Validation method for optical measuring system

Abstract

To validate displacement or deformation of an object measured by an optical measuring apparatus.SOLUTION: A test body 9 is placed on a testing device (table) 14 displaceable in a predetermined direction, and also each of markers 10a, 10b is supported by the test body 9. In a state before the test body 9 is displaced, each of positions of the markers 10a, 10b is detected by a detector 11, and an initial position of each of the markers 10a, 10b is obtained. In a state in which the testing device 14 is displaced in the predetermined direction, each of the positions of the markers 10a, 10b is detected by the detector 11, and a displacement magnitude from the initial position of each of the markers 10a, 10b is calculated. An error in a displacement magnitude of the remaining markers 10b with respect to the displacement magnitude of a reference marker 10a which is any one of the plurality of markers 10a, 10b is calculated, and on the basis of the error, the displacement or deformation of the test body 9 measured by a measuring system 13 is validated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for validating an optical measurement system, for example for measuring the displacement or deformation of an object. [Background technology]

[0002] Optical measurement systems called motion capture systems have been known for some time as devices for measuring the movements of people and objects such as automobiles, building materials, and buildings, for example, as described in Japanese Patent Laid-Open Publication No. 10-74249. In optical measurement systems, markers that are supported at multiple points on the surface of an object to be measured and that reflect or emit light such as infrared light are detected by a detection device such as a camera, and the movement (displacement or deformation) of the object is measured by determining the deviation of each of the positions of the markers detected by the detection device from their initial positions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-74249 Summary of the Invention [Problem to be solved by the invention]

[0004] When using optical measurement systems, it is important to know (verify) how accurately they are able to measure the displacement or deformation of an object to ensure the test results are reliable.

[0005] For example, when a camera is used as a detection device, a convex lens that becomes thinner from the center to the edge is usually used. Therefore, the image captured by the camera has distortions such as volume anamorphism, in which the subject stretches toward the edge. Such distortions may affect the accuracy and variability of the measurement of the displacement or deformation of the object. Such problems become more noticeable when measuring large objects such as building materials and buildings.

[0006] In view of the above-mentioned circumstances, an object of the present invention is to confirm the validity of the displacement or deformation of an object measured by an optical measurement system. [Means for solving the problem]

[0007] A measurement system for an object that is the subject of a method for validating an optical measurement system according to one aspect of the present invention includes: A plurality of markers each supported on an object and capable of reflecting or emitting light; a detection device for detecting the position of each of the markers; Equipped with The displacement or deformation of the object is measured by determining the deviation of each of the positions of the markers detected by the detection device from their initial positions.

[0008] A method for validating an optical measurement system according to one aspect of the present invention includes: an object is placed on a testing device that is displaceable in a predetermined direction, and each of the markers is supported on the object; Detecting the positions of the markers by the detection device in a state before displacing the object, and acquiring initial positions of the markers; detecting the positions of the markers by the detection device while displacing the testing device in a predetermined direction, and determining the amount of displacement of each of the markers from an initial position; The error between the displacement amount of the remaining markers and the displacement amount of a reference marker, which is any one of the multiple markers, is determined, and the validity of the displacement or deformation of the object measured by the measurement system is confirmed based on the error.

[0009] In a method for validating an optical measurement system according to one aspect of the present invention, the reference marker may be a marker among the markers that is positioned near a central position of a range that can be detected by the detection device.

[0010] In a method for validating an optical measurement system according to one aspect of the present invention, the detection device may include a plurality of cameras. In this case, the light can be infrared light (infrared rays). Alternatively, the light may be ultraviolet light (ultraviolet light) or visible light.

[0011] A method for validating an optical measurement system according to one aspect of the present invention may include a step of determining whether an error in the displacement amount of the remaining markers relative to the displacement amount of the reference marker is equal to or less than a predetermined threshold value.

[0012] A method for validating an optical measurement system according to one embodiment of the present invention may include a step of calculating a z-value of the error in the displacement amount of the remaining markers relative to the displacement amount of the reference marker, and determining whether the z-value is below a predetermined threshold value.

[0013] When various performance tests such as wind pressure resistance tests and interlayer displacement tests are performed on building materials such as curtain walls and opening devices using an optical measurement system that is the subject of the method for verifying the validity of an optical measurement system according to one aspect of the present invention, the building materials that are the subject of the various performance tests can be used as the object. In other words, the object used in performing the test to verify the validity can also be used as is for various performance tests such as wind pressure resistance tests and interlayer displacement tests. Alternatively, the object used in carrying out the test to confirm the validity may be a different object from the building material that is the subject of the various performance tests.

[0014] Alternatively, the optical measurement system that is the subject of the method for verifying the validity of an optical measurement system according to one aspect of the present invention can be used to measure the movements of a person or an object such as an automobile. Again, the test object for validation purposes may be the object being measured, such as a person or a car, or may be something else.

[0015] The present invention can be carried out by appropriately combining the above-mentioned respective aspects as long as no contradiction occurs. Effect of the Invention

[0016] According to a method for verifying the validity of an optical measurement system according to one aspect of the present invention, it is possible to verify the validity of the displacement or deformation of an object measured by a non-contact optical measurement system. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic perspective view showing an optical measurement system according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic plan view showing an optical measurement system according to the first example. [Diagram 3] FIG. 3 is a front view showing a manner in which the marker is attached. [Figure 4] FIG. 4 is a flowchart showing a procedure for confirming the validity of the displacement or deformation of a test piece measured by an optical measurement system. [Diagram 5] FIG. 5 is a side view showing another example of the installation mode of the camera. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] [Example 1] A first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 4. In this embodiment, the present invention is applied to a measurement system 13 that measures the displacement or deformation of a test specimen by emitting infrared light (infrared rays) from cameras 12a and 12b constituting a detection device 11 to a plurality of reflective markers 10a and 10b supported on the test specimen such as a skeleton or curtain wall, detecting the light reflected by each of the markers 10a and 10b with the cameras 12a and 12b, and acquiring the positions of each of the markers 10a and 10b at that time. That is, the measurement system 13 has basically the same configuration as an optical motion capture system.

[0019] In the following description, the up-down direction refers to the direction in which gravity acts, as indicated by the arrow X in FIG. 1, the front-to-back direction refers to the direction in which the test specimen 9 moves away from the cameras 12a and 12b, as indicated by the arrow Y in FIG. 1, and the left-to-right direction refers to the direction perpendicular to the up-down direction and the front-to-back direction, as indicated by the arrow Z in FIG. 1.

[0020] In this example, a rectangular flat gypsum board is used as the test specimen 9. The test specimen 9 is placed on the upper surface of a table 14 constituting a test device that can independently perform displacement in the front-rear direction, left-right direction, and up-down direction, as well as displacement in a rotational direction about an axis extending in each direction. The displacement in each direction by the test device is mechanically or electrically controlled with high precision according to the required measurement precision.

[0021] It is preferable that the test specimen 9 has a low emissivity and hardly reflects infrared light. This is not limited to the plaster board in this example, but is also applicable to other objects.

[0022] Each of the markers 10a and 10b has a spherical surface that reflects infrared light. That is, each of the markers 10a and 10b is made of a material that reflects infrared light (having a higher emissivity than gypsum), or the spherical surface is covered with a material that reflects infrared light.

[0023] Each of the markers 10a, 10b is supported at a plurality of locations (25 locations in the illustrated example) at equal intervals in the vertical and horizontal directions on the surface (front side) of the test body 9 that faces the cameras 12a, 12b. That is, each of the markers 10a, 10b is supported in a grid pattern on the surface of the test body 9. Also, each of the markers 10a, 10b is supported and fixed to the surface of the test body 9 by adhesive, screw fastening, or the like so as not to accidentally shift or move.

[0024] The detection device 11 detects the positions of the markers 10a and 10b. In this example, the detection device 11 includes a plurality of cameras 12a and 12b. Each of the cameras 12a and 12b is installed in a portion that does not move during measurement, and captures the test object 9, which is the subject of the image capture, from a different direction.

[0025] Each of the cameras 12a and 12b has a light emitting unit that emits infrared light and a detection unit that detects reflected infrared light. That is, the cameras 12a and 12b emit infrared light from the light emitting unit toward the test piece 9, and detect the reflected light reflected by the markers 10a and 10b by the detection unit.

[0026] Specifically, in this example, the detection device 11 includes two cameras 12a and 12b. The cameras 12a and 12b are disposed forward of the test object 9, spaced apart from each other in the left-right direction, and are installed so that the entire test object 9 is included in each of the angles of view as large as possible.

[0027] The angle θ between the lines of sight of the two cameras 12a and 12b, i.e., the lines connecting the viewpoints and the gaze points, is appropriately determined depending on the performance of the cameras 12a and 12b, the size of the test object 9, or the distance between the test object 9 and the cameras 12a and 12b. For example, the angle θ can be set to 15 degrees or more and 120 degrees or less, preferably 45 degrees or more and 90 degrees or less, and more preferably 70 degrees or more and 80 degrees or less.

[0028] Next, a test method for confirming the validity of the displacement or deformation of the test piece 9 measured by the measurement system 13 will be described.

[0029] First, before displacing the test object 9 placed on the table 14 of the testing device, the detection device 11 acquires the positions (three-dimensional coordinates) of the markers 10a, 10b supported on the surface of the test object 9. That is, infrared light is emitted from the light emitting units of the two cameras 12a, 12b toward the surface of the test object 9, and the reflected light reflected by the markers 10a, 10b supported on the surface of the test object 9 is detected by the detection units of the cameras 12a, 12b. Then, based on the detection results of the two cameras 12a, 12b, the positions of the markers 10a, 10b are obtained by the principle of triangulation, and the positions are set as the initial positions of the markers 10a, 10b.

[0030] Next, the table 14 is displaced in a predetermined direction, i.e., forward / backward, left / right, or rotational. Thereafter, the positions of the markers 10a, 10b supported on the surface of the test piece 9 are obtained again by the detection device 11, and the amount of displacement of the markers 10a, 10b from their initial positions is calculated. It is also possible to obtain the positions of the markers 10a, 10b while displacing the table 14 in a predetermined direction, and to calculate the amount of displacement of the markers 10a, 10b from their initial positions.

[0031] Next, the error in the amount of displacement of the remaining marker 10b relative to the amount of displacement of the reference marker 10a, which is one of the multiple markers 10a, 10b, is calculated. In this example, of the multiple markers 10a, 10b, the marker 10a supported at the center position of the surface of the test piece 9 is set as the reference marker, and the error in the amount of displacement of all the remaining markers 10b relative to the amount of displacement of the reference marker 10a is calculated.

[0032] Then, based on the error obtained as described above, the validity of the displacement or deformation of the test piece 9 measured by the measurement system 13 is evaluated (confirmed). In other words, based on the error, it is confirmed whether the measurement system 13 has the desired measurement accuracy.

[0033] In this example, the test specimen 9 is made of gypsum board. Therefore, even if the table 14 is displaced in a predetermined direction, the test specimen 9 is not displaced. Therefore, the error in the displacement amount of the remaining markers 10b relative to the displacement amount of the reference marker 10a measured by the measurement system 13 is ideally zero. However, in reality, the displacement amounts of the markers 10a and 10b measured by the measurement system 13 vary.

[0034] Therefore, in this example, first, the error (e i ) is equal to or smaller than a first threshold value (t) (|e i Determine whether |≦t.

[0035] In addition, i is a serial number given to the remaining markers 10b excluding the reference marker 10a, and e i is the error in the amount of displacement of each marker 10b. The value of the first threshold value t is appropriately set according to the accuracy required for the measurement system 13 based on the content of the test performed using the measurement system 13, etc.

[0036] If it is determined that the error in the displacement amount of any one of the remaining markers 10b relative to the displacement amount of the reference marker 10a is greater than the first threshold value (t), it is determined that the measurement system 13 does not have sufficient accuracy. In this case, the mounting positions of the markers 10a and 10b and the positions of the cameras 12a and 12b are adjusted, and then the test is performed again.

[0037] When it is determined that the error of the displacement amount of all the remaining markers 10b with respect to the displacement amount of the reference marker 10a is equal to or smaller than the first threshold value t, the z value (z i ) is a predetermined second threshold (t z ) or less.

[0038] The z value of the error of the displacement of the remaining marker 10b relative to the displacement of the reference marker 10a (z i ) is expressed by the following equation (1).

number

[0039] The error in the amount of displacement e i is expressed by the following equation (2).

number

[0040] The average value E of the errors is expressed by the following formula (3).

number

[0041] Moreover, the standard deviation s of the error is expressed by the following equation (4).

number

[0042] The z value of the error in the displacement amount of the marker 10b obtained as described above (z i ) are calculated based on the second threshold t z Whether it is less than or equal to (|z i |≦t z ) is used to evaluate the validity of the displacement or deformation of the test piece 9 measured by the measurement system 13, that is, to confirm whether the variation in the measurement accuracy of the measurement system 13 falls within a desired range.

[0043] That is, the z values ​​of the displacement errors for all the remaining markers 10b except for the reference marker 10a (z i ) is the second threshold t z If it is equal to or less than this, it can be determined that the variation of the measurement system 13 falls within a desired range.

[0044] On the other hand, if any one of the remaining markers 10b other than the reference marker 10a has a z value of the displacement error (z i ) is the second threshold t z If the difference is larger than , it is determined that the variation in the measurement accuracy of the measurement system 13 is not within the desired range. In this case, the mounting positions of the markers 10a, 10b and the positions of the cameras 12a, 12b are adjusted, and then the test is performed again.

[0045] In addition, the second threshold t z The value of is set appropriately according to the performance required of measurement system 13 based on the content of the test to be performed using measurement system 13, but can be smaller than 3, for example, and is preferably 2 or less.

[0046] As described above, according to this example, it is possible to confirm (evaluate) the validity of the displacement amount of the markers 10a, 10b measured by the optical measuring system 13, that is, to confirm whether the measuring system 13 has the desired performance. Then, various performance tests such as a wind pressure resistance test and an inter-story displacement test can be performed using the measuring system 13 whose performance has been accurately grasped, so that the reliability of the test results can be sufficiently ensured.

[0047] In particular, in this example, the optical measurement system 13 includes cameras 12a and 12b. The cameras 12a and 12b use convex lenses that become thinner from the center toward the edges. For this reason, images captured by the cameras 12a and 12b suffer from distortions such as volume anamorphism, in which the subject appears stretched toward the edges.

[0048] When various performance tests are performed using the optical measurement system 13, in order to minimize the number of cameras 12a and 12b used, almost the entire angle of view of each of the cameras 12a and 12b is used to measure the displacement or deformation of the test specimen. For this reason, distortion of the images acquired by the cameras 12a and 12b is likely to affect the accuracy and variability of the measurement of the displacement or deformation of the test specimen by the measurement system 13. Therefore, when using an optical measurement system 13 equipped with the cameras 12a and 12b, it is important to confirm in advance the validity of the displacement or deformation of the test specimen 9 measured by the measurement system 13 by the method of this example as described above.

[0049] It is preferable that the evaluation test for confirming (evaluating) the validity of the displacement or deformation of the test specimen 9 measured by the measurement system 13 and various performance tests such as the wind pressure resistance test and the inter-story displacement test are performed in the same environment after the evaluation test is performed, without moving the test specimen 9 or re-installing the markers 10a, 10b and the detection device 11. In this case, the test specimen 9 can be composed of the test specimen that is the subject of the performance test. However, as long as the results of the evaluation test can be effectively utilized, the evaluation test and the performance test can be performed in different environments.

[0050] In an evaluation test for confirming the validity of the amount of displacement of the markers 10a, 10b measured by the measurement system 13, the amount or angle of displacement of the test body 9 in each of the forward / backward, left / right, up / down, and rotational directions is appropriately determined according to the content of the performance test to be performed. Therefore, an evaluation test can be performed for each of the forward / backward, left / right, up / down, and rotational directions.

[0051] In this example, the test specimen 9 is made of a rectangular flat gypsum board, but when the present invention is implemented, the test specimen is not particularly limited and can be made of, for example, a building frame, a curtain wall, or an opening device such as a sash or a door. In addition, as long as the results of the evaluation test for confirming validity can be effectively utilized, the test specimen used in the evaluation test can be different from the test specimen that is the subject of the performance test.

[0052] In this example, reflective markers that reflect infrared light are used as the markers 10a and 10b, but when implementing the present invention, active markers that emit infrared light can also be used as the markers. Alternatively, a measurement system can be used in which a camera emits visible light and the camera detects the visible light reflected by a marker supported on the test piece, or the camera detects the visible light emitted by a marker supported on the test piece.

[0053] In this example, a detection device 11 is used in which two cameras 12a, 12b are arranged in front of the test object 9 and spaced apart from each other in the left-right direction. However, as shown in Fig. 5, the detection device 11 can also be arranged in which two cameras 12a, 12b are arranged in front of the test object 9 and spaced apart from each other in the up-down direction. Also, in this example, the detection device 11 is provided with two cameras 12a, 12b, but when implementing the present invention, the detection device can also be provided with three or more cameras.

[0054] Alternatively, when implementing the present invention, the detection device is not limited to one equipped with a camera, and may have any structure as long as it can detect the position of the marker by detecting the light reflected or emitted by the marker. Specifically, for example, the detection device may be a laser measuring device that irradiates the marker with laser light and detects the distance to the marker based on the light reflected from the marker.

[0055] Furthermore, when a large test object is to be tested, the object can be divided into a plurality of regions, and a plurality of markers can be provided in each region, with a detection device being provided for detecting the markers.

[0056] In this example, the error in the displacement amount of the remaining markers 10b relative to the displacement amount of the reference marker 10a and the z-value of the error are obtained to confirm (evaluate) the validity of the displacement or deformation of the test specimen 9 measured by the measurement system 13. However, when implementing the present invention, the method for confirming the validity of the displacement or deformation of the test specimen measured by the measurement system is not particularly limited, and can also be performed using, for example, the standard deviation or the average value of the errors.

[0057] In this example, the method for validating an optical measurement system according to one embodiment of the present invention has been described as being performed to grasp the performance of the optical measurement system 13 in preparation for use in various performance tests, such as wind pressure tests and story displacement tests, of test bodies such as buildings and curtain walls. However, the method for validating an optical measurement system according to one embodiment of the present invention is not limited to this example, and can be performed to grasp the performance of the measurement system in preparation for measuring the movement of a person or the movement of an object such as an automobile, building material, or building using the optical measurement system. [Explanation of symbols]

[0058] 9 Test specimen (panel) 10a, 10b markers 11 Detection device 12a, 12b Camera 13 Measurement System 14 Tables

Claims

1. A plurality of markers each supported on an object and capable of reflecting or emitting light; a detection device for detecting the position of each of the markers; Equipped with A method for validating an optical measurement system, comprising: determining a deviation of each of the positions of the markers detected by the detection device from an initial position to measure a displacement or deformation of the object, the method comprising: an object is placed on a testing device that is displaceable in a predetermined direction, and each of the markers is supported on the object; Detecting the positions of the markers by the detection device in a state before displacing the object, and acquiring initial positions of the markers; detecting the positions of the markers by the detection device while displacing the testing device in a predetermined direction, and determining the amount of displacement of each of the markers from an initial position; determining an error between the amount of displacement of a reference marker, which is any one of the plurality of markers, and the remaining markers, and confirming the validity of the displacement or deformation of the object measured by the optical measurement system based on the error; How to validate optical measurement systems.

2. The reference marker is a marker that is disposed near a central position of a range that can be detected by the detection device among the markers.

2. A method for validating an optical measurement system according to claim 1.

3. The detection device comprises a plurality of cameras.

2. A method for validating an optical measurement system according to claim 1.

4. The light is infrared light.

4. A method for validating an optical measurement system according to claim 3.

5. The method further includes a step of determining whether an error in the displacement amount of the remaining markers relative to the displacement amount of the reference marker is equal to or smaller than a predetermined threshold value.

2. A method for validating an optical measurement system according to claim 1.

6. determining a z-value of an error of the displacement amount of the remaining markers relative to the displacement amount of the reference marker, and determining whether the z-value is equal to or smaller than a predetermined threshold value; 2. A method for validating an optical measurement system according to claim 1.

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