with the complexity of the device configuration and the maintenance is troublesome. Furthermore, since the result of the shape inspection largely depends on the accuracy of the positioning device, there is a problem that a highly accurate positioning device must be used.

The present invention is intended to solve such a problem, and has a simpler structure than the conventional one, and can inspect the shape of a curved plate-like member capable of improving the measurement accuracy more than the conventional one. It is an object to provide a method and a device.

[0009]

In order to achieve such an object, the present invention comprises the steps of projecting light from a strip-shaped light source on a curved plate, and capturing an image of the curved plate. A step of extracting an edge of the curved plate-shaped body and an edge of a reflection image of the strip-shaped light source from the captured image, and determining whether the bending shape of the curved plate-shaped body is good or bad based on the inclination of the edge. A method for inspecting the shape of a curved plate-shaped body, comprising: The curved plate-shaped body is preferably a glass plate used for an automobile window.

Further, according to the present invention, a strip-shaped light source for projecting light of a strip-shaped light source onto a curved plate-shaped body, an image pickup means for capturing an image of the curved plate-shaped body, and the curved plate-shaped body from the captured image. And an image analysis determination unit that determines whether the bending shape of the curved plate-shaped body is good or bad, based on the inclination of the edge and the edge of the reflection image of the belt-shaped light source. A shape inspection device for a curved plate is provided. The curved plate-shaped body is preferably a glass plate used for an automobile window.

Now, the inspection principle of the present invention will be described with reference to the drawings. FIG. 5 shows an apparatus for verifying the relationship between the deviation of the bus and the reflected image. As shown in the figure, the glass plate 1 is installed on the precision stage 7. The precision stage 7 can horizontally move the glass plate 1 by a desired distance and can rotate the glass plate 1 by a desired angle, and is expected to occur when the glass plate 1 is actually conveyed. Linear deviation X and turning deviation Y
Can be reproduced.

A strip light source 2 made of a fluorescent lamp or the like and a two-dimensional CCD (Charge Coupl) are provided vertically above the glass plate 1.
ed device) and a CCD camera 3 provided with a sensor. The light emitted from the band-shaped light source 2 is applied to the surface of the glass plate 1, and the reflected image 10 is projected on the glass plate 1. The reflected image 10 is picked up by the CCD camera 3, and the image data obtained by the picked-up image is transmitted to the image analysis / judgment device 3a composed of a personal computer or the like, and is also analyzed by the image analysis / judgment device 3a.

FIG. 6 shows image analysis by the image analysis / determination device 3, that is, the inclination of the glass plate based on the captured image.
A procedure for detecting the inclination of the reflected image will be shown. The CCD camera 3 captures the reflection image 10 together with the image of the glass plate 1 (a). The image analysis determination device 3a operates according to a built-in image extraction program to extract the edge of the glass plate 1 from the image data of the glass plate 1 (b),
The reflection image 10 is extracted (d).

After that, the image analysis / determination device 3a extracts the reference edge (here, the edge 1a) at a preset position from the extracted edges of the glass plate 1 and the orthogonal coordinates set in the image. The inclination α of the edge 1a with respect to the vertical direction y of the system is calculated (c). Further, the image analysis determination device 3a obtains the inclination β of the edge of the reflected image 10 with respect to the horizontal direction x of the rectangular coordinate system set in the image (e).

FIG. 7 is a graph showing the relationship between the rotation angle of the glass plate and the angle of the reflected image. This graph shows that the radii of curvature are 1,000 mm, 2,000 mm and 3,000.
The results of inspecting the relationship between the glass rotation angle and the reflected image angle using the apparatus of FIG. 5 are shown for each glass plate of mm.
The distance between the CCD camera 3 and the glass plate 1 is 100
It was set to 0 mm.

As is apparent from the graph, there is a proportional relationship between the rotation angle of the glass plate 1 and the angle of the reflected image 10. Therefore, the inclination of the generatrix of the glass plate 1 can be indirectly known from the angle β of the reflected image 10. Also, the glass plate 1
Since the conveyance direction of can be known from the inclination α of the edge 1a, the state of the generatrix of the glass plate 1 can be known by examining these α and β.

Here, the non-defective product / defective product of the glass plate 1 is determined by using the equation (1). r is the radius of curvature of the glass plate 1, H is the height of the CCD camera 3, C is a model-specific constant (a constant determined according to the shape of the glass plate, and is measured in advance with good glass), and e Is a good product range. All of these parameters are known.

[0018]

[Equation 1]

Since the larger the rotation angle of the glass plate is, the greater the deviation from the proportional relationship is, the inspection apparatus of the present invention has an area where the proportional relationship is substantially maintained (hereinafter referred to as area A).
Is used for inspection. The setting range of the area A is empirically derived and is preferably set according to the shape and size of the glass plate.

As described above, according to the present invention, it is possible to know the state of the generatrix of the curved plate-like body by image analysis, and the positioning device, which has been essential in the past, is unnecessary. Therefore, the inspection device can be provided at low cost. Further, since the accuracy of the positioning device is not affected, the measurement accuracy can be improved as compared with the conventional case.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Next, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 1A shows an apparatus for inspecting a large glass plate such as a windshield and a rear glass. As shown in the figure, a long roller 6a, a belt conveyor 5, and rollers 6b and 6c equivalent to the roller 6a are sequentially arranged in close proximity to each other. These are all motors and other drive systems (not shown)
And the glass plate 1 is rotated by these driving forces to convey the glass plate 1 in the direction of the arrow in the figure.

A belt-shaped light source 2 made of a fluorescent lamp or the like is arranged vertically above the belt conveyor 5 so as to be orthogonal to the direction in which the glass plate 1 is conveyed. The strip light source 2 has a substantially center and the strip light source 2
A CCD camera 3 having a two-dimensional CCD sensor is installed at the same height as. Band-shaped light sources 4a and 4b for irradiating the edge of the glass plate 1 with light are arranged on both sides of the belt conveyor 5 near the center thereof. Band-shaped light source 4a,
4b illuminates the edge of the glass plate 1 so that C
The CD camera 3 facilitates the imaging of edges.

On the other hand, FIG. 1B shows an apparatus for inspecting window glass of small articles such as a rear quarter of an automobile. It is composed of the same parts as in FIG. 3A, except that the strip-shaped light source 2 is installed so that the longitudinal direction of the strip-shaped light source 2 and the conveyance direction of the glass plate 1 are parallel to each other. Further, the glass plate 1 is conveyed on the belt conveyor 5 so that its bus bar is orthogonal to the conveying direction. The installation direction of the band-shaped light source 2 may be manually changed, or may be automatically changed by a motor or the like.

Next, the inspection procedure will be described with reference to the drawings. FIG. 2 shows a state in which images picked up by a CCD camera are arranged in chronological order. Further, FIG. 3 is a flowchart showing the inspection procedure.

First, the glass plate 1 is conveyed by the belt conveyor 5, and the CCD camera 3 continuously captures images on the belt conveyor 5 (steps S1 and S2). For example, the CCD camera 3 captures an image at 30 frames / second,
The image data obtained by imaging is transmitted to the image analysis device 3a.

The image analysis device 3a performs image processing on the received image data to determine whether the glass plate 1 is reflected in the image (step S3). The image data is analyzed by using the reflection image 1 by the edge 1a of the glass plate 1 and the band-shaped light source 2.
It continues until the edge 1b of 0 is extracted (step S
4). Then, using the edges 1a and 1b, the above-described inclinations α and β are obtained (step S5).

Next, using the formula (1), the above α and β are compared with the above reference values C−e and C + e, and if the values are within the range of the formula (1), the glass plate 1 is judged to be a good product. If not, it is determined as a defective product (steps S6 and S7). Similarly thereafter, the image analysis / determination device 3a determines a non-defective product / defective product based on an image of a glass plate being conveyed and an analysis of the obtained image data.

[0028]

As described above, according to the present invention, the edge of the glass plate and the edge of the anti-mapping are detected by image processing, and the state of the busbar is inspected from the inclination of these edges. No equipment required.
Therefore, according to the present invention, it is possible to obtain the effects of simplifying the device configuration, reducing the device cost, and facilitating maintenance.

[Brief description of drawings]

FIG. 1A is a perspective view showing one embodiment of the present invention (inspection apparatus for front doors and rear doors), and FIG.
It is a perspective view showing one embodiment (inspection device of small glass, such as a rear quota) of the present invention.

FIG. 2 is a plan view showing a captured image.

FIG. 3 is a flowchart showing an inspection procedure.

FIG. 4 is a perspective view showing (a) a normal glass plate having a bus bar and (b) a glass plate having a bus bar displaced.

FIG. 5 is a perspective view showing an apparatus for verifying a relationship between a displacement of a bus bar and a reflected image.

FIG. 6 is a plan view showing a procedure for detecting a tilt of a glass plate and a tilt of an anti-mapping based on a captured image.

FIG. 7 is a graph showing the relationship between the rotation angle of the glass plate and the angle of the reflected image.

[Explanation of symbols]

1: Glass plate 1a: Edge of glass 1b: Edge of reflected image 2: Light source 3: CCD camera 3a: Image analysis determination device 4: Precision stage 5: Belt conveyor 6a, 6b, 6c: rollers 7a, 7b: light source 10: Anti-mapping 20: Normal bus 21: Abnormal busbar

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Claims (4)

[Claims] 1. A step of projecting light of a strip-shaped light source onto a curved plate-shaped body, a step of capturing an image of the curved plate-shaped body,
Extracting an edge of the curved plate-shaped body and an edge of a reflected image of the belt-shaped light source from the captured image,
A step of judging whether the bending shape of the curved plate-shaped body is good or bad based on the inclination of the edge, the shape inspection method of the curved plate-shaped body. 2. The method for inspecting the shape of a curved plate-shaped body according to claim 1, wherein the curved plate-shaped body is a glass plate used for an automobile window. 3. A belt-shaped light source for projecting light of a belt-shaped light source onto the curved plate-shaped body, and an image pickup means for capturing an image of the curved plate-shaped body.
An image analysis determination that extracts the edge of the curved plate and the edge of the reflection image of the belt-shaped light source from the captured image, and determines whether the curved shape of the curved plate is good or bad based on the inclination of the edge. A device for inspecting a shape of a curved plate-shaped body, comprising: 4. The shape inspection device for a curved plate-shaped body according to claim 3, wherein the curved plate-shaped body is a glass plate used for a window for an automobile.