JP2007263611A - Distortion measuring instrument and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distortion measuring instrument and a distortion measuring method capable of measuring easily a distortion, in particular, the three-dimensional distortion, in a rubber product such as a tire, a hose, a conveyer belt, and a fender. <P>SOLUTION: This distortion measuring instrument of the present invention has a photographing part for photographing a measuring object together with a marker, by providing the plane marker in the measuring object, a three-dimensional shape measuring part for obtaining a three-dimensional shape data of the measuring object, an image processing part for calculating a two-dimensional position data of each position of the marker in the photographed image, a data processing part for correlating the three-dimensional shape data of the measuring object with the two-dimensional position data of the marker, and a distortion measuring part for calculating the distortion of the measuring object, using the three-dimensional shape data of the measuring object, before deformed, correlated with the two-dimensional position data of the marker before deformed, and using the three-dimensional shape data of the measuring object, after deformed, correlated with the two-dimensional position data of the marker after deformed. The marker is different from the measuring object in any of chromaticity, chromasaturation, and brightness. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a strain measuring device and a strain measuring method for measuring strain associated with deformation of rubber products such as tires, conveyor belts, hoses, or fenders, and in particular, tires, conveyor belts, hoses, or fenders. The present invention relates to a strain measuring apparatus and a strain measuring method capable of easily measuring three-dimensional strains such as rubber products.

  In rubber products such as tires, hoses, conveyor belts, and fenders, it is possible to accurately know the cause of failure or design factors such as improved durability by measuring surface strain with high resolution. For this reason, conventionally, as a method for measuring the surface strain of a rubber product, a reference mark is written on the surface of the object to be measured, and the position before and after the deformation of the reference mark is measured to obtain the surface strain. Various methods for measuring such surface strain have been proposed (see Patent Document 1).

In the surface strain measurement method disclosed in Patent Document 1, a surface strain measurement sheet is cut to an appropriate size and then attached to the sidewall surface of a tire that is a rubber product to be measured. Then, the surface strain measurement sheet grid is colored, and the surface strain measurement sheet grid is transferred to a recording medium such as paper or a transparent OHP sheet. Thereby, the lattice pattern before the deformation of the sidewall is obtained.
Next, a load is applied to the tire to deform the sidewall surface to color the lattice of the surface strain measurement sheet, and this lattice is transferred to a recording medium such as paper or a transparent OHP sheet. Thereby, the lattice pattern after the deformation of the sidewall is obtained. In this manner, in the surface strain measurement method disclosed in Patent Document 1, the lattice pattern before the side wall deformation and the lattice pattern after the side wall deformation are acquired. For these lattice patterns, the coordinates of the lattice are obtained, and the surface strain of the rubber product to be measured is calculated based on these coordinates.

JP 2004-317316 A

  However, the surface strain measurement method disclosed in Patent Document 1 has a problem that although it can measure surface strain, it cannot measure three-dimensional strain. For this reason, for example, when measuring the strain before and after inflation for a tire, there is a problem that the strain cannot be measured with sufficient accuracy.

  An object of the present invention is to solve the above-described problems of the prior art, and easily measure strains, particularly three-dimensional strains, of rubber products such as tires, hoses, conveyor belts, and fenders. An object of the present invention is to provide a strain measuring apparatus and a strain measuring method capable of performing the above.

  In order to achieve the above object, a first aspect of the present invention is a strain measuring apparatus for measuring strain generated along with deformation of a measurement object, wherein a planar marker is provided on the measurement object, An imaging unit that images the measurement object together with a marker, a three-dimensional shape measurement unit that measures the three-dimensional shape of the measurement object and obtains three-dimensional shape data, and each position of the marker of the image captured by the imaging unit An image processing unit for calculating two-dimensional position data, a data processing unit for associating the three-dimensional shape data of the measurement object and the two-dimensional position data of the marker, and the two-dimensional position data before deformation of the marker The three-dimensional shape data before deformation of the measurement object and the three-dimensional shape data after deformation of the measurement object associated with the two-dimensional position data after deformation of the marker are used. A distortion measuring unit that calculates distortion of the measurement object, and the marker is different from the measurement object in any of chromaticity, saturation, and brightness. A strain measuring device is provided.

In the present invention, the marker is formed on a film with a different chromaticity, saturation, and brightness with respect to the measurement object, and the film is attached to the measurement object. It is preferable that the measuring object is provided.
In the present invention, it is preferable that the marker is directly formed on the measurement object with an ink having any one of chromaticity, saturation, and brightness different from those of the measurement object.
Furthermore, in the present invention, it is preferable that the marker has a square lattice pattern.

  Furthermore, in the present invention, the measurement object is, for example, a rubber product such as a tire, a conveyor belt, a hose, or a fender.

  Further, a second aspect of the present invention is a strain measurement method for measuring strain generated due to deformation of a measurement object, and images the measurement object provided with a planar marker together with the marker before deformation. And measuring the three-dimensional shape before deformation of the measurement object, photographing the measurement object provided with the marker together with the marker after deformation, and three-dimensional shape after deformation of the measurement object Measuring three-dimensional shape data of the three-dimensional shape before deformation of the measurement object, and two-dimensional position data of each position of the marker before deformation of the measurement object, A step of associating position data with three-dimensional shape data before deformation of the measurement object, three-dimensional shape data of the three-dimensional shape after deformation of the measurement object, and change of the measurement object; A step of obtaining two-dimensional position data of each of the subsequent marker positions, associating the two-dimensional position data of the marker with the three-dimensional shape data after deformation of the measurement object, and two-dimensional position data before deformation of the marker The three-dimensional shape data before deformation of the measurement object associated with the three-dimensional shape data after deformation of the measurement object associated with the two-dimensional position data after deformation of the marker And a step of calculating a strain of the measurement object.

  In the present invention, the measurement object is, for example, a rubber product such as a tire, a conveyor belt, a hose, or a fender.

  According to the strain measuring device and the strain measuring method of the present invention, before and after the deformation of the measurement object provided with the marker is photographed, and the three-dimensional shape before and after the deformation of the measurement object provided with the marker is measured. The two-dimensional position data of each position of the marker before and after the deformation of the measurement object is obtained, the three-dimensional shape data before the deformation of the measurement object associated with the two-dimensional position data before the deformation of the marker, and the deformation of the marker By calculating the three-dimensional distortion of the deformed measurement object using the deformed three-dimensional shape data of the measurement object associated with the later two-dimensional position data, the three-dimensional distortion of the measurement object is calculated. Can be easily measured. For this reason, according to the strain measuring apparatus and strain measuring method of the present invention, for example, three-dimensional strain of rubber products such as tires, conveyor belts, hoses, or fenders can be easily measured.

Hereinafter, a strain measuring apparatus and a strain measuring method according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
FIG. 1 is a schematic view showing a strain measuring apparatus according to the first embodiment of the present invention. FIG. 2 is a schematic diagram showing a light source unit of the strain measuring apparatus shown in FIG. FIG. 3 is a schematic diagram showing a three-dimensional measuring unit of the strain measuring apparatus shown in FIG.

  As shown in FIG. 1, the strain measurement apparatus 10 has a function of measuring the three-dimensional shape of the surface 102 of the measurement object 100, and includes a light source unit 12, a three-dimensional measurement unit 14, a strain measurement unit 16, a control unit 18, It has the input part 18a and the display part 18b.

Here, in the present invention, a marker 104 for measuring strain is provided on the surface 102 of the measurement object 100.
The marker 104 has a planar shape, and when the three-dimensional shape is measured, the surface 102 is not uneven, and does not affect the shape of the surface 102. In addition, the marker 104 is different from the measurement object 100 in any of chromaticity, saturation, and brightness.

Note that the pattern of the marker 104 is not particularly limited, and marks having a shape such as a circle, a triangle, or a square may be discretely arranged at equal intervals. Furthermore, the marker 104 may be a square lattice pattern or a diagonal lattice pattern.
Further, the marker 104 is formed on the measurement object by forming a mark or pattern on the film using ink or the like having different chromaticity, saturation, and brightness, and attaching the film to the measurement object. But you can.
In addition, the marker 104 may be formed on the measurement object 100 by using an ink having a different chromaticity, saturation, or lightness with respect to the measurement object, and painting using a mask having a predetermined pattern. . Further, the marker 104 may be formed on the measurement object 100 using an ink jet recording type recording apparatus, or may be formed on the measurement object 100 by printing or the like.

  As shown in FIG. 2, the light source unit 12 includes a laser diode 20, a light projecting lens system 22, a galvano mirror 24, and a driver 26. The laser diode 20 is a light source that emits laser light, and the laser diode 20 is connected to a driver 26.

The light projecting lens system 22 irradiates the galvano mirror 24 with laser light emitted from the laser diode 20 with a predetermined slit width.
The galvanometer mirror 24 scans the surface 102 of the measuring object 100 with the laser light from the laser diode 20 formed into slit light by the light projecting lens system 22. The galvanometer mirror 24 is provided with a scanning mechanism (not shown) for deflecting slit light. This scanning mechanism is connected to the driver 26.
The driver 26 drives a scanning mechanism (not shown) of the laser diode 20 and the galvanometer mirror 24. The driver 26 is connected to the control unit 18, and the control unit 18 controls the lighting of the laser diode 20 and the scanning of the galvano mirror 24, that is, the scanning of the slit light (scanning light) through the driver 26. Is done.

  As shown in FIG. 3, the three-dimensional measuring unit 14 receives the reflected light of the slit light emitted from the light source unit 12, performs analysis, measures the three-dimensional shape of the measuring object, and measures the measuring object. To obtain three-dimensional data. The three-dimensional measuring unit 14 is provided in the order of the lens 30, the CCD element 32, the A / D converter 34, the FIFO 36, and the image processing unit 38 from the incident side of the reflected light of the slit light. Are connected to the frame memory 39.

The lens 30 makes slit light enter the CCD element 32. The lens 30 is provided with a zoom mechanism (not shown) and a focus adjustment function (not shown). The zoom mechanism and the focus adjustment function are connected to the control unit 18, and the operation of the zoom mechanism and the focus adjustment function is controlled by the control unit 18. For this reason, even if the distance to the measurement object changes, an image can be formed at an appropriate position with respect to the CCD element 32, and an appropriate image can be obtained.
In this embodiment, since the distance from the three-dimensional measurement unit 14 to the measurement object 100 is accurately measured, the control unit 18 controls the zoom mechanism and the focus adjustment function based on the distance measurement result. Thus, an image can be formed at an appropriate position with respect to the CCD element 32, and an appropriate image can be obtained.
The CCD element 32 functions as a distance measuring sensor for specifying the three-dimensional position of the measurement object 100 as well as functioning as an imaging unit that images the measurement object.

The A / D converter 34 converts the output signal of the CCD element 32 into a digital signal.
The FIFO 36 supplies the digital signal obtained by the CCD element 32 to the image processing unit 38 in order.

  The image processing unit 38 obtains the three-dimensional shape data (three-dimensional measurement coordinates) of the measurement object based on the reflected light of the slit light, and the marker based on the captured image of the measurement object obtained by the CCD element 32. Two-dimensional position data (two-dimensional position coordinates) is obtained.

  Further, as the processing method for generating three-dimensional shape data from the image signal of the CCD element in the image processing unit 38, a known light cutting method algorithm is used. In this light cutting method, slit light is irradiated onto the measurement object 100, the band-like reflected light bent at the surface 102 of the measurement object 100 is photographed by the CCD element 32, and the three-dimensional shape data is obtained from the imaging position in the image. It is a method to seek. At this time, the calculation for obtaining the three-dimensional shape data is performed based on the principle of triangulation.

  Further, the image processing unit 38 extracts a marker from the captured image of the measurement target obtained by the CCD element 32 by, for example, edge detection. Then, two-dimensional position coordinates representing the position of each extracted marker are obtained. At this time, since the distance to the measurement object 100 is accurately measured, three-dimensional position coordinates representing the position of each marker can also be obtained.

In the frame memory 39, the three-dimensional shape data (three-dimensional measurement coordinates) of the measurement object generated by the image processing unit 38 and the two-dimensional position data (two-dimensional position coordinates) of the marker are sequentially written. This is called by the image processing unit 38.
Further, the image processing unit 38 is connected to the distortion measuring unit 16. The three-dimensional shape data (three-dimensional measurement coordinates) of the measurement object generated by the image processing unit 38 and the two-dimensional position data (three-dimensional position coordinates) of the marker are output to the data processing unit 16a of the strain measurement unit 16. Is done.

  As shown in FIG. 1, the strain measurement unit 16 calculates a three-dimensional strain of the measurement object, and includes a data processing unit 16a and a strain calculation unit 16b.

The data processing unit 16a associates the three-dimensional shape data (three-dimensional measurement coordinates) of the measurement object generated by the image processing unit 38 with the two-dimensional position data (two-dimensional position coordinates) of the marker. As this association, for example, the three-dimensional shape data (three-dimensional measurement coordinates) of the measurement object and the two-dimensional position data (two-dimensional position coordinates) of the marker are converted into the same coordinate system. By this data processing unit 16a, the two-dimensional position data of the marker obtained by imaging with the CCD element 32 can be accurately matched to the three-dimensional shape data of the measurement object 100, and the marker can be aligned with the measurement object. It can be placed at an accurate position.
Thereby, the two-dimensional position coordinates of the marker before and after the deformation can be accurately matched to the measurement object, and the distortion can be accurately obtained from the correspondence between the marker before the deformation and the marker after the deformation.
In addition, since the distance to the measurement object 100 is accurately measured, three-dimensional position coordinates representing the position of each marker can be obtained, so that the three-dimensional shape of the measurement object generated by the image processing unit 38 is obtained. By associating the data (three-dimensional measurement coordinates) with the three-dimensional position data (three-dimensional position coordinates) of the marker, the three-dimensional distortion is accurately obtained from the correspondence between the marker before deformation and the marker after deformation. be able to.

  Note that the three-dimensional shape data (three-dimensional measurement coordinates) of the measurement object generated by the image processing unit 38 is associated with the two-dimensional position data (two-dimensional position coordinates) of the marker. This association is not particularly limited, and the three-dimensional shape data of the measurement object and the two-dimensional position data of the marker may be converted into values of coordinate systems different from each other and associated with each other.

Here, in the present embodiment, since the CCD element 32 serves as both a sensor for measuring the distance and an image pickup element for photographing the measurement object, each pixel of the CCD element 32 is an object of the measurement object. Corresponds to each measurement point. Therefore, the three-dimensional position coordinates are measured for each pixel in the captured image captured by the CCD element 32. Therefore, by extracting a marker provided on the measurement object, obtaining two-dimensional position data (two-dimensional position coordinates) indicating the position of the marker, and aligning the two-dimensional position coordinates of the marker with the measurement object. The marker can be accurately placed on the surface 102 of the measurement object 100.
In this case, since the measurement condition of the three-dimensional shape of the measurement object and the imaging condition of the measurement object do not necessarily match, the data processing unit 16a has the imaging condition of the measurement object and the measurement object. 3D shape data of the 3D shape of the measurement object and the 2D position of the intersection of the markers based on the difference in imaging magnification and angle of view (difference in the position of the lens 30) with the measurement conditions of the 3D shape Match coordinates.

  For example, in the data processing unit 16a, the two-dimensional position data of the markers obtained in advance under various imaging conditions, and the three-dimensional shape data of the measurement object obtained in various measurement conditions for the three-dimensional measurement unit 14a. And a conversion formula between the two-dimensional position data of the marker and the three-dimensional shape data of the measurement object is provided. In the data processing unit 16a, the conversion formula is used to associate the three-dimensional shape data of the three-dimensional shape of the measurement object with the two-dimensional position coordinates of the intersection of the markers. Thereby, the two-dimensional position coordinates of the marker can be accurately adjusted to the three-dimensional shape data.

  The distortion calculation unit 16b calculates the distortion based on the change in the position of each marker before and after the deformation of the measurement object. The strain calculation unit 16b can also calculate the strain distribution, the deformation amount, and the deformation amount distribution of the measurement object 100.

  The control unit 18 is connected to the light source unit 12, the three-dimensional measurement unit 14, and the strain measurement unit 16, and controls the operation of each device of the light source unit 12, the three-dimensional measurement unit 14, and the strain measurement unit 16. Is. The control unit 18 includes a clock generator (not shown) for adjusting the driving timing.

Moreover, the input part 18a and the display part 18b are connected to the control part 18, for example, an operator inputs an instruction from the input part 18a while looking at the display part 18b.
The input unit 18a is an input device such as a mouse and a keyboard.
The display unit 18b displays a three-dimensional shape reproduced using the three-dimensional shape data of the measurement object, a captured image captured by the CCD element 32, and the like. It also displays an input screen for various processes.

In the distortion measuring apparatus 10 of the present embodiment, the control unit 18 generates a trigger signal for starting measurement, and activates the clock generator to generate a clock signal in response to an instruction input from the operator input unit 18a. This clock signal is supplied to the CCD element 32, the A / D converter 34, the FIFO 36, and the image processing unit 38.
On the other hand, the control unit 18 outputs a trigger signal to the driver 26, the driver 26 generates a laser light irradiation signal, supplies the signal to the laser diode 20, and the laser diode 20 emits the laser light. Next, the laser light is converted into slit light through the light projecting lens system 22, and the galvano mirror 24 is scanned by a scanning drive mechanism in accordance with the irradiation signal of the laser light, and the surface 102 of the measurement object 100 is slit. The laser beam is scanned. The CCD element 32 images the measurement object 100 together with the marker 104.

Further, in the strain measurement apparatus 10 of the present embodiment, the CCD element 32 of the three-dimensional measurement unit 14 is used as a sensor for imaging a marker provided on the measurement object and a three-dimensional shape measurement, and further in the image processing unit 38. The two-dimensional position coordinates of the marker are obtained, and further, the two-dimensional position coordinates of the marker obtained by imaging with the CCD element 32 in the data processing unit 16a of the distortion measuring unit 16 and the three-dimensional shape of the measuring object 100 When the data is associated, the marker can be arranged at an accurate position with respect to the measurement object. For this reason, the position of the marker before and after the deformation can be set to an accurate position with respect to the measurement object, and the distortion can be accurately obtained from the correspondence relationship between the marker before the deformation and the marker after the deformation. In addition, since the distance to the measurement object is also measured, the distortion of the measurement object can be obtained in three dimensions.
In addition, as such a strain measuring apparatus 10, the non-contact three-dimensional digitizer VIVID9i (made by Konica Minolta Co., Ltd.) which used the optical cutting method can be used, for example.

Next, a strain measurement method using the strain measurement apparatus 10 of the present embodiment will be described by taking as an example the distortion of a prism made of an elastic body such as rubber.
4A is a perspective view showing a prism made of an elastic body, and FIG. 4B is a perspective view showing a deformed state by applying a compressive load to the prism shown in FIG. 4A.
FIG. 5A is a side view of the prism shown in FIG. 4A, and FIG. 5B is a side view of the prism shown in FIG. 4B.

  The prism 40 shown in FIG. 4A has a lattice pattern marker 42 formed on a side surface 40a. This marker 42 is provided by printing a square lattice pattern on a film with ink having different chromaticity, saturation and brightness, and this film is attached to the side surface 40a of the prism 40. is there.

In the strain measurement method of the present embodiment, first, the three-dimensional shape of the side surface 40a of the prism 40 is measured by the three-dimensional measurement unit 14.
The side surface 40 a of the prism 40 is imaged together with the marker 42 by the CCD element 32 of the three-dimensional measuring unit 14.
Next, in the image processing unit 38 of the three-dimensional measuring unit 14, three-dimensional shape data of the three-dimensional shape of the side surface 40a of the prism 40 is obtained.
Further, for the captured image of the CCD element 32, the image processing unit 38 extracts the marker 42 by using, for example, edge detection. Then, the intersection of the lattice patterns is obtained. Next, the two-dimensional position coordinates of the intersection of the markers 42 in the captured image are obtained by the image analysis unit 38.

Next, the three-dimensional shape data of the three-dimensional shape of the side surface 40 a of the prism 40 and the two-dimensional position coordinates of the intersection of the markers 42 are stored in the frame memory 39.
Next, the three-dimensional shape data of the three-dimensional shape of the side surface 40a of the prism 40 and the two-dimensional position coordinates of the intersection of the markers 42 are output to the data processing unit 16a of the strain measuring unit 16, and the three-dimensional of the side surface 40a of the prism 40 is output. The three-dimensional shape data of the shape is associated with the two-dimensional position coordinates of the intersection of the marker 42 before the deformation, and the two-dimensional position coordinates of the intersection of the marker 42 are set to the correct position in the three-dimensional shape data of the side surface 40a before the deformation. Match.
At this time, the side surface 40a of the prism 40 is determined based on the difference in imaging magnification, field angle, etc. (difference in the position of the lens 30) between the imaging condition of the measurement object and the measurement condition of the three-dimensional shape of the measurement object. The two-dimensional position coordinates of the intersection before the deformation of the marker 42 are associated with the three-dimensional shape data of the three-dimensional shape.

Next, as shown in FIG. 4B, a compression load F was applied to the prism 40, and the side surface 40a was deformed by a displacement amount δ in a direction orthogonal to the compression load F direction. At this time, the three-dimensional shape measurement is performed on the side surface 40a of the prism 40 as before the deformation.
The three-dimensional shape is measured by the three-dimensional measuring unit 14 on the side surface 40a of the prism 40, and the three-dimensional shape of the three-dimensional shape of the side surface 40a of the prism 40 after deformation is measured in the image processing unit 38 of the three-dimensional measuring unit 14. Data is obtained. At this time, the side surface 40a is displaced by a displacement amount δ in a direction orthogonal to the direction of the compression load F, and this displacement amount δ is reflected in the three-dimensional shape data of the three-dimensional shape.

  For the captured image of the side surface 40a photographed together with the marker 42a by the CCD element 32 of the three-dimensional measuring unit 14, the image processing unit 38 extracts the marker 42a by using, for example, edge detection. Then, the intersection of the lattice patterns is obtained. Next, the two-dimensional position coordinates of the intersection of the markers 42a in the captured image are obtained by the image analysis unit 38.

  Next, the three-dimensional shape data of the three-dimensional shape of the side surface 40a of the prism 40 after deformation and the two-dimensional position coordinates of the intersection of the markers 42a are output to the data processing unit 16a of the strain measuring unit 16, and the data processing unit 16a Is a side surface of the prism 40 after deformation based on differences in imaging magnification, field angle, etc. (difference in the position of the lens 30) between the imaging conditions of the measurement object and the measurement conditions of the three-dimensional shape of the measurement object. The three-dimensional shape data of the three-dimensional shape of 40a is associated with the two-dimensional position coordinates of the intersection of the marker 42a, and the two-dimensional position coordinates of the intersection of the marker 42 are set to the correct position in the three-dimensional shape data of the side surface 40a after deformation. Match.

  Next, in the strain calculation unit 16b of the strain measurement unit 16, the correspondence between the three-dimensional position coordinates associated with the intersection of the marker 42 before the deformation and the intersection of the deformed marker 42a corresponding to the marker 42 before the deformation. The obtained three-dimensional position coordinates are compared to calculate a three-dimensional distortion. Further, since the deformation amount can be obtained in addition to the strain, a distribution of the deformation amount state can be obtained. In this case, by assigning an identification number to the intersection (three-dimensional position coordinate) of the marker 42, it is possible to correspond to the intersection (three-dimensional position coordinate) of the deformed marker 42a.

As shown in FIG. 5A, at the intersections of the markers 42 before deformation, identification numbers P _{1 to} P ₄ are given to the intersections that form square corners. As shown in FIG. 5 (b), in the marker 42a after deformation, when connecting the intersections _P 1 to P _4, a square distorted. At this time, for the intersection points P _{1 to} P ₄ , accurate three-dimensional position coordinates are obtained before and after the deformation by three-dimensional measurement. Therefore, in the strain measurement method of this embodiment, the three-dimensional distortion is accurately determined. Can be requested.

  The distortion calculation result is output to the control unit 18. The control unit 18 causes the display unit 18b to display the distortion result as a numerical value. In addition, the control unit 18 can display the distortion result on the display unit 18b as a contour map as a line drawing. Further, the control unit 18 can display the display unit 18b with a color or the like changed according to the distortion level. You may make it make it.

Next, a second embodiment of the present invention will be described.
FIG. 6 is a schematic diagram illustrating a strain measuring apparatus according to the second embodiment of the present invention, and FIG. 7 is a schematic diagram illustrating an imaging unit of the strain measuring apparatus illustrated in FIG.
In addition, the same code | symbol is attached | subjected to the same structure as the distortion measuring device 10 which concerns on the 1st Embodiment of this invention shown in FIGS. 1-3, and the detailed description is abbreviate | omitted.

  Compared to the strain measurement apparatus 10 (see FIG. 1) of the first embodiment, the strain measurement apparatus 50 of the present embodiment is provided with a photographing unit 52. Further, in the three-dimensional measurement unit 14a, the CCD element 32 is provided. However, the image processing unit 38 does not obtain the two-dimensional position coordinates of the marker from the image captured by the CCD element 32 and the data processing of the data processing unit 16a of the distortion measuring unit 16 is not performed. The differences are different, and the rest of the configuration is the same as that of the strain measurement apparatus 10 of the first embodiment, and thus detailed description thereof is omitted.

In the distortion measuring apparatus 50 of the present embodiment, the imaging unit 52 captures the measurement area of the measurement object 100 from two directions by two imaging units, and obtains three-dimensional position data of the marker 104.
As shown in FIG. 7, the photographing unit 52 includes two lenses 60a and 60b, two CCD elements 62a and 62b, two A / D converters 64a and 64b, and an image processing unit 66. Each A / D converter 64 a and 64 b is connected to the image processing unit 66.
The lens 60a, the CCD element 62a, and the A / D converter 64a constitute one photographing unit, and the lens 60b, the CCD element 62b, and the A / D converter 64b constitute one photographing unit.
Further, lenses 60a and 60b, CCD elements 62a and 62b, A / D converters 64a and 64b, and an image processing unit 66 are arranged in this order from the light receiving side.

The lens 60a forms an image of light on the CCD element 62a. The lens 60a is provided with a zoom mechanism (not shown) and a focus adjustment function (not shown). The zoom mechanism and the focus adjustment function are connected to the control unit 18, and the operation of the zoom mechanism and the focus adjustment function is controlled by the control unit 18. For this reason, even if the distance to the measurement object changes, an image can be formed at an appropriate position with respect to the CCD element 62a, and an appropriate image can be obtained.
In the control unit 18, the geometrical arrangement relationship between the light source unit 12, the three-dimensional measurement unit 14 a, and the imaging unit 52 is stored.

The CCD element 62a images the measurement object.
The A / D converter 64a converts the output signal of the CCD element 62a into a digital signal.
Since the lens 60b, the CCD element 62b, and the A / D converter 64b have the same configuration as the lens 60a, the CCD element 62a, and the A / D converter 64a, detailed description thereof is omitted.

The image processing unit 66 uses two captured images obtained by photographing the measurement object obtained by the CCD elements 62a and 62b from two directions, and uses a known photogrammetry method (stereo method) based on the principle of triangulation to detect the marker. Three-dimensional position data (three-dimensional position coordinates) is obtained.
Further, in the image processing unit 66, a marker is extracted from the captured image of the measurement object obtained by the CCD element 62, for example, by edge detection. And the three-dimensional position coordinate which shows the position of each extracted marker is calculated | required by the well-known photogrammetry (stereo method) using two picked-up images. The image processing unit 66 is connected to the data processing unit 16 a of the distortion measuring unit 16. Then, the three-dimensional position coordinates of the marker are output to the data processing unit 16 a of the strain measuring unit 16.

  In the present embodiment, the CCD element 32 does not serve as both a sensor for measuring the distance and an imaging element for photographing the measurement object, and each pixel of the CCD element 32 corresponds to each measurement point of the measurement object. Not done. From this, the two-dimensional position data of the marker obtained by the imaging unit 52 and the three-dimensional shape data of the measurement object 100 obtained by the three-dimensional measurement unit 14a do not necessarily match. For this reason, in the data processing unit 16a, the three-dimensional position data of the markers obtained in advance for the photographing unit 52 under various photographing conditions and the measurement object obtained in the various measuring conditions for the three-dimensional measuring unit 14a. The relationship with the three-dimensional shape data is examined, and a conversion formula between the three-dimensional position data of the marker and the three-dimensional shape data of the measurement object is provided. In the data processing unit 16a, using this conversion formula, the three-dimensional shape data of the three-dimensional shape of the measurement object is associated with the three-dimensional position coordinates of the intersection of the markers. Thereby, the three-dimensional position coordinates of the marker can be accurately adjusted to the three-dimensional shape data.

Next, as for the strain measuring method using the strain measuring device 50 of the present embodiment, the prism 40 (FIGS. 4A and 4B and FIGS. 5A and 5B) as in the first embodiment. Reference).
Compared to the strain measurement method using the strain measurement apparatus 10 of the first embodiment, the strain measurement method using the strain measurement apparatus 50 of the present embodiment uses the two-dimensional position coordinates of the marker in the three-dimensional measurement unit 14a. The difference is that the imaging unit 52 obtains the three-dimensional position coordinates of the marker without obtaining the point and the data processing unit 16a associates the three-dimensional shape data of the measurement object with the three-dimensional position data of the marker. Since this strain measurement method is the same as the strain measurement method using the strain measurement apparatus 10 of the first embodiment, a detailed description thereof will be omitted.

In the strain measuring method using the strain measuring device 50 of the present embodiment, first, slit light is irradiated from the light source unit 12 to the surface 40a of the prism 40 and the reflected light is three-dimensionally applied to the prism 40 before deformation. Analysis is performed by the measurement unit 14 to obtain three-dimensional shape data of the prism 40.
At this time, also in the imaging | photography part 52, the surface 40a of the prism 40 is imaged from two directions, and two captured images are obtained. In this photographing unit 52, the three-dimensional position coordinates of the marker before deformation are obtained for the two captured images by a known photogrammetry method.

  Next, in the data processing unit 16a of the distortion measuring unit 16, differences in imaging magnification, angle of view, etc. (differences in the position of the lens 30) between the imaging conditions of the measurement object and the measurement conditions of the three-dimensional shape of the measurement object. ) And the like, the three-dimensional shape data before the deformation and the three-dimensional position coordinates of the marker are associated, and the three-dimensional position coordinates of the marker 42 are accurately matched to the three-dimensional shape data of the surface 40a of the prism 40 before the deformation. .

  Next, slit light is applied to the surface 40a of the prism 40 from the light source unit 12 with respect to the deformed prism 40, and the three-dimensional measurement unit 14 obtains three-dimensional shape data of the surface 40a of the prism 40. At this time, the photographing unit 52 also uses the two photographed images photographed from two directions with respect to the surface 40a of the deformed prism 40, and calculates the three-dimensional position coordinates of the deformed marker by a known photogrammetry method. Ask.

  Next, in the data processing unit 16a of the distortion measuring unit 16, differences in imaging magnification, angle of view, etc. (differences in the position of the lens 30) between the imaging conditions of the measurement object and the measurement conditions of the three-dimensional shape of the measurement object. ) And the like, the three-dimensional shape data after the deformation is associated with the three-dimensional position coordinates of the marker, and the three-dimensional position coordinates of the marker are accurately matched to the three-dimensional shape data of the surface 40a of the prism 40 after the deformation.

Next, the strain calculation unit 16b of the strain measurement unit 16 calculates the strain from the three-dimensional position coordinates of the marker before and after the deformation. Thus, also in the strain measuring method using the strain measuring apparatus 50 of the present embodiment, the strain of the surface 40a of the prism 40 after deformation can be calculated. Note that the strain measurement apparatus 50 according to the present embodiment can also calculate the strain distribution, the deformation amount, and the deformation amount distribution in addition to the strain.
As described above, also in the strain measuring device 50 of the present embodiment and the strain measuring method using the same, the same effects as those of the strain measuring device 10 of the first embodiment and the strain measuring method using the same can be obtained. .

Next, a tire surface strain measurement device (hereinafter referred to as a tire strain measurement device) using the strain measurement device 10 of the first embodiment of the present invention will be described.
FIG. 8 is a schematic perspective view showing a tire surface strain measuring apparatus including the strain measuring apparatus according to the first embodiment of the present invention, and FIG. 9 is a first embodiment of the present invention shown in FIG. FIG. 2 is a schematic plan view showing a tire surface strain measuring device including the strain measuring device.

  The tire strain measuring device 70 shown in FIG. 8 is a case where a three-dimensional shape of a pneumatic tire T (measurement object) that is an assembly of a tire 90 and a wheel 92 is arranged in accordance with a predetermined position and orientation. The three-dimensional shape data of the entire pneumatic tire T is calculated, and the distortion of the surface 90a of the tire 90 when the tire 90 is inflated by inflating the pneumatic tire T is recorded and retained. .

  The tire strain measuring device 70 houses a tire stand 74 having a rotating shaft 72, a strain measuring device 10, a light source unit 12, a three-dimensional measuring unit 14, a strain measuring unit 16, and a control unit 18 of the strain measuring device 10. The case 76 and the moving table 78 on which the case 76 is placed have a moving mechanism 80 that moves in a circular arc shape on a plane including the rotation axis with the point A on the rotation axis of the rotation shaft 72 as a center point. Is. In the tire strain measuring device 70, the input unit 18 a and the display unit 18 b are provided outside the case 76.

The tire stand 74 includes a rotating shaft 72 that pivotally supports the wheel 92 of the pneumatic tire T, and can freely rotate the pneumatic tire T that is supported for measurement automatically or manually by an operator. Can do.
The moving table 78 is provided on a rotary moving plate 82 that rotates around a point B vertically below the point A on the rotation axis of the rotary shaft 72. A case 76 in which a part of the strain measuring device 10 (the light source unit 12, the three-dimensional measuring unit 14, the strain measuring unit 16, and the control unit 18) is housed is placed on the movable table 78.
Further, the rotational movement plate 82 is fixed to a drive shaft 84 that rotates about the point B, and by rotation of a motor (not shown) connected below the point B, or by manual operation of the operator, A drive shaft 84 is configured to rotate. The case 76 placed on the moving table 78 moves in an arc shape on a plane including the rotation axis of the rotation shaft 72 with the point A as a center point by the movement of the rotation moving plate 82.

  As shown in FIG. 9, the pneumatic tire T pivotally supported on the rotating shaft 72 is attached within a set tire mounting range in the axial direction of the rotating shaft 72. It is provided within the range. The point A is set within the tire wearing range so that the distance from the strain measuring device 10 to the pneumatic tire T does not change greatly even when the case 76 of the strain measuring device 10 moves in an arc shape. is there. This eliminates the need for focus adjustment of the optical system of the strain measurement apparatus 10 using laser light.

  The strain measuring device 10 measures the three-dimensional shape of the pneumatic tire T and the rotating shaft 72 located in the measurement space, and further calculates a three-dimensional strain. The strain measuring device 10 measures a three-dimensional shape of a tire in a limited range in the tire circumferential direction. The strain measuring device 10 rotates a rotating shaft 72 that supports a pneumatic tire T by a predetermined angle. By doing so, it is comprised so that the range of the perimeter of a tire peripheral direction may be measured.

Hereinafter, a method for measuring strain on the surface 90a of the tire 90 will be described.
FIG. 10 is a schematic diagram showing the measurement result of the three-dimensional shape of the tire surface, and FIG. 11 is a schematic diagram showing a photographed image of the tire surface. FIG. 12A is a schematic diagram showing the measurement result of the tire before inflation, and FIG. 12B is a schematic diagram showing the measurement result of the tire after inflation.

In addition, the measuring method of the three-dimensional shape of the pneumatic tire T in the tire strain measuring apparatus 70 is basically the same as the measuring method in the strain measuring apparatus 10 of the first embodiment described above.
The tire 90 used for measurement has a plurality of patterns of land portions 94a to 94e and a plurality of groove portions 98 formed on the surface 90a. Further, markers 96a to 96e are provided on the land portions 94a to 94e of the pattern by attaching a film on which a square lattice pattern is printed.

In the method for measuring strain on the surface 90 a of the tire 90, first, the wheel 92 of the tire 90 is attached to the rotating shaft 72.
Next, the three-dimensional shape of the surface 90a of the tire 90 is measured in a state where the tire 90 is mounted on the wheel 92, that is, in a state where the tire 90 is not filled with air and the tire 90 is fitted to the wheel 92. Obtain 3D data. At this time, since the markers 96a to 96e are printed on the film, the unevenness is small, and the markers 96a to 96e are provided on the surface 90a of the tire 90. However, as shown in FIG. Are not reflected in the result of the three-dimensional shape measurement, and only the three-dimensional shapes of the land portions 94a to 94e and the plurality of groove portions 98 of the plurality of patterns on the surface 90a of the tire 90 are obtained.

  Further, the surface 90a of the tire 90 is photographed by the CCD element 32 of the three-dimensional measuring unit 14 to obtain a photographed image. At this time, as shown in FIG. 11, the markers 96 a to 96 e are different in chromaticity, saturation, and brightness, and therefore, in the captured image together with the land portions 94 a to 94 e and the groove portions 98 of a plurality of patterns. Exists.

Hereinafter, the strain measurement will be described by taking the land portion 94b of the pattern among the land portions 94a to 94e of the plurality of patterns formed on the surface 90a of the tire 90 as an example.
Three-dimensional measurement is performed on the land portion 94b of the pattern before inflation to obtain three-dimensional shape data.
On the other hand, edge extraction is performed on the marker 96b from the photographed image of the land portion 94b of the pattern, and two-dimensional position data (three-dimensional position coordinates) of the intersection in the land portion 94b of the pattern before inflation is obtained.

  Next, the three-dimensional shape data of the land portion 94b of the pattern before inflation and the two-dimensional position coordinates of the intersection of the markers 96b are converted into the same coordinate system, for example, and associated with each other. The position of the intersection before the deformation of the marker 96b is accurately matched to the three-dimensional shape data of the land portion 94b of the pattern. Thereby, as shown in FIG. 12A, in the tire 90 before being inflated, the marker 96b is arranged at an accurate position with respect to the land portion 94b of the pattern.

Next, the tire 90 is filled with air, for example, the internal pressure of the tire 90 is set to 900 kPa. As described above, the tire 90 is filled with air, that is, the tire 90 is inflated, the surface 90a of the tire 90 is three-dimensionally measured, the surface shape is measured, and the land portion 94b of the pattern after inflation is measured. 3D shape data is obtained.
On the other hand, edge extraction is performed on the marker 96b, and the two-dimensional position coordinates of the intersection point in the land portion 94b of the pattern after inflation are obtained.

Next, the three-dimensional shape data of the land portion 94b of the inflated pattern is associated with the two-dimensional position coordinates of the intersection of the marker 96b, and the three-dimensional shape data of the land portion 94b of the pattern is converted into the three-dimensional shape data after the deformation of the marker 96b. The position of the intersection of As a result, as shown in FIG. 12 (b), in the inflated tire 90, the marker 96b is placed at an accurate position with respect to the land portion 94b of the pattern.
Next, the distortion measuring unit 18 compares the three-dimensional position coordinates associated with the intersections of the markers 96b before and after the inflation to determine the deformation amount, and further determines the three-dimensional distortion.

Tire 90 of the present embodiment, for example, in the marker 96b, as shown in FIG. 12 (a), the intersection point _P 11 _{to P 14} to the corners of the substantially square, after the blown, shown in FIG. 12 (b) as described above, by deformation, when connecting between the intersections _P 11 _{to P 14,} it becomes substantially a parallelogram.
Further, although the position of the surface 90a of the tire 90 (see FIG. 9) changes before and after inflation, since the three-dimensional measurement is performed, the change in the position of the surface 90a of the tire 90 is also measured. Thereby, the distortion before and after the inflation of the tire 90 can be calculated as a three-dimensional one.

Thus, since the three-dimensional distortion of the surface 90a of the tire 90 can be measured accurately and easily, the three-dimensional distortion generated at the time of inflation, which is a problem in the tire 90, can be easily obtained. Therefore, it is possible to easily and accurately measure which part of the surface 90a of the tire 90 has a large three-dimensional strain. The pneumatic tire T can be evaluated by the measured three-dimensional strain.
As described above, not only the strain but also the strain distribution, the deformation amount, and the deformation amount distribution can be easily and accurately measured.

In the tire strain measuring device 70, the applied strain measuring device is not limited to the strain measuring device 10 of the first embodiment, and the strain measuring device 50 of the second embodiment may be used. The strain on the surface 90a of the tire 90 can be accurately and easily measured, and the same effect as that of the strain measuring device 10 of the first embodiment can be obtained.
The strain measuring device of the present invention is not limited to tire strain measurement, and can be used for strain measurement of various rubber products such as a conveyor belt, a hose, and a fender. Furthermore, it can also be used for strain measurement other than various rubber products.

  The strain measuring apparatus and the strain measuring method of the present invention have been described above, but the present invention is not limited to the above-described embodiment, and various improvements or modifications may be made without departing from the gist of the present invention. Of course.

It is a mimetic diagram showing a distortion measuring device concerning a 1st embodiment of the present invention. It is a schematic diagram which shows the light source part of the distortion measuring apparatus shown in FIG. It is a schematic diagram which shows the three-dimensional measurement part of the distortion measuring apparatus shown in FIG. (A) is a perspective view which shows the prism which consists of an elastic body, (b) is a perspective view which shows the state which made the square column of FIG. (A) is a side view of the prism shown in FIG. 4 (a), (b) is a side view of the prism shown in FIG. 4 (b). It is a schematic diagram which shows the distortion measuring apparatus which concerns on the 2nd Embodiment of this invention. It is a schematic diagram which shows the imaging | photography part of the distortion measuring apparatus shown in FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view showing a tire surface strain measuring device including a strain measuring device according to a first embodiment of the present invention. FIG. 9 is a schematic plan view showing a tire surface strain measurement apparatus including the strain measurement apparatus according to the first embodiment of the present invention shown in FIG. 8. It is a schematic diagram which shows the three-dimensional shape measurement result of the surface of a tire. It is a schematic diagram which shows the picked-up image of the surface of a tire. (A) is a schematic diagram which shows the measurement result of the tire before inflation, (b) is a schematic diagram which shows the measurement result of the tire after inflation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 50 Strain measuring apparatus 12 Light source part 14 Three-dimensional measuring part 16 Strain measuring part 18 Control part 18a Input part 18b Display part 52 Image pick-up part 70 Strain measuring apparatus (tire distortion measuring apparatus) of tire surface
72 the rotating shaft 74 tire stand 76 case 78 moving base 80 moving mechanism 82 rotates the movable plate 84 the drive shaft 90 tire 92 wheel 94a~94e pattern of the land portion 96a~96e, 104 markers 100 measuring object 102 surface P ₁ to P _4, P ₁₁ ~P ₁₄ intersection T pneumatic tire

Claims (8)

A strain measuring device for measuring strain generated with deformation of a measurement object,
A plane-shaped marker is provided on the measurement object, and an imaging unit that images the measurement object together with the marker;
A three-dimensional shape measuring unit for measuring a three-dimensional shape of the measurement object and obtaining three-dimensional shape data;
An image processing unit for calculating two-dimensional position data of each position of a marker of a photographed image by the photographing unit;
A data processing unit for associating the three-dimensional shape data of the measurement object and the two-dimensional position data of the marker;
The three-dimensional shape data before deformation of the measurement object associated with the two-dimensional position data before deformation of the marker, and the deformation of the measurement object associated with the two-dimensional position data after deformation of the marker A strain measuring unit that calculates strain of the measurement object using the later three-dimensional shape data,
The marker is characterized in that any one of chromaticity, saturation, and brightness differs from the measurement object.   The marker is formed on a film with a different chromaticity, saturation, or lightness from the measurement object, and the film is attached to the measurement object and the measurement object The strain measuring apparatus according to claim 1, which is provided in the apparatus.   The strain measurement apparatus according to claim 1, wherein the marker is directly formed on the measurement object with an ink having any one of chromaticity, saturation, and brightness different from the measurement object.   The strain measurement apparatus according to claim 1, wherein the marker has a square lattice pattern.   The strain measurement apparatus according to claim 1, wherein the measurement object is a rubber product.   The strain measurement apparatus according to claim 5, wherein the rubber product is a tire. A strain measurement method for measuring strain generated with deformation of a measurement object,
Photographing a measurement object provided with a planar marker together with the marker before deformation, and measuring a three-dimensional shape of the measurement object before deformation;
Photographing the measurement object provided with the marker together with the marker after deformation, and measuring the three-dimensional shape after deformation of the measurement object;
Three-dimensional shape data of a three-dimensional shape before deformation of the measurement object and two-dimensional position data of each position of the marker before deformation of the measurement object are obtained, and the two-dimensional position data of the marker and the measurement object Associating the three-dimensional shape data before deformation of the object;
Three-dimensional shape data of the three-dimensional shape after deformation of the measurement object and two-dimensional position data of each position of the marker after deformation of the measurement object are obtained, and the two-dimensional position data of the marker and the measurement object Associating the three-dimensional shape data after deformation of the object;
The three-dimensional shape data before deformation of the measurement object associated with the two-dimensional position data before deformation of the marker, and the deformation of the measurement object associated with the two-dimensional position data after deformation of the marker And a step of calculating strain of the measurement object using subsequent three-dimensional shape data.   The strain measurement method according to claim 7, wherein the measurement object is a rubber product.

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