Displacement measurement system, displacement measurement program, displacement measurement method, and displacement measurement device

Abstract

To provide a displacement measurement system, a displacement measurement program, a displacement measurement method, and a displacement measurement device, which enable accurate measurement of an amount of displacement of a measurement target in an in-plane direction.SOLUTION: A displacement measurement system disclosed herein comprises a displacement measurement device configured to measure an amount of displacement of a surface of a measurement target in an in-plane direction thereof using a two-dimensional image obtained by capturing a two-dimensional grating pattern provided on the measurement target, and an image capturing device for capturing the two-dimensional grating pattern provided on the measurement target. The displacement measurement device is configured to perform pixel-by-pixel displacement computation processing to compute an amount of displacement of each pixel in an analysis area including the two-dimensional grating pattern in the two-dimensional image, and determination processing for determining whether the analysis area includes a missing area or not on the basis of the variation in the amount of displacement of each pixel.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a displacement amount measuring system, a displacement amount measuring program, a displacement amount measuring method, and a displacement amount measuring device. [Background technology]

[0002] In inspection work of measurement objects such as bridges and steel towers, for example, the amount of displacement in an in-plane direction of the measurement object is measured. Patent Document 1 discloses an example of a method for measuring the amount of displacement in an in-plane direction of a measurement object. In the displacement measurement method disclosed in Patent Document 1, a two-dimensional image of a two-dimensional lattice pattern placed on the measurement object is used to measure the amount of displacement in an in-plane direction of the surface of the measurement object. The two-dimensional image is captured by, for example, an imaging device. An analysis region including the two-dimensional lattice pattern is set in the two-dimensional image.

[0003] In the displacement measurement method of Patent Document 1, when a two-dimensional image contains missing areas due to, for example, a failure in transferring a two-dimensional grid pattern to a measurement object, the missing areas of the two-dimensional image are complemented by machine learning to calculate the in-plane displacement of the measurement object. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-25845 Summary of the Invention [Problem to be solved by the invention]

[0005] If the displacement of a measurement object is calculated using a 2D image that includes missing areas, the displacement cannot be measured correctly. In the above displacement measurement method, the missing areas of the 2D image are filled in by machine learning, but depending on the accuracy of the machine learning, the missing areas may not be filled in sufficiently.

[0006] An object of the present invention is to provide a displacement amount measuring system, a displacement amount measuring program, a displacement amount measuring method, and a displacement amount measuring device that can accurately measure the amount of displacement in an in-plane direction of a measurement object. [Means for solving the problem]

[0007] A displacement measuring system according to a first aspect of the present invention is a displacement measuring system comprising a displacement measuring device that measures an in-plane displacement amount of a surface of a measurement object using a two-dimensional image of a two-dimensional grid pattern placed on the measurement object, and an imaging device that images the two-dimensional grid pattern placed on the measurement object, wherein the displacement measuring device executes a pixel-by-pixel displacement amount calculation process that calculates a displacement amount for each pixel in an analysis area including the two-dimensional grid pattern in the two-dimensional image, and a determination process that determines whether the analysis area includes a missing area based on a variance in the displacement amount for each pixel.

[0008] When the analysis area does not include a missing area, the amount of displacement for each pixel in the analysis area is roughly constant. On the other hand, when the analysis area includes a missing area, the amount of displacement for each pixel in the missing area is significantly different from the amount of displacement for each pixel in the area other than the missing area, so that the amount of displacement for each pixel in the analysis area as a whole varies greatly.

[0009] According to the above-mentioned displacement amount measuring system, it is possible to extract two-dimensional images that are determined in the determination process to have a large variation in the amount of displacement for each pixel, in other words, two-dimensional images that are determined to include missing areas, and therefore it is possible to measure the amount of displacement of the measurement object using two-dimensional images other than the two-dimensional images that include missing areas. Therefore, it is possible to accurately measure the amount of displacement of the measurement object in the in-plane direction of the measurement object.

[0010] A displacement measuring system according to a second aspect of the present invention is a displacement measuring system according to the first aspect, wherein the displacement measuring device calculates an in-plane displacement amount of the surface of the measurement object based on only an average displacement amount of the two-dimensional grid pattern in the two-dimensional image that is determined to be valid in the determination process, out of the average displacement amounts of the two-dimensional grid pattern in the analysis area.

[0011] According to the above-described displacement amount measuring system, the amount of displacement of the measurement object in the in-plane direction of the measurement object can be measured with high accuracy.

[0012] A displacement measurement system according to a third aspect of the present invention is a displacement measurement system according to the first or second aspect, wherein the displacement measurement device, in the judgment process, judges whether the analysis area includes a missing area based on a differential value of the displacement amounts of adjacent pixels.

[0013] According to the above-described displacement amount measuring system, the amount of displacement of the measurement object in the in-plane direction of the measurement object can be measured with high accuracy.

[0014] A displacement measurement system according to a fourth aspect of the present invention is a displacement measurement system according to the first or second aspect, wherein in the determination process, the displacement measurement device determines whether or not the analysis area includes a missing area based on the standard deviation of the displacement amounts for each pixel within the analysis area.

[0015] According to the above-described displacement amount measuring system, the amount of displacement of the measurement object in the in-plane direction of the measurement object can be measured with high accuracy.

[0016] A displacement measurement program according to a fifth aspect of the present invention is a displacement measurement program that measures an in-plane displacement amount of a surface of a measurement object using a two-dimensional image of a two-dimensional grid pattern placed on the measurement object, and causes a computer to execute a pixel-by-pixel displacement amount calculation process that calculates a displacement amount for each pixel in an analysis area including the two-dimensional grid pattern in the two-dimensional image, and a determination process that determines whether the analysis area includes a missing area based on the variance in the displacement amount for each pixel.

[0017] According to the above displacement amount measuring program, the same effects as those of the displacement amount measuring system according to the first aspect can be obtained.

[0018] A displacement measuring method according to a sixth aspect of the present invention is a displacement measuring method for measuring an in-plane displacement amount of a surface of a measurement object using a two-dimensional image of a two-dimensional grid pattern placed on the measurement object, and includes a pixel-by-pixel displacement amount calculation process for calculating a displacement amount for each pixel in an analysis area including the two-dimensional grid pattern in the two-dimensional image, and a determination process for determining whether or not the analysis area includes a missing area based on a variance in the displacement amount for each pixel.

[0019] According to the above displacement amount measuring method, the same effects as those of the displacement amount measuring system according to the first aspect can be obtained.

[0020] A displacement measuring device according to a seventh aspect of the present invention is a displacement measuring device that measures the amount of displacement in the in-plane direction of the surface of a measurement object using a two-dimensional image of a two-dimensional grid pattern placed on the measurement object, and executes a pixel-by-pixel displacement calculation process that calculates the amount of displacement for each pixel in an analysis area including the two-dimensional grid pattern in the two-dimensional image, and a determination process that determines whether the analysis area includes a missing area based on the variance in the displacement amount for each pixel.

[0021] According to the displacement amount measuring device, the same effects as those of the displacement amount measuring system according to the first aspect can be obtained. Effect of the Invention

[0022] According to the displacement amount measuring system, displacement amount measuring program, displacement amount measuring method, and displacement amount measuring device of the present invention, which can accurately measure the amount of displacement in the in-plane direction of a measurement object, the amount of displacement in the in-plane direction of a measurement object can be measured with high accuracy. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic configuration diagram of a displacement amount measuring system according to an embodiment. [Diagram 2] A front view of a measurement target on which a two-dimensional grid pattern is placed. [Diagram 3] FIG. 13 is a diagram showing an example of a two-dimensional lattice image. [Figure 4] A diagram showing the analysis region of Figure 3. [Diagram 5] A diagram showing the state in which a missing area has been formed in the analysis area of ​​Figure 4. [Figure 6] FIG. 2 is a diagram of functional blocks constructed in the control device of FIG. 1. [Figure 7] 4 is a diagram showing an example of the displacement amount for each pixel when the analysis region in FIG. 3 does not include a missing region. [Figure 8] 4 is a diagram showing an example of the displacement amount for each pixel when the analysis region in FIG. 3 includes a missing region. [Figure 9] 8 is a diagram showing an example of a calculation result of a differential value of the amount of displacement of adjacent pixels in FIG. 7. [Figure 10] 9 is a diagram showing an example of a calculation result of a differential value of the amount of displacement of adjacent pixels in FIG. 8. [Figure 11] 11 is a flowchart showing an example of a processing procedure of an in-plane displacement amount calculation process. [Figure 12] 13 is a graph showing an example of a measurement result of the amount of displacement in a phase unwrapped mode when the system according to the embodiment is not applied. [Figure 13] 13 is a graph showing an example of a measurement result of the amount of displacement in a non-phase unwrapping mode when the system according to the embodiment is not applied. [Figure 14] 13 is a graph showing an example of a measurement result of the amount of displacement in a phase unwrapped mode when the system according to the embodiment is applied. [Figure 15]13 is a graph showing an example of a measurement result of the amount of displacement in a no phase unwrapping mode when the system according to the embodiment is applied. [Figure 16] 10 is a flowchart showing an example of a processing procedure of an in-plane displacement amount calculation process executed by a displacement amount measuring system according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A displacement measurement device according to an embodiment of the present invention and a displacement measurement system including the same will be described below with reference to the drawings.

[0025] <1. Overall configuration of the displacement measurement system> FIG. 1 is a schematic diagram of a displacement amount measuring system 10 (hereinafter referred to as "system 10"). System 10 is a system that measures the amount of displacement in an in-plane direction of measurement object 100 by using a two-dimensional image (hereinafter referred to as "two-dimensional lattice image") obtained by capturing a two-dimensional lattice pattern 200 (see FIG. 2) placed on measurement object 100. Measurement object 100 is, for example, an infrastructure structure. Infrastructure structures are, for example, elevated roads, bridges, railway bridges, or tunnels. Displacement amount measuring system 10 includes a displacement amount measuring device 20 and an imaging device 30.

[0026] <2. Hardware configuration of the displacement measurement system> The displacement amount 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. The storage device 21A and the control device 21B are connected so as to be able to communicate with each other via a bus 24. The storage device 21A is, for example, a hard disk or a solid state drive. The storage device 21A stores one or more application software (hereinafter referred to as "displacement amount calculation software") related to calculation of the displacement amount in the in-plane direction of the measurement object 100.

[0027] The control device 21B includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), etc., and executes functions described below. The control device 21B executes in-plane displacement amount calculation software stored in the storage device 21A in response to a request from the input device 22. As a result of the control device 21B executing the in-plane displacement amount calculation software, one or more function blocks described below are constructed in the displacement amount measuring device 20.

[0028] The input device 22 is, for example, a keyboard, 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 a signal 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.

[0029] The imaging device 30 is configured to be able to execute an imaging process for capturing a two-dimensional lattice 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 wired. The two-dimensional lattice image captured by the imaging device 30 is transmitted to the displacement measuring device 20 and stored in, for example, the storage device 21A. The imaging device 30 may be a camera mounted on a tablet terminal or a camera mounted on a smartphone.

[0030] <3.2-dimensional lattice pattern> One or more two-dimensional grating patterns 200 are provided on the measurement object 100 shown in Fig. 2. The specific configuration of the two-dimensional grating pattern 200 can be selected arbitrarily. In this embodiment, the two-dimensional grating pattern 200 is printed on a seal member configured to be affixed to the measurement object 100. The two-dimensional grating pattern 200 may be drawn directly on the measurement object 100, or may be printed or engraved on a member such as a plate fixed to the measurement object 100.

[0031] 3 is a diagram showing a two-dimensional lattice image 300. In measuring the amount of displacement in an in-plane direction of the measurement object 100, an analysis region 50 is set within the two-dimensional lattice image 300.

[0032] Fig. 4 is a diagram showing an example of the analysis region 50. The analysis region 50 includes a plurality of pixels 50A. In the example shown in Fig. 4, the analysis region 50 has a total of 100 pixels 50A arranged in 10 rows and 10 columns. In measuring the amount of displacement in the in-plane direction of the measurement object 100, the amount of displacement for each pixel 50A is calculated, and the average value of the amounts of displacement for all the pixels 50A is calculated as the average amount of displacement of the two-dimensional grid pattern 200 in the analysis region 50.

[0033] In measuring the amount of displacement in the in-plane direction of the measurement object 100, at least a part of the two-dimensional lattice pattern 200 may be temporarily blocked by an external factor such as a person after the measurement is started. In such a case, as shown in FIG. 5, a missing area 50X (a part filled in black in FIG. 5) is formed in the analysis area 50. The missing area 50X is an area in the analysis area 50 where the two-dimensional lattice pattern 200 is blocked by an external factor. If the amount of displacement of the measurement object 100 is calculated using a two-dimensional lattice image 300 including the missing area 50X, the accuracy of the calculation of the amount of displacement is greatly reduced. In this embodiment, the control device 21B extracts the two-dimensional lattice image 300 including the missing area 50X based on the variation in the amount of displacement for each pixel 50A in an in-plane displacement calculation process described later, and measures the amount of displacement of the measurement object 100 using the two-dimensional lattice image 300 other than the two-dimensional lattice image 300 including the missing area 50X.

[0034] <4. Software configuration of the displacement measurement system> 6, functional blocks configured by the control device 21B executing the displacement amount calculation software stored in the storage device 21A (see FIG. 1) include, for example, an analysis area extraction unit 41, a pixel-by-pixel displacement amount calculation unit 42, an average displacement amount calculation unit 43, a total displacement amount calculation unit 44, and a determination unit 45. By constructing these functional blocks in the displacement amount measuring device 20, an in-plane displacement amount calculation process is executed to calculate the amount of displacement in the in-plane direction of the measurement object 100. Each functional block will be described in detail below.

[0035] <4-1.Analysis area extraction part> The analytical region extraction unit 41 executes an analytical region extraction process to extract a region including the two-dimensional lattice pattern 200 from the two-dimensional lattice image 300 (see FIG. 3) as the analytical region 50. The analytical region 50 may be the entire region in the two-dimensional lattice image 300 in which the two-dimensional lattice pattern 200 is captured, or may be a part of the region. In this embodiment, the analytical region extraction unit 41 extracts a part of the region in the two-dimensional lattice image 300 in which the two-dimensional lattice pattern 200 is captured as the analytical region 50 in the analytical region extraction process. The shape of the analytical region 50 can be selected arbitrarily. In this embodiment, the shape of the analytical region 50 is a square. The shape of the analytical region 50 may be a rectangle, a rhombus, a triangle, a polygon with pentagons or more, a circle, or an ellipse.

[0036] <4-2. Pixel-by-pixel displacement calculation section> The pixel-by-pixel displacement amount calculation unit 42 executes a pixel-by-pixel displacement amount calculation process that calculates the amount of displacement for each pixel 50A in the analysis region 50. For example, when the images captured by the imaging device 30 are continuous still images, the pixel-by-pixel displacement amount calculation unit 42 calculates the amount of displacement for all pixels 50A in the analysis region 50 for each still image in the pixel-by-pixel displacement amount calculation process. For example, when the images captured by the imaging device 30 are moving images, the pixel-by-pixel displacement amount calculation unit 42 calculates the amount of displacement for all pixels 50A in the analysis region 50 for each frame in the pixel-by-pixel displacement amount calculation process.

[0037] <4-3. Average Displacement Calculation Section> The average displacement amount calculation unit 43 executes an average displacement amount calculation process to calculate an average displacement amount of the two-dimensional lattice pattern 200 in the analysis area 50. In the average displacement amount calculation process, an average value of the displacement amounts of all pixels 50A in the analysis area 50 in one still image or one frame of a moving image is calculated as an average displacement amount. In the average displacement amount calculation process, the average displacement amount calculation unit 43 calculates an average displacement amount dAx in the X-axis direction and an average displacement amount dAy in the Y-axis direction of the two-dimensional lattice pattern 200 in the analysis area 50. The calculation of the average displacement amounts dAx and dAy can be performed using a known method described in, for example, Japanese Patent No. 4831703.

[0038] <4-4. Total Displacement Calculation Section> The total displacement amount calculation unit 44 executes a total displacement amount calculation process to calculate the total displacement amount of the two-dimensional lattice pattern 200. In the total displacement amount calculation process, the total displacement amount calculation unit 44 calculates the total displacement amount of the two-dimensional lattice pattern 200 by adding the average displacement amounts dAx and dAy calculated by the average displacement amount calculation process to the accumulated displacement amount of the two-dimensional lattice pattern 200.

[0039] <4-5. Judgment section> The determination unit 45 executes a determination process to determine whether the analysis region 50 includes a missing region 50X or not, based on the variation in the amount of displacement for each pixel 50A in the analysis region 50. FIG. 7 is a diagram showing an example of the analysis region 50 when the analysis region 50 does not include a missing region 50X. For ease of understanding, FIG. 7 shows the amount of displacement (mm) in the X-axis direction in each pixel 50A. When the analysis region 50 does not include a missing region 50X, the amount of displacement for each pixel 50A in the analysis region 50 is roughly constant.

[0040] 8 is a diagram showing an example of an analysis region 50 in which a missing region 50X is included in the analysis region 50. In FIG. 8, for ease of understanding, the displacement amount (mm) in the X-axis direction is written in each pixel 50A. When the analysis region 50 includes a missing region 50X, the displacement amount of each pixel 50A in the missing region 50X is significantly different from the displacement amount of each pixel 50A in the region other than the missing region 50X. For this reason, the variation in the displacement amount of each pixel 50A becomes large in the analysis region 50 as a whole.

[0041] In the determination process, the determination unit 45 determines, based on a differential value of the amount of displacement between adjacent pixels 50A in the analysis region 50, whether or not the variation in the amount of displacement between the pixels 50A is large.

[0042] 9 is an example of the result of calculating the differential value of the displacement between adjacent pixels 50A in the analysis region 50 in the example of FIG. 7, that is, when the analysis region 50 does not include the missing region 50X. For example, in the example shown in FIG. 9, the differential value of the displacement of the pixel 50A in the 1st row and 10th column, "0.1", is calculated based on the difference between the displacement of the pixel 50A in the 1st row and 10th column, "2.1", and the displacement of the pixel 50A in the 1st row and 9th column, "2.0", in the example shown in FIG. 9. When the analysis region 50 does not include the missing region 50X, as shown in FIG. 9, the differential value of the displacement between adjacent pixels 50A in the analysis region 50 is small.

[0043] Fig. 10 shows an example of the result of calculating the differential value of the displacement between adjacent pixels 50A in the analysis region 50 in the example of Fig. 8, that is, when the analysis region 50 includes a missing region 50X. For example, in the example shown in Fig. 10, the differential value of the displacement of the pixel 50A in the 8th row and 10th column, "-7.1", is calculated based on the difference between the displacement of the pixel 50A in the 8th row and 10th column, "-3.4", and the displacement of the pixel 50A in the 8th row and 9th column, "3.7", in the example shown in Fig. 8. As shown in Fig. 10, when the analysis region 50 includes the missing region 50X, the differential value of the displacement between adjacent pixels 50A in the missing region 50X is large.

[0044] When at least one of the absolute values ​​of the differential values ​​of the displacement amounts between adjacent pixels 50A in the analysis region 50 is equal to or greater than the threshold value, the determination unit 45 determines that the variation in the displacement amounts between the pixels 50A is large, i.e., that the analysis region 50 includes a missing region 50X. When all of the absolute values ​​of the differential values ​​of the displacement amounts between adjacent pixels 50A in the analysis region 50 are less than the threshold value, the determination unit 45 determines that the variation in the displacement amounts between the pixels 50A is small, i.e., that the analysis region 50 does not include a missing region 50X. The threshold value is a value at which it can be determined that a missing region 50X exists, and is determined in advance by testing.

[0045] <5. In-plane displacement calculation process> An example of a processing procedure for an in-plane displacement amount calculation process will be described with reference to FIG. The control device 21B starts the in-plane displacement amount calculation process, for example, when an arbitrary two-dimensional lattice image 300 is stored in the storage device 21A and a request is received from the user.

[0046] In step S11, the control device 21B sets the first two-dimensional lattice image 300, or sets a reference displacement of the two-dimensional lattice pattern 200 from the first frame of the two-dimensional lattice image 300.

[0047] In step S12, the control device 21B calculates the amount of displacement for each pixel 50A in the analysis region 50.

[0048] In step S13, the control device 21B calculates the average displacement amounts dAx, dAy of the two-dimensional grid pattern 200 based on the displacement amount for each pixel 50A in the analysis region 50.

[0049] In step S14, the control device 21B calculates a differential value of the amount of displacement between adjacent pixels 50A in the analysis region 50.

[0050] In step S15, the control device 21B determines whether or not at least one of the absolute values ​​of the differential values ​​of the displacement amounts between adjacent pixels 50A is equal to or greater than a threshold value. If the determination in step S15 is negative, that is, if all of the absolute values ​​of the differential values ​​of the displacement amounts between adjacent pixels 50A are less than the threshold value, the control device 21B determines that the analysis region 50 does not include the missing region 50X, and executes the process of step S16.

[0051] In step S16, the control device 21B adds the average displacement amount dAx and the average displacement amount dAy to the cumulative displacement amount to calculate the total displacement amount of the two-dimensional grid pattern 200.

[0052] On the other hand, if step S15 is judged to be positive, i.e., if at least one of the differential values ​​of the displacement between adjacent pixels 50A is equal to or greater than a threshold value, the control device 21B judges that the analysis area 50 includes a missing area 50X, and executes processing of step S17.

[0053] In step S17, the control device 21B does not add the average displacement amount dAx and the average displacement amount dAy to the accumulated displacement amount.

[0054] In step S18, the control device 21B judges whether or not a signal requesting termination of the in-plane displacement amount calculation process has been input from the user. If the determination in step S18 is positive, the control device 21B terminates the in-plane displacement amount calculation process. If the determination in step S18 is negative, the control device 21B repeatedly executes the processes in step S12 and onward. Note that in step S18, the control device 21B may judge whether or not a predetermined time set in advance has elapsed. If the determination in step S18 is positive, that is, if the predetermined time has elapsed, the control device 21B terminates the in-plane displacement amount calculation process. If the determination in step S18 is negative, that is, if the predetermined time has not elapsed, the control device 21B repeatedly executes the processes in step S12 and onward.

[0055] 6. Effects of the embodiment According to the system 10 configured as above, the following effects can be obtained.

[0056] <6-1> According to the system 10, in step S15 of the in-plane displacement amount calculation process, it is possible to extract two-dimensional lattice images 300 that are determined to have a large variation in the displacement amount for each pixel 50A, in other words, two-dimensional lattice images 300 that are determined to include missing areas 50X, and therefore it is possible to measure the displacement amount of the measurement object 100 using two-dimensional lattice images 300 other than the two-dimensional lattice images 300 that include missing areas 50X. Therefore, it is possible to accurately measure the displacement amount of the measurement object 100 in the in-plane direction.

[0057] The system 10 can be suitably applied to both a known mode with phase unwrapping and a mode without phase unwrapping, which measure the amount of displacement in an in-plane direction of the measurement object 100. The mode with phase unwrapping is a mode that measures an amount of displacement that is half or more of the lattice pitch of the two-dimensional lattice pattern 200. The mode without phase unwrapping is a mode that measures an amount of displacement that is half or less of the lattice pitch of the two-dimensional lattice pattern 200.

[0058] Fig. 12 is a graph showing an example of a measurement result of the amount of displacement of the measurement object 100 in the phase unwrapping mode when the system 10 is not applied. Fig. 13 is a graph showing an example of a measurement result of the amount of displacement of the measurement object 100 in the non-phase unwrapping mode when the system 10 is not applied.

[0059] 12 and 13 are portions where the amount of displacement of the measurement object 100 was measured using the two-dimensional lattice image 300 including the missing region 50X. It can be seen that the measurement values ​​are significantly distorted in the portions where the amount of displacement of the measurement object 100 was measured using the two-dimensional lattice image 300 including the missing region 50X.

[0060] 14 is a graph showing an example of the measurement result of the displacement amount of the measurement object 100 in the phase unwrapping mode when the system 10 is applied. In the system 10, the two-dimensional lattice image 300 determined to include the missing region 50X is excluded, and the displacement amount of the measurement object 100 is measured using the two-dimensional lattice image 300 that does not include the missing region 50X, so that the displacement amount of the measurement object 100 can be suitably measured.

[0061] 15 is a graph showing an example of a measurement result of the amount of displacement of the measurement object 100 in the no phase unwrapping mode when the system 10 is applied. In the system 10, the two-dimensional lattice image 300 determined to include the missing region 50X is excluded, and the amount of displacement of the measurement object 100 is measured using the two-dimensional lattice image 300 that does not include the missing region 50X, so that the amount of displacement of the measurement object 100 can be suitably measured.

[0062] <6-2> In the determination process, the determination unit 45 determines whether or not the variation in the amount of displacement for each pixel 50A is large based on the differential value of the amount of displacement between adjacent pixels 50A in the analysis region 50. Therefore, it is possible to continue measuring the amount of displacement in the in-plane direction of the measurement object 100 without checking the two-dimensional lattice image 300.

[0063] <7. Variations> The above-mentioned embodiments are examples of forms that the displacement measurement system, displacement measurement program, displacement measurement method, and displacement measurement device according to the present invention may take, and are not intended to limit the forms. The displacement measurement system, displacement measurement program, displacement measurement method, and displacement measurement device according to the present invention may take forms different from those exemplified in the embodiments. One example is a form in which part of the configuration of the embodiments is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Below are some examples of modified embodiments. The following modified embodiments can be combined with each other as long as they are not technically inconsistent.

[0064] <7-1> In the above embodiment, the determination unit 45 may determine whether or not the analysis region 50 includes a missing region 50X based on the standard deviation of the displacement amount for each pixel 50A in the analysis region 50. In this modification, the determination unit 45 calculates the difference ΔX between the average displacement amounts dAx, dAy of the two-dimensional grid pattern 200 and the displacement amount for each pixel 50A, and calculates the standard deviation by dividing the sum of all the differences ΔX by the number of pixels 50A.

[0065] In the example shown in Fig. 7, the average displacement amount dAx of the two-dimensional lattice pattern 200 is 2.0 mm, and the standard deviation of the displacement amount for each pixel 50A in the analysis region 50 is 0.1 mm. In the example shown in Fig. 8, the average displacement amount dAx of the two-dimensional lattice pattern 200 is 2.0 mm, and the standard deviation of the displacement amount for each pixel 50A in the analysis region 50 is 1.0 mm.

[0066] When the standard deviation of the amount of displacement for each pixel 50A in the analysis region 50 is equal to or greater than the threshold, the determination unit 45 determines that the variation in the amount of displacement for each pixel 50A is large, i.e., that the analysis region 50 includes a missing region 50X. When the standard deviation of the amount of displacement for each pixel 50A in the analysis region 50 is less than the threshold, the determination unit 45 determines that the variation in the amount of displacement for each pixel 50A is small, i.e., that the analysis region 50 does not include a missing region 50X. The threshold is a value at which it can be determined that a missing region 50X exists, and is determined in advance by testing.

[0067] Fig. 16 is a flowchart showing an example of an in-plane displacement amount calculation process executed by the modified displacement amount measurement system 10. The in-plane displacement amount calculation process shown in Fig. 16 differs from the in-plane displacement amount calculation process shown in Fig. 11 in that it has a process of step S21 instead of the process of step S14 and has a process of step S22 instead of step S15.

[0068] In step S21, the control device 21B calculates the standard deviation of the displacement amount for each pixel 50A.

[0069] In step S22, the control device 21B determines whether the standard deviation of the displacement amount for each pixel 50A is equal to or greater than a threshold value. If the determination in step S22 is negative, that is, if the standard deviation of the displacement amount for each pixel 50A is less than the threshold value, the control device 21B determines that the analysis region 50 does not include the missing region 50X, and executes the process of step S16.

[0070] On the other hand, if step S22 returns a positive determination, that is, if the standard deviation of the displacement amounts for each pixel 50A is equal to or greater than the threshold value, the control device 21B determines that the analysis region 50 includes a missing region 50X, and executes the process of step S17.

[0071] <7-2> In the above embodiment, the analytical region 50 is set by the analytical region extraction unit 41, but the analytical region 50 may be set by a user.

[0072] <7-3> In the above embodiment, the displacement measuring device 20 is connected to the imaging device 30 so as to be able to communicate wirelessly or by wire, but the displacement measuring device 20 and the imaging device 30 do not have to be connected so as to be able to communicate with each other. 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 an SD memory card. The displacement measuring device 20 executes the in-plane displacement calculation process by acquiring the two-dimensional lattice image 300 from the auxiliary storage device. [Explanation of symbols]

[0073] 10: Displacement measurement system 20: Displacement measuring device 30: Imaging device 50:Analysis area 100: Measurement object 200: 2D grid pattern

Claims

1. a displacement amount measuring device that measures a displacement amount in an in-plane direction of a surface of a measurement object by using a two-dimensional image obtained by capturing a two-dimensional grid pattern placed on the measurement object; an imaging device that captures the two-dimensional grid pattern installed on the measurement object, The displacement amount measuring device is a pixel-by-pixel displacement amount calculation process for calculating a displacement amount for each pixel in an analysis region including the two-dimensional grid pattern in the two-dimensional image; and executing a determination process of determining whether or not the analysis region includes a missing region based on the variation in the displacement amount for each pixel. Displacement measurement system.

2. The displacement amount measuring device is Calculating an in-plane displacement amount of the surface of the measurement object based on only the average displacement amount of the two-dimensional grid pattern in the two-dimensional image determined to be valid in the determination process, out of the average displacement amounts of the two-dimensional grid pattern in the analysis region. The displacement measurement system according to claim 1 .

3. The displacement amount measuring device is In the determination process, it is determined whether or not the analysis area includes a missing area based on a differential value of the amount of displacement between adjacent pixels.

3. The displacement measurement system according to claim 1 or 2.

4. The displacement amount measuring device is In the determination process, it is determined whether the analysis region includes a missing region based on a standard deviation of the amount of displacement for each pixel in the analysis region.

3. The displacement measurement system according to claim 1 or 2.

5. A displacement amount measurement program for measuring an amount of displacement in an in-plane direction of a surface of a measurement object by using a two-dimensional image obtained by capturing a two-dimensional grid pattern placed on the measurement object, a pixel-by-pixel displacement amount calculation process for calculating a displacement amount for each pixel in an analysis region including the two-dimensional grid pattern in the two-dimensional image; and determining whether or not the analysis region includes a missing region based on the variation in the amount of displacement for each pixel. Displacement measurement method.

6. A displacement amount measuring method for measuring an amount of displacement in an in-plane direction of a surface of a measurement object using a two-dimensional image obtained by capturing a two-dimensional grid pattern placed on the measurement object, comprising: a pixel-by-pixel displacement amount calculation process for calculating a displacement amount for each pixel in an analysis region including the two-dimensional grid pattern in the two-dimensional image; and a determination process for determining whether or not the analysis region includes a missing region based on the variation in the amount of displacement for each pixel. Displacement measurement method.

7. A displacement amount measuring device that measures an amount of displacement in an in-plane direction of a surface of a measurement object by using a two-dimensional image obtained by capturing a two-dimensional grid pattern placed on the measurement object, a pixel-by-pixel displacement amount calculation process for calculating a displacement amount for each pixel in an analysis region including the two-dimensional grid pattern in the two-dimensional image; and executing a determination process of determining whether or not the analysis region includes a missing region based on the variation in the displacement amount for each pixel. Displacement measuring device.

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