JP7009346B2 - Displacement measurement method and displacement measurement system - Google Patents

Description

The present invention relates to a displacement measurement method and a displacement measurement system for measuring the displacement of a measurement target portion of an object by using a sampling moire method.

Conventionally, as a technique in such a field, the displacement measuring method described in Patent Document 1 below is known. This document proposes a method of obtaining a three-dimensional displacement amount of an object using one imaging device. Specifically, a grid marker installed on an object is imaged by a camera, and the amount of out-of-plane displacement is obtained by using the sampling moiré method from a minute change due to the out-of-plane displacement of the phase of the grid pitch on the image. Similarly, the amount of out-of-plane and in-plane displacement can be obtained from the minute changes due to in-plane and out-of-plane displacement of the phase of the same lattice using the sampling moire method, and the effect of apparent in-plane displacement is excluded and three-dimensional. The amount of displacement is calculated.

Republished Patent WO 2017/029905 Gazette

However, in the above measurement method, complicated arithmetic processing using a special algorithm is required when calculating the in-plane displacement and the out-of-plane displacement of the grid marker. An object of the present invention is to make it possible to acquire a three-dimensional displacement amount of a measurement target by a relatively simple arithmetic process using a sampling moire method using one imaging device.

The displacement measurement method of the present invention is a displacement measurement method for measuring the displacement of the measurement target by using the sampling moire method, and is a first moire marker located in a posture intersecting a predetermined axis on the measurement target and a measurement target. There is a second moire marker located at a position intersecting a plane orthogonal to a predetermined axis, and a first moire marker and a virtual image of the second moire marker reflected on a mirror surface isolated from the measurement target are along the predetermined axis. The displacement amount of the measurement target in the direction orthogonal to the predetermined axis is acquired by the sampling moire method based on the image pickup process of taking an image with the image pickup device from the above direction and the image captured by the first moire marker obtained by the image pickup device. 1 Based on the displacement acquisition step and the image captured of the imaginary image obtained by the imaging device, the amount of displacement of the imaginary image in the direction orthogonal to the predetermined axis is calculated by the sampling moire method, and based on the calculated displacement, the displacement is set to the predetermined axis. A second displacement acquisition step of acquiring the displacement amount of the measurement target in the parallel direction is provided.

According to this displacement measurement method, the displacement amount of the measurement target in the direction orthogonal to the predetermined axis corresponds to the displacement amount of the first moire marker in the direction orthogonal to the predetermined axis, and can be calculated by a normal sampling moire method. be. On the other hand, the displacement of the measurement target in the direction parallel to the predetermined axis corresponds to the displacement of the second moire marker in the direction parallel to the predetermined axis, and the displacement of the virtual image in the direction orthogonal to the predetermined axis when viewed from the image pickup apparatus. Appears as. The amount of displacement of the virtual image in the direction orthogonal to the predetermined axis can be calculated by a normal sampling moire method. The correlation between the amount of displacement of the virtual image in the direction orthogonal to the predetermined axis and the amount of displacement of the second moire marker in the direction parallel to the predetermined axis is known to depend on the arrangement of each element such as the moire marker and the mirror surface. belongs to. Therefore, based on the correlation, it is possible to know the displacement amount of the second moire marker in the direction parallel to the predetermined axis, that is, the displacement amount of the measurement target in the direction parallel to the predetermined axis. In this way, using one image pickup device and using the normal sampling moire method, the displacement amount of the measurement target in the direction orthogonal to the predetermined axis and the displacement amount of the measurement target in the direction parallel to the predetermined axis are determined. That is, the three-dimensional displacement amount of the measurement target can be obtained. Further, both the calculation of the displacement amount of the first moire marker and the calculation of the displacement amount of the virtual image in the direction orthogonal to the predetermined axis can be executed by a relatively simple arithmetic process because the normal sampling moire method can be applied. It is possible.

Further, the first moire marker may be positioned in a posture substantially orthogonal to the predetermined axis, and the second moire marker may be positioned in a posture substantially parallel to the predetermined axis.

Further, in the imaging step, the captured image of the first moire marker and the captured image of the virtual image may be acquired on substantially the same scale. In this case, since the same algorithm can be used for the operation related to the first moire marker and the operation related to the virtual image, the burden of the calculation process is reduced.

The displacement measurement system of the present invention is a displacement measurement system that measures the displacement of the measurement target by using the sampling moire method, and has a first moire marker located at a posture intersecting a predetermined axis on the measurement target and a measurement target. There is a second moire marker located at a position intersecting a plane orthogonal to a predetermined axis, and a first moire marker and a virtual image of the second moire marker reflected on a mirror surface isolated from the measurement target are along the predetermined axis. First displacement acquisition using the sampling moire method to acquire the amount of displacement of the measurement target in the direction orthogonal to the predetermined axis line based on the image pickup device that captures images from different directions and the image captured by the first moire marker obtained by the image pickup device. Based on the means and the captured image of the imaginary image obtained by the image pickup device, the displacement amount of the imaginary image in the direction orthogonal to the predetermined axis line is calculated by the sampling moire method, and the direction parallel to the predetermined axis line is calculated based on the calculated displacement amount. A second displacement acquisition means for acquiring the amount of displacement of the object to be measured is provided.

The displacement measurement method of the present invention is a displacement measurement method for measuring the displacement of a measurement target by using a sampling moire method, and is positioned in a posture that intersects a predetermined axis and intersects a plane orthogonal to the predetermined axis on the measurement target. There is a moire marker, and an image pickup process in which the moire marker and the imaginary image of the moire marker reflected on a mirror surface isolated from the measurement target are imaged by an image pickup device from a direction along a predetermined axis, and an image pickup of the moire marker obtained by the image pickup device. Based on the first displacement acquisition step of acquiring the displacement amount of the measurement target in the direction orthogonal to the predetermined axis based on the image by using the sampling moire method, and the image captured by the image pickup device, the displacement is orthogonal to the predetermined axis. It is provided with a second displacement acquisition step of calculating the displacement amount of the imaginary image in the direction to be measured by the sampling moire method and acquiring the displacement amount of the measurement target in the direction parallel to the predetermined axis line based on the calculated displacement amount. ..

The displacement measurement system of the present invention is a displacement measurement system that measures the displacement of the measurement target by using the sampling moire method, and is positioned in a posture that intersects a predetermined axis and intersects a plane orthogonal to the predetermined axis on the measurement target. Based on the image pickup device that captures the displacement marker and the virtual image of the displacement marker reflected on the mirror surface isolated from the measurement target from the direction along the predetermined axis, and the image pickup image of the displacement marker obtained by the image pickup device. , In the direction orthogonal to the predetermined axis, based on the first displacement acquisition means for acquiring the displacement amount of the measurement target in the direction orthogonal to the predetermined axis using the sampling moire method and the captured image of the imaginary image obtained by the imaging device. It is provided with a second displacement acquisition means for calculating the displacement amount of the virtual image of the above by the sampling moire method and acquiring the displacement amount of the measurement target in the direction parallel to the predetermined axis line based on the calculated displacement amount.

According to this displacement measurement system, the above-mentioned displacement measurement method can be executed.

According to the displacement measurement method and the displacement measurement system of the present invention, it is possible to acquire the three-dimensional displacement amount of the measurement target by a relatively simple arithmetic process using the sampling moire method using one image pickup device.

It is a perspective view which shows the displacement measurement system which concerns on 1st Embodiment. It is a top view which enlarges and shows the vicinity of the measurement point of 1st Embodiment. It is a front view which shows the state which looked at the vicinity of the measurement point of 1st Embodiment from a camera. It is a perspective view which shows the displacement measurement system which concerns on 2nd Embodiment. It is a top view which enlarges and shows the vicinity of the measurement point of 2nd Embodiment. It is a front view which shows the state which looked at the vicinity of the measurement point of 2nd Embodiment from a camera.

(First Embodiment)
Hereinafter, the displacement measuring method and the first embodiment of the displacement measuring system according to the present invention will be described in detail with reference to the drawings. The displacement measurement method and the displacement measurement system of the present embodiment measure a minute displacement amount of a measurement point on an object by using a sampling moire method. Examples of the above objects include slopes, tunnels, mountains, piers for railway construction, bridges, buildings, and the like.

Here, as shown in FIG. 1, displacement measurement for the road bridge 90 will be described as an example. In the following description, as shown in the figure, the bridge axis direction of the road bridge 90 is the Z direction, the direction perpendicular to the bridge axis is the X direction, and the direction orthogonal to both the Z direction and the X direction is the Y direction. .. Further, a virtual plane orthogonal to the Z direction may be referred to as an XY plane, a virtual plane orthogonal to the X direction may be referred to as a YZ plane, and a virtual plane orthogonal to the Y direction may be referred to as a ZX plane. Further, the displacement in the X direction, the displacement in the Y direction, and the displacement in the Z direction may be simply referred to as X displacement, Y displacement, and Z displacement, respectively. Further, the displacement in the XY plane, the displacement in the YZ plane, and the displacement in the ZX plane may be simply referred to as XY displacement, YZ displacement, and ZX displacement, respectively.

In the present embodiment, a plurality of measurement points 91 (measurement targets) arranged in the bridge axis direction at predetermined intervals are set on the bridge girder of the road bridge 90, and the three-dimensional displacement amount of each measurement point 91 is measured. Will be done. The three-dimensional displacement amount measured here is a relative displacement amount with respect to the ground of the road bridge 90 below the bridge girder as an immovable reference object. The distance between the measurement points 91 to each other is, for example, 10 to 20 m. In this embodiment, it is assumed that three measurement points 91 are set as shown in FIG. When distinguishing each measurement point 91, it shall be referred to as measurement points 91a, 91b, 91c from the side closer to the camera 3 described later, respectively.

The displacement measurement system 1 of the present embodiment includes targets 13 and 14 installed at each measurement point 91, and a mirror body 15 installed in the vicinity of each target 13 and 14. Further, the displacement measurement system 1 includes one camera 3 (imaging device) that captures images of measurement points 91a to 91c, and an arithmetic unit 5 that performs calculations based on the images captured by the cameras 3.

The installation modes of the targets 13 and 14 and the mirror body 15 at the measurement point 91 will be described with reference to FIGS. 1 to 3. FIG. 2 is a plan view showing one measurement point 91 and the vicinity of the camera 3. FIG. 3 is a front view showing the measurement point 91 as seen from the camera 3. Since the installation modes of the targets 13, 14 and the mirror body 15 at the three measurement points 91a to 91c are all the same, overlapping description will be omitted.

The target 13 is, for example, a rectangular flat plate-shaped member having a size of about 20 cm × 30 cm in length. The target 13 is, for example, a plate material made of polycarbonate. A moire marker 11 (first moire marker) having a predetermined pattern is formed on the surface of the target 13. At the measurement point 91, the target 13 is fixed to the side surface 93 of the road bridge 90 in a posture in which the moire marker 11 is directed toward the camera 3 and the moire marker 11 is parallel to the XY plane. The target 13 is installed so as to project to the left from the side surface 93 of the road bridge 90 when viewed from the camera 3.

The target 14 is a rectangular flat plate-shaped member having the same size as the target 13 and made of the same material. A moire marker 12 (second moire marker) having the same size and pattern as the moire marker 11 is formed on the surface of the target 14. The target 14 is fixed to the side surface 93 of the road bridge 90 in a posture in which the moire marker 12 faces the outside of the road bridge 90 and the moire marker 12 is parallel to the YZ plane. The moire marker 12 is installed in a posture orthogonal to the moire marker 11.

Since the targets 13 and 14 are fixed to the measurement point 91, when the measurement point 91 is displaced, the moire markers 11 and 12 are also displaced by the same displacement amount following the measurement point 91.

The patterns of the moire markers 11 and 12 are spatially and regularly repeated patterns, that is, patterns to which the sampling moire method can be applied. As the patterns of the moire markers 11 and 12, for example, a grid pattern at equal intervals, a striped pattern at equal intervals, and the like are used. Here, in order to measure the XY displacement amount of the measurement point 91, a grid pattern which is a repeating pattern in the X direction and the Y direction is used as the moire marker 11. For example, the repetition pitch in the X direction and the repetition pitch in the Y direction of the grid pattern are the same. Similarly, in order to measure the YZ displacement amount of the measurement point 91, a grid pattern which is a repeating pattern in the Y direction and the Z direction is used as the moire marker 12. Further, for example, the repetition pitch in the Y direction and the repetition pitch in the Z direction of the grid pattern are the same. The more markers 11 and 12 may be drawn directly on the surfaces of the targets 13 and 14, for example, or may be configured by attaching a patterned sheet or the like to the surfaces of the targets 13 and 14.

The mirror body 15 is a plane mirror having a mirror surface 16 on one surface thereof. The mirror body 15 is installed so that the mirror surface 16 can be seen from the camera 3. In the installed state of the mirror body 15, the mirror surface 16 intersects the XY plane at an angle of approximately 45 degrees, intersects the YZ plane at an angle of approximately 45 degrees, and is substantially orthogonal to the ZX plane. Further, the mirror body 15 is installed so as to be insulated from the measurement point 91. That is, even when the measurement point 91 is displaced, the mirror body 15 does not displace following the measurement point 91. In order to realize such an insulating structure, for example, an installation pedestal 17 is constructed on the ground below the bridge girder of the road bridge 90, and the mirror body 15 is fixed to the installation pedestal 17. As the installation pedestal 17, for example, a structure in which a single pipe is combined may be used. The mirror body 15 is installed immediately to the left of the target 13 when viewed from the camera 3.

As the camera 3, a camera having a resolution suitable for the sampling moire method is adopted. Further, as the camera 3, a camera suitable for use as a network camera that transmits image pickup data through a predetermined network may be adopted.

The camera 3 captures all the measurement points 91a to 91c from the direction along the Z axis (predetermined axis). That is, the camera 3 captures the three moire markers 11 and the three mirror surfaces 16 on the same screen from a direction substantially orthogonal to the moire markers 11. The camera 3 is installed in the vicinity of the side surface 93 of the road bridge 90, and the camera 3 is directed to the moire marker 11 side from this installation position. The distance from the camera 3 to the measurement point 91a is, for example, about 50 m. The camera 3 is installed so as to be insulated from the road bridge 90, and even when each measurement point 91 is displaced, the camera 3 is not displaced following the displacement. In order to realize such an insulating structure, for example, an installation pedestal 19 is constructed on the ground below the bridge girder of the road bridge 90, and the camera 3 is fixed to the installation pedestal 19. As the installation pedestal 19, for example, a structure in which a single pipe is combined may be used.

In order to see all the three moire markers 11 and the three mirror surfaces 16 arranged in the Z direction from the camera 3, the camera 3 is installed at a position slightly deviated from the virtual straight line passing through the three moire markers 11. Therefore, the direction in which the camera 3 takes an image of the moire marker 11 or the like is not a direction exactly orthogonal to the moire marker 11, but a direction "substantially orthogonal to" the moire marker 11. However, if the ratio between the distance between the camera 3 and the measurement point 91a (about 50 m) and the vertical dimension of the target 13 (about 30 cm) is taken into consideration, the influence of the error can be ignored. Therefore, the direction in which the camera 3 takes an image of the moire marker 11 or the like may be treated as being orthogonal to the moire marker 11.

Further, the collimation axis H of the camera 3 may be deviated from the Z direction as long as the three moire markers 11 and the three mirror surfaces 16 enter the image pickup screen of the camera 3. However, since the moire marker 11 and the mirror surface 16 are imaged near the center of the image pickup screen of the camera 3, it is preferable that the camera 3 is installed in such a posture that the collimation axis H of the camera 3 is along the Z direction. In other words, it is preferable that the collimation axis H of the camera 3 is substantially parallel to the Z direction.

According to the arrangement of the camera 3, the targets 13, 14 and the mirror body 15 as described above, the moire marker 11 is imaged by the camera 3 from a direction substantially orthogonal to the moire marker 11. On the other hand, although the moire marker 12 itself can hardly be seen directly from the camera 3, the camera 3 can see the moire marker 12 reflected on the mirror surface 16. That is, according to the arrangement of the mirror surface 16 and the like as described above, as shown in FIG. 3, the virtual image 12'of the moire marker 12 reflected on the mirror surface 16 can be seen side by side immediately on the left side of the moire marker 11. That is, the virtual image 12'of the moire marker 12 is imaged by the camera 3 from a direction substantially orthogonal to the virtual image 12'.

As shown in FIG. 2, the virtual image 12'is slightly farther from the camera 3 than the moire marker 11. However, considering the ratio between the distance between the camera 3 and the measurement point 91a (about 50 m) and the lateral dimension of the target 13 (about 20 cm), the moire marker 11 and the virtual image 12'are seen from the camera 3. , It can be said that they are located at almost equal distances. Further, as described above, the moire marker 11 and the moire marker 12 have the same size and the same pattern. Therefore, it can be said that the moire marker 11 and the virtual image 12'are imaged on substantially the same scale by the camera 3.

The arithmetic unit 5 is, for example, a computer system connected to the camera 3 through the network 7. The network 7 is, for example, the Internet. A wireless router 9 for connecting the camera 3 to the network 7 may be arranged in the vicinity of the camera 3. Further, the wireless router 9 may be packaged together with the power supply switch hub and the earth leakage breaker and installed on the installation pedestal 19, for example. The arithmetic unit 5 can acquire image pickup data from the camera 3 through the network 7.

Then, the arithmetic unit 5 executes image processing based on the acquired image pickup data, and calculates the three-dimensional displacement amount of each measurement point 91a, 91b, 91c by using the sampling moire method. It is not essential that the arithmetic unit 5 and the camera 3 are connected to each other via a network 7 such as the Internet, and the arithmetic unit 5 and the camera 3 may be installed in the vicinity and directly connected to each other.

More specifically, the arithmetic unit 5 includes a first displacement acquisition unit 21, a second displacement acquisition unit 22, an imaging data acquisition unit 23, and a displacement data transmission unit 24 as functional components. There is. The first displacement acquisition unit 21 (first displacement acquisition means), the second displacement acquisition unit 22 (second displacement acquisition means), the imaging data acquisition unit 23, and the displacement data transmission unit 24 are calculated. It is a component realized by operating the device 5 according to a predetermined program.

As described above, the image pickup data acquisition unit 23 acquires the image pickup data captured by the camera 3 via the network 7. The first displacement acquisition unit 21 applies the sampling moire method to the image of the moire marker 11 included in the image pickup data based on the image pickup data acquired by the image pickup data acquisition unit 23, and the in-plane displacement amount of the moire marker 11 is applied. (XY displacement amount) is calculated. Specifically, the first displacement acquisition unit 21 compares the moire fringes obtained by the sampling moire method from the image of the current moire marker 11 with the moire fringes similarly obtained at the time of the previous measurement, and XY of the moire fringes. Based on the displacement amount, the XY displacement amount of the moire marker 11 from the time of the previous measurement to the present time is calculated. The XY displacement amount of the moire marker 11 acquired here directly corresponds to the XY displacement amount of the measurement point 91.

The second displacement acquisition unit 22 applies the sampling moire method to the virtual image 12'of the moire marker 12 reflected on the mirror surface 16 in the image pickup data based on the image pickup data acquired by the image pickup data acquisition unit 23, and applies the sampling moire method to the virtual image. The in-plane displacement amount (XY displacement amount) of 12'is calculated. Specifically, the second displacement acquisition unit 22 compares the moire fringes obtained by the sampling moire method from the image of the current virtual image 12'and the moire fringes similarly obtained at the time of the previous measurement, and the moire fringes of the moire fringes. Based on the XY displacement amount, the XY displacement amount of the virtual image 12'from the time of the previous measurement to the present time is calculated.

Here, according to the positional relationship of the moire marker 12, the mirror surface 16, and the camera 3 as described above, when the moire marker 12 is displaced in the + Z direction, the virtual image 12'is displaced in the −X direction from the camera 3. Observed. Further, when the moire marker 12 is displaced in the + Y direction, the camera 3 observes that the virtual image 12'is displaced in the + Y direction. Then, it is geometrically clear that the correlation between the displacement amount (Δ1) of the moire marker 12 in the + Z direction and the displacement amount (Δ1') of the virtual image 12'in the −X direction is Δ1 = Δ1 ′. Is. It is also geometrically clear that the correlation between the displacement amount of the moire marker 12 in the + Y direction (Δ2) and the displacement amount of the virtual image 12'in the + Y direction (Δ2') is Δ2 = Δ2'. be. Based on this finding, the XY displacement amount of the virtual image 12'acquired by the second displacement acquisition unit 22 corresponds to the YZ displacement amount of the actual moire marker 12, that is, corresponds to the YZ displacement amount of the measurement point 91.

In the above-mentioned sampling moire method, a moire marker is imaged by an image pickup device such as a camera, and moire fringes generated by interference between the repeating pattern of the moire marker and the pixels of the image pickup device are acquired by a predetermined image processing, and the displacement of the moire fringes is obtained. This is a method of obtaining the actual displacement amount of the moire marker based on the amount. Since the sampling moiré method is known as a method for calculating the displacement amount of the moiré marker with high accuracy by utilizing the moiré phenomenon as described above, further detailed description thereof will be omitted. In the normal sampling moire method, the displacement amount of the moire marker included in the imaging data in the direction parallel to the imaging screen (XY displacement amount in the present embodiment) can be calculated.

Further, when a plurality of moire markers appear on the imaging data, it is possible to individually apply the sampling moire method for each moire marker to calculate the displacement amount for each moire marker. Further, a program capable of processing a plurality of moire markers appearing on the imaging data together may be used, and by executing such a program, the above-mentioned first displacement acquisition unit 21 and second displacement acquisition unit 22 are realized together. You may. In the present embodiment, a total of six moire markers, such as the moire markers 11 at the measurement points 91a to 91c and the virtual image 12'of the moire markers 12, may be processed together by the program as described above.

Further, the measurement accuracy of the sampling moiré method depends on the arrangement pitch of the pixels of the camera 3, the repetition pitch of the patterns of the moiré markers 11 and 12, and the like. Therefore, for example, by appropriately adjusting the repetition pitch of the patterns of the moiré markers 11 and 12. , The measurement accuracy of the displacement amount of the measurement point 91 can be adjusted. For example, in the present embodiment, the measurement accuracy is set to about 1/1000 of the repetition pitch of the patterns of the moire markers 11 and 12, and the displacement amount of the measurement point 91 can be measured in units of 0.1 mm.

If the X-displacement amount and the Y-displacement amount obtained by the first displacement acquisition unit 21 and the Y-displacement amount and the Z-displacement amount obtained by the second displacement acquisition unit 22 are combined as described above, the XYZ of the measurement point 91 is combined. The amount of three-dimensional displacement in the direction can be obtained. Then, by executing the above processing for each measurement point 91, it is possible to acquire the three-dimensional displacement amounts of the three measurement points 91a to 91c in the XYZ direction. By acquiring the three-dimensional displacement amounts of the measurement points 91a to 91c, it is possible to know the strain generated in the road bridge 90. The displacement measurement of the measurement point 91 as described above may be repeatedly executed, for example, at intervals of several minutes. The three-dimensional displacement amount obtained here is relative to the reference object with the object / location where the camera 3 and the mirror body 15 are fixed (that is, the ground below the bridge girder of the road bridge 90) as an immovable reference object. This is the amount of displacement of the measurement point 91.

The displacement data transmission unit 24 transmits the information on the three-dimensional displacement amount of the measurement point 91 obtained as described above to the computer terminal 8 for the administrator via the network 7. As a result, the manager can know the displacement amount of the measurement point 91 in almost real time. Further, the displacement amount of the measurement point 91 repeatedly measured at intervals of several minutes may be visualized as a graph of time-series change and presented to the computer terminal 8. Further, such information may be made available for download to the computer terminal 8. The computer terminal 8 may be, for example, a smartphone terminal held by an administrator. It is not essential that the computer terminal 8 is connected to the arithmetic unit 5 via the network 7, and may be installed in the vicinity of the arithmetic unit 5 and directly connected to the arithmetic unit 5. Further, a specific authorized person may be able to access the arithmetic unit 5 via the network 7 so that the information on the displacement amount can be viewed.

Further, the displacement data transmission unit 24 compares the obtained three-dimensional displacement amount of the measurement point 91 with the allowable reference value stored in advance. Then, when the displacement amount of the measurement point 91 exceeds the above allowable standard value, alarm information (for example, an alarm mail) is transmitted to the computer terminal 8 for the administrator via the network 7. With such warning information, the manager can recognize the possibility of abnormal displacement of the measurement point 91 of the road bridge 90 and take appropriate measures.

As described above, if data is exchanged between the camera 3, the arithmetic unit 5, and the computer terminal 8 via a network 7 such as the Internet, the displacement of the road bridge 90 can be constantly and remotely controlled in real time. It will be possible to monitor with.

Subsequently, an example of the displacement measurement method using the displacement measurement system 1 described above will be described.

First, the camera 3 takes an image of the moire marker 11 and the virtual image 12'of the moire marker 12 reflected on the mirror surface 16 (imaging step). The imaging data obtained in this imaging step is transmitted from the camera 3 to the arithmetic unit 5 via the network 7. The image pickup data acquisition unit 23 of the arithmetic unit 5 receives the image pickup data. The first displacement acquisition unit 21 calculates the XY displacement amount of the moire marker 11 with respect to the previous measurement by the sampling moire method based on the captured image of the moire marker 11 included in the imaging data. This displacement amount is acquired as the XY displacement amount of the measurement point 91. (First displacement acquisition step).

Further, in the arithmetic unit 5, the second displacement acquisition unit 22 measures the XY displacement amount of the virtual image 12'with respect to the previous measurement based on the image captured by the virtual image 12'included in the image pickup data by the sampling moire method. Calculated by As described above, this displacement amount is acquired as the YZ displacement amount of the measurement point 91. (Second displacement acquisition process).

By combining the XY displacement amount (X displacement amount and Y displacement amount) of the measurement point 91 and the YZ displacement amount (Y displacement amount and Z displacement amount) obtained as described above, the arithmetic unit 5 can be used. The amount of three-dimensional displacement of the measurement point 91 in the XYZ direction is recognized.

Here, for example, the X-displacement amount and the Y-displacement amount of the measurement point 91 obtained in the first displacement acquisition step and the Z-displacement amount of the measurement point 91 obtained in the second displacement acquisition step are combined to form the above-mentioned tertiary. It may be the original displacement amount. Alternatively, the X-displacement amount of the measurement point 91 obtained in the first displacement acquisition step and the Y-displacement amount and Z-displacement amount of the measurement point 91 obtained in the second displacement acquisition step are combined to form the above three-dimensional displacement amount. May be.

The displacement data transmission unit 24 of the arithmetic unit 5 transmits the information on the three-dimensional displacement amount to the computer terminal 8 for the administrator via the network 7. Further, the displacement data transmission unit 24 transmits alarm information to the computer terminal 8 via the network 7 when the three-dimensional displacement amount exceeds a predetermined allowable standard value.

Subsequently, the operation and effect of the displacement measurement system 1 and the displacement measurement method described above will be described. According to the displacement measurement system 1 and the displacement measurement method, the moire marker 11 parallel to the XY plane is imaged by the camera 3 from the substantially Z direction. Therefore, the XY displacement amount of the moire marker 11 can be calculated by a normal sampling moire method, and the XY displacement amount corresponds to the XY displacement amount of the measurement point 91.

Further, the camera 3 captures a virtual image 12'of the moire marker 12 reflected on the mirror surface 16. The XY displacement of the virtual image 12'observed by the camera 3 corresponds to the YZ displacement of the actual moire marker 12. Therefore, if the normal sampling moire method is applied to the virtual image 12'of the moire marker 12 and the XY displacement amount of the virtual image 12' is calculated, the calculated XY displacement amount is adopted as the actual YZ displacement amount of the moire marker 12. can do. Then, as described above, the YZ displacement amount of the moire marker 12 corresponds to the YZ displacement amount of the measurement point 91.

As described above, the XY displacement amount and the YZ displacement amount of the measurement point 91 can be measured by using one camera 3. That is, the three-dimensional displacement amount of the measurement point 91 can be acquired by using one camera 3. Further, in calculating the XY displacement amount of the moire marker 11 and the XY displacement amount of the virtual image 12'as described above, a normal sampling moire method may be used for both, and the calculation can be performed by a relatively simple arithmetic process. .. Further, the displacement amount in the depth direction (Z direction) when viewed from the camera 3 can be measured with the same accuracy as the displacement amount in the directions parallel to the image pickup screen of the camera 3 (X direction and Y direction) by the sampling moire method. Is.

Further, as described above, the captured image of the moire marker 11 and the captured image of the virtual image 12'are acquired on substantially the same scale. Therefore, the calculation of the XY displacement amount of the moire marker 11 and the calculation of the XY displacement amount of the virtual image 12'(YZ displacement amount of the moire marker 12) may be executed by almost the same algorithm. Becomes smaller. Further, since the captured image of the moire marker 11 and the captured image of the virtual image 12'are acquired on substantially the same scale, each displacement amount in the XYZ direction is acquired with the same degree of accuracy.

Further, in the displacement measurement system 1 and the displacement measurement method of the present embodiment, the displacement of the road bridge 90 is displaced by relatively inexpensive equipment such as targets 13, 14, mirror body 15, camera 3, etc. installed at the site of the road bridge 90. Can be monitored unattended and with high accuracy. Further, if the camera 3 can acquire imaging data such as the moire marker 11, the displacement can be measured even at night.

(Second Embodiment)
Subsequently, the displacement measuring method and the second embodiment of the displacement measuring system according to the present invention will be described in detail with reference to FIGS. 4 to 6. As shown in FIG. 4, the displacement measurement system 201 of the present embodiment includes the target 39 instead of the targets 13 and 14 in the first embodiment. With respect to other points, since the displacement measurement system 201 of the present embodiment has the same configuration as the displacement measurement system 1 of the first embodiment, the same or equivalent components are designated by the same reference numerals in the drawings. However, duplicate explanations will be omitted.

The target 39 is a rectangular flat plate-shaped member having the same size as the targets 13 and 14 and made of the same material. On the surface of the target 39, a moire marker 37 having the same size as the moire markers 11 and 12 and having the same pattern is formed. At each measurement point 91, the target 39 is attached to the side surface 93 so as to project from the side surface 93 of the road bridge 90 at an angle of 45 °. The moire marker 37 is located on the surface of the target 39 on the camera 3 side, and forms a vertical surface that intersects the XY plane at an angle of 45 °.

According to the arrangement of the target 39, the camera 3, and the mirror body 15, as shown in FIGS. 5 and 6, the camera 3 has a moire marker 37 and a virtual image 37 of the moire marker 37 reflected on the mirror surface 16. 'Sees side by side in the X direction. As shown in FIG. 5, the virtual image 37'is slightly farther from the camera 3 than the moire marker 11. However, considering the ratio between the distance between the camera 3 and the measurement point 91a (about 50 m) and the lateral dimension of the target 39 (about 20 cm), the moire marker 37 and the virtual image 37'are seen from the camera 3. , It can be said that they are located at almost equal distances. Further, it can be said that the moire marker 37 and the virtual image 37'are imaged on substantially the same scale by the camera 3.

Further, since the moire marker 37 and the virtual image 37'are tilted with respect to the Z direction, strictly speaking, the grid pattern of the moire marker 37 and the virtual image 37'is slightly trapezoidal when viewed from the Z direction with the camera 3. Looks distorted. However, considering the ratio between the distance between the camera 3 and the measurement point 91a (about 50 m) and the lateral dimension of the target 39 (about 20 cm), the moire marker 37 and the virtual image 37'are formed as a rectangular grid pattern. You may handle it.

Here, according to the positional relationship as described above of the moire marker 37, the mirror surface 16, and the camera 3, when the moire marker 37 is displaced in the + Z direction, the virtual image 37'is displaced in the −X direction from the camera 3. Observed. Further, when the moire marker 37 is displaced in the + Y direction, the camera 3 observes that the virtual image 37'is displaced in the + Y direction.

Therefore, the second displacement acquisition unit 22 of the arithmetic unit 5 can calculate the XY displacement amount of the virtual image 37'by applying the sampling moire method to the image captured by the virtual image 37'by the camera 3. Then, the YZ displacement amount of the moire marker 37 can be calculated based on the calculated XY displacement amount (second displacement acquisition step). Here, it is geometrically clear that the −X displacement amount of the virtual image 37 ′ corresponds to the + Z displacement amount of the moire marker 37, and the Y displacement amount of the virtual image 37 ′ corresponds to the Y displacement amount of the moire marker 37. be. Further, the first displacement acquisition unit 21 of the arithmetic unit 5 can calculate the in-plane displacement amount (XY displacement amount) of the moire marker 37 by applying the sampling moire method to the captured image of the moire marker 37. (First displacement acquisition step).

In the moire marker 37 and the virtual image 37'observed by the camera 3, the repetition pitch of the grid pattern in the X direction is reduced by 1 / (√2) times as compared with the above-mentioned moire marker 11 and the virtual image 12'. , The influence may be corrected by an appropriate calculation. Alternatively, the above-mentioned influence may be offset by adopting a grid pattern in which the moire markers 11 and 12 are stretched (√2) times in the horizontal direction in advance as the moire markers 37.

If the X-displacement amount and the Y-displacement amount obtained by the first displacement acquisition unit 21 and the Y-displacement amount and the Z-displacement amount obtained by the second displacement acquisition unit 22 are combined as described above, the XYZ of the measurement point 91 is combined. The amount of three-dimensional displacement in the direction can be obtained.

In the displacement measurement system 201 of the present embodiment, it can be considered that the moire marker 11 (first moire marker) and the moire marker 12 (second moire marker) in the first embodiment are shared to form one moire marker 37. .. That is, it can be considered that the moire marker 37 in the present embodiment has both the functions of the moire marker 11 and the moire marker 12 in the first embodiment.

The present invention can be carried out in various forms having various changes and improvements based on the knowledge of those skilled in the art, including the above-mentioned embodiment. It is also possible to construct a modified example by utilizing the technical matters described in the above-described embodiment. The configurations of the respective embodiments may be combined and used as appropriate.

For example, in the above-described embodiment, the example in which a plurality of measurement points 91 exist is shown, but the measurement points 91 may be one place. Further, for example, it is not essential to install the mirror body 15, and the existing mirror surface reflecting the moire markers 12 and 37 may be used instead of the mirror surface 16. For example, the window glass surface of the building adjacent to the road bridge 90 may be used instead of the mirror surface 16, and the image pickup data of the virtual image of the moire marker 12 reflected on the window glass surface may be used for the displacement amount calculation. Further, in the above-described embodiment, the moire markers 12 and 37 are reflected on one mirror surface 16 and imaged by the camera 3, but the moire markers 12 and 37 may be reflected a plurality of times by the mirror and imaged.

Further, it is not essential to install the targets 13, 14, 39 and the moire markers 11, 12, and 37 on the measurement target, and an existing pattern existing on the measurement target may be used as the moire marker. For example, if there are rivets, tiles, windows, etc. that are regularly arranged on the surface of the measurement target, these may be used instead of the moire markers 11, 12, and 37.

Further, in the above-described embodiment, the displacement measurement system 1,201 acquires the three-dimensional displacement amount of the measurement point 91 in the XYZ direction. However, in the displacement measurement system 1,201, for example, the Z of the measurement point 91 is obtained. Only the displacement may be acquired. For example, in the displacement measurement system 1, only the virtual image 12'is observed from the camera 3 and the Z displacement of the moire marker 12 (that is, the Z displacement of the measurement point 91) is acquired based on the X displacement of the virtual image 12'. It is also good. Similarly, in the displacement measurement system 201, only the virtual image 37'is observed from the camera 3 and the Z displacement of the moire marker 37 (that is, the Z displacement of the measurement point 91) is acquired based on the X displacement of the virtual image 37'. You may. In these cases, the X-displacement and Y-displacement of the measurement point 91 may be acquired separately by another system.

Further, in the first embodiment, it is not essential that both the moire markers 11 and 12 have a grid pattern. For example, since it is sufficient that at least the Z displacement amount can be obtained from the moire marker 12, the moire marker 12 may be a one-dimensional repeating pattern (for example, a striped pattern) that is repeated only in the Z direction. In this case, the moire marker 11 is a two-dimensional repeating pattern (for example, a grid pattern) that is repeated in the X direction and the Y direction in order to acquire the X displacement amount and the Y displacement amount. Alternatively, the moire marker 11 may be a one-dimensional repeating pattern that is repeated only in the X direction, and the moire marker 12 may be a two-dimensional repeating pattern that is repeated in the Y direction and the Z direction. In this case, the X displacement amount is obtained from the moire marker 11, and the Y displacement amount and the Z displacement amount are obtained from the moire marker 12.

Further, the target 13 and the target 14 in the first embodiment may be collectively formed as an integral member.

Further, in the above-mentioned first embodiment, the posture of the moire marker 11 is parallel to the XY plane, but if the influence on the calculation result of the XY displacement is negligible, the deviation of the posture of the moire marker 11 is allowed. That is, the posture of the moire marker 11 may be substantially parallel to the XY plane. Similarly, the posture of the moire marker 12 may be substantially parallel to the YZ plane.

Further, the posture of the moire marker 11 is not limited to substantially parallel to the XY plane, and the moire marker 11 may be in a posture that intersects in the Z direction. That is, the moire marker 11 may be in a posture that is not parallel to the Z direction. Similarly, the posture of the moire marker 12 is not limited to being substantially parallel to the YZ plane, and the moire marker 12 may be in a posture that intersects the XY plane. That is, the moire marker 12 may have a posture that is not parallel to the XY plane. As an example, the moire marker 12 may exist in a posture parallel to the ZX plane, such as being arranged on the bottom surface or the upper surface of the road bridge 90.

However, when the moire marker 12 exists in an inclined posture from the YZ plane, or when the image pickup direction of the camera 3 is set to deviate from the Z axis, the correlation of Δ2 = Δ2'as described above may not be established. be. However, even in this case, since the correlation between Δ2 and Δ2'is known based on the positional relationship between the moire marker 12, the camera 3, and the mirror surface 16, the calculation may be performed based on the known correlation. Similarly, even when the moire marker 11 is tilted from the XY plane or the image pickup direction of the camera 3 is set to deviate from the Z axis, the moire marker 11 is displaced in a direction parallel to the image pickup screen. The amount may be corrected based on a known correlation to calculate the XY displacement amount of the moire marker 11.

1,201 ... Displacement measurement system, 3 ... Camera (imaging device), 11 ... More remarker (1st moire marker), 12 ... More remarker (2nd moire marker), 37 ... 21 ... First displacement acquisition unit (first displacement acquisition means), 22 ... Second displacement acquisition unit (second displacement acquisition means), 91, 91a, 91b, 91c ... Measurement points (measurement target).

Claims (6)

It is a displacement measurement method that measures the displacement of the measurement target using the sampling moiré method.
There is a first moire marker located on the measurement target in a posture that intersects a predetermined axis, and a second moire marker that is located on the measurement target in a posture that intersects a plane orthogonal to the predetermined axis.
An imaging step of photographing the first moire marker and a virtual image of the second moire marker reflected on a mirror surface insulated from the measurement target with an image pickup device from a direction along the predetermined axis.
A first displacement acquisition step of acquiring a displacement amount of the measurement target in a direction orthogonal to the predetermined axis by using a sampling moire method based on an image captured by the first moire marker obtained by the image pickup device.
Based on the captured image of the virtual image obtained by the imaging device, the displacement amount of the virtual image in the direction orthogonal to the predetermined axis is calculated by the sampling moire method, and based on the calculated displacement amount, the displacement is parallel to the predetermined axis. The second displacement acquisition step of acquiring the displacement amount of the measurement target in the desired direction, and
Displacement measurement method. The displacement measuring method according to claim 1, wherein the first moire marker is located in a posture substantially orthogonal to the predetermined axis, and the second moire marker is located in a posture substantially parallel to the predetermined axis. In the imaging step,
The displacement measuring method according to claim 1 or 2, wherein the captured image of the first moire marker and the captured image of the virtual image are acquired on substantially the same scale. It is a displacement measurement system that measures the displacement of the measurement target using the sampling moiré method.
There is a first moire marker located on the measurement target in a posture that intersects a predetermined axis, and a second moire marker that is located on the measurement target in a posture that intersects a plane orthogonal to the predetermined axis.
An image pickup device that captures an image of the first moire marker and a virtual image of the second moire marker reflected on a mirror surface isolated from the measurement target from a direction along the predetermined axis.
Based on the image captured by the first moire marker obtained by the image pickup apparatus, the first displacement acquisition means for acquiring the displacement amount of the measurement target in the direction orthogonal to the predetermined axis by using the sampling moire method.
Based on the captured image of the virtual image obtained by the imaging device, the displacement amount of the virtual image in the direction orthogonal to the predetermined axis is calculated by the sampling moire method, and based on the calculated displacement amount, the displacement is parallel to the predetermined axis. A second displacement acquisition means for acquiring the amount of displacement of the measurement target in a different direction,
Displacement measurement system. It is a displacement measurement method that measures the displacement of the measurement target using the sampling moiré method.
There is a moire marker located on the measurement target in a posture that intersects a predetermined axis and intersects a plane orthogonal to the predetermined axis.
An imaging step of imaging the moire marker and a virtual image of the moire marker reflected on a mirror surface insulated from the measurement target with an image pickup device from a direction along the predetermined axis.
The first displacement acquisition step of acquiring the displacement amount of the measurement target in the direction orthogonal to the predetermined axis by using the sampling moire method based on the image captured by the moire marker obtained by the image pickup device.
Based on the captured image of the virtual image obtained by the imaging device, the displacement amount of the virtual image in the direction orthogonal to the predetermined axis is calculated by the sampling moire method, and based on the calculated displacement amount, the displacement is parallel to the predetermined axis. The second displacement acquisition step of acquiring the displacement amount of the measurement target in the desired direction, and
Displacement measurement method. It is a displacement measurement system that measures the displacement of the measurement target using the sampling moiré method.
There is a moire marker located on the measurement target in a posture that intersects a predetermined axis and intersects a plane orthogonal to the predetermined axis.
An imaging device that captures the moire marker and a virtual image of the moire marker reflected on a mirror surface isolated from the measurement target from a direction along the predetermined axis.
Based on the image captured by the moire marker obtained by the image pickup device, a first displacement acquisition means for acquiring the displacement amount of the measurement target in a direction orthogonal to the predetermined axis by using a sampling moire method.
Based on the captured image of the virtual image obtained by the imaging device, the displacement amount of the virtual image in the direction orthogonal to the predetermined axis is calculated by the sampling moire method, and based on the calculated displacement amount, the displacement is parallel to the predetermined axis. A second displacement acquisition means for acquiring the amount of displacement of the measurement target in a different direction,
Displacement measurement system.

Images