JPH1172310A - Method and apparatus for distortion inspection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect a distortion of a plate material to be inspected and the surface thereof with a miniaturized apparatus by a method wherein a specified inspection pattern formed by an inspection pattern forming means is made to pass through a plate material to be inspected, and the pattern is photographed by a camera arranged therebehind and the results are analyzed by an image analysis means. SOLUTION: When projected by a projector 4 onto a screen 1, an inspection pattern is made to pass through a sample plate 2 to be taken by a CCD camera 3. When an internal distortion exists at any point as the pattern pass, the pattern is photographed being deformed oval or into other shapes according to the degree of the distortion. The resulting image is sent to an image analysis part 5 to be turned black and white by a binary coding so that a measuring range is limited to obtain image data of round shapes by inversion and the diameter of each round shape is measured. A standard deviation of the diameter of all the round shapes is calculated separately in the vertical and horizontal directions of each oval form corresponding to the distortion. A ratio between a standard deviation actually calculated for the sample plate 2 as object to be inspected and the standard deviation of the plate material as reference sample stored in the image analysis part 5 is converted to obtain a standard deviation ratio thereby objectively learning the internal distortion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distortion inspection method and apparatus for inspecting internal distortion of a transparent resin plate or the like and surface smoothness of the resin plate or metal plate.

[0002]

2. Description of the Related Art A resin plate is manufactured by molding a resin into a plate shape by a press molding method, an extrusion molding method, or the like. The occurrence of optical and physical distortions due to surface undulations due to differences cannot be avoided. And, when improving the manufacturing process of the resin plate or performing quality inspection of the product,
It may be necessary to inspect the degree of distortion of the resin plate in detail. Such distortion is caused by the inspector observing a linear image of a fluorescent lamp or the like transmitted through the resin plate or reflected on the surface from an oblique direction and observing the degree of distortion of the image of the fluorescent lamp or the like which should be a straight line. It can also be judged and inspected. However, in the manual inspection method, it is difficult to determine an objective judgment standard, so that the inspection results are likely to vary due to individual differences among inspectors, and a reliable inspection cannot be performed.

Therefore, the present applicant has already proposed a transparent resin plate distortion inspection apparatus and method as shown in FIG. 13 (Japanese Patent Laid-Open No. 7-243819). This inspection device
A large number of circular inspection patterns are projected from the projector 4 and transmitted through the sample plate 2 such as a transparent resin plate to form a projected image formed on the screen 1 by the CCD camera 3. And C
The image of the projection image picked up by the CD camera 3 is
To measure the diameter of each circle, create a histogram of these diameters, calculate the standard deviation, and check the degree of variation in each diameter. When a circular inspection pattern is projected through the sample plate 2, each circle of the projected image is deformed into an elliptical shape or the like according to the distortion of the sample plate 2. Therefore, by measuring the diameter of each circle of the projected image, the degree of deformation of each circle can be determined, and the distortion of the sample plate 2 can be inspected by examining the degree of variation.

On the other hand, the surface of the opaque resin plate or the transparent resin plate may be bent or deteriorated due to internal physical distortion or unevenness of thickness, which impairs the smoothness of the surface of the resin plate which should be originally smooth. Ripples may appear. Therefore, the present applicant has already proposed a surface smoothness inspection method and apparatus as shown in FIG. 14 (Japanese Patent Application No. 8-219278).
issue). In this inspection method and its apparatus, the same inspection pattern as that shown in FIG. 13 is projected from the projector 1 onto the sample plate 2, the projected image reflected here is formed on the screen 4,
An image is taken by the D camera 6. Then, the diameter of each circle of the projection image picked up by the CCD camera 6 is measured by the image processing unit 8 of the image analysis unit 7 in the same manner as in the case of FIG. 13, and the degree of variation of each diameter is checked by the distortion inspection unit 9. It has become. When a circular inspection pattern is reflected on the surface of the sample plate 2 and projected, each circle of the projected image is deformed into an elliptical shape or the like according to the waving condition of the surface of the sample plate 2. Therefore, in this case as well,
By examining the degree of variation due to each circular deformation of the projected image, the smoothness of the surface of the sample plate 2 can be inspected.

[0005]

However, the above-mentioned conventional inspection apparatus has a problem in that the screen 1 must be arranged between the sample plate 2 and the CCD camera 3, so that the apparatus tends to become large. Was. Further, since the projection image of the inspection pattern is enlarged and projected on the screen 1 by the projector 4, a certain distance or more is required between the projector 4 and the screen 1, which results in an increase in the size of the apparatus. There was also.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a distortion inspection method and a distortion inspection method capable of reducing the size of an apparatus by directly imaging an inspection pattern formed in advance through a plate to be inspected or the surface of a material to be inspected by a camera. It is intended to provide such a device.

[0007]

According to a first aspect of the present invention, there is provided a distortion inspection method, comprising: transmitting a predetermined inspection pattern formed by an inspection pattern forming means through a plate to be inspected; An image is taken by a camera arranged behind the plate material, and the degree of distortion of the image of the taken inspection pattern is inspected by image analysis means.

According to the first aspect, the inspection pattern is transmitted through the plate to be inspected and is imaged by the camera. Therefore, if there is a distortion in the plate to be inspected, the inspection pattern is deformed and imaged. Therefore, if the distortion of the image of the inspection pattern is inspected by the image analysis means, the internal distortion of the inspection target plate material can be objectively examined.

According to a second aspect of the present invention, there is provided a distortion inspection apparatus for forming a predetermined inspection pattern, and a test pattern formed by the inspection pattern forming means, which is arranged obliquely in front of the inspection pattern. The camera is characterized by comprising a camera for transmitting an image through an inspection plate material and an image analyzing means for inspecting the degree of distortion of an image of the inspection pattern captured by the camera.

According to the second aspect, the camera captures an image of the inspection pattern formed by the inspection pattern forming means, by transmitting the inspection target plate material arranged at an angle. At this time, if the plate material to be inspected has a distortion, the inspection pattern of the image captured by the camera is deformed according to the internal distortion. Therefore, if the distortion of the image of the inspection pattern is inspected by the image analysis means, the internal distortion of the inspection target plate material can be objectively examined.

According to a third aspect of the present invention, the predetermined inspection pattern formed by the inspection pattern forming means is reflected on the surface of the inspection material, and is imaged by a camera arranged on the front surface of the inspection material. The degree of distortion of the image of the captured inspection pattern is inspected by the image analysis means.

According to the third aspect of the present invention, the inspection pattern is reflected on the surface of the material to be inspected and imaged by the camera. Therefore, if the surface of the material to be inspected is wavy or the like, the inspection pattern is deformed and imaged. Therefore, if the distortion of the image of the inspection pattern is inspected by the image analysis means, the surface smoothness of the inspection object can be objectively examined.

According to a fourth aspect of the present invention, there is provided a distortion inspection apparatus, wherein an inspection pattern forming means for forming a predetermined inspection pattern, and a test pattern formed by the inspection pattern forming means, are arranged obliquely in front of the inspection pattern. The camera is characterized by comprising a camera that reflects and reflects an image on the surface of the inspection material and an image analysis unit that inspects the degree of distortion of the image of the inspection pattern captured by the camera.

According to the fourth aspect, the camera captures an image of the inspection pattern formed by the inspection pattern forming means by reflecting the inspection pattern on the surface of the material to be inspected which is arranged at an angle. At this time, if the surface of the material to be inspected has waving or the like, the inspection pattern of the image captured by the camera is deformed according to the waving or the like.
Therefore, if the distortion of the image of the inspection pattern is inspected by the image analysis means, the surface smoothness of the inspection object can be objectively examined.

According to a fifth aspect of the present invention, there is provided a distortion inspection apparatus, wherein an inspection pattern forming means for forming a predetermined inspection pattern, and a test pattern formed by the inspection pattern forming means are arranged obliquely in front of the inspection pattern. A first camera for transmitting an image through the inspection plate and capturing an image, a second camera for reflecting and imaging the surface of the inspection target plate, and the first and second cameras
Image analysis means for inspecting the degree of distortion of the image of the inspection pattern captured by the camera.

According to the fifth aspect, the first camera picks up an image of the inspection pattern formed by the inspection pattern forming means by transmitting the inspection target plate material arranged obliquely. On this occasion,
If the plate material to be inspected has a distortion, the inspection pattern of the image captured by the first camera is deformed according to the internal distortion. The second camera captures an image by reflecting the same inspection pattern on the surface of the plate material to be inspected. At this time, if the surface of the plate material to be inspected has waving or the like, the inspection pattern of the image captured by the second camera is deformed according to the waving or the like. Therefore, if the distortion of the image of these inspection patterns is inspected by the image analysis means, the internal distortion and the surface smoothness of the plate material to be inspected can be objectively examined at once,
The labor of setting the plate material to be inspected is reduced. Moreover, since the plate to be inspected is set at the same position and at the same angle and the internal distortion and the surface smoothness can be inspected, the data of these inspection results can be easily matched. Further, it is also possible to inspect only one of the internal distortion and the surface smoothness of the plate material to be inspected.

[0017] The distortion inspection method or apparatus according to claim 6 is
The inspection pattern forming means forms a projection image of a predetermined inspection pattern on a screen by a projector.

According to the sixth aspect, the inspection pattern is formed by the projected image projected on the screen from the projector in the same manner as in the prior art. Therefore, the configuration is the same as that of the related art except that the position of the screen changes from the camera side to the projection image side. However, in the case of inspecting the internal distortion and the surface smoothness of the plate material to be inspected at once as in the distortion inspection apparatus of claim 5, only one screen is sufficient and the screen is located in front of the first and second cameras. There is no need to arrange each one.

A distortion inspection method or apparatus according to claim 7 is
It is characterized in that the inspection pattern forming means represents a predetermined inspection pattern on a flat surface.

According to the present invention, since the inspection pattern is large, for example, printed on a flat surface in advance, it is not necessary to perform enlarged projection with a projection image.
The device can be downsized. Note that this flat surface is appropriately illuminated so that the inspection pattern can be clearly seen.

According to a eighth aspect of the present invention, there is provided a distortion inspection method or apparatus.
It is characterized in that the inspection pattern forming means expresses a predetermined inspection pattern on the surface of the light-transmitting plate which has been backlit from behind.

According to the eighth aspect, since the inspection pattern is largely represented on the surface of the light transmitting plate, there is no need to perform enlarged projection by a projected image, so that the apparatus can be downsized. In addition, since the light-transmitting plate surface is back-lit from behind, the inspection pattern appears clearly.

According to a ninth aspect of the present invention, there is provided a distortion inspection method or apparatus.
The camera is characterized in that a light quantity limiting filter is disposed in front of the camera.

According to the ninth aspect, even when the inspection pattern is too bright due to illumination such as a backlight, the light amount can be attenuated by the light amount limiting filter.
It is possible to prevent halation or the like from occurring in an image captured by the camera.

According to a tenth aspect of the present invention, in the distortion inspection method or apparatus, the inspection pattern formed by the inspection pattern forming means includes a plurality of two-dimensionally arranged identical isolated figures at appropriate intervals. However, it is characterized in that the degree of distortion of the image of the inspection pattern is determined based on the degree of variation of the figure characteristic value measured for each isolated figure.

According to the tenth aspect, since the inspection pattern is not a single figure but a large number of isolated figures, these isolated figures can be easily cut out by image processing area division. By examining the degree of variation in the graphic feature values of the above, the degree of distortion of the image of the inspection pattern can be easily measured.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings.

1 to 7 show a first embodiment of the present invention. FIG. 1 is a side view showing a configuration of a distortion inspection apparatus for inspecting internal distortion of a sample plate, and FIG. 2 is an image processing unit. 3 is a diagram showing image data of a sample plate without internal distortion, FIG. 4 is a diagram showing image data of a sample plate with internal distortion, and FIG. 5 is an integrated projector and screen. FIG. 6 is a side view showing a configuration of a distortion inspection apparatus for inspecting the surface smoothness of a sample plate, FIG. 6 is a side view showing a configuration of a distortion inspection apparatus for inspecting the surface smoothness of a sample plate, and FIG. It is a side view showing the composition of the distortion inspection device which inspects the surface smoothness of the integrated sample plate. 13 and 14.
Components having the same functions as those of the conventional example shown in FIG.

In the distortion inspection apparatus according to the present embodiment, as shown in FIG. 1, a sample plate 2 is arranged in front of a screen 1 at an angle, and a CCD camera 3 is arranged behind the sample plate 2. . The screen 1 is made of a cloth, an optical ground glass, which is not so thick that scatters and transmits light.
It is a ground glass-like resin plate, an opaque resin sheet, or a colored film or a sheet in which a sheet or the like is stretched flat, and a liquid crystal light control material can also be used. The liquid crystal light control material is provided with transparent electrodes on both sides of a resin dispersed liquid crystal sheet. When a voltage is applied between the transparent electrodes, the resin dispersed liquid crystal sheet becomes transparent, but when no voltage is applied, the resin is dispersed. The dispersed liquid crystal sheet becomes cloudy and can be used as the screen 1. In front of the screen 1 is a projector 4
Is arranged. The projector 4 is a slide projector combining a light source such as a halogen lamp and an optical lens,
A slide representing an inspection pattern in which a large number of circles having the same diameter are arranged at equal intervals is projected on the screen 1, and the inspection pattern is enlarged and projected. Also,
The screen 1 also projects this inspection pattern on the back side. The projector 4 is not limited to such a slide projector, as long as the projector 4 can project the inspection pattern on the screen 1. The projector 4 emits laser light while scanning it vertically and horizontally to obtain a desired size. And the like that form a projected image of the inspection pattern described above.

The sample plate 2 here is a transparent resin plate or other transparent plate material. By arranging the sample plate 2 at an appropriate angle with respect to the optical axis of the projector 4,
The distortion inside the sample plate 2 and the waving of the surface are enlarged. The CCD camera 3 is arranged behind the sample plate 2, and is configured to image the inspection pattern projected on the back surface of the screen 1 through the sample plate 2. The CCD camera 3 has a CCD [Charg
e Coupled Device], and converts an inspection pattern on the screen 1 into an image signal. However, if the inspection pattern is imaged,
A solid-state imaging device other than a CCD, an electron tube imaging device, or the like can also be used. It is preferable that the screen 1 is arranged so as to be orthogonal to the optical axis of the projection image from the projector 4 and also orthogonal to the optical axis of the light received by the CCD camera 3. However, even if these optical axes are inclined with respect to the screen 1, all the circles of the inspection pattern are only uniformly deformed into elliptical shapes. It is possible.

An image signal of the inspection pattern picked up by the CCD camera 3 is sent to an image analyzer 5. The image analysis unit 5 is constituted by a data processing device such as a computer which analyzes an image signal of the inspection pattern to measure the diameter of each figure of the inspection pattern and checks the degree of variation in the measured diameter.

A method for inspecting distortion using the inspection apparatus having the above configuration will be described. When the projector 4 projects the inspection pattern on the screen 1, the CCD camera 3 captures an image of the inspection pattern through the sample plate 2. At this time, if there is no distortion inside the sample plate 2, each circle of the inspection pattern is imaged as it is, but if there is internal distortion at the transmission position, it is deformed into an elliptical shape or the like according to the degree of this distortion. It is imaged.

An image signal of the inspection pattern captured by the CCD camera 3 is sent to an image analysis unit 5. The image analysis unit 5 first captures an image signal in step (hereinafter referred to as “S”) 1 shown in FIG. 2 and binarizes the image signal into black and white to limit the measurement range (S
2) Invert the black and white (S3) to obtain image data in which a large number of black circles are displayed on a white background (S4). Then, the diameter of each circle of the image data is measured. In the measurement of the diameter, each circular area is recognized by first classifying each pixel of the image data based on the connectivity of black pixels. Next, the length (number of pixels) of a portion (intercept) where a vertical straight line intersects each circular region along the array of pixels is detected, and for each circular region, the length of the straight line intersecting this region is determined. Then, the one having the maximum length of the section is selected, and this is defined as the diameter of the circle. Similarly, the diameter of each circle is determined for a horizontal straight line along the array of pixels. The diameter of each circle may be obtained only in the vertical direction or the horizontal direction, or a diameter in an oblique direction at an arbitrary angle may be obtained.
For example, image data in which the sample plate 2 has no internal distortion is
As shown in FIG. 3, since the circle is hardly deformed, the diameters in the vertical direction and the horizontal direction are substantially equal in all the circles. On the other hand, in the image data when the sample plate 2 has an internal distortion, the circle in the region corresponding to the distortion is deformed into, for example, an elliptical shape as shown in FIG. Only the lateral diameter of the ellipse is longer than the others.

When the image analysis unit 5 measures the diameters in the vertical and horizontal directions for each circle of the image data, it then calculates the standard deviation of the diameters of all the circles in each of the vertical and horizontal directions. The standard deviation s represents the degree of variation in the diameter of the circle, where n is the number of circles and x1 is the diameter of each circle.
Assuming that xn is the average value of the diameters of all the circles, x is obtained by the calculation of Expression 1.

(Equation 1)

The image analyzing section 5 has a diameter of each circular shape when a plate material of a reference sample such as a float glass which has almost no internal distortion and has a substantially perfect smooth surface is used as the sample plate 2. Are respectively stored in advance in the vertical and horizontal directions. The standard deviation of these criteria is a very small value because the circle is hardly deformed. Then, the standard deviation in the vertical and horizontal directions actually calculated for the sample plate 2 to be inspected is converted into the ratio of the standard deviation of this reference to obtain the standard deviation ratio. Therefore, the value of this standard deviation ratio is substantially “1” when the internal strain of the sample plate 2 is equal to that of the reference sample, and
When the internal distortion is larger than this, the value becomes larger according to the degree. In addition, by obtaining such a standard deviation ratio, it is possible to cancel the influence of errors in the diameter of each circle represented in the inspection pattern, distortion of the optical system, and the like.

When the image analysis unit 5 calculates the standard deviation ratio, the internal distortion of the sample plate 2 can be objectively known by this digitization. Further, by determining whether or not the standard deviation ratio exceeds a predetermined inspection reference value, a defective product having a large internal distortion can be selected. Further, so-called vertical distortion or horizontal distortion can be detected by distinguishing between vertical and horizontal standard deviation ratios. Further, by examining the standard deviation ratio for various sample plates 2, it is possible to objectively compare the internal strains of these sample plates 2.

As described above, according to the inspection method and apparatus of this embodiment, since the internal strain of the sample plate 2 is specifically quantified by the standard deviation ratio, the manufacturing process can be improved and the quality of the product can be inspected. In such a case, it is possible to obtain objective and easy-to-understand judgment data.

In the above embodiment, in order to project the inspection pattern onto the screen 1 in an enlarged manner, it is necessary to increase the distance between the screen 1 and the projector 4. However, it is possible to shorten this distance by increasing the magnification of the projector 4, and in this case, as shown in FIG. It is also possible to convert.

In the above embodiment, the distortion inspection method and apparatus for inspecting the internal distortion of the sample plate 2 have been described. However, as shown in FIG.
If the inspection pattern on the screen 1 is reflected by the surface of the sample plate 2 and an image is taken,
The smoothness of the surface of the sample plate 2 can also be inspected. When such a surface smoothness inspection is performed, the sample plate 2 also
It is not necessary to be a transparent plate, but may be an opaque resin plate, a metal plate, or the like, or a plate other than a plate having a substantially flat reflecting surface. Moreover, in this case as well, as shown in FIG. 7, the projector 4 and the screen 1 can be connected and integrated by the cover 6.

Further, the distortion inspection apparatus of the above embodiment is
The CCD camera 3 is arranged behind the sample plate 2 as shown in FIGS. 1 and 5, and also arranged laterally as shown in FIGS. The gender may be checked at once.

8 to 12 show a second embodiment of the present invention. FIG. 8 is a side view showing a configuration of a distortion inspection apparatus for inspecting internal distortion of a sample plate, and FIG. 9 is an inspection pattern plate. 11 is a side view showing a configuration of a distortion inspection apparatus for inspecting internal distortion of a sample plate provided with a backlight behind, FIG. 10 is a side view showing a configuration of a distortion inspection apparatus for inspecting the surface smoothness of the sample plate, and FIG. Is a side view showing a configuration of a distortion inspection device for inspecting the surface smoothness of a sample plate provided with a backlight behind the inspection pattern plate, and FIG. 12 is a distortion inspection device for inspecting the internal distortion and the surface smoothness of the sample plate. It is a longitudinal cross-sectional side view which shows a structure. Components having the same functions as those of the first embodiment shown in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof is omitted.

The inspection apparatus of this embodiment uses a test pattern plate 7 as shown in FIG. 8 instead of the projector 4 and the screen 1 in the first embodiment. The inspection pattern plate 7 is the screen 1 of the first embodiment.
The inspection pattern is enlarged by printing or the like on a flat surface having the same size as that of the inspection pattern. However, the inspection pattern plate 7 in the case shown in FIG. 8 does not necessarily have to be plate-shaped as long as it has a flat surface representing the inspection pattern. The sample plate 2 and the CCD camera 3 are the same as those in the first embodiment. In FIG. 8, the sample plate 2 is arranged in front of the inspection pattern plate 7 while being inclined, and behind the sample plate 2 The CCD camera 3 is arranged. Further, the inspection pattern plate 7 is appropriately illuminated from behind or on the side so that the inspection pattern can be imaged by the CCD camera 3, so that the inspection pattern can be clearly displayed.

A method for inspecting distortion using the inspection apparatus having the above configuration will be described. The inspection pattern displayed on the surface of the inspection pattern plate 7 is imaged by the CCD camera 3 through the sample plate 2. At this time, if there is no distortion inside the sample plate 2, each circle of the inspection pattern is imaged as it is, but if there is internal distortion at the transmission position, it is deformed into an elliptical shape or the like according to the degree of this distortion. It is imaged. Then, the image signal of the inspection pattern imaged by the CCD camera 3 is sent to the image analysis unit 5 not shown in FIG. 8, and the same processing as in the first embodiment is performed, and the standard deviation ratio is calculated. Is calculated.

Accordingly, also in the case of the inspection method and the apparatus according to the present embodiment, the internal distortion of the sample plate 2 is objectively inspected,
It can be used as a material for selecting and comparing defective products.
In addition, since the inspection pattern is previously displayed on the surface of the inspection pattern plate 7, it is not necessary to use the projector 4,
Further, since it is not necessary to dispose the projector 4 at a remote position, the size and cost of the apparatus can be reduced.

In the above embodiment, the image was taken by illuminating the test pattern on the test pattern plate 7 with appropriate illumination. However, as shown in FIG. The light 8 can be applied. In this case, the inspection pattern plate 7 may be a transparent resin plate or the like, or may be an optical ground glass, a cloudy resin sheet, or the like. As the backlight 8, it is preferable to use a planar illuminant that uniformly illuminates from behind the test pattern plate 7, but a fluorescent tube or the like may be used. However, when a transparent resin plate or the like is used as the inspection pattern plate 7, it is necessary to arrange a light scattering plate between the inspection pattern plate 7 and the illumination light to make the illumination uniform.

In the above embodiment, the distortion inspection method and the apparatus for inspecting the internal distortion of the sample plate 2 have been described. However, as shown in FIG. If the test pattern on the test pattern plate 7 is reflected on the surface of the sample plate 2 and an image is taken, the smoothness of the surface of the sample plate 2 can be tested. When such a surface smoothness test is performed, the sample plate 2 does not need to be a transparent plate material, and is not an opaque resin plate, a metal plate, or a plate material other than a plate material having a substantially flat reflecting surface. It may be. Moreover, in this case as well, FIG.
The backlight 8 can be provided behind the test pattern plate 7 as shown in FIG.

Further, in the distortion inspection apparatus according to the present embodiment, the CCD camera 3 is moved to the sample plate 2 as shown in FIGS.
And at the side as shown in FIGS. 10 and 11, so that the internal distortion and surface smoothness of the sample plate 2 can be inspected at a time. For example, as shown in FIG. 12, an inspection pattern plate 7 provided with a backlight 8 behind it and two CCD cameras 3 are attached to a housing 9.
The inspection apparatus can be made more compact and easy to handle. In this case, if the sample plate insertion portion 9a is provided in the housing 9, the sample plate 2 is inserted here and simply disposed obliquely in the housing 9,
Inspection of internal distortion and surface smoothness can be performed immediately. Further, the image analysis unit 5 can be arranged in the housing 9. However, when the sample plate 2 is an opaque resin plate or a metal plate, only the surface smoothness inspection can be performed.

Further, the inspection method and the apparatus according to the first and second embodiments can be carried out on a production line in which the sample plate 2 is sequentially conveyed by rollers or the like by an extrusion molding method or the like. In this case, since the sample plate 2 is sequentially transported endlessly, the inspection can be continuously performed while the CCD camera 3 and the like are fixed on the transport path or the like. When the width of the sample plate 2 to be conveyed is large, the CCD camera 3 is moved in the width direction, or a plurality of CCD cameras 3 are moved.
Are provided in the width direction, so that inspection of internal strain and surface smoothness can be performed over a wide area.

Further, in the first and second embodiments,
Although the case where a circle is used as the figure of the inspection pattern has been described, the figure is not limited to such a circle, and a figure having an arbitrary shape such as a quadrangle or an elongated line can be used, and it is not always necessary to arrange them at equal intervals. Also, the case where the image analysis unit 5 measures the diameter most suitable as the circular graphic feature value has been described. However, the image analysis unit 5 changes according to the internal distortion and the surface smoothness of the sample plate 2 according to the graphic used for the inspection pattern. Arbitrary graphic feature values can be measured. The figure characteristic value is a characteristic value of a figure area used for shape analysis or the like in image processing. In addition to the diameter, for example, a geometric characteristic such as a figure area, a perimeter, and a line length is used. Etc. can be used.

Further, in the first and second embodiments,
The image analysis unit 5 calculates the ratio between the standard deviation obtained by actually measuring the sample plate 2 and the standard deviation of the reference of the reference sample, but other comparison methods such as calculating the difference between the standard deviation of the standard and the standard deviation May be used, and the standard deviation itself obtained by measuring the sample plate 2 may be used as the degree of variation. Further, for example, the degree of variation can be indicated by obtaining a histogram of the diameter of each circle obtained by measuring the sample plate 2.

Further, in the first and second embodiments,
Although the case where a large number of isolated figures such as circles are used as the inspection pattern has been described, it is not always necessary to use such a large number of isolated figures, and it is also possible to form the inspection pattern using only a single pattern. In this case, the standard deviation cannot be used because the pattern is a single pattern. However, graphic feature values (eg, graphic area and line linearity) that change when the pattern is deformed due to internal distortion or surface smoothness. The same test can be performed if is measured.

[0052]

As is clear from the above description, according to the distortion inspection method and apparatus of the present invention, it is possible to easily inspect the internal distortion and the surface smoothness of a material to be inspected. In addition, the internal distortion and surface smoothness can be inspected by the same inspection apparatus to reduce the labor for setting the plate material to be inspected and to easily match the data of the inspection results. In addition, in this case, it is not necessary to arrange one screen each in front of the first and second cameras, so that it is possible to contribute to downsizing of the apparatus. Furthermore, if the inspection pattern is represented in a large size in advance, it is not necessary to perform enlarged projection using a projection image, so that the apparatus can be downsized.

[Brief description of the drawings]

FIG. 1, showing a first embodiment of the present invention, is a side view showing a configuration of a distortion inspection apparatus for inspecting internal distortion of a sample plate.

FIG. 2 illustrates the first embodiment of the present invention, and is a process diagram illustrating processing steps of an image processing unit.

FIG. 3, showing the first embodiment of the present invention, is a view showing image data of a sample plate having no internal distortion.

FIG. 4 shows the first embodiment of the present invention, and is a diagram showing image data of a sample plate having internal distortion.

FIG. 5, showing the first embodiment of the present invention, is a side view showing a configuration of a distortion inspection apparatus for inspecting the surface smoothness of a sample plate in which a projector and a screen are integrated.

FIG. 6 shows the first embodiment of the present invention, and is a side view showing a configuration of a distortion inspection apparatus for inspecting the surface smoothness of a sample plate.

FIG. 7 shows the first embodiment of the present invention, and is a side view showing a configuration of a distortion inspection apparatus for inspecting the surface smoothness of a sample plate in which a projector and a screen are integrated.

FIG. 8 shows the second embodiment of the present invention, and is a side view showing the configuration of a distortion inspection device for inspecting internal distortion of a sample plate.

FIG. 9 shows a second embodiment of the present invention, and is a side view showing a configuration of a distortion inspection device for inspecting internal distortion of a sample plate provided with a backlight behind an inspection pattern plate.

FIG. 10 shows a second embodiment of the present invention,
It is a side view showing the composition of the distortion inspection device which inspects the surface smoothness of a sample plate.

FIG. 11 shows a second embodiment of the present invention,
It is a side view showing the composition of the distortion inspection device which inspects the surface smoothness of the sample board provided with the backlight behind the inspection pattern board.

FIG. 12 shows a second embodiment of the present invention,
It is a longitudinal section side view showing composition of a distortion inspection device which inspects internal distortion and surface smoothness of a sample plate.

FIG. 13 is a side view showing a conventional example and showing a configuration of a distortion inspection apparatus for inspecting internal distortion of a sample plate.

FIG. 14 is a side view showing another conventional example and showing a configuration of a distortion inspection apparatus for inspecting the surface smoothness of a sample plate.

[Explanation of symbols]

 Reference Signs List 1 screen 2 sample plate 3 CCD camera 4 projector 5 image analysis unit 7 inspection pattern plate 8 backlight

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Masao Kubo, 2-3-13 Azuchicho, Chuo-ku, Osaka City Inside Takiron Co., Ltd. (72) Takaaki Kato 2-3-13, Azuchicho, Chuo-ku, Osaka City Takiron Co., Ltd.

Claims (10)

[Claims] An image of a predetermined inspection pattern formed by an inspection pattern forming means is transmitted through a plate to be inspected by a camera disposed behind the plate to be inspected, and the image of the captured inspection pattern is distorted. A distortion inspection method characterized by inspecting the degree of image distortion by image analysis means. 2. An inspection pattern forming means for forming a predetermined inspection pattern, and an inspection pattern formed by the inspection pattern forming means,
A camera for transmitting an image of a plate to be inspected inclined to the front of the inspection pattern and imaging the image, and image analysis means for inspecting the degree of distortion of the image of the inspection pattern imaged by the camera. Strain inspection equipment. 3. A predetermined inspection pattern formed by an inspection pattern forming means is reflected on a surface of a material to be inspected, an image is taken by a camera arranged in front of the material to be inspected, and an image of the image of the taken inspection pattern is taken. A distortion inspection method, wherein the degree of distortion is inspected by image analysis means. 4. An inspection pattern forming means for forming a predetermined inspection pattern, and an inspection pattern formed by the inspection pattern forming means,
A camera that reflects an image on the surface of the inspection material that is inclined and is arranged in front of the inspection pattern and captures an image; and an image analysis unit that inspects a degree of distortion of an image of the inspection pattern captured by the camera. Characteristic strain inspection device. 5. An inspection pattern forming means for forming a predetermined inspection pattern, and an inspection pattern formed by the inspection pattern forming means,
A first camera that transmits and captures an image of a plate to be inspected that is arranged obliquely in front of the inspection pattern, a second camera that reflects and reflects an image on the surface of the plate to be inspected, 2. A distortion inspection apparatus comprising: image analysis means for inspecting the degree of distortion of an image of an inspection pattern captured by a second camera. 6. The inspection pattern forming means for forming a projection image of a predetermined inspection pattern on a screen by a projector.
Or the apparatus for inspecting distortion. 7. The distortion inspection method or apparatus according to claim 1, wherein said inspection pattern forming means represents a predetermined inspection pattern on a flat surface. 8. The inspection pattern forming means according to claim 1, wherein said inspection pattern forming means expresses a predetermined inspection pattern on a surface of a light-transmitting plate on which a backlight is provided from behind.
Or the apparatus for inspecting distortion. 9. The distortion inspection method or apparatus according to claim 1, wherein the camera has a light quantity limiting filter disposed in front thereof. 10. An inspection pattern formed by the inspection pattern forming means, wherein a large number of identical isolated figures are two-dimensionally arranged at appropriate intervals, and wherein the image analysis means measures a figure characteristic measured for each isolated figure. 10. The distortion inspection method or apparatus according to claim 1, wherein the degree of image distortion of the inspection pattern is determined based on the degree of value variation.