JP7315936B2 - Displacement measurement method, displacement measurement device, displacement measurement system, and displacement measurement program - Google Patents

Description

The present invention relates to a displacement measuring method, a displacement measuring device, a displacement measuring system, and a displacement measuring program.

In inspection work of measurement objects such as bridges and steel towers, for example, the amount of displacement in the in-plane direction of the measurement object is measured. Patent Literature 1 discloses an example of a method for measuring an in-plane displacement amount of an object to be measured. In the displacement amount measuring method disclosed in Patent Document 1, the amount of displacement in the in-plane direction of the surface of the object to be measured is measured using a two-dimensional image obtained by photographing a two-dimensional lattice pattern set on the object to be measured.

Japanese Patent No. 4831703

In the displacement measurement method, for example, when the angle of the axis of the two-dimensional lattice pattern set on the measurement object is deviated with respect to the axis of the measurement object, the two-dimensional lattice pattern set on the measurement object is displaced in the Y direction, the two-dimensional grid pattern is measured as if displaced in the X direction by the angle difference with the axis of the object to be measured, although it is not actually displaced in the X direction. . Similarly, when the two-dimensional lattice pattern placed on the object to be measured is displaced in the X direction, the two-dimensional lattice pattern does not actually displace in the Y direction. It is measured as displaced in the Y direction by the angular difference. Therefore, the accuracy of measurement of the displacement amount in the in-plane direction of the object to be measured is low.

An object of the present invention is to provide a displacement measurement method, a displacement measurement device, a displacement measurement system, and a displacement measurement program capable of accurately measuring the displacement of an object in the in-plane direction.

A displacement measurement method according to a first aspect of the present invention measures the amount of displacement in the in-plane direction of the surface of a measurement object using a two-dimensional image obtained by photographing a two-dimensional lattice pattern installed on the measurement object. A displacement measurement method, comprising: a photographing process of photographing the two-dimensional grid pattern set on the object to be measured as a two-dimensional image by an imaging device; analysis region extraction processing for extracting a region containing a pattern as an analysis region; sub-region setting processing for setting a plurality of sub-regions from the analysis region; a first displacement amount calculation process for calculating displacement amounts in the in-plane direction in the plurality of sub-regions using an image; a lattice position calculation process for calculating the inclination or angle change amount of the displacement axis of the two-dimensional lattice pattern installed in the two-dimensional lattice pattern based on the inclination or angle change amount of the displacement axis of the two-dimensional lattice pattern and a second displacement amount calculation process for calculating the displacement amount of the measurement object in the in-plane direction by correcting the displacement amount in the in-plane direction.

In the displacement measurement method, the displacement in the in-plane direction of the object to be measured is corrected based on the inclination or angle change amount of the displacement axis of the two-dimensional lattice pattern. Even if the angle of the axis of is shifted, the amount of displacement in the in-plane direction of the object to be measured can be accurately measured.

A displacement measuring method according to a second aspect of the present invention is the displacement measuring method according to the first aspect, wherein the plurality of sub-regions have the same area.

In the displacement amount measuring method, the first displacement amount calculation process can be efficiently performed.

A displacement measurement method according to a third aspect of the present invention is the displacement measurement method according to the first aspect or the second aspect, wherein in the second displacement amount calculation process, a reference installed other than the object to be measured The tilt of the displacement axis or the amount of change in angle of the two-dimensional grid pattern placed on the object to be measured is corrected based on the tilt of the axis of displacement or the amount of change in angle of the grid pattern.

In the displacement measurement method described above, in the second displacement amount calculation process, the inclination or angle change amount of the displacement axis of the two-dimensional lattice pattern set on the measurement object is corrected. Quantity can be measured with high accuracy.

A displacement amount measuring method according to a fourth aspect of the present invention is the displacement amount measuring method according to the third aspect, wherein in the second displacement amount calculating process, based on the in-plane displacement amount of the reference grid pattern, , to correct the in-plane displacement amount of the two-dimensional lattice pattern.

In the above-described displacement amount measuring method, in the second displacement amount calculation process, the displacement amount of the two-dimensional lattice pattern in the in-plane direction is corrected based on the in-plane displacement amount of the reference lattice pattern. It is possible to accurately measure the amount of displacement in the in-plane direction.

A displacement amount measuring method according to a fifth aspect of the present invention is the displacement amount measuring method according to any one of the first to fourth aspects, wherein in the second displacement amount calculation process, the center of the analysis region and the displacement amount of the two-dimensional lattice pattern in the in-plane direction is corrected based on the distance to an arbitrary point on the object to be measured.

In the above-described displacement amount measuring method, the displacement amount in the in-plane direction of the object to be measured can be accurately measured based on an arbitrary point on the object to be measured.

A displacement amount measuring method according to a sixth aspect of the present invention is the displacement amount measuring method according to any one of the first aspect to the fifth aspect, wherein in the sub-area setting process, three or more sub-areas are In the lattice position calculation process, an average value of inclination or angle change amount of the displacement axis of the two-dimensional lattice pattern in the plurality of sub-regions is calculated, and in the second displacement amount calculation process, the plurality of sub-regions The displacement amount of the two-dimensional lattice pattern in the in-plane direction is corrected based on the average value of the inclination or the angular change amount of the displacement axis of the two-dimensional lattice pattern in the area.

Since many sub-regions are set in the displacement amount measuring method, the inclination or angle change amount of the displacement axis of the two-dimensional lattice pattern can be calculated more accurately in the lattice position calculation process.

A displacement measurement apparatus according to a seventh aspect of the present invention is a displacement amount for measuring the displacement amount in the in-plane direction of the surface of the measurement object using an image obtained by photographing a two-dimensional lattice pattern set on the measurement object. A measurement device, comprising: an analysis region extraction unit that extracts a region including the two-dimensional lattice pattern from the two-dimensional image captured by an imaging device as an analysis region; and a sub-region setting that sets a plurality of sub-regions from the analysis region. and a first displacement amount calculation unit that calculates the amount of displacement in the in-plane direction in the plurality of sub-regions using a two-dimensional image of one of the set sub-regions; a lattice position calculation unit that calculates an inclination or an angular change amount of a displacement axis of the two-dimensional lattice pattern set on the measurement object based on the in-plane displacement amounts of the plurality of sub-regions; A second displacement for calculating an in-plane displacement amount of the object to be measured by correcting the in-plane displacement amount of the two-dimensional lattice pattern based on the inclination or angle change amount of the displacement axis of the lattice pattern. and a quantity calculator.

According to the displacement measuring device, the same effect as the displacement measuring method according to the first aspect can be obtained.

A displacement measurement system according to an eighth aspect of the present invention includes the displacement measurement device according to the seventh aspect and the imaging device.

According to the displacement measurement system, the same effect as the displacement measurement method according to the first aspect can be obtained.

A displacement measurement program according to a seventh aspect of the present invention measures the amount of displacement in the in-plane direction of the surface of the object to be measured using a two-dimensional image obtained by photographing a two-dimensional lattice pattern set on the object to be measured. A displacement measurement program comprising: analysis region extraction processing for extracting a region including the two-dimensional lattice pattern from the two-dimensional image captured by an imaging device as an analysis region; a first displacement amount calculation process for calculating an in-plane displacement amount in the plurality of sub-regions using a two-dimensional image of one of the set sub-regions; grid position calculation processing for calculating the inclination or angle change amount of the displacement axis of the two-dimensional grid pattern set on the measurement object based on the calculated displacement amounts in the in-plane direction of the plurality of sub-regions; A second method for calculating the in-plane displacement amount of the object to be measured by correcting the in-plane displacement amount of the two-dimensional lattice pattern based on the inclination or angle change amount of the displacement axis of the dimensional lattice pattern. A computer is made to perform a displacement amount calculation process.

According to the displacement measurement program, the same effect as the displacement measurement method according to the first aspect can be obtained.

According to the displacement measurement method, the displacement measurement device, the displacement measurement system, and the displacement measurement program according to the present invention, the displacement in the in-plane direction of the object to be measured can be accurately measured.

1 is a schematic configuration diagram of a displacement measurement system according to a first embodiment; FIG. 1 is a front view of a forging press in which a two-dimensional lattice pattern is installed; FIG. FIG. 4 is a diagram for explaining the deviation between the axis of the object to be measured and the axis of the two-dimensional lattice pattern set on the object to be measured; FIG. 2 is a diagram related to functional blocks constructed in the control device of FIG. 1; FIG. 4 is a diagram related to analysis region extraction processing; FIG. 10 is a diagram related to sub-region setting processing; 4 is a flowchart showing an example of a processing procedure of in-plane displacement amount calculation processing; The figure regarding the test result of a displacement amount measurement system. The figure for demonstrating the displacement amount measuring system of 2nd Embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A displacement measuring device according to an embodiment of the present invention and a displacement measuring system including the same will be described below with reference to the drawings.

[First embodiment]
<1. Overall Configuration of Displacement Measurement System>
FIG. 1 is a schematic configuration diagram of a displacement measurement system 10 (hereinafter referred to as "system 10"). The system 10 uses a secondary image (hereinafter referred to as a "two-dimensional grid image") obtained by photographing a two-dimensional grid pattern 200 placed on the measurement target 100 (see FIG. 2) to obtain a surface of the measurement target 100. This is a system that measures the amount of displacement in the inward direction. According to the system 10, inspection work of the measurement object 100 can be performed in a short time. The measurement object 100 is, for example, an upper die of a forging press, a movable die of an injection molding machine, or an infrastructure structure. Infrastructure structures are, for example, flyovers, bridges, railway bridges or tunnels. The displacement measurement system 10 of the present embodiment is used for inspection work of a measurement object 100 that operates with a stroke of a predetermined length, such as the upper die of a forging press and the movable die of an injection molding machine. In the example shown in FIG. 2 , the measurement object 100 is the upper die 420 of the forging press 500 . The displacement measuring system 10 includes a displacement measuring device 20 and an imaging device 30 .

<2. Hardware Configuration of Displacement Measurement System>
The displacement measuring device 20 has a main body 21 , an input device 22 and an output device 23 . The main body 21 has a storage device 21A and a control device 21B. Storage device 21A and control device 21B are communicatively connected via bus 24 . The storage device 21A is, for example, a hard disk or solid state drive. The storage device 21A stores one or a plurality of application software (hereinafter referred to as "in-plane displacement amount calculation software") relating to calculation of the in-plane displacement amount of the measurement object 100. FIG.

The control device 21B includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), etc., and executes functions to be described later. In response to a request from the input device 22, the control device 21B executes in-plane displacement amount calculation software stored in the storage device 21A. By executing the in-plane displacement amount calculation software by the control device 21B, one or a plurality of functional blocks, which will be described later, are constructed in the displacement amount measuring device 20 .

The input device 22 is a keyboard, for example, and is connected to the main body 21 . The output device 23 is, for example, a liquid crystal display, and is connected to the main body 21 so as to receive signals output from the main body 21 . Note that the main body 21, the input device 22, and the output device 23 may be integrally configured like a notebook personal computer.

The imaging device 30 is configured to be able to execute imaging processing for imaging a two-dimensional grid image. In this embodiment, the imaging device 30 is a camera. In this embodiment, the imaging device 30 is connected to the displacement measuring device 20 so as to be able to communicate wirelessly or by wire. The two-dimensional lattice image captured by the imaging device 30 is transmitted to the displacement amount measuring device 20 and stored in, for example, the storage device 21A.

<3. Two-dimensional lattice pattern>
As shown in FIG. 2, a forging press 500 including the measurement object 100 is provided with one or more two-dimensional lattice patterns 200. As shown in FIG. In this embodiment, for example, two two-dimensional grid patterns 200 are installed in the forging press 500 . Hereinafter, in order to distinguish between the two two-dimensional grid patterns 200, one of the two two-dimensional grid patterns 200 may be referred to as the two-dimensional grid pattern 210 and the other may be referred to as the two-dimensional grid pattern 220. The two-dimensional lattice pattern 210 is installed on the lower die 410 of the forging press 500. As shown in FIG. The two-dimensional lattice pattern 220 is placed on the upper mold 420 which is the object 100 to be measured. The upper die 420 moves with a predetermined stroke so as to approach and separate from the lower die 410 along the vertical axis direction. A specific configuration of the two-dimensional lattice pattern 200 can be arbitrarily selected. In this embodiment, the two-dimensional grid pattern 200 is printed on a seal member configured to be attached to the lower mold 410 and the upper mold 420 . The two-dimensional grid pattern 200 may be directly drawn on the bottom mold 410 and the top mold 420 .

From the viewpoint of inspecting the object to be measured 100 in a short time, it is extremely difficult to install the two-dimensional lattice pattern 200 without tilting with respect to the object to be measured 100, regardless of the specific configuration of the two-dimensional lattice pattern 200. is. Therefore, as shown in FIG. 3, the axis XA of the measurement object 100 and the axis XB of the two-dimensional grid pattern 200 placed on the measurement object 100 may deviate by a predetermined angle θX. Under such circumstances, when the two-dimensional grid pattern 200 is displaced in the Y direction as indicated by the arrows in FIG. , the angle θX may be measured as if it were displaced in the X direction. Similarly, when the two-dimensional grid pattern 200 placed on the measurement object 100 is displaced in the X direction, the two-dimensional grid pattern 200 is actually displaced by the angle θX even though it is not displaced in the Y direction. , may be measured as if it were displaced in the Y direction.

The inventors of the present application prefer that the object 100 to be measured is a stationary object such as an infrastructure structure, and the upper die 420 of the forging press 500 and the movable die of an injection molding machine have a predetermined length. It has been found that the above-described problem caused by the deviation of the predetermined angle θX appears more conspicuously in the case of an object that moves with a stroke of a small angle. In the system 10 of the present embodiment, even if the angle of the axis XB of the two-dimensional grid pattern 200 is deviated from the axis XA of the measurement object 100 by a predetermined angle θX, the in-plane direction of the measurement object 100 is configured to be able to accurately measure the amount of displacement of

<4. Software configuration of the displacement measurement system>
As shown in FIG. 4, the functional blocks configured by the control device 21B executing the in-plane displacement amount calculation software stored in the storage device 21A (see FIG. 1) include, for example, the analysis region extraction unit 41 , a sub-region setting unit 42 , a first displacement amount calculation unit 43 , a lattice position calculation unit 44 , and a second displacement amount calculation unit 45 . By constructing these functional blocks in the displacement amount measuring device 20, an in-plane displacement amount calculation process for calculating the in-plane displacement amount of the measurement object 100 is executed. Details of each functional block will be described below. In this embodiment, in order to increase the accuracy of calculation of the in-plane displacement amount of the measurement object 100, a two-dimensional lattice pattern 210 (hereinafter referred to as a Then, the inclination of the displacement axis of the two-dimensional lattice pattern 220 installed on the measurement object 100 is corrected based on the inclination of the displacement axis of the reference lattice pattern. Therefore, each process performed by each functional block below is performed for each of the two-dimensional grid pattern 210 and the two-dimensional grid pattern 220 .

<4-1. Analysis Region Extraction Unit>
The analysis region extracting unit 41 executes analysis region extraction processing for extracting a region including the two-dimensional grid pattern 200 as the analysis region 50 from the two-dimensional grid image 300 (see FIG. 5). The analysis region 50 may be the entire region of the two-dimensional grid image 300 in which the two-dimensional grid pattern 200 is shown, or a portion thereof. In the present embodiment, the analysis region extraction unit 41 extracts a part of the region in which the two-dimensional grid pattern 200 is shown in the two-dimensional grid image 300 as the analysis region 50 in the analysis region extraction process. The shape of the analysis area 50 can be arbitrarily selected. In this embodiment, the shape of the analysis area 50 is a square. The shape of the analysis area 50 may be a rectangle, a rhombus, a triangle, a polygon with pentagons or more, a circle, or an ellipse.

<4-2. Sub-area setting section>
The sub-region setting unit 42 executes sub-region setting processing for setting a plurality of sub-regions 60 by dividing the analysis region 50 . The number of sub-regions 60 set in the sub-region setting process can be arbitrarily selected as long as it is two or more. In this embodiment, the sub-region setting unit 42 sets two sub-regions 60 in the sub-region setting process. Below, the two sub-regions may be referred to as first sub-region 61 and second sub-region 62 . The shape of the plurality of sub-regions 60 can be arbitrarily selected. In this embodiment, the shape of the plurality of sub-regions 60 is rectangular. The shape of the plurality of sub-regions 60 may be a square, a rhombus, a triangle, a polygon with pentagons or more, a circle, or an ellipse. Note that the setting of the plurality of sub-regions 60 may be performed by the user. When the user sets a plurality of sub-regions 60, the sub-region setting unit 42 corrects the shape of the sub-regions 60 set by the user so that the shapes and areas of the plurality of sub-regions 60 match. is preferred. Note that the sub-region 60 may be set in units of one pixel.

<4-3. First Displacement Calculation Section>
The first displacement amount calculator 43 uses a two-dimensional image of any one of the plurality of sub-regions 60 set by the sub-region setting unit 42 to calculate displacement in the in-plane direction in the plurality of sub-regions 60. A first displacement amount calculation process for calculating the amount is executed. In the present embodiment, the first displacement amount calculator 43 uses a two-dimensional image of the first sub-area 61 of the plurality of sub-areas 61 and 62 in the first displacement amount calculation process to , 62 in the in-plane direction.

In the first displacement amount calculation process, the first displacement amount calculator 43 uses the two-dimensional image of the first sub-area 61 to determine the displacement amount dAx in the X direction in the first sub-area 61 and the Y A directional displacement amount dAy, an X-direction displacement amount dBx in the second sub-region 62, and a Y-direction displacement amount dBy in the second sub-region 62 are calculated. In the present embodiment, two sub-regions, in other words, the first sub-region 61 and the second sub-region 62 are set by the sub-region setting unit 42, so the first sub-region 61 serves as a reference sub-region. . Therefore, the X-direction displacement amount dAx in the first sub-region 61 and the Y-direction displacement amount dAy in the first sub-region 61 are zero. Note that the displacement amounts dAx, dAy, dBx, and dBy can be calculated using a known method described in Patent Document 1, for example.

<4-4. Lattice position calculator>
The lattice position calculation unit 44 is installed on the measurement object 100 based on the in-plane displacement amounts dAx, dAy, dBx, and dBy of the plurality of sub-regions 61 and 62 calculated by the first displacement amount calculation unit 43. Grid position calculation processing for calculating the inclination of the displacement axis of the two-dimensional grid pattern 200 is executed.

In the lattice position calculation process, the lattice position calculator 44 calculates the inclination tan θ of the two-dimensional lattice pattern 200 based on the following formula (1) or (2).
tan θ=(dBy−dAy)/(dBx−dAx) (1)
tan θ=(dBx−dAx)/(dBy−dAy) (2)

In this embodiment, the sub-region setting unit 42 sets a plurality of sub-regions 60 by dividing the analysis region 50 in the X-axis direction. Therefore, in the grid position calculation process, the grid position calculator 44 calculates the inclination tan θ of the two-dimensional grid pattern 200 based on Equation (1). When the sub-region setting unit 42 sets a plurality of sub-regions 60 by dividing the analysis region 50 in the Y-axis direction, the lattice position calculation unit 44 calculates the inclination tan θ of the two-dimensional lattice pattern 200 in the lattice position calculation process. is calculated based on the formula (2). In the grid position calculation process, the grid position calculation unit 44 may use the average value of the slopes calculated by the equations (1) and (2) as the slope tan θ of the two-dimensional grid pattern 200 . Hereinafter, the inclination of the two-dimensional lattice pattern 210, which is the reference lattice pattern, is referred to as an inclination tan θA, and the inclination of the two-dimensional lattice pattern 220 is referred to as an inclination tan θB.

<4-5. Second Displacement Calculation Section>
The second displacement amount calculator 45 executes second displacement amount calculation processing for correcting the in-plane displacement amounts Dx and Dy of the measurement object 100 based on the inclination of the displacement axis of the two-dimensional grid pattern 200 . In the second displacement amount calculation process, the second displacement amount calculation unit 45 calculates the following based on the inclination of the displacement axis of the two-dimensional lattice pattern 210, which is the reference lattice pattern, as shown in the following equations (3) and (4). By correcting the inclination of the displacement axis of the two-dimensional grid pattern 220, the corrected in-plane displacement amounts HDx and HDy of the measurement object 100 are calculated. Furthermore, in the second displacement amount calculation process, the second displacement amount calculation unit 45 calculates the displacement of the measured two-dimensional lattice pattern 220 based on the displacement amounts ADx and ADy of the measured two-dimensional lattice pattern 210 in the in-plane direction. By correcting the in-plane displacement amounts Dx and Dy, the corrected in-plane displacement amounts HDx and HDy of the measurement object 100 are calculated. Therefore, even when the imaging device 30 vibrates, the displacement amounts HDx and HDy can be calculated with high accuracy.
HDx=Dx+[Dy·(tan θB−tan θA)]−ADx (3)
HDy=Dy+[Dx·(tan θB−tan θA)]−ADy (4)

An example of the processing procedure of the in-plane displacement amount calculation processing will be described with reference to FIG.
For example, when an arbitrary two-dimensional grid image 300 is stored in the storage device 21A and a request is received from the user, the control device 21B starts the in-plane displacement amount calculation processing.

In step S11, the control device 21B executes an analysis region extraction step. When step S11 ends, the analysis region 50 is extracted from the two-dimensional lattice image 300. FIG.

At step S12, the control device 21B executes a sub-region setting step. When step S12 ends, sub-regions 61 and 62 are set in the analysis region 50. FIG.

In step S13, the control device 21B executes a first displacement amount calculation step. When step S13 ends, displacement amounts dAx, dAy, dBx, and dBy are calculated.

In step S14, the control device 21B executes grid position calculation processing. When step S14 ends, the inclination tan θA of the two-dimensional lattice pattern 210 and the inclination tan θB of the two-dimensional lattice pattern 220, which are the reference lattice patterns, are calculated.

In step S15, the control device 21B executes a second displacement amount calculation process. When step S15 ends, the corrected in-plane displacement amounts HDx and HDy of the measurement object 100 are calculated.

<5. Effects of First Embodiment>
According to the system 10 configured as described above, the following effects can be obtained.
In order to correct the in-plane displacement amounts Dx and Dy of the measurement object 100 based on the inclination of the displacement axis of the two-dimensional lattice pattern 220, the axis of the two-dimensional lattice pattern 220 is shifted with respect to the axis of the measurement object 100. Even if the angle of is deviated, the amount of displacement in the in-plane direction of the object 100 to be measured can be accurately measured.

Further, according to the system 10, the deviation of the installation angle of the two-dimensional lattice pattern 220 with respect to the measurement object 100 can be canceled, and the displacement amount of the measurement object 100 in the in-plane direction can be calculated. For this reason, for example, even though the measurement object 100 is actually displaced in the X direction or the Y direction in the in-plane direction, the measurement object may be displaced due to the deviation of the installation angle of the two-dimensional lattice pattern 220 with respect to the measurement object 100 . A situation in which the displacement of the object 100 in the X direction or the Y direction is canceled and the displacement of the measurement object 100 in the X direction or the Y direction is not measured is less likely to occur.

<6. Measurement results of the displacement measurement system of the present embodiment>
A measurement result of the in-plane displacement amount of the measurement object 100 by the displacement amount measurement system 10 will be described with reference to FIG. 8 . The measurement object 100 is the upper die 420 of the forging press machine 500 . A two-dimensional grid pattern 210 , which is a reference grid pattern, is installed on the lower die 410 of the forging press 500 . The two-dimensional grid pattern 220 is installed on the upper die 420 of the forging press 500 . The axis of the two-dimensional lattice pattern 220 is set in a state of being shifted by a predetermined angle with respect to the axis of the object 100 to be measured. The upper mold 420 moves 30 mm so as to approach the lower mold 410 . The imaging device 30 is installed in front of the forging press machine 500 . The distance between the imaging device 30 and the forging press machine 500 is 1 m. The frame rate of the imaging device 30 is 100 fps. The grid pitch of the two-dimensional grid pattern 200 is 5 mm. The image size of the analysis area 50 is 128×128 pixels.

As shown in FIG. 8, when the displacement amount in the X direction is not corrected using the inclination tan θA of the two-dimensional lattice pattern 210 and the inclination tan θB of the two-dimensional lattice pattern 220, the movement of the upper die 420 in the Y direction causes , the upper die 420 is measured as if it were largely displaced in the X direction. On the other hand, in the displacement measurement system 10, the displacement in the X direction is corrected using the inclination tan θA of the two-dimensional lattice pattern 210 and the inclination tan θB of the two-dimensional lattice pattern 220. Therefore, the upper die 420 moves in the Y direction. It is measured with high accuracy that the upper mold 420 is not substantially displaced in the X direction even if it moves.

[Second embodiment]
The system 10 of the second embodiment differs from the first embodiment in the lattice position calculation process and the second displacement amount calculation process, and the rest of the configuration is the same as that of the first embodiment. Below, the system 10 of the second embodiment will be described, focusing on the parts that are different from the system 10 of the first embodiment.

<7. System of Second Embodiment>
As shown in FIG. 9, in the measurement of the in-plane displacement amount of the measurement object 100, the two-dimensional lattice patterns 210 and 220 may rotate to change the angle. Solid lines in FIG. 9 indicate the two-dimensional grid pattern 210 and the two-dimensional grid pattern 220 at the initial position. Broken lines in FIG. 9 indicate the two-dimensional grid pattern 210 and the two-dimensional grid pattern 220 when the angle is changed from the initial position. The system 10 of the present embodiment is configured to accurately calculate HDx and HDy in the in-plane direction of the measurement object 100 even when the angle of the two-dimensional grid pattern 200 changes.

In the system 10 of the present embodiment, the lattice position calculator 44 calculates displacement amounts dAx, dAy, Based on dBx and dBy, the angular change amount of the two-dimensional lattice pattern 200 placed on the measurement object 100 is calculated.

In the grid position calculation process, the grid position calculation unit 44 calculates the installation angle θ after the angle of the two-dimensional grid pattern 200 is changed based on the inverse trigonometric function of formula (1) or (2) of the first embodiment. do. Hereinafter, the installation angle of the two-dimensional grid pattern 210, which is the reference grid pattern, will be referred to as the installation angle θA, and the installation angle of the two-dimensional grid pattern 220 will be referred to as the installation angle θB. Further, the angular change amount of the two-dimensional lattice pattern 210 is called an angular change amount ΔθA, and the angular change amount of the two-dimensional lattice pattern 220 is called an angular change amount ΔθB. The angle change amount ΔθA is the angle of the central axis XA2 of the two-dimensional lattice pattern 210 at the installation angle θA with respect to the central axis XA1 of the analysis area 50. FIG. The angle change amount ΔθB is the angle of the central axis XB2 of the two-dimensional lattice pattern 220 at the installation angle θB with respect to the central axis XB1 of the analysis region 50 .

The second displacement amount calculator 45 performs a second displacement amount calculation process for correcting the in-plane displacement amounts Dx and Dy of the measurement object 100 based on the angular change amounts ΔθA and ΔθB of the two-dimensional lattice patterns 210 and 220. to run. In the second displacement amount calculation process, the second displacement amount calculation unit 45 calculates the angle change amount ΔθA of the two-dimensional lattice pattern 210, which is the reference lattice pattern, as shown in the following equations (5) and (6). Then, by correcting the angle change amount ΔθB of the two-dimensional lattice pattern 220, the corrected in-plane displacement amounts HDx and HDy of the measurement object 100 are calculated. Furthermore, in the second displacement amount calculation process, the second displacement amount calculation unit 45 calculates the displacement of the measured two-dimensional lattice pattern 220 based on the displacement amounts ADx and ADy of the measured two-dimensional lattice pattern 210 in the in-plane direction. By correcting the in-plane displacement amounts Dx and Dy, the corrected in-plane displacement amounts HDx and HDy of the measurement object 100 are calculated. Therefore, even when the imaging device 30 is tilted due to vibration or the like, the displacement amounts HDx and HDy can be calculated with high accuracy.

HDx=[Dx·cos(ΔθB−ΔθA)+Dy·sin(ΔθB−ΔθA)]−[ADx·cos(ΔθA)+ADy·sin(ΔθA)] (5)

HDy=[Dy·cos(ΔθB−ΔθA)−Dx·sin(ΔθB−ΔθA)]−[ADy·cos(ΔθA)−ADx·sin(ΔθA)] (6)

In the example shown in FIG. 9, an arbitrary point 100X of the measurement object 100 to be measured matches the center 50X of the analysis region 50, but the point 100X and the center 50X do not match. It doesn't have to be. The point 100X may be located within the two-dimensional grid pattern 210 or outside the two-dimensional grid pattern 210 as long as it is on the measurement object 100 . If the point 100X and the center 50X do not match, in the second displacement amount calculation process, the distance (x , y), the amount of displacement of the two-dimensional grid pattern 210 in the in-plane direction is preferably corrected.

HDx=((Dx+x)cos(ΔθB-ΔθA)+(Dy+y)sin(ΔθB-ΔθA))−(ADxcos(ΔθA)+ADysin(ΔθA)) (7)

HDy=((Dy+y)cos(ΔθB-ΔθA)-(Dx+x)sin(ΔθB-ΔθA))-(ADycos(ΔθA)-ADxsin(ΔθA)) (8)

<8. Effect of Second Embodiment>
According to the system 10 of the second embodiment, the following effects can be obtained in addition to the effects obtained by the system 10 of the first embodiment.

Since the in-plane displacement amounts Dx and Dy of the measurement object 100 are corrected based on the angle change amount ΔθB of the two-dimensional lattice pattern 220, even if the angle of the two-dimensional lattice pattern 220 changes, the measurement can be performed. The in-plane displacement amounts HDx and HDy of the object 100 can be calculated with high accuracy. Further, when the angle of the axis of the two-dimensional lattice pattern 220 is shifted with respect to the axis of the measurement object 100, in other words, the two-dimensional lattice pattern 220 is installed at an angle with respect to the measurement object 100. Even in this case, the in-plane displacement amounts HDx and HDy of the measurement object 100 can be calculated with high accuracy.

<9. Variation>
The above-described embodiments are examples of forms that the displacement measuring method, displacement measuring apparatus, displacement measuring system, and displacement measuring program can take, and are not intended to limit the forms. The displacement measuring method, the displacement measuring device, the displacement measuring system, and the displacement measuring program according to the present invention can take forms different from those exemplified in each embodiment. One example is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Some examples of modifications of each embodiment are shown below. Note that the following modifications can be combined with each other within a technically consistent range.

<9-1>
In the first embodiment, the specific contents of the in-plane displacement amount calculation process can be arbitrarily changed. For example, the sub-region setting unit 42 can set a third sub-region in addition to the first sub-region 61 and the second sub-region 62 in the sub-region setting process. In this case, in the first displacement amount calculation process, the first displacement amount calculator 43 uses the two-dimensional image of the first sub-area 61 to calculate the displacement amounts dAx, dAy, dBx, and dBy, as well as the third sub-area. X-direction displacement amount dCx of and Y-direction displacement amount dCy of the third sub-region are calculated.

In the grid position calculation process, the grid position calculator 44 uses the displacement amounts dAx, dAy, dBx, and dBy to calculate the inclination tan θ1 of the two-dimensional grid pattern 220 based on the following equation (9) or (10). .
tan θ1=(dBy−dAy)/(dBx−dAx) (9)
tan θ1=(dBx−dAx)/(dBy−dAy) (10)

When the sub-region setting unit 42 sets a plurality of sub-regions 60 by dividing the analysis region 50 in the direction of the X-axis, the grid position calculation unit 44 performs the grid position calculation process using the inclination tan θ1 of the two-dimensional grid pattern 220 is calculated based on the formula (9). When the sub-region setting unit 42 sets a plurality of sub-regions 60 by dividing the analysis region 50 in the direction of the Y-axis, the grid position calculation unit 44 performs the grid position calculation process using the inclination tan θ1 of the two-dimensional grid pattern 220 is calculated based on the formula (10).

Furthermore, in the grid position calculation process, the grid position calculation unit 44 uses the displacement amounts dAx, dAy, dCx, and dCy to calculate the inclination tan θ2 of the two-dimensional grid pattern 220 based on the following equation (11) or (12). calculate.
tan θ2=(dCy−dAy)/(dCx−dAx) (11)
tan θ2=(dCx−dAx)/(dCy−dAy) (12)

When the sub-region setting unit 42 sets a plurality of sub-regions 60 by dividing the analysis region 50 in the direction of the X-axis, the lattice position calculation unit 44 calculates the inclination tan θ2 of the two-dimensional lattice pattern 220 in the lattice position calculation process. is calculated based on the formula (11). When the sub-region setting unit 42 sets a plurality of sub-regions 60 by dividing the analysis region 50 in the direction of the Y-axis, the lattice position calculation unit 44 calculates the inclination tan θ2 of the two-dimensional lattice pattern 220 in the lattice position calculation process. is calculated based on equation (12).

The grid position calculation unit 44 calculates an average slope tan θ3 of the slopes tan θ1 and tan θ2 in the grid position calculation process. The grid position calculator 44 determines the slope tan θ3 as the slope tan θB of the two-dimensional grid pattern 220 .

In this manner, the average value of the slopes calculated for each of the plurality of sub-regions 60 is used as the slope tan θB of the two-dimensional grid pattern 220 according to the number of sub-regions 60 set in the sub-region setting process. The amount of displacement of the object 100 in the in-plane direction can be measured with high accuracy. Note that this modification can be similarly applied even when the number of sub-regions 60 set in the sub-region setting process is four or more. Moreover, this modification can be similarly applied to the second embodiment. In a modified example of the second embodiment, the average value of the installation angles calculated for each of the plurality of sub-regions 60 may be used as the installation angle θB of the two-dimensional grid pattern 220 to calculate the average value of the angle change amounts ΔθB. .

<9-2>
In the first embodiment, the second displacement amount calculator 45 calculates the displacement axis of the two-dimensional lattice pattern 220 based on the inclination of the displacement axis of the two-dimensional lattice pattern 210, which is the reference lattice pattern, in the second displacement amount calculation process. is corrected, the tilt of the displacement axis of the two-dimensional lattice pattern 220 may not be corrected. Similarly, in the second embodiment, the second displacement amount calculator 45 calculates the two-dimensional lattice pattern 220 based on the angle change amount ΔθA of the two-dimensional lattice pattern 210, which is the reference lattice pattern, in the second displacement amount calculation process. is corrected, the angle change amount .DELTA..theta.B of the two-dimensional grid pattern 220 need not be corrected. In this case, the angle change amount ΔθA in equations (3) and (4) can be set to zero.

<9-3>
In the first embodiment and the second embodiment, in the second displacement amount calculation process, the second displacement amount calculation unit 45 calculates the two-dimensional lattice based on the displacement amounts ADx and ADy of the two-dimensional lattice pattern 210 in the in-plane direction. Although the in-plane displacement amounts Dx and Dy of the pattern 220 are corrected, the displacement amounts Dx and Dy may not be corrected based on the displacement amounts ADx and ADy.

<9-4>
In the above-described embodiment, the displacement measurement device 20 is connected to the imaging device 30 for wireless or wired communication, but the displacement measurement device 20 and the imaging device 30 are not communicably connected. good too. In this case, the two-dimensional lattice image 300 captured by the imaging device 30 is stored in an auxiliary storage device such as a USB flash memory or SD memory card. The displacement measuring device 20 executes in-plane displacement calculation processing by acquiring the two-dimensional lattice image 300 from the auxiliary storage device.

10: Displacement amount measuring system 20: Displacement amount measuring device 30: Imaging device 41: Analysis region extraction unit 42: Sub-region setting unit 43: First displacement amount calculation unit 44: Lattice position calculation unit 45: Second displacement amount calculation unit 50: Analysis area 60: Sub-area 100: Measurement object 200: Two-dimensional lattice pattern 300: Two-dimensional lattice image

Claims (9)

A displacement amount measuring method for measuring the amount of displacement in the in-plane direction of the surface of the measurement object using a two-dimensional image obtained by photographing a two-dimensional lattice pattern set on the measurement object,
a photographing process of photographing the two-dimensional grid pattern installed on the measurement target as a two-dimensional image with an imaging device;
analysis region extraction processing for extracting a region including the two-dimensional lattice pattern from the two-dimensional image captured by the imaging device as an analysis region;
a sub-region setting process for setting a plurality of sub-regions from the analysis region;
a first displacement amount calculation process for calculating an in-plane displacement amount for each of the plurality of sub-regions using a two-dimensional image of one of the set sub-regions;
grid position calculation processing for calculating the tilt or angle change amount of the displacement axis of the two-dimensional grid pattern set on the measurement object based on the calculated displacement amount in the in-plane direction for each of the plurality of sub-regions;
calculating an in-plane displacement amount of the object to be measured by correcting the in-plane displacement amount of the two-dimensional lattice pattern based on the inclination or angle change amount of the displacement axis of the two-dimensional lattice pattern; a second displacement amount calculation process;
Displacement measurement method, including The displacement amount measuring method according to claim 1, wherein the plurality of sub-regions have the same area. In the second displacement amount calculation process, the displacement axis of the two-dimensional grid pattern placed on the object to be measured is based on the inclination or angle change amount of the displacement axis of the reference grid pattern placed on the object other than the object to be measured. The displacement measuring method according to claim 1 or 2, wherein the amount of change in inclination or angle of is corrected. The displacement amount measuring method according to claim 3, wherein in the second displacement amount calculation process, the in-plane displacement amount of the two-dimensional lattice pattern is corrected based on the in-plane displacement amount of the reference lattice pattern. In the second displacement amount calculation process, the displacement amount in the in-plane direction of the two-dimensional lattice pattern is corrected based on the distance between the center of the analysis area and an arbitrary point of the measurement object. 5. The displacement measuring method according to any one of 4. In the sub-region setting process, three or more sub-regions are set;
In the lattice position calculation process, calculating an average value of inclination or angle change amount of the displacement axis of the two-dimensional lattice pattern in the plurality of sub-regions;
In the second displacement amount calculation process, the displacement amount of the two-dimensional lattice pattern in the in-plane direction is corrected based on an average value of inclination or angle variation of the displacement axis of the two-dimensional lattice pattern in the plurality of sub-regions. The displacement measuring method according to any one of claims 1 to 5. A displacement amount measuring device for measuring the amount of displacement in the in-plane direction of the surface of the object to be measured using an image obtained by photographing a two-dimensional lattice pattern set on the object to be measured,
an analysis region extraction unit that extracts, as an analysis region, a region containing the two-dimensional lattice pattern from the two-dimensional image captured by an imaging device;
a sub-region setting unit that sets a plurality of sub-regions from the analysis region;
a first displacement amount calculator that calculates an in-plane displacement amount for each of the plurality of sub-regions using a two-dimensional image of one of the set sub-regions;
a lattice position calculation unit that calculates an inclination or an angle change amount of a displacement axis of the two-dimensional lattice pattern set on the measurement object based on the calculated amount of displacement in the in-plane direction for each of the plurality of sub-regions;
calculating an in-plane displacement amount of the object to be measured by correcting the in-plane displacement amount of the two-dimensional lattice pattern based on the inclination or angle change amount of the displacement axis of the two-dimensional lattice pattern; a second displacement amount calculator;
Displacement measuring device, including A displacement measuring device according to claim 7;
and the imaging device. A displacement measurement system. A displacement amount measurement program for measuring the amount of displacement in the in-plane direction of the surface of the measurement object using a two-dimensional image obtained by photographing a two-dimensional lattice pattern set on the measurement object,
analysis region extraction processing for extracting, as an analysis region, a region containing the two-dimensional grid pattern from the two-dimensional image captured by an imaging device;
a sub-region setting process for setting a plurality of sub-regions from the analysis region;
a first displacement amount calculation process for calculating an in-plane displacement amount for each of the plurality of sub-regions using a two-dimensional image of one of the set sub-regions;
grid position calculation processing for calculating the inclination or angle change amount of the displacement axis of the two-dimensional grid pattern set on the measurement object based on the calculated displacement amount in the in-plane direction for each of the plurality of sub-regions;
calculating an in-plane displacement amount of the object to be measured by correcting the in-plane displacement amount of the two-dimensional lattice pattern based on the inclination or angle change amount of the displacement axis of the two-dimensional lattice pattern; A displacement measurement program that causes a computer to execute a second displacement calculation process.