Correction parameter calculation method and device, displacement calculation method and device

Abstract

The correction parameter calculation method includes: a first acquisition step (S11) of acquiring image data obtained by imaging an object (50) on which a marker (60) capable of detecting a specific coordinate is mounted from an imaging device (10); a second acquisition step (S21) of acquiring displacement direction information indicating a direction of displacement intersecting an imaging surface of the imaging device among directions of displacement of the object; a detection step (S12) of detecting the specific coordinate based on the marker (60) included in the image data; an estimation step (S13) of estimating a position of the imaging device (10) based on the detection result; a distance calculation step (S14) of calculating distance data from the imaging device (10) to the object (50) based on the position of the imaging device (10); and a parameter calculation step (S15) of calculating a correction parameter for converting a pixel displacement amount of the object (50) into an actual size displacement amount using the distance data and the displacement direction information.

Description

TECHNICAL FIELD

[0001] The present application relates to a correction parameter calculation method, a displacement amount calculation method, a correction parameter calculation device, and a displacement amount calculation device for calculating a correction parameter for measuring an actual size displacement amount using an image, the actual size displacement amount being an actual size value representing displacement of a subject. BACKGROUND

[0002] In the past, a camera device has been disclosed that is capable of using image data captured by a camera of a subject and a distance measurement value to the subject measured by a distance measuring device such as a laser range finder, instead of contact measuring a state of the surroundings of the subject (see Patent Document 1). The state, for example, is a deflection amount of a bridge in the case where the subject is a bridge.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENT

[0005] Patent Document 1: Japanese Patent No. 5281610 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] Incidentally, in displacement measurement using an image, it is desirable to be able to easily measure an actual size value of a displacement amount. In the camera device of Patent Document 1 described above, a distance measuring device is required in addition to the camera, and it is difficult to say that an actual size value of a displacement amount can be easily measured.

[0008] Therefore, the present application relates to a correction parameter calculation method and the like that is capable of easily calculating a correction parameter for converting a displacement amount into an actual size value in displacement measurement using an image.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] A correction parameter calculation method according to one aspect of the present invention is a correction parameter calculation method for calculating a correction parameter used for measuring an actual size displacement amount of an object using an image, the actual size displacement amount being an actual size value indicating a displacement of the object, the correction parameter calculation method including: a first acquisition step of acquiring first image data obtained by imaging the object on which a marker capable of detecting a specific coordinate is mounted from an imaging device; a second acquisition step of acquiring displacement direction information indicating a direction of displacement that intersects with an imaging surface of the imaging device among directions of displacement of the object; a detection step of detecting the specific coordinate based on the marker included in the first image data; an estimation step of estimating a position of the imaging device based on a result of the detection of the specific coordinate and a parameter of the imaging device; a distance calculation step of calculating distance data from the imaging device to the object based on the specific coordinate and the position of the imaging device; and a parameter calculation step of calculating the correction parameter using the distance data and the displacement direction information, the correction parameter being used for converting a pixel displacement amount of a measurement point of the object in two or more second image data imaged by the imaging device at different points in time into the actual size displacement amount.

[0011] A displacement amount calculation method according to one aspect of the present invention includes: a third acquisition step of acquiring the correction parameter calculated using the correction parameter calculation method; a fourth acquisition step of acquiring the two or more second image data; and a conversion step of converting the pixel displacement amount in the two or more second image data into the actual size displacement amount based on the correction parameter.

[0012] A correction parameter calculation device according to one aspect of the present invention is a correction parameter calculation device that calculates a correction parameter used for measuring an actual size displacement amount using an image, the actual size displacement amount being an actual size value indicating a displacement of a subject, the correction parameter calculation device including: a first acquisition unit that acquires first image data obtained by imaging the subject on which a marker capable of detecting a specific coordinate is mounted; a second acquisition unit that acquires displacement direction information indicating a direction of displacement that intersects with an imaging surface of an imaging device among directions of displacement of the subject; a position detection unit that detects the specific coordinate based on the marker included in the first image data; a position estimation unit that estimates a position of the imaging device based on a result of the detection of the specific coordinate and a parameter of the imaging device; a distance calculation unit that calculates distance data from the imaging device to the subject based on the specific coordinate and the position of the imaging device; and a parameter calculation unit that calculates the correction parameter using the distance data and the displacement direction information, the correction parameter being used to convert a pixel displacement amount of a measurement point of the subject in two or more second image data imaged by the imaging device at different points in time into an actual size displacement amount.

[0013] A displacement amount calculation device according to one aspect of the present invention includes: a third acquisition unit that acquires the correction parameter calculated by the correction parameter calculation device; a fourth acquisition unit that acquires the two or more second image data; and a conversion unit that converts the pixel displacement amount in the two or more second image data into the actual size displacement amount based on the correction parameter.

[0014] A correction parameter calculation method according to an aspect of the present invention calculates a correction parameter used for measuring an actual size displacement amount using an image, the actual size displacement amount being an actual size value indicating a displacement of a subject, the correction parameter calculation method including: a first acquisition step of acquiring first image data obtained by imaging the subject on which a marker capable of detecting a specific coordinate is mounted, from an imaging device; a second acquisition step of acquiring displacement direction information indicating a direction of displacement intersecting an imaging surface of the imaging device among directions of displacement of the subject; a detection step of detecting the specific coordinate based on the marker included in the first image data and inferring a posture of the imaging device; an inference step of inferring a position of the imaging device based on a result of detection of the specific coordinate and the posture and a parameter of the imaging device; a distance calculation step of calculating distance data from the imaging device to the subject based on the specific coordinate and the position of the imaging device; and a parameter calculation step of calculating the correction parameter using the distance data and the displacement direction information, the correction parameter being used to convert a pixel displacement amount of a measurement point of the subject in two or more second image data imaged by the imaging device at different points in time into an actual size displacement amount.

[0015] Effects of Invention

[0016] According to the correction parameter calculation method and the like according to an aspect of the present invention, a correction parameter used to convert a displacement amount into an actual size value can be easily calculated in displacement measurement using an image. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a diagram showing a schematic configuration of a displacement measurement system according to an embodiment.

[0018] Figure 2 is a block diagram showing a functional configuration of a displacement measurement system according to an embodiment.

[0019] Figure 3 is a diagram showing an example of a marker attached to a subject according to an embodiment.

[0020] Figure 4 is a flowchart showing an operation of a displacement measurement system according to an embodiment.

[0021] Figure 5 is a diagram for explaining a detection result of a position detection unit according to an embodiment.

[0022] Figure 6 is a diagram for explaining an actual size conversion method of a displacement according to an embodiment.

[0023] Figure 7is a flowchart showing the operation of a displacement measurement system according to a modification of the embodiment.

[0024] Figure 8A is a first diagram for explaining displacement correction according to a modification of the embodiment, taking into account the direction of displacement.

[0025] Figure 8B is a second diagram for explaining displacement correction according to a modification of the embodiment, taking into account the direction of displacement.

[0026] Figure 9 is a diagram for explaining a method of converting the actual size of displacement according to a modification of the embodiment. DETAILED DESCRIPTION

[0027] (History of the Invention)

[0028] In displacement measurement using an image, the amount of displacement (the number of pixels) on the image can be measured from the image, but the actual size value of the displacement cannot be measured. Therefore, the distance from the camera to the object is obtained, and the amount of displacement on the image is converted into the actual size value using the obtained distance. For example, in the camera device described in Patent Literature 1, a configuration is disclosed in which a distance measurement device that measures the distance to the object is provided. Therefore, at the measurement site, it is necessary to provide both the camera and the distance measurement device. Furthermore, in order to accurately measure the displacement of the object, it is necessary to arrange the camera and the distance measurement device so that the optical axis of the camera is parallel to the optical axis of the distance measurement device.

[0029] In addition, as another method of measuring the actual size value of the displacement, there is a method in which, for an object on which displacement measurement is performed, an image of a specific portion having a known length is imaged, and a correction value for converting one pixel into the actual size value is calculated based on the amount of displacement on the image of the specific portion and the known length. However, in this method, it is necessary to previously obtain the length of the specific portion. In addition, in a case where the length of the specific portion is not known, the measurement of the actual size value of the displacement cannot be performed.

[0030] As described above, in the conventional method, it is necessary to prepare a distance measurement device for measuring the distance, or since it is necessary to previously obtain the distance of the specific portion, the actual size value of the displacement of the object cannot be easily measured.

[0031] Therefore, the inventors of the present application have intensively studied a correction parameter calculation method and the like by which the amount of displacement can be easily converted into the actual size value in displacement measurement using an image, and have made the correction parameter calculation method and the like described below.

[0032] A correction parameter calculation method according to one aspect of the present invention is a correction parameter calculation method for calculating a correction parameter used for measuring an actual size displacement amount of an object using an image, the actual size displacement amount being an actual size value indicating a displacement of the object, the correction parameter calculation method including: a first acquisition step of acquiring first image data obtained by imaging the object on which a marker capable of detecting a specific coordinate is mounted from an imaging device; a detection step of detecting the specific coordinate based on the marker included in the first image data; an estimation step of estimating a position of the imaging device based on a result of the detection of the specific coordinate and a parameter of the imaging device; a distance calculation step of calculating distance data from the imaging device to the object based on the specific coordinate and the position of the imaging device; and a parameter calculation step of calculating the correction parameter using the distance data, the correction parameter being used to convert a pixel displacement amount of a measurement point of the object in two or more second image data imaged by the imaging device at different points in time into an actual size displacement amount.

[0033] Thus, by using the correction parameter calculation method, it is possible to calculate the correction parameter used to convert the displacement amount into the actual size value only by imaging the object including the marker by the imaging device. For example, it is possible to calculate the correction parameter without using a distance measuring device that measures the distance to the object or without previously acquiring the length of a specific portion of the object. Thus, according to the correction parameter calculation method, it is possible to easily perform the correction parameter used to convert the displacement amount into the actual size value in the displacement measurement using the image.

[0034] Further, for example, it can also be that the correction parameter calculation method further includes a second acquisition step of acquiring displacement direction information indicating a direction of the displacement of the object; and the parameter calculation step calculates the correction parameter using the displacement direction information.

[0035] Thus, according to the correction parameter calculation method, by using the displacement direction information, it is possible to calculate the correction value that can convert the pixel displacement amount in the two-dimensional space (projection plane of the imaging device) into the actual size displacement amount in the three-dimensional space. Thus, according to the correction parameter calculation method, it is possible to more accurately measure the actual size value of the displacement.

[0036] Further, for example, it can also be that the marker is mounted on a planar portion of the object; and the direction indicated by the displacement direction information is defined with respect to the planar portion.

[0037] Thus, it is possible to correctly acquire the displacement direction regardless of the positional relationship between the imaging device and the object.

[0038] Further, for example, it can also be that the marker is a QR code (registered trademark); and the displacement direction information is stored in the QR code.

[0039] Thus, according to the correction parameter calculation method, only by acquiring the displacement direction information stored in the QR code, the actual size value of the displacement can be measured with higher precision. Thus, according to the correction parameter calculation method, the correction parameter that can calculate the actual size value of the displacement with good precision can be calculated more simply.

[0040] The displacement amount calculation method according to one aspect of the present application includes: a third acquisition step of acquiring the correction parameter calculated using the correction parameter calculation method described above; a fourth acquisition step of acquiring the two or more second image data described above; and a conversion step of converting the pixel displacement amount in the two or more second image data described above into the actual size displacement amount based on the correction parameter.

[0041] Thus, since the actual size displacement amount can be measured using the correction parameter calculated by the correction parameter calculation method described above, the actual size displacement amount of the object can be calculated simply.

[0042] The correction parameter calculation device according to one aspect of the present application is a correction parameter calculation device that calculates a correction parameter used for measuring an actual size displacement amount using an image, the actual size displacement amount indicating an actual size value of displacement of movement of an object, the correction parameter calculation device including: a first acquisition unit that acquires first image data obtained by imaging the object on which a marker capable of detecting a specific coordinate is mounted from an imaging device; a position detection unit that detects the specific coordinate based on the marker included in the first image data; a position estimation unit that estimates a position of the imaging device based on a detection result of the specific coordinate and a parameter of the imaging device; a distance calculation unit that calculates distance data from the imaging device to the object based on the specific coordinate and the position of the imaging device; and a parameter calculation unit that calculates the correction parameter using the distance data, the correction parameter being used for converting a pixel displacement amount of a measurement point of the object in two or more second image data imaged by the imaging device at different points in time into an actual size displacement amount.

[0043] Thus, the same effects as those of the correction parameter calculation method described above are exerted.

[0044] The displacement amount calculation device according to one aspect of the present application includes: a second acquisition unit that acquires the correction parameter calculated using the correction parameter calculation device described in Technical Solution 6; a third acquisition unit that acquires the two or more second image data described above; and a conversion unit that converts the pixel displacement amount in the two or more second image data described above into the actual size displacement amount based on the correction parameter.

[0045] Thus, the same effects as those of the displacement amount calculation method described above are exerted.

[0046] In addition, these global or specific technical solutions can also be implemented by a system, a method, an integrated circuit, a computer program or a recording medium readable by a computer such as a CD-ROM, or any combination of the system, the method, the integrated circuit, the computer program and the recording medium. The program can be pre-stored in the recording medium and supplied to the recording medium via a wide area communication network including the Internet.

[0047] Hereinafter, the embodiments will be described in detail with reference to the drawings. Figure 1 Hereinafter, the embodiments will be described in detail with reference to the drawings.

[0048] In addition, the embodiments and the modified examples described below are indicative of inclusive or specific examples. Thus, the numerical values, shapes, materials, constituent elements, arrangement positions and connection modes of the constituent elements, steps, order of the steps and the like indicated in the embodiments and the modified examples below are examples and are not intended to limit the present application. Furthermore, with respect to the constituent elements in the embodiments below that are not described in the independent claims which represent the most general concept of the present application, the constituent elements are described as arbitrary constituent elements.

[0049] In addition, each drawing is a schematic view and is not necessarily strictly illustrated. Furthermore, in each drawing, the same reference numerals are given to substantially the same constituent elements and repeated description or simplified description is omitted.

[0050] Furthermore, in the present specification, the relational terms and numerical values between the elements indicating the relationship are not only expressions in the strict sense, but also expressions in a range substantially equivalent thereto, for example, expressions including a difference of several percent or so.

[0051] Furthermore, in the specification below, the image is a still image, but can also be a moving image.

[0052] (Embodiment)

[0053] Hereinafter, the embodiments will be described in detail with reference to the drawings. Figures 1-6 Hereinafter, the embodiments will be described in detail with reference to the drawings.

[0054] [1. Configuration of displacement measurement system]

[0055] First, with reference to FIG. 1 and FIG. 2, a displacement measurement system 1 provided with a correction parameter calculation unit 110 that executes a correction parameter calculation method relating to the present embodiment will be described. Figure 1 and Figure 2 First, with reference to FIG. 1 and FIG. 2, a displacement measurement system 1 provided with a correction parameter calculation unit 110 that executes a correction parameter calculation method relating to the present embodiment will be described. Figure 1 is a diagram showing the schematic configuration of the displacement measurement system 1 relating to the present embodiment. Figure 2 is a block diagram showing the functional configuration of the displacement measurement system 1 relating to the present embodiment.

[0056] As Figure 1 indicated, a displacement measurement system 1 relating to the present embodiment is an information processing system that measures an actual size value of displacement of an object 50 using one camera device. The object 50 is an object of measurement of displacement, and is, for example, a device such as a motor that displaces (vibrates, etc.) when in operation, but is not limited thereto, and can be, for example, a structure such as an infrastructure structure that displaces (deforms, etc.) due to stress from the outside. The infrastructure structure can be, for example, a bridge on which a vehicle such as an automobile or a railway travels. In addition, in the displacement in the present specification, not only vibration of the object 50 but also deformation and change in position of the object 50 are included. The displacement can be said to represent movement of the object.

[0057] Further, one or more markers 60 are attached (fixed) to the surface of the object 50 in the present application. The marker 60 is not particularly limited as long as its size is known and, for example, can be detected as four or more coordinates, and can be, for example, a QR (Quick Response) code (registered trademark), an AR marker, a checkerboard marker, or the like. Hereinafter, an example in which the marker 60 is a QR code will be described. In addition, each of the four or more coordinates is an example of a specific coordinate.

[0058] As Figure 1 and Figure 2 indicated, the displacement measurement system 1 includes a camera device 10, a displacement measurement device 20, an output device 30, and an input device 40.

[0059] The camera device 10 images an image used to measure displacement of the object 50. The image imaged by the camera device 10 is used to detect an amount of displacement (number of pixels) on the image with respect to displacement of the object 50. In addition, the amount of displacement on the image with respect to displacement of the object 50 will also be referred to as a pixel displacement amount hereinafter. Further, the image can be used to calculate a correction value described later.

[0060] The camera device 10 images in a manner that at least one marker 60 is imaged. The camera device 10 is, for example, disposed at a position at which at least one marker 60 is imaged.

[0061] The camera device 10 is, for example, a monochrome camera. In other words, the image is, for example, a monochrome image. In addition, the camera device 10 is not limited to being a monochrome camera, and can be a color camera. The camera device 10 is, for example, a digital camera or a digital still camera having an image sensor. In addition, the camera device 10 is an example of a taking device.

[0062] The displacement measuring device 20 is an information processing device that calculates a correction value for converting a pixel displacement amount on an image into an actual size displacement amount indicating an actual size value of a displacement of the object 50, based on image data acquired from the imaging device 10, and outputs information of the actual size displacement amount of the object 50 using the calculated correction value. The displacement measuring device 20 can also be, for example, a server device. The displacement measuring device 20 has a correction parameter calculating section 110, a displacement detecting section 120, and a displacement amount calculating section 130.

[0063] The correction parameter calculating section 110 calculates a correction value for converting a pixel displacement amount into an actual size displacement amount, based on image data acquired from the imaging device 10. The correction parameter calculating section 110 has an acquisition section 111, a position detecting section 112, a position inferring section 113, a distance calculating section 114, and a correction value calculating section 115.

[0064] The acquisition section 111 acquires image data indicating an image from the imaging device 10. The acquisition section 111 is configured including a communication interface (communication circuit) communicably connected to the imaging device 10 via wireless communication or wired communication. The acquisition section 111 is an example of a first acquisition section.

[0065] The position detecting section 112 detects the marker 60 from the image data, and detects a specific coordinate based on the detected marker 60. The position detecting section 112 detects a plurality of specific coordinates (for example, four or more coordinates) based on the marker 60. The specific coordinates are used to infer the position of the imaging device 10. The specific coordinates can be set to four or more from the viewpoint of improving the accuracy of the inference of the position of the imaging device 10. Further, the coordinates are three-dimensional coordinates.

[0066] Further, the position inferring section 113 infers the position of the imaging device 10 based on the image data, coordinate information indicating the specific coordinates, and internal parameters of the imaging device 10. Note that the internal parameters of the imaging device 10 are assumed to be known. Further, the internal parameters include, for example, at least one of a 3-by-3 parameter matrix (cameraMatrix), a distortion coefficient (distCoeffs) of a lens, a focal distance, and the like.

[0067] The distance calculating section 114 calculates distance information (distance data) indicating a distance from the imaging device 10 to the object 50, based on a specific coordinate and position information indicating a position of the imaging device 10. The distance calculating section 114, for example, calculates a distance to each of one or more measurement points of the object 50 from the imaging device 10. The distance calculating section 114, for example, can also calculate distances to a plurality of surface points including one or more measurement points of the displacement of the object 50. Further, the distance calculating section 114 can generate a distance map in which distances from the imaging device 10 to the object 50 are arranged. Note that the number of measurement points of the object 50 is not particularly limited and can be two or more.

[0068] The correction value calculating section 115 calculates a correction value for converting a pixel displacement amount into an actual size displacement amount, based on a position of the imaging device 10, a distance from the imaging device 10 to the object 50, and an internal parameter of the imaging device 10. The calculation of the correction value by the correction value calculating section 115 will be described later. Further, the correction value calculating section 115, for example, can calculate a correction value in each of a plurality of surface points and generate a correction value map in which the calculated correction values are arranged. Note that the correction value and the correction value map are examples of a correction parameter. Further, the correction value calculating section 115 is an example of a parameter calculating section.

[0069] Note that the example in which the correction parameter calculating section 110 is built in the displacement measuring device 20 is described, but the present technology is not limited thereto. The correction parameter calculating section 110 can be realized as a separate device. In this case, the correction parameter calculating section 110 functions as a correction parameter calculating device.

[0070] Further, the displacement measuring device 20 is an example of a displacement amount calculating device.

[0071] The displacement detecting section 120 detects a pixel displacement amount (pixel number) on an image corresponding to the displacement of the object 50, based on two or more pieces of image data imaged by the imaging device 10. The displacement detecting section 120, for example, detects a pixel displacement amount for each measurement point.

[0072] The displacement amount calculating section 130 calculates an actual size displacement amount of the object 50 by converting a pixel displacement amount into an actual size displacement amount based on the pixel displacement amount and correction information indicating a correction parameter. The displacement amount calculating section 130, for example, calculates an actual size displacement amount for each of a plurality of measurement points of the object 50, based on a correction value for each of the plurality of measurement points and a pixel displacement amount for each of the plurality of measurement points.

[0073] The output device 30 is a device that acquires the prompt information including the actual size displacement amount from the displacement measuring device 20 and outputs the acquired prompt information. The output device 30 is, for example, a display device that displays the prompt information as an image. The output device 30 is a liquid crystal display or the like. The image output by the output device 30 is visually confirmed by the operator.

[0074] The output device 30 can be a device of a fixed installation type or a device possessed by a portable terminal held by the operator. The portable terminal is not particularly limited as long as it has the output device 30 and is capable of communicating with the displacement measuring device 20, and can be, for example, a smartphone or a tablet or the like. In the case where the portable terminal has the output device 30, the operator can know the actual size displacement amount by confirming the output device 30 of the portable terminal in the vicinity of the object 50. In addition, the operator is an example of a user.

[0075] The displacement measuring system 1 can also have a display device or a device that outputs sound instead of the display device as the output device 30. Furthermore, the displacement measuring system 1 can also have a device such as a projector that displays the prompt information on an object (for example, a screen) as the output device 30. Furthermore, in the case where the displacement measuring device 20 is configured at a remote location, the displacement measuring device 20 and the output device 30 can also be connected via a network.

[0076] The input device 40 is a user interface that receives the prescribed information in the measurement of the displacement from the operator. The input device 40 can receive, for example, information used to calculate the correction value from the operator, can receive information about the displacement direction of the object 50, and can receive information about the approximate position of the imaging device 10. Furthermore, the input device 40 can also receive the input of the prescribed information by voice. In addition, the approximate position can be an estimated value of the setting position of the imaging device 10.

[0077] The input device 40 is implemented by a hardware key (hardware button), a slide switch, a touch panel, or the like. The input device 40 can be a device of a fixed installation type or a device possessed by a portable terminal held by the operator.

[0078] Here, the mark 60 attached to the object 50 will be described with reference to Figure 3 Figure 3 is a diagram illustrating an example of the mark 60 attached to the object 50a in the present embodiment. The mark 60 is, for example, a QR code and is attached to the surface of the object 50a. In addition, in the present embodiment, the object 50a is a rectangular parallelepiped for convenience. Figure 3

[0079] As described above, the mark 60 is attached to the object 50a. The mark 60 is, for example, a QR code. The mark 60 is attached to the surface of the object 50a. The mark 60 is attached to the surface of the object 50a in a manner such that the mark 60 is not hidden by the imaging device 10 when the imaging device 10 is set to the object 50a. Figure 3 ​​As illustrated, the object 50a has one or more markers 60a, 60b attached thereto. For example, the markers 60a, 60b are attached to mutually different surfaces of the plurality of surfaces that constitute the object 50a. The markers 60a, 60b are attached at positions that can be imaged by the imaging device 10. Further, the markers 60a, 60b can be attached to, for example, a planar portion of the object 50a.

[0080] In the case where the markers 60a and 60b are QR codes, information can not be stored in the QR codes, or information on an allowable value of displacement or the like can be stored.

[0081] The markers 60a, 60b are configured to be able to acquire coordinates (three-dimensional coordinates) of, for example, four or more positions (detection points).

[0082] Further, the markers 60a, 60b can be attached to a curved surface portion or the like of the object 50a as long as the coordinates in a three-dimensional space can be detected. Further, a plurality of markers 60a, 60b can be attached to one plane. Further, the markers 60a, 60b can each be provided in correspondence with a measurement point of the object 50a. For example, in the case where there are a plurality of measurement points of displacement of the object 50a, the markers 60a, 60b can be attached around each of the plurality of measurement points.

[0083] The markers 60a, 60b are quadrilaterals (for example, squares), but are not limited thereto, and can be, for example, polygons of five or more sides (for example, regular polygons).

[0084] [2. Action of displacement measurement system]

[0085] Next, the action of the displacement measurement system 1 will be described with reference to Figures 4-6 to FIG. 9. Figure 4 is a flowchart showing the action of the displacement measurement system 1 according to the present embodiment. Specifically, Figure 4 is a flowchart showing the action of the displacement measurement device 20. Further, Figure 4 The steps S11 to S15 shown in FIG. 9 represent the action of the correction parameter calculation section 110.

[0086] As shown in Figure 4 , the acquisition section 111 acquires image data representing an image from the imaging device 10 (S11). The image includes the marker 60. Further, the acquisition section 111 can acquire only one piece of image data in step S11 in order to calculate the correction value. Further, the acquisition section 111 can acquire two or more pieces of image data imaged at mutually different points in time in step S11 in order to measure displacement.

[0087] When acquiring multiple image data, the acquisition unit 111 outputs at least one image data to the position detection unit 112 and outputs two or more image data to the displacement detection unit 120. The acquisition unit 111 can output different image data to the position detection unit 112 and the displacement detection unit 120, or it can output at least some of the same image data. The at least one image data output to the position detection unit 112 is an example of first image data, and the two or more image data output to the displacement detection unit 120 is an example of second image data. Furthermore, step S11 is an example of the first acquisition step. Furthermore, step S11 can also be an example of the fourth acquisition step in the displacement calculation method described later. Furthermore, the acquisition unit 111 can also function as a third acquisition unit that acquires two or more second image data. Additionally, the first image data and the second image data are each image data representing an image captured under the same camera parameters.

[0088] Next, the position detection unit 112 detects the marker 60 based on image data including the marker 60, and detects specific coordinates based on the detected marker 60 (S12). For example, the position detection unit 112 detects the four corners of the marker 60, which is a QR code, and detects the coordinates of these four corners. In this way, the position detection unit 112 detects multiple coordinates in step S12. The position detection unit 112 can also be said to set multiple coordinates based on the marker 60.

[0089] Furthermore, when reading QR codes, the quadrilaterals (cut-out symbols) at the four corners are detected to determine the position and shape of the QR code. By setting the position of this automatic detection to the location of specific coordinates, the processing of determining the location of specific coordinates can be eliminated.

[0090] While referring to Figure 5 The coordinate settings performed by the position detection unit 112 are explained. Figure 5 This diagram illustrates the detection results of the position detection unit 112 in this embodiment. If we assume... Figure 5 Let the left-right direction on the paper be the x-axis, the up-down direction be the y-axis, and the perpendicular direction relative to the paper be the z-axis. In the following three-dimensional coordinates (x, y, z), "x" represents the position on the x-axis, "y" represents the position on the y-axis, and "z" represents the position on the z-axis. Furthermore, the x-axis, y-axis, and z-axis are mutually orthogonal.

[0091] like Figure 5The position detection section 112 detects the four corners of the mark 60, and sets coordinates for the detected points Q1 to Q4. The position detection section 112 sets the coordinates based on the positional relationship of the detected points Q1 to Q4. The position detection section 112 sets the coordinates based on, for example, the distances between the detected points Q1 to Q4 (e.g., the distance between the detected points Q1 and Q2). Note that the detected points Q1 to Q4 can be, for example, portions of the four corners of a square QR code. In the present embodiment, the first distance between the detected points Q1 and Q2, the second distance between the detected points Q2 and Q4, the third distance between the detected points Q4 and Q3, and the fourth distance between the detected points Q3 and Q1 are equal to each other, but are not limited thereto.

[0092] The position detection section 112 sets the coordinates of the other detected points in accordance with the positions (distances) from the detected point Q1, with the coordinates of the detected point Q1 set as (0, 0, 0). The position detection section 112 sets the coordinates of the detected point Q2 as (1, 0, 0), the coordinates of the detected point Q3 as (0, 1, 0), and the coordinates of the detected point Q4 as (1, 1, 0), because the first distance to the fourth distance are equal to each other. Note that the detected points Q1 and Q2 can be, for example, the lower left and lower right corners of a square QR code, and the detected points Q3 and Q4 can be, for example, the upper left and upper right corners of the square QR code. Figure 5 The position detection section 112 sets the coordinates of the detected point Q3 as (0, 2, 0) when the detected point Q3 is at a position that is below the detected point Q1 and at a distance that is twice the fourth distance. In this way, the position detection section 112 sets the coordinates of the detected points in accordance with the ratio of the distances (e.g., the ratio of the actual size values). The position detection section 112 can set the coordinates of the detected points in accordance with the distances (number of pixels) between the detected points on the image, for example.

[0093] The position detection section 112 outputs the coordinate information indicating the specific coordinates to the position estimation section 113. Note that the step S12 is an example of a detection step. Further, the coordinate information is an example of a detection result.

[0094] Next, the position estimation section 113 estimates the position of the imaging device 10 based on the image data (the position on the image data), the coordinate information, and the internal parameters of the imaging device 10 (S13). The position estimation section 113 can estimate the position of the imaging device 10 by solving the PnP problem (Perspective-n-Point Problem) when the three-dimensional position of the object 50 (here, the three-dimensional position of the mark 60) and the internal parameters of the imaging device 10 are known. In the present embodiment, the number of detected points is four (n = 4), and thus the position estimation section 113 estimates the position of the imaging device 10 by solving the P4P problem. The position of the imaging device 10 is expressed as, for example, a three-dimensional coordinate with the detected point Q1 as the origin.

[0095] The position inference unit 113 can also infer the posture of the camera device 10 by solving the PnP problem.

[0096] The position inference unit 113 outputs position information indicating the inferred position of the camera device 10 to the distance calculation unit 114. Step S13 is an example of an inference step.

[0097] The distance calculation unit 114 calculates the distance from the camera device 10 to the object 50 based on coordinate information and position information (S14). The distance calculation unit 114 calculates the distance from the camera device 10 to the object 50 based on the position (coordinates) of the camera device 10 included in the position information and the actual length corresponding to the distance "1" at those coordinates. Thus, the position of the object 50 as observed from the camera device 10 is obtained. For example, the distance to each measurement point of the object 50 as observed from the camera device 10 is obtained. The actual length corresponding to the distance "1" at the coordinates can be pre-stored in the correction parameter calculation unit 110 or obtained via the input device 40; if the marker 60 is a QR code, it can also be stored in that QR code. The distance calculation unit 114 outputs the distance information representing the distance between the camera device 10 and the object 50 to the correction value calculation unit 115. Step S14 is an example of a distance calculation step.

[0098] The correction value calculation unit 115 calculates a correction value (S15) for converting pixel displacement into actual size displacement based on the position and distance information of the imaging device 10 and the internal parameters of the imaging device 10. When the marker 60 included in the image data is one, the correction value calculation unit 115 calculates one correction value for the object 50, for example. The correction value includes, for example, information representing the actual size value corresponding to one pixel of the measurement point. Step S15 is an example of a parameter calculation step. Furthermore, step S15 can also be an example of a third acquisition step.

[0099] Furthermore, when the correction parameter calculation unit 110 acquires image data of multiple markers 60, it can also calculate correction values ​​for each of the multiple markers 60. When the multiple markers 60 are each installed on a plane of the object 50 at different distances from the camera device 10, correction values ​​can be calculated for each plane, thus enabling accurate measurement of the actual displacement value.

[0100] Here, refer to Figure 6 The processing of the correction value calculation unit 115 will be explained. Figure 6 This is a diagram used to illustrate the actual size conversion method for displacement in this embodiment. Additionally, in Figure 6 The example shown illustrates the displacement of object 50 in a direction parallel to the projection plane (camera plane) of the camera device 10. Figure 6The position T (Tx, Ty, Tz) of the camera 10 shown indicates the position of the lens 11 of the camera 10, the optical center O indicates the center of the lens 11 of the camera 10, the position Pl (x, y) indicates the position on the imaging surface corresponding to the position Ml (X, Y, Z) of the measurement point of the 1st point of the object 50, and the displacement (Δxl, Δyl) on the image indicates the difference between the position P2 on the imaging surface corresponding to the position M2 of the measurement point of the 2nd point different from the 1st point and the position Pl. The displacement (Δxl, Δyl) is the number of pixels on the image.

[0101] As shown in Figure 6 the triangle ΔOP1P2 and the triangle ΔOM1M2 are in a similar relationship, the correction value calculation section 115, for example, uses the similar relationship to calculate a correction value for converting the pixel displacement amount into the actual size displacement amount. If the distance of the image center (cx, cy) of the projection plane of the camera 10 from the optical center O is the focal distance f, the distance Ll of the optical center O from the position Pl is calculated by

[0102]

[0103] The 1st point is, for example, an initial point at which the object 50 does not displace.

[0104] Further, if the actual size displacement amount is the displacement (Dxl, Dy1), according to the similar relationship of the triangle ΔOP1P2 and the triangle ΔOM1M2, with respect to the distance L2 of the optical center O and the position Ml,

[0105] L2: Ll = Dy1: Δyl = Dx1: Δxl (Equation 2)

[0106] is established. According to (Equation 2), as long as the distance L2, that is, the distance from the optical center O to the position Ml is known, the displacement (Dxl, Dy1) as the actual size displacement amount can be calculated. Since the distance L2 can be different according to each measurement point, the distance calculation section 114 calculates the distance L2 according to each measurement point.

[0107] The correction value calculation section 115 calculates the correction value based on the above (Equation 2). According to (Equation 2), the correction value for calculating the displacement Dx1 is L2 / Ll. Further, according to (Equation 2), the correction value for calculating the displacement Dy1 is also L2 / Ll.

[0108] In addition, the image center (cx, cy) and the focal distance f are acquired as the internal parameters of the camera 10. The correction value calculation section 115 can also calculate the internal parameters of the camera 10 using a chart image.

[0109] The correction value calculation section 115 outputs correction information indicating the calculated correction value to the displacement amount calculation section 130. The displacement amount calculation section 130 acquires the correction information from the correction value calculation section 115. The displacement amount calculation section 130 functions as a second acquisition section that acquires the correction parameter.

[0110] Next, the displacement detection section 120 calculates pixel displacement amounts on the image data on which the displacement of the object 50 is calculated from the image data (S16). The displacement detection section 120, for example, calculates the pixel displacement amounts from the displacement of the object 50 projected on the projection plane of the imaging device 10. The displacement detection section 120, for example, calculates, for each of a plurality of measurement points of the object 50, which pixel on the image the displacement at the measurement point is. The displacement detection section 120 outputs the calculated pixel displacement amounts to the displacement amount calculation section 130.

[0111] The displacement amount calculation section 130 calculates the actual size displacement amounts based on the pixel displacement amounts and the correction value (S17). The displacement amount calculation section 130 calculates the actual size displacement amounts at each of a plurality of measurement points of the object 50 by operating the pixel displacement amounts and the correction value at the measurement point. In this way, the displacement amount calculation section 130 functions as a conversion section that converts the pixel displacement amounts in the two or more second image data into the actual size displacement amounts based on the correction information.

[0112] The displacement amount calculation section 130 outputs the prompt information including the calculated actual size displacement amounts to the output device 30 (S18). Also, the output device 30 displays the prompt information acquired from the displacement amount calculation section 130 as an image. Note that the step S18 is an example of the conversion step.

[0113] In addition, Figure 4 The operations of the steps S11 to S15 shown above can be performed each time the process of calculating the actual size displacement amounts of the object 50 is executed, or each time at least one of the set position, the posture, and the camera parameter (including the internal parameter) of the imaging device 10 is changed. Further, the correction value calculation section 115 can store the calculated correction value in a storage section (not shown). Also, the correction value calculation section 115 can read out the correction value from the storage section and output the read-out correction value to the displacement amount calculation section 130 in the case of calculating the actual size displacement amounts of the object 50. That is, the correction value calculation section 115 can use the correction value calculated in the past as the correction value for calculating the current actual size displacement amounts. Thus, it is possible to reduce the processing amount of the correction parameter calculation section 110.

[0114] The steps Sll to S15 described above are processing performed in a correction parameter calculation method of calculating a correction parameter. Further, the steps S16 to S18 described above are processing performed in a displacement amount calculation method of calculating an actual size displacement amount. In addition, the displacement amount calculation method can also include the processing of steps Sll to S15.

[0115] As described above, the displacement measurement system 1 relating to the present embodiment is provided with the imaging device 10 and the displacement measurement device 20 having the correction parameter calculation section 110. The correction parameter calculation section 110 infers the position of the imaging device 10 based on the marker 60 included in the image data acquired from the imaging device 10, and calculates a correction value for converting a pixel displacement amount into an actual size displacement amount based on the position.

[0116] Thus, according to the displacement measurement system 1, since the correction value can be calculated by acquiring the image data including the marker 60 from the imaging device 10 without using other devices (e.g., a distance measurement device) and the like, the correction parameter can be calculated easily.

[0117] Further, the displacement measurement device 20 measures the actual size displacement amount of the displacement of the object 50 using two or more pieces of image data imaged by the imaging device 10. Thus, the displacement measurement device 20 can measure the actual size displacement amount even if the displacement of the object 50 is periodic vibration that cannot be measured using a laser distance meter or the like.

[0118] (Modified example of the embodiment)

[0119] Hereinafter, the operation of the displacement measurement system 1 relating to the present modified example will be described with reference to Figures 7-9 The correction parameter calculation method and the like relating to the present modified example will be described with reference to the flowchart of FIG. 12. In the following description, the same reference numerals are assigned to the same components as those of the embodiment, and the description thereof will be omitted or simplified. The configuration of the displacement measurement system relating to the present modified example is the same as that of the displacement measurement system 1 relating to the embodiment, and the description thereof will be omitted.

[0120] The displacement measurement system 1 relating to the present modified example is characterized in that it can calculate an actual size displacement amount with high accuracy even if the direction of the displacement of the object 50 is different from the direction horizontal to the projection surface (imaging surface) of the imaging device. Figure 7 is a flowchart showing the operation of the displacement measurement system 1 relating to the present modified example.

[0121] As Figure 7As shown, the correction value calculation section 115 acquires displacement direction information of the object 50 (S21). The correction value calculation section 115 can acquire the displacement direction information via the input device 40, for example. The displacement direction information can be information indicating a displacement direction based on a driving direction of a driving section of a motor, for example, in the case where the object 50 is a motor. Further, the displacement direction information can be information indicating a predicted displacement direction, for example, in the case where a displacement direction of the object 50 can be predicted in design. Further, the displacement direction information can be information indicating a direction (e.g., a vertical direction) in which a stress is received, for example, in the case where the object 50 is a bridge or the like that receives a stress from a vehicle or the like. Further, the displacement direction information can indicate not one but two or more (two or more directions). Step S21 is an example of a second acquisition step.

[0122] Further, the displacement direction information is not limited to being acquired via the input device 40. The displacement direction information can be acquired based on image data. In the case where the marker 60 is a QR code, information about a displacement direction of the object 50 can be stored in the QR code. The correction value calculation section 115 can acquire the displacement direction of the object 50 based on the QR code included in the image data. In this case, the displacement direction is a direction with respect to a face (plane) of the object 50 on which the QR code is pasted, for example.

[0123] Further, the correction value calculation section 115 calculates a correction value for converting a pixel displacement amount into an actual size displacement amount based on the position of the imaging device 10, the distance information, the internal parameter of the imaging device 10, and the displacement direction information (S22). That is, the correction value calculation section 115 calculates the correction value using the displacement direction information in addition to the embodiment. Further, step S22 is an example of a parameter calculation step.

[0124] Here, the displacement correction using the displacement direction information will be described with reference to Figure 8A and Figure 8B Figure 8A is a first view for explaining the displacement correction considering the displacement direction according to the present modification. Further, Figure 8B is a second view for explaining the displacement correction considering the displacement direction according to the present modification. Figure 8A and Figure 8B are plan views of the object 50b viewed from above. Further, the shape of the object 50b is a square for convenience.

[0125] As shown in Figure 8A and Figure 8B ​As shown, when the object 50b is viewed from above, if the displacement direction of the object 50b relative to the projection plane of the imaging device 10 is not parallel to the projection plane, only the displacement of the object 50b in the direction parallel to the projection plane is projected on the projection plane. Figure 8A In this context, the displacement direction is the direction connecting the upper left and lower right sides of the paper. For example, if the displacement of the measuring point of object 50b is D1, then the displacement of the measuring point of object 50b projected onto the projection plane is D2. Displacement D2 is the component of displacement D1 in the direction parallel to the projection plane.

[0126] In addition, Figure 8B In this context, the displacement direction is the direction connecting the lower left and upper right sides of the paper. For example, if the displacement of the measuring point of object 50b is D3, then the displacement of the measuring point of object 50b projected onto the projection plane is D4. Displacement D4 is the component of displacement D3 in the direction parallel to the projection plane. For example, if the directions of displacement D1 and displacement D3 are orthogonal and equal in magnitude, then the directions and magnitudes of displacements D2 and D4 on the projection plane are equal. Furthermore, displacements D1 and D3 are actual size displacements, such as actual size values. Additionally, displacements D2 and D4 are pixel displacements, such as the number of pixels.

[0127] Thus, displacements D1 and D3, which have different actual displacement directions, can be detected as displacements in the same direction on the projection plane. Up to this point, displacements in the direction horizontal to the projection plane can be measured, but displacements in the direction perpendicular to the projection plane cannot be measured.

[0128] Therefore, in this modified example, as described above, the correction value calculation unit 115 obtains the displacement direction information of the object 50 in step S21, and uses this displacement direction information in step S22 to calculate a correction value for converting the pixel displacement of the object 50 on the image data into an actual size displacement. This correction value includes information representing the actual size value corresponding to one pixel and the displacement direction. For example, the correction value may also include information representing the actual size value (Xa, Yb, Zc) corresponding to one pixel. The actual size value Xa represents the actual size value of the displacement in the x-axis direction of the three-dimensional orthogonal coordinate system in actual space when the projection plane moves by one pixel. The actual size value Xb represents the actual size value of the displacement in the y-axis direction of the three-dimensional orthogonal coordinate system in actual space when the projection plane moves by one pixel. Xc represents the actual size value of the displacement in the z-axis direction of the three-dimensional orthogonal coordinate system in actual space when the projection plane moves by one pixel. The actual size values ​​(Xa, Yb, Zc) are an example of correction parameters.

[0129] Here, refer to Figure 9The processing of the correction value calculation section 115 will be described. Figure 9 is a view for explaining the actual size conversion method of the displacement relating to the present modification example.

[0130] As shown in Figure 9 , if the position P1 on the projection plane corresponding to the position M1 (X, Y, Z) of the measurement point of the object 50 at the first time point is set as (x, y), the distance L1 from the optical center O to the position P1 can be calculated by (Formula 1). The first time point is, for example, the initial time point at which the object 50 does not displace. Further, if the difference (displacement) between the position P3 on the projection plane corresponding to the position M3 of the measurement point at the second time point different from the first time point and the position P1 is set as (Δx2, Δy2), the first correction value can be calculated by (Formula 2). The first correction value here is a value that can calculate the actual size displacement amount in the direction parallel to the projection plane of the imaging device 10. The first correction value is, for example, a value of the displacement (Dx2, Dy2) in the actual size value that can be calculated from the displacement (Δx2, Δy2) on the image.

[0131] The correction value calculation section 115 converts the first correction value calculated by the first correction value calculation section 115 into the second correction value as three-dimensional information based on the displacement direction information. The correction value calculation section 115 calculates the second correction value for converting the pixel displacement amount as two-dimensional information indicating the displacement on the projection plane into the actual size displacement amount as three-dimensional information. The correction value calculation section 115 can also calculate the second correction value based on the first correction value and the angle formed by the projection plane of the imaging device 10 and the displacement direction. The second correction value is, for example, a value of the displacement (Dx2, Dy2, Dz2) in the actual size value that can be calculated from the displacement (Δx2, Δy2) on the image. Note that the method of calculating the second correction value by the correction value calculation section 115 is not limited to the above.

[0132] As described above, the correction parameter calculation section 110 of the displacement measurement system 1 relating to the present modification example also uses the displacement direction information indicating the displacement direction of the object 50 to calculate the correction value for converting the pixel displacement amount into the actual size displacement amount.

[0133] Thus, in the case where the object 50 displaces in the direction intersecting the projection plane of the imaging device 10 when the object 50 is viewed from above, the displacement measurement system 1 can calculate the correction value using the displacement direction information, so the actual size value of the displacement can be measured with good accuracy.

[0134] (Other Embodiments)

[0135] The above describes the correction parameter calculation method and the like relating to one or more technical solutions of the present application based on the embodiments and modifications (hereinafter also referred to as embodiments and the like). However, the present application is not limited to the embodiments and the like. As long as the embodiments and the like are not deviated from the gist of the present application, various modifications that can be thought of by those skilled in the art, or configurations constructed by combining the constituent elements of different embodiments can also be included in the scope of one or more technical solutions of the present application.

[0136] For example, in the above embodiments and the like, an example in which the imaging device is fixed to the ground is described, but is not limited thereto. The imaging device can be, for example, an imaging device provided on a flying body such as a drone.

[0137] Further, in the above embodiments and the like, an example in which the marker is a QR code or the like and is attached to the object is described, but is not limited thereto. The marker can be, for example, a pattern, a character, or the like provided on the surface of the object. Further, the marker can be, for example, a concave-convex or the like provided on the surface of the object. In the pattern, the character, and the concave-convex, and the like, the distance between the prescribed positions is known in advance. Further, the marker can be a seal, a sticker, or the like of a known size. For example, the marker can be a plain seal of several cm square or the like.

[0138] Further, in the above embodiments and the like, an example in which the acquisition unit is a communication unit is described, but is not limited thereto. The acquisition unit can be, for example, a connection unit that connects a recording medium. The connection unit can be, for example, a USB terminal that connects a USB (Universal Serial Bus), an SD card slot into which an SD card is inserted, an optical drive into which an optical disc is inserted, or the like.

[0139] Further, the order in which the steps in the flowchart are executed is exemplified in order to specifically describe the present application, and can be in an order other than the above. Further, a part of the above steps can be executed simultaneously (in parallel) with other steps.

[0140] Further, the division of the functional blocks in the block diagram is an example, and a plurality of functional blocks can be implemented as one functional block, or one functional block can be divided into a plurality, or a part of the functions can be transferred to other functional blocks. Further, the functions of a plurality of functional blocks having similar functions can be processed in parallel or time-division by a single hardware or software.

[0141] Further, the correction parameter calculation device in the above embodiments and the like can be implemented by a single device, or can be implemented by a plurality of devices connected to each other. In the case where the correction parameter calculation device is implemented by a plurality of devices, how the constituent elements possessed by the correction parameter calculation device are distributed to the plurality of devices can be arbitrary.

[0142] Further, in the above embodiment and the like, the displacement measuring device is described as an example in which the displacement measuring device and the output device are separate, but the output device can be provided. In this case, the output device functions as an output portion (for example, a display portion) that is a part of the displacement measuring device.

[0143] Further, the communication method between the devices included in the displacement measuring system in the above embodiment and the like is not particularly limited. Wireless communication or wired communication can be performed between the devices. Further, wireless communication and wired communication can be combined between the devices.

[0144] Further, a part or all of the constituent elements included in the computing device in the above embodiment and the like can be configured by one system LSI (Large Scale Integration).

[0145] The system LSI is a super multi-functional LSI in which a plurality of processing portions are integrated into one chip, and specifically, is a computer system including a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. A computer program is stored in the ROM. The system LSI functions by the microprocessor acting according to the computer program.

[0146] In addition, the system LSI is assumed here, but depending on the difference in integration degree, it can also be referred to as an IC, an LSI, a super LSI, or a ultra LSI. Further, the method of integration is not limited to the LSI, and can be realized by a dedicated circuit or a general-purpose processor. A FPGA (Field Programmable Gate Array) that can be programmed after the manufacture of the LSI, or a reconfigurable processor in which the connections and the settings of circuit cells included in the LSI can be reconfigured can be used.

[0147] Further, if an integrated circuit technology that replaces the LSI appears due to the progress of semiconductor technology or other technology, integration of the functional blocks can be naturally performed using the technology. Application of biotechnology is possible.

[0148] Further, all or a part of the above various processes can be realized by hardware such as an electronic circuit, and can be realized using software. Further, the process performed by the software can be realized by a processor included in the displacement measuring device executing a program stored in a memory.

[0149] Further, one aspect of the present application can be a computer program that causes a computer to execute the characteristic steps included in the parameter correction calculation method and the displacement amount calculation method. Further, one aspect of the present application can be a non-transitory recording medium that is readable by a computer and on which such a program is recorded. For example, such a program can be distributed or circulated by being recorded in a recording medium. For example, by installing the distributed program in a device having another processor and causing the processor to execute the program, the device can be caused to perform the above-described processing.

[0150] Industrial Applicability

[0151] The present application can be widely used in a device that measures an actual size value of displacement in displacement measurement of an object using an image, and the like.

[0152] Label Explanation

[0153] 1 Displacement measurement system

[0154] 10 Imaging device

[0155] 11 Lens

[0156] 20 Displacement measurement device

[0157] 30 Output device

[0158] 40 Input device

[0159] 50, 50a, 50b Object

[0160] 60, 60a, 60b Mark

[0161] 110 Correction parameter calculation section (correction parameter calculation device)

[0162] 111 Acquisition section (first acquisition section)

[0163] 112 Position detection section

[0164] 113 Position estimation section

[0165] 114 Distance calculation section

[0166] 115 Correction value calculation section (parameter calculation section)

[0167] 120 Displacement detection section

[0168] 130 Displacement amount calculation section (conversion section)

[0169] f Focal distance

[0170] L1, L2 Distance

[0171] M1 to M3, P1 to P3, T Position

[0172] O optical center

[0173] Q1-Q4 detection points

Claims

1. A correction parameter calculation method of calculating a correction parameter for measuring an actual size displacement amount using an image, the actual size displacement amount being an actual size value indicating a displacement of a movement of an object, the correction parameter calculation method comprising: a first acquisition step of acquiring first image data obtained by imaging the object on which a marker capable of detecting a specific coordinate is mounted, from an imaging device; a second acquisition step of acquiring displacement direction information indicating a direction of displacement that intersects with an imaging surface of the imaging device among directions of displacement of the object; a detection step of detecting the specific coordinate based on the marker included in the first image data; an estimation step of estimating a position of the imaging device based on a result of detection of the specific coordinate and a parameter of the imaging device; a distance calculation step of calculating distance data from the imaging device to the object based on the specific coordinate and the position of the imaging device; and a parameter calculation step of calculating the correction parameter using the distance data and the displacement direction information, the correction parameter being used to convert pixel displacement amounts of measurement points of the object in two or more second image data imaged by the imaging device at mutually different times into actual size displacement amounts, the direction of displacement of the object being a direction predicted on design in the object.

2. The correction parameter calculation method according to claim 1, the displacement direction information being acquired via an input device.

3. The correction parameter calculation method according to claim 1 or 2, the marker being mounted on a planar portion of the object; the direction indicated by the displacement direction information being defined with respect to the planar portion, the displacement direction information being acquired based on the planar portion.

4. The correction parameter calculation method according to claim 1, the marker being a registered trademark, i.e., a QR code; the displacement direction information being stored in the QR code, the displacement direction information being acquired based on the QR code.

5. A displacement amount calculation method, comprising: a third acquisition step of acquiring the correction parameter calculated using the correction parameter calculation method according to any one of claims 1, 2, and 4; a fourth acquisition step of acquiring the two or more second image data; and a conversion step of converting the pixel displacement amounts in the two or more second image data into the actual size displacement amounts based on the correction parameter.

6. A correction parameter calculation apparatus of calculating a correction parameter for measuring an actual size displacement amount using an image, the actual size displacement amount being an actual size value indicating a displacement of a movement of an object, the correction parameter calculation apparatus comprising: a first acquisition section of acquiring first image data obtained by imaging the object on which a marker capable of detecting a specific coordinate is mounted, from an imaging device; a second acquisition section of acquiring displacement direction information indicating a direction of displacement that intersects with an imaging surface of the imaging device among directions of displacement of the object; a position detection section of detecting the specific coordinate based on the marker included in the first image data; and a parameter calculation section of calculating the correction parameter using the distance data and the displacement direction information, the correction parameter being used to convert pixel displacement amounts of measurement points of the object in two or more second image data imaged by the imaging device at mutually different times into actual size displacement amounts. a position estimation unit configured to estimate a position of the imaging device based on the detection result of the specific coordinate and a parameter of the imaging device; a distance calculation unit configured to calculate distance data from the imaging device to the object based on the specific coordinate and the position of the imaging device; and a parameter calculation unit configured to calculate a correction parameter for converting a pixel displacement amount of a measurement point of the object in two or more second image data captured by the imaging device at different times into an actual size displacement amount using the distance data and the direction information of the displacement, the direction of the displacement of the object is a direction predicted in design in the object.

7. A displacement amount calculation apparatus, comprising: a third acquisition unit configured to acquire the correction parameter calculated by the correction parameter calculation apparatus according to claim 6; a fourth acquisition unit configured to acquire the two or more second image data; and a conversion unit configured to convert the pixel displacement amount in the two or more second image data into the actual size displacement amount based on the correction parameter.

Images