Data acquisition device and method

Abstract

To provide a data acquisition device and a data acquisition method with which, when acquiring internal data of a hollow columnar structure, it is possible to internal data that shows a clue to find a direction in which the data was acquired.SOLUTION: This data acquisition device S comprises: a mark formation unit 1 for forming a first linear mark that extends in one direction to an interior of a hollow columnar structure which is a hollow columnar member and a second mark of a prescribed shape in one region on one side or in other region on other side relative to the first mark; a data acquisition unit 2 for acquiring prescribed data that represents an internal state of the hollow columnar structure; and a direction detection unit 3 for finding a direction in which the data acquisition unit 2 acquired data in the inside of the hollow columnar structure, on the basis of the first and the second marks.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a data acquisition device and a data acquisition method for acquiring predetermined data representing the internal state (condition, state) of a hollow columnar structure. [Background technology]

[0002] For example, the inside of hollow columnar structures, which are hollow columnar bodies such as chimneys and pipes, is usually inspected (inspected, measured) for maintenance, management, etc. When inspecting the inside of such hollow columnar structures, a relatively large temporary structure such as a scaffold or a gondola is installed and used. The temporary structure requires cost and time for installation and dismantling, and therefore it is desirable to reduce the cost and time. In response to such a demand, an inspection method has been proposed, for example, as disclosed in Patent Document 1.

[0003] The inspection method using an unmanned small aerial vehicle disclosed in Patent Document 1 is a method of inspection using an unmanned small aerial vehicle in which an unmanned small aerial vehicle is flown into the internal space of a structure to inspect the inside of the structure, in which the unmanned small aerial vehicle is provided with a guide for guiding the aircraft along a linear body, the linear body is placed in an extended state within the internal space, and the interior of the structure is inspected while the unmanned small aerial vehicle is flown along the linear body using the guide. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6505927 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when inspecting a hollow columnar structure based on predetermined data (internal data, for example, an image of the inside) obtained by acquiring the internal data showing the state of the inside of the hollow columnar structure, if there are few characteristic points inside the hollow columnar structure, particularly if the structure is a cylindrical structure with almost no characteristic points, it becomes difficult to know in which direction the internal data is. Even with the inspection method disclosed in Patent Document 1, if the unmanned small aerial vehicle shifts in the circumferential direction while moving along the guide, or if the guide is twisted by the movement of the unmanned small aerial vehicle, it becomes difficult to know in which direction the image captured by the unmanned small aerial vehicle is.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and its object is to provide a data acquisition device and a data acquisition method that can acquire internal data representing the internal state of a hollow columnar structure, with the data acquisition direction being known. [Means for solving the problem]

[0007] As a result of various studies, the inventors of the present invention have found that the above object can be achieved by the present invention described below. That is, a data acquisition device according to one aspect of the present invention includes a mark forming unit that forms a linear first mark extending in one direction on an inner surface of a hollow columnar structure, which is a hollow columnar member, and a second mark of a predetermined shape in one of one area on one side of the first mark and another area on the other side of the first mark, a data acquisition unit that acquires predetermined data representing the state of the inside of the hollow columnar structure, and a direction detection unit that determines the data acquisition direction of the data acquisition unit inside the hollow columnar structure based on the first and second marks. In the above data acquisition device, preferably, the hollow columnar structure is a structure whose cross section perpendicular to the extension direction is a circle, an ellipse, a polygon, or a regular polygon (for example, a triangle, an equilateral triangle, a rectangle, a square, a hexagon, a regular hexagon, an octagon, a regular octagon, etc.). In the above data acquisition device, preferably, the hollow columnar structure is a chimney or a pipe. Preferably, in the data acquisition device described above, the hollow columnar structure is a chimney of a thermal power plant or a water pipe of a hydroelectric power plant. Preferably, in the data acquisition device described above, the second mark extends linearly from the first mark at a predetermined position of the first mark at a predetermined angle. Preferably, the predetermined angle is approximately 90 degrees. Preferably, in the data acquisition device described above, the second mark is formed at a predetermined position spaced apart from the first mark. Preferably, in the data acquisition device described above, the mark forming unit is a light source unit that irradiates light so as to become the first and second marks formed on the inner surface of the hollow columnar structure. Preferably, the light source unit is a laser light source device, a light emitting diode, or the like. Preferably, in the data acquisition device described above, the mark forming unit is a phosphorescent member (a phosphorescent member) that emits phosphorescence so as to become the first and second marks formed on the inner surface of the hollow columnar structure. Preferably, the above-mentioned data acquisition device further comprises a reflecting member that emits reflected light so as to form the first and second marks on the inner surface of the hollow columnar structure, and a light source unit that irradiates light onto the reflecting member.Preferably, in the data acquisition device, the direction detection unit determines the data acquisition direction in an orthogonal plane perpendicular to the extension direction of the hollow columnar structure based on the first and second marks. Preferably, in the above-mentioned data acquisition device, the direction detection unit includes a camera (imaging unit) that captures the first and second marks, and a direction processing unit that determines the data acquisition direction of the data acquisition unit based on the image captured by the camera. Preferably, in the above-mentioned data acquisition device, the predetermined data is an image of the inside of the hollow columnar structure, the data acquisition unit is a camera that generates an image, and the data acquisition direction of the data acquisition unit is the imaging direction of the camera. Preferably, in the above-mentioned data acquisition device, the predetermined data is a heat distribution inside the hollow columnar structure, the data acquisition unit is a thermograph that measures the heat distribution, and the data acquisition direction of the data acquisition unit is a measurement direction of the thermograph. Preferably, in the above-mentioned data acquisition device, the specified data is a surface unevenness distribution (radial height distribution) on the inner wall surface of the hollow columnar structure, the data acquisition unit is a distance measuring device (e.g., a laser distance measuring device, etc.) that measures the distance from the data acquisition device to the inner wall surface of the hollow columnar structure, and the data acquisition direction of the data acquisition unit is the measurement direction of the distance measuring device.

[0008] Since such a data acquisition device includes a mark forming section, the data acquisition direction can be obtained using the first and second marks formed by the mark forming section as guides. Therefore, when acquiring predetermined internal data that represents the internal state of a hollow columnar structure, the data acquisition device can acquire internal data that indicates the data acquisition direction.

[0009] In another aspect, the data acquisition device further includes an aviation unit that has the data acquisition unit and the direction detection unit and flies. Preferably, in the data acquisition device, the aviation unit flies autonomously.

[0010] Since such a data acquisition device is equipped with an aerial unit, it is possible to acquire the internal data of the hollow columnar structure at multiple locations (positions) inside the hollow columnar structure without using relatively large-scale temporary structures such as scaffolding or gondolas.

[0011] In another aspect, the data acquisition device further includes a position measurement unit that measures the position of the aviation unit inside the hollow columnar structure, and a position control unit that controls the aviation unit so that the aviation unit is located at a central position of the hollow columnar structure in a perpendicular plane perpendicular to the extension direction of the hollow columnar structure based on the position of the aviation unit measured by the position measurement unit, and the aviation unit has the position measurement unit and the position control unit. Preferably, in the data acquisition device described above, the central position of the hollow columnar structure is the center of a circumscribing circle for a cross-sectional shape of the hollow columnar structure on the perpendicular plane.

[0012] In the inspection method disclosed in Patent Document 1, when the linear body is a wire, thread, or rope (paragraph

[0022] of Patent Document 1), when the unmanned small aerial vehicle moves along the linear body, the position of the linear body in the intersecting plane intersecting the extension direction of the linear body is shifted due to this movement, and as a result, the position of the unmanned small aerial vehicle may also be shifted. When the position of the unmanned small aerial vehicle is shifted, the distance between the camera mounted on the unmanned small aerial vehicle and the structure is shifted, so that if the angle of view is fixed, the inside of the structure cannot be imaged with the expected area size. For this reason, the size of the subject captured per pixel deviates from the expected size, and an image cannot be obtained with the expected accuracy. On the other hand, when the linear body is composed of a rod-shaped body, there is a possibility that such positional deviation can be reduced, but when the rod-shaped body is relatively long, when one end of the rod-shaped body is fixed, the position of the rod-shaped body may be shifted at the other end of the rod-shaped body, and even when both ends are fixed, the position of the rod-shaped body may be shifted near the center position. There is also a risk that temporary structures may be required to install the rod-shaped body.

[0013] The data acquisition device controls the aerial section so that it is positioned at the center of the hollow columnar structure in the perpendicular plane based on the measured position of the aerial section, so that internal data of the hollow columnar structure can be acquired with the expected accuracy.

[0014] In another aspect, in the data acquisition device described above, the cross-sectional shape of the hollow columnar structure in the orthogonal plane is a circle, an ellipse, a rectangle, or a regular polygon, the position measurement unit includes a distance measurement unit that measures the distance from the aviation unit to the hollow columnar structure in the orthogonal plane, and the position control unit controls the aviation unit based on the maximum or minimum value of the distance measured by the distance measurement unit. Preferably, in the data acquisition device described above, the position control unit further controls the aviation unit so that the data acquisition unit faces a predetermined direction based on the data acquisition direction of the data acquisition unit determined by the direction detection unit. Preferably, in the data acquisition device described above, the data acquisition device further includes an altitude measurement unit that measures the altitude of the aviation unit, the aviation unit has the altitude measurement unit, and the position control unit further controls the aviation unit so that the aviation unit is at a predetermined altitude based on the altitude determined by the altitude measurement unit.

[0015] When the structure of the hollow columnar structure is known, the maximum or minimum value from the center position to the hollow columnar structure can also be obtained in advance. The data acquisition device controls the aviation unit so that the distance measured by the distance measuring unit becomes the maximum or minimum value, thereby controlling the aviation unit to be located at the center position.

[0016] In another aspect, the above-mentioned data acquisition device further includes a ranging unit that measures the distance of the aerial unit from the hollow columnar structure, and a position control unit that controls the aerial unit so that it is positioned at a predetermined distance from the hollow columnar structure in a predetermined direction in an orthogonal plane perpendicular to the extension direction of the hollow columnar structure based on the data acquisition direction of the data acquisition unit determined by the direction detection unit and the distance of the aerial unit measured by the ranging unit, and the aerial unit has the ranging unit and the position control unit.

[0017] Such a data acquisition device controls the aerial section so that it is positioned at a predetermined distance from the hollow columnar structure in a predetermined direction in an orthogonal plane, so that internal data of the hollow columnar structure can be acquired with expected accuracy.

[0018] In another aspect, the data acquisition device further includes a second direction detection unit that detects rotational motion to determine the data acquisition direction of the data acquisition unit, and when it is determined that the direction detection unit has made an erroneous detection, a second detection result of the second direction detection unit is used instead of the detection result of the direction detection unit. Preferably, in the data acquisition device, the second direction detection unit includes a gyro that detects rotational motion about at least one axis. Preferably, in the data acquisition device, the second direction detection unit includes an inertial measurement unit (IMU) that determines three-dimensional angular velocity and acceleration using a three-axis gyro and a three-directional accelerometer.

[0019] Since such a data acquisition device further includes a second direction detection unit, it can back up the direction detection unit.

[0020] In another aspect, the data acquisition device described above further comprises a second distance measuring section whose measurement direction is a direction opposite to the direction toward the inner surface of the hollow columnar structure in which the first and second marks are formed.

[0021] Since such a data acquisition device further includes a second distance measuring section, if there is an obstacle in the direction opposite to the direction toward the inner surface of the hollow columnar structure, it becomes possible to avoid the obstacle.

[0022] A data acquisition method according to another aspect of the present invention includes a mark forming step of forming a linear first mark extending in one direction on an inner surface of a hollow columnar structure which is a hollow columnar member, and a second mark having a predetermined shape in one of one area on one side of the first mark and another area on the other side of the first mark, a data acquisition step of acquiring predetermined data representing the state of the inside of the hollow columnar structure, and a direction detection step of determining a data acquisition direction in the data acquisition step inside the hollow columnar structure based on the first and second marks. Since such a data acquisition method includes a mark forming step, the data acquisition direction can be obtained using the first and second marks formed in the mark forming step as landmarks. Therefore, when acquiring predetermined internal data that represents the internal state of a hollow columnar structure, the data acquisition method can acquire internal data with a clear data acquisition direction. Effect of the Invention

[0023] The data acquisition device and data acquisition method according to the present invention can acquire internal data showing the internal state of a hollow columnar structure from a known data acquisition direction. [Brief description of the drawings]

[0024] [Figure 1] 1 is a block diagram showing a configuration of a data acquisition device according to an embodiment. [Diagram 2] 1A to 1C are diagrams for explaining the manner in which the data acquisition device flies inside a hollow columnar structure. [Diagram 3] 5A to 5C are diagrams illustrating marks formed on the inner surface of the hollow columnar structure. [Figure 4] 5A and 5B are diagrams for explaining the relationship between an image of a direction detection unit and a data acquisition direction in the data acquisition device. [Diagram 5] FIG. 4 is a diagram for explaining position control of the data acquisition device. [Figure 6]5 is a flowchart showing the operation of the data acquisition device with respect to acquisition of internal data of the hollow columnar structure. [Figure 7] 11 is a diagram for explaining how internal data of the hollow columnar structure is acquired by the data acquisition device. FIG. [Figure 8] 4A to 4C are diagrams for explaining control of a data acquisition direction in the data acquisition device. [Figure 9] FIG. 13 is a diagram for explaining a data acquisition device in the first modified embodiment. [Figure 10] FIG. 13 is a diagram for explaining a data acquisition device in a second modified embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments. In addition, configurations with the same reference numerals in each drawing indicate that they are the same configurations, and their description will be omitted as appropriate. In this specification, when referring to a general term, a reference numeral without a subscript is used, and when referring to an individual configuration, a reference numeral with a subscript is used.

[0026] The data acquisition device in this embodiment includes a mark forming section that forms a linear first mark extending in one direction on the inner surface of a hollow columnar structure, which is a hollow columnar member, and a second mark of a predetermined shape in one of one area on one side of the first mark and another area on the other side of the first mark, a data acquisition section that acquires predetermined data representing the state of the inside of the hollow columnar structure, and a direction detection section that determines the data acquisition direction of the data acquisition section inside the hollow columnar structure based on the first and second marks. Such a data acquisition device will be described in more detail below.

[0027] FIG. 1 is a block diagram showing the configuration of a data acquisition device in an embodiment. FIG. 2 is a diagram for explaining the state in which the data acquisition device flies inside the hollow columnar structure. FIG. 3 is a diagram for explaining a mark formed on the inner surface of the hollow columnar structure. FIG. 4 is a diagram for explaining the relationship between the image of the direction detection unit and the data acquisition direction in the data acquisition device. FIG. 4A is a diagram for explaining the definition of the data acquisition direction with respect to the image of the direction detection unit, and FIG. 4B and FIG. 4C are diagrams for explaining the data acquisition direction obtained based on the mark image. FIG. 5 is a diagram for explaining the position control of the data acquisition device. FIG. 5A shows a case in which the cross section perpendicular to the extension direction of the hollow columnar structure is square, and FIG. 5B shows a case in which the cross section perpendicular to the extension direction of the hollow columnar structure is circular.

[0028] 1, the data acquisition device S in the embodiment includes a mark forming unit 1, a data acquisition unit 2, and a direction detection unit 3. In the example shown in FIG. 1, the data acquisition device S further includes a first position measurement unit 4, a second position measurement unit 5, an altitude measurement unit 6, an aviation unit 7, a control processing unit 8, a memory unit 9, an interface unit (IF unit) 10, a communication unit 11, an inertial measurement unit 12, and an emergency operation unit 13.

[0029] The mark forming unit 1 is a device that forms a linear first mark extending in one direction on the inner surface of a hollow columnar structure, which is a hollow columnar member, and a second mark of a predetermined shape in one of one area on one side of the first mark and another area on the other side.

[0030] The hollow columnar structure may be any structure so long as it is a hollow columnar member, for example, a structure whose cross section perpendicular to its extension direction is a circle, an ellipse, a polygon, or a regular polygon (for example, a triangle, an equilateral triangle, a quadrilateral (for example, a rectangle, etc.), a square, a hexagon, a regular hexagon, an octagon, a regular octagon, etc.). Preferably, for example, the hollow columnar structure is a cylindrical structure that is long in the height direction (vertical direction), or a cylindrical structure that is long in the horizontal direction, vertical direction, etc. and is difficult for people to enter or is dangerous. Representative examples of cylindrical structures that are such cylindrical members include chimneys of incineration facilities, chimneys of power plants (for example, thermal power plants, etc.), chimneys of steelworks, chimneys and piping of chemical plants, water pipes of hydroelectric power plants (for example, water pipes to turbines, etc.), and ventilation pipes of tunnels. In the example shown in FIG. 2, the hollow columnar structure CB has a square cross section, and the mark forming unit 1 forms a mark MK on the bottom surface of this hollow columnar structure CB.

[0031] More specifically, in the example shown in FIG. 2, the mark forming unit 1 forms a linear first mark MK1 that passes through a center position CP of the bottom surface and extends in one direction parallel to one side from the center position CP, and a second mark MK2 of a predetermined shape in one of one area on one side of the first mark MK1 and the other area on the other side. In this way, a mark MK consisting of the first and second marks MK1 and MK2 is formed. Note that the first mark MK1 does not necessarily have to pass through the center position CP of the bottom surface, and may extend along a direction intersecting the side as long as it is linear. Such a mark MK is formed in various appropriate shapes, and may be, for example, marks MKa to MKe having shapes shown in FIGS. 3A to 3E. In the marks MKa to MKc shown in FIGS. 3A to 3C, the second marks MK2a to MK2c extend linearly from the first marks MK1a to MK1c at a predetermined position on the first marks MK1a to MK1c at a predetermined angle. More specifically, the mark Mka shown in FIG. 3A is composed of a linear first mark MK1a extending in one direction, and a second mark MK2a extending linearly from the first mark MK1a at approximately 90 degrees at the center position in the extension direction of the first mark MK1a. The mark MKb shown in FIG. 3B is composed of a linear first mark MK1b extending in one direction, and a second mark MK2b extending linearly from the first mark MK1b at a predetermined position closer to one end than the center position in the extension direction of the first mark MK1b at a predetermined angle θ that is acute (smaller) than 90 degrees. The mark MKc shown in FIG. 3C is composed of a linear first mark MK1c extending in one direction, and a second mark MK2c extending linearly from the first mark MK1c at approximately 90 degrees at the other end of the first mark MK1c. That is, the mark MKc has an approximately L-shape in plan view due to the first and second marks MK1c and MK2c. In the marks MKc and MKd shown in Fig. 3D and Fig. 3E, the second marks MK2c and MK2d are formed at predetermined positions spaced apart from the first marks MK1c and MK1d. More specifically, the mark MKd shown in Fig. 3D is composed of a linear first mark MK1d extending in one direction, and a linear second mark MK2d extending in a direction perpendicular to the extension direction of the first mark MK1d at a predetermined position spaced apart from the first mark MK1d.The mark MKe shown in Fig. 3E is composed of a linear first mark MK1e extending in one direction, and a circular second mark MK2e located at a predetermined position spaced apart from the first mark MK1e. In short, the mark MK is composed of a linear first mark MK1 extending in one direction, and a second mark MK2 that makes the mark MK asymmetric with respect to the first mark MK1. The following describes the case of the mark MKa shown in Fig. 3A, but the same description can be applied to cases where the mark MK has another form.

[0032] Such a mark forming unit 1 is, for example, a light source unit that irradiates light so as to form the first and second marks MK1 and MK2 on the inner surface of the hollow columnar structure CB. The light source unit is, for example, a laser light source device or a light emitting diode. When forming the first and second marks MK1a to MK1e and MK2a to MK2d, the light source unit is, for example, a laser light source device that irradiates a sheet-like (slit-like) laser light or a plurality of light emitting diodes (for example, LED tape lights, etc.) arranged in a line. When forming the second mark MK2e, the light source unit is, for example, a laser light source device that irradiates a laser light in a circular spot shape or one or a plurality of light emitting diodes arranged in a circular spot shape. Alternatively, for example, the mark forming unit 1 is a phosphorescent member (a phosphorescent member) that emits phosphorescence so as to form the first and second marks MK1 and MK2 on the inner surface of the hollow columnar structure CB. Alternatively, for example, the mark forming section 1 includes a reflecting member that emits reflected light and a light source section that irradiates the reflecting member with light so as to form first and second marks MK1, MK2 on the inner surface of the hollow columnar structure CB.

[0033] The data acquisition unit 2 is connected to the control processing unit 8, and is a device that acquires predetermined data (internal data) that represents the state (situation, condition) of the inside of the hollow columnar structure under the control of the control processing unit 8. The internal data is, for example, an image of the inside of the hollow columnar structure CB, and in this case, the data acquisition unit 2 is a camera (first camera) 2 that generates an image. Alternatively, for example, the internal data is a heat distribution inside the hollow columnar structure CB, and in this case, the data acquisition unit 2 is a thermograph 2 that measures the heat distribution. Alternatively, for example, the internal data is a surface unevenness distribution (radial height distribution) of the inner wall surface (inner surface) of the hollow columnar structure CB, and in this case, the data acquisition unit 2 is a distance measuring device (for example, a laser distance measuring device, etc.) 2 that measures the distance from the data acquisition device S to the inner wall surface of the hollow columnar structure CB. In the following, a case where the internal data is an image of the inside of the hollow columnar structure CB, for example, its inner wall surface (inner surface), will be described, but the same explanation can be given when the internal data is other types of data. The first camera 2 as an example of the data acquisition unit 2 may be a monochrome camera, a color camera, an infrared camera, or the like, and is appropriately selected depending on the purpose of acquiring an image inside the hollow columnar structure CB. The resolution of the first camera 2 is appropriately selected depending on the purpose of acquiring an image inside the hollow columnar structure CB. For example, when the purpose is to inspect the inside of the hollow columnar structure CB, a digital camera having an area image sensor with a number of pixels suitable for capturing an abnormality such as a sub-millimeter order crack on an inner wall surface with a side length of 5 m or an inner wall surface with a diameter of 5 m is used as the first camera 2. The data acquisition unit 2 outputs the acquired internal data, which in this embodiment is an image inside the hollow columnar structure CB (structure internal image), to the control processing unit 8.

[0034] The direction detection unit 3 is a device that determines the data acquisition direction (the orientation of the aviation unit 7) of the data acquisition unit 2 inside the hollow columnar structure based on the mark MK consisting of the first and second marks MK1 and MK2 formed by the mark formation unit 1. In this embodiment, the data acquisition direction is a direction in an orthogonal plane perpendicular to the extension direction of the hollow columnar structure CB. The linear first mark MK1 extending in one direction in the mark MK serves as a reference for the data acquisition direction of the data acquisition unit 2. In this embodiment, the data acquisition direction is the imaging direction (first imaging direction) of the first camera 2. Note that when the data acquisition unit 2 is a thermography 2, the data acquisition direction is the measurement direction of the thermography 2, and when the data acquisition unit 2 is a distance measurement device 2, the data acquisition direction is the measurement direction of the distance measurement device 2.

[0035] In this embodiment, as an example, the direction detection unit 3 determines the data acquisition direction relative to the extension direction of the linear first mark MK1 based on an image (mark image) of the mark MK, in this example, the first imaging direction of the first camera 2 (the direction of the aviation unit 7). More specifically, the direction detection unit 3 includes a camera (imaging unit, second camera) that images the mark MK consisting of the first and second marks MK1 and MK2, and an information processing circuit (information processing circuit for direction detection) such as a microcomputer that determines the data acquisition direction of the data acquisition unit 2 (imaging direction of the first camera) based on the image captured by the second camera. The second camera is, for example, a digital camera similar to the first camera 2. The information processing circuit for direction detection detects the mark MK from the mark image captured by the second camera, and determines the data acquisition direction based on the detected mark MK.

[0036] More specifically, the direction detection information processing circuit extracts the mark MK from the mark image. For example, the direction detection information processing circuit detects linear regions with high brightness as the first and second marks MK1 and MK2 by binarizing the mark image with a predetermined threshold value. Then, the direction detection information processing circuit detects a relatively long linear region as the first mark MK1 and a relatively short linear region as the second mark MK2 from the shape of the mark MK in the case of the mark MKA shown in FIG. 3A. Alternatively, the direction detection information processing circuit detects a linear region extending from the middle of one of the linear regions as the second mark MK2 and detects the one linear region as the first mark MK1 from the shape of the mark MK in the case of the mark MKA shown in FIG. 3A. The direction detection information processing circuit may further detect edges on both sides of a linear region with high brightness by detecting edges from a binarized mark image using an edge filter, and detect the center lines of the detected edges (sides) as the linear first and second marks MK1 and NK2. The direction detection information processing circuit may further obtain two straight lines for each of the detected edges by a Hough transform, and detect the center lines of the obtained straight lines as the linear first and second marks MK1 and NK2. The direction detection information processing circuit then obtains the data acquisition direction from the extracted first and second marks MK1 and MK2 using pre-stored orientation correspondence data. The orientation correspondence data is data that represents the correspondence between the direction of the image acquired by the second camera and the orientation of the aviation unit 7 (data acquisition direction, in this example, the first imaging direction of the first camera 2). For example, as shown in Fig. 4A, a directed line segment HL that is parallel to the lateral direction (x-axis, horizontal direction, lateral direction of the area image sensor) of the mark image and runs from the inside of the mark image to the side (the right side in plan view in the example shown in Fig. 4A) opposite to the side on which the y-axis is set (the left side in plan view in the example shown in Fig. 4A), is defined as the orientation of the aviation unit 7, and the directed line segment HL is data that corresponds to the orientation of the aviation unit 7. In Figs. 4A to 4C, in the mark image generated by the first camera 2 as an example of the data acquisition unit 2, an xy Cartesian coordinate system is set with the pixel at the upper left corner as the origin in plan view, the left-right direction as the x-axis, and the up-down direction as the y-axis.This xy orthogonal coordinate system is a local coordinate system set in the mark image (image pickup element of the first camera), and the data acquisition direction is, for example, a direction in a world coordinate system set in a hollow columnar member. An xy orthogonal coordinate system is also set in Fig. 8A to Fig. 8D described later. More specifically, the direction detection information processing circuit refers to the position of the second mark MK2 relative to the first mark MK1 in the xy orthogonal coordinate system, and, for example, when the data acquisition direction is set to 0 degrees when the first mark MK1 extends parallel to the x-axis and the second mark MK1 extends parallel to the y-axis in the -y direction, the direction detection information processing circuit determines the orientation of the aviation unit 7 as the data acquisition direction by determining the angle between the extracted first mark MK1 and the directed line segment HL. For example, as shown in Fig. 4B, when the position of the second mark MK2 relative to the first mark MK1 is referenced in an xy orthogonal coordinate system, and the second mark MK2 extends from the first mark MK1 in a planar view in a substantially -y direction, and the angle between the extracted first mark MK1 and the directional line segment HL is α°, the aviation unit 7 (data acquisition unit 2) faces in the α° direction. Also, as shown in Fig. 4C, when the position of the second mark MK2 relative to the first mark MK1 is referenced in an xy orthogonal coordinate system, and the second mark MK2 extends from the first mark MK1 in a planar view in a substantially +y direction, and the angle between the extracted first mark MK1 and the directional line segment HL is β°, the aviation unit 7 (data acquisition unit 2) faces in the β° direction. The orientation (data acquisition direction) of the aviation unit 7 in the case shown in Fig. 4B and the orientation (data acquisition direction) of the aviation unit 7 in the case shown in Fig. 4C are 180 degrees different and are exactly opposite directions, but by referring to the position of the second mark MK2, which makes the mark MK asymmetric with respect to the first mark MK1, relative to the first mark MK1 in the xy orthogonal coordinate system, the direction detection information processing circuit can distinguish between the orientation (data acquisition direction) of the aviation unit 7 in the case shown in Fig. 4B and the orientation (data acquisition direction) of the aviation unit 7 in the case shown in Fig. 4C, and can appropriately determine the orientation (data acquisition direction) of the aviation unit 7. The direction detection information processing circuit outputs this determined orientation of the aviation unit 7 (data acquisition direction of the data acquisition unit 2) to the control processing unit 8.

[0037] The first position measurement unit 4 is connected to the control processing unit 8 and is a device that measures the position of the aviation unit 7 (the position of the data acquisition unit 2 (the position of the first camera 2 in this example)) inside the hollow columnar structure under the control of the control processing unit 8. In this embodiment, the position of the aviation unit 7 obtained by the first position measurement unit 4 is a position in an orthogonal plane (a horizontal plane in this embodiment) perpendicular to the extension direction of the hollow columnar structure CB, and the position of the aviation unit 7 is obtained by measuring the distance (horizontal distance) from the aviation unit 7 to the inner wall surface of the hollow columnar structure CB in the orthogonal plane in a plurality of measurement directions that are different from each other in the circumferential direction of the hollow columnar structure CB. For this reason, the first position measurement unit 4 is configured to include a distance measurement device that is configured to be able to measure in the plurality of measurement directions and that measures the distance from the aviation unit 7 to the inner wall surface of the hollow columnar structure CB in the orthogonal plane. More specifically, the first position measurement unit 4 is configured to include a range finder that measures the distance (horizontal distance) multiple times during one revolution at a predetermined sampling interval while rotating the measurement direction in the circumferential direction in the orthogonal plane, for example, a range finder that determines the distance by a so-called TOF (Time of Flight) method by transmitting and receiving measurement pulse waves such as light or ultrasound, such as LiDAR (Light Detection and Ranging). The first position measurement unit 4 is configured to rotate the range finder itself, for example. Alternatively, the first position measurement unit 4 is configured to rotate the measurement pulse waves, for example, by a polygon mirror, during the transmission and reception. The first position measurement unit 4 outputs each of the distances measured in the multiple measurement directions to the control processing unit 8.

[0038] The second position measurement unit 5 is connected to the control processing unit 8 in the same manner as the first position measurement unit 4, and is a device that measures the position of the aviation unit 7 inside the hollow columnar structure according to the control of the control processing unit 8. The second position measurement unit 5 backs up the first position measurement unit 4 when the measurement of the distance by the first position measurement unit 4 is not performed properly, and performs a so-called fail-safe function. For example, when the hollow columnar structure CB is branched or a through hole is formed on the inner wall surface, the measurement of the distance may not work properly with the TOF type range finder. For this reason, the second position measurement unit 5 is a device that measures the distance from the aviation unit 7 to the inner wall surface of the hollow columnar structure CB by a range finder method different from the range finder method of the first position measurement unit 4. More specifically, the second position measurement unit 5 is configured to include a range finder that measures the distance in the same measurement direction as the first position measurement unit 4 while rotating the measurement direction in the circumferential direction, for example, a range finder that obtains the distance by a stereo camera method. In the stereo camera method, the parallax is calculated based on a pair of left and right images captured by a pair of left and right stereo cameras arranged at a base length apart so that their optical axes are parallel to each other, and the distance is calculated based on the calculated parallax and the principle of so-called triangulation. The second position measurement unit 5 outputs the distance measured in the same measurement direction as the first position measurement unit 4 to the control processing unit 8.

[0039] The altitude measurement unit 6 is connected to the control processing unit 8, and is a device that measures the altitude (height) of the aviation unit 7 (the altitude of the data acquisition unit 2 (in this example, the altitude of the first camera 2)) under the control of the control processing unit 8. The altitude measurement unit 6 outputs this measured altitude to the control processing unit 8. The altitude measurement unit 6 is configured to include, for example, a barometer, or a rangefinder that measures the distance from the bottom surface of the hollow columnar structure.

[0040] The IF unit 10 is connected to the control processing unit 8, and is a circuit that inputs and outputs data to and from an external device according to the control of the control processing unit 8. The data is, for example, data inside the structure, and the data inside the structure includes data (in this example, an image inside the structure) acquired by the data acquisition unit 2, which is stored in the storage unit 9 as described below, a data acquisition direction of the data acquisition unit 2 detected by the direction detection unit 3 when acquiring the internal data, and an altitude of the data acquisition unit 2 measured by the altitude measurement unit 6 when acquiring the internal data. The IF unit 10 is configured to include, for example, an interface circuit using the Bluetooth (registered trademark) standard, an interface circuit performing infrared communication such as the IrDA (Infrared Data Association) standard, or an interface circuit using the USB (Universal Serial Bus) standard.

[0041] The communication unit 11 is a device that is connected to the control processing unit 8 and wirelessly communicates with external devices in accordance with the control of the control processing unit 8, and in this embodiment, communicates with the emergency operation unit 13. The communication unit 11 is configured to include, for example, an interface circuit using the Bluetooth (registered trademark) standard, or an interface circuit that performs infrared communication such as the IrDA standard, and may be used in combination with the IF unit 10.

[0042] The inertial measurement unit 12 is connected to the control processing unit 8, and is a device that determines three-dimensional angular velocity and acceleration using a three-axis gyro and a three-directional accelerometer under the control of the control processing unit 8. The inertial measurement unit 12 outputs the measured three-dimensional angular velocity and acceleration to the control processing unit 8. These three-dimensional angular velocity and acceleration are used for attitude control of the aviation unit 7 when flying autonomously.

[0043] The aviation unit 7 is a device that flies autonomously in the atmosphere. In this embodiment, since it flies inside the hollow columnar structure CB, it is configured to include a so-called unmanned aircraft (drone), such as a helicopter or a multicopter. More specifically, the aviation unit 7 is configured to include a multicopter that includes a main body, four arms extending in all directions from the main body, and four rotors provided at the respective tips of the arms. The aviation unit 7 is equipped with a data acquisition unit 2, a direction detection unit 3, first and second position measurement units 4 and 5, an altitude measurement unit 6, a control processing unit 8, a memory unit 9, an IF unit 10, a communication unit 11, and an inertial measurement unit 12. The data acquisition unit 2 is disposed in the main body of the aviation unit 7 so that its data acquisition direction (the first imaging direction of the first camera 2) faces outward along the horizontal direction, and similarly, the first and second position measurement units 4 and 5 are disposed in the main body of the aviation unit 7 so that their respective measurement directions face outward along the horizontal direction. The direction detection unit 3 is disposed in the main body of the aviation unit 7 so that the imaging direction (second imaging direction) of the second camera faces downward along the vertical direction so that the mark MK consisting of the first and second marks MK1 and MK2 can be imaged, and in the example shown in FIG. 2, the bottom surface of the hollow columnar structure CB can be imaged. The second imaging direction of the second camera preferably coincides with a perpendicular line (a line along the vertical direction) passing through the center position of the aviation unit 7. The altitude measurement unit 6 is housed in the main body of the aviation unit 7 so as to be measurable, the control processing unit 8 and the memory unit 9 are housed in the main body of the aviation unit 7 so as to be measurable, the IF unit 10 is housed in the main body of the aviation unit 7 so as to be input / output capable, the communication unit 11 is housed in the main body of the aviation unit 7 so as to be communicable, and the inertial measurement unit 12 is housed in the main body of the aviation unit 7 so as to be measurable. The inertial measurement unit 12 is preferably housed in the main body of the aviation unit 7 so as to be located at the center of gravity of the data acquisition device S.

[0044] The aviation unit 7 is equipped with a microcomputer and the like that controls the autonomous flight by performing attitude control and the like based on the measurement results of various sensors, such as the inertial measurement unit 12, which are necessary for the aviation unit 7 to fly autonomously, using known conventional methods. During the autonomous flight of the aviation unit 7, in this embodiment, the control processing unit 8 instructs the position, altitude, and orientation in the horizontal plane, and the aviation unit 7 flies according to these instructions, thereby controlling the aviation unit 7. The microcomputer of the aviation unit 7 may also serve as the control processing unit 8 and the memory unit 9.

[0045] The storage unit 9 is connected to the control processing unit 8 and is a circuit that stores various predetermined programs and various predetermined data under the control of the control processing unit 8. The various predetermined programs include, for example, a control processing program, which includes a control program that controls each of the units 2 to 7, 9 to 12 of the data acquisition device S according to the function of each unit, a position control program that controls the aviation unit 7 so that the aviation unit 7 is located at the center of the hollow columnar structure in a perpendicular plane (horizontal plane in this embodiment) perpendicular to the extension direction of the hollow columnar structure based on the position of the aviation unit 7 measured by the first and second position measurement units 4 and 5, and an emergency processing program that performs emergency processing such as collision avoidance. The various predetermined data include, for example, data required to execute each of these programs, internal data of the structure, etc. Such a storage unit 9 includes, for example, a ROM (Read Only Memory) which is a nonvolatile storage element, an EEPROM (Electrically Erasable Programmable Read Only Memory) which is a rewritable nonvolatile storage element, etc. The storage unit 9 includes a RAM (Random Access Memory) that serves as a so-called working memory of the control processing unit 8 for storing data and the like generated during execution of the predetermined program.

[0046] In addition, the direction detection information processing circuit of the direction detection unit 3 may be used as both the control processing unit 8 and the memory unit 9, and the memory unit 9 may store the orientation correspondence data as one of the various types of specified data.

[0047] The control processing unit 8 is a circuit for controlling each of the units 2-7, 9-12 of the data acquisition device S according to the function of each unit, and acquiring internal data of the hollow columnar structure by the data acquisition unit 2 while controlling the position, altitude, and orientation of the aerial unit 7. The control processing unit 8 is configured, for example, with a CPU (Central Processing Unit) and its peripheral circuits. In the control processing unit 8, a control unit 81, a position control unit 82, and an emergency processing unit 83 are functionally configured by executing the control processing program.

[0048] The control unit 81 controls each of the units 2 to 7, 9 to 12 of the data acquisition device S according to the function of each unit, and is responsible for controlling the entire data acquisition device S. In this embodiment, when the control unit 81 is notified by the position control unit 82 of the data acquisition direction of the data acquisition unit 2, the altitude of the aviation unit 7, and an instruction for data acquisition, the control unit 81 causes the data acquisition unit 2 to acquire internal data in accordance with the data acquisition instruction, acquires the internal data from the data acquisition unit 2, and stores the acquired internal data in the storage unit 9 as one piece of structure internal data by associating it with the data acquisition direction of the data acquisition unit 2 and the altitude of the aviation unit 7 notified by the position control unit 82.

[0049] The position control unit 82 controls the aviation unit 7 based on the position of the aviation unit 7 determined by the first and second position measurement units 4 and 5 so as to position the aviation unit 7 at the center position of the hollow columnar structure in an orthogonal plane (a horizontal plane in this embodiment) perpendicular to the extension direction of the hollow columnar structure. The center position of the hollow columnar structure is the center of a circumscribing circle for the cross-sectional shape of the orthogonal plane of the hollow columnar structure. More specifically, the position control unit 82 controls the aviation unit 7 based on the position of the aviation unit 7 determined by the first and second position measurement units 4 and 5 to position the aviation unit 7 at the center position of the orthogonal plane of the hollow columnar structure CB by instructing the aviation unit 7 to move by a predetermined movement amount in order to position the aviation unit 7 at the center position of the orthogonal plane of the hollow columnar structure CB.

[0050] More specifically, since the second position measurement unit 5 is a backup for the first position measurement unit 4, the position control unit 82 calculates the specified amount of movement based on each distance measured by the rangefinder of the first position measurement unit 4 in multiple different measurement directions, and controls the aviation unit 7 to move the calculated specified amount of movement.

[0051] For example, the position control unit 82 determines the predetermined amount of movement based on the maximum value of each distance measured by the range finder of the first position measurement unit 4 in a plurality of different measurement directions, and controls the aviation unit 7 to move the determined predetermined amount of movement. In this embodiment, as described above, since the cross-sectional shape of the orthogonal plane of the hollow columnar structure CB is a square, the intersection of two diagonals is the center position of the hollow columnar structure CB as shown in Fig. 5A, and the length of the diagonal as viewed from the center position is a maximum (=(half the length of the diagonal)), which is known from design drawings, actual measurement, etc. For this reason, first, the length of half the diagonal is stored in the memory unit 9 as one of the various data as a position control reference value, and the position control unit 82 extracts the maximum value from among the distances measured by the rangefinder of the first position measurement unit 4 in multiple different measurement directions, and calculates the specified movement amount so that the distance (first distance) in the measurement direction (first measurement direction, for example, the direction of line DS1) in which the maximum value of the extracted distance was measured approaches the position control reference value, while the distance (second distance) in the measurement direction opposite to the first measurement direction (second measurement direction, for example, the direction of line DS9), the distance (third distance) in the measurement direction perpendicular to the first measurement direction at 90 degrees clockwise (third measurement direction, for example, the direction of line DS5), and the distance (fourth measurement direction, for example, the direction of line DS13) each become the position control reference value, and controls the aviation unit 7 to move the specified movement amount thus calculated. For example, if the aviation unit 7 (data acquisition device S) is located near the line DS9 shown in Fig. 5A, the distance is maximized in the measurement direction of the line DS1, and the measurement direction of the line DS1 is set as the first measurement direction, and the distance approaches the position control reference value, while the second to fourth distances in the second to fourth measurement directions, respectively, become the position control reference value. As a result, the aviation unit 7 (data acquisition device S) is located at the center position of the hollow columnar structure CB. The same applies to a regular polygon having a size of at least one square.

[0052] Here, when using such a maximum value, as described above, in cases where the hollow columnar structure CB is branched, or where a through hole is formed on the inner wall surface, etc., the distance in the measurement direction substantially along the diagonal line may not be the maximum value. For this reason, when extracting the maximum value, it is preferable to set a predetermined limit value (upper limit value) in advance, remove distances exceeding the limit value from each of the distances measured by the distance meter of the first position measurement unit 4 in a plurality of different measurement directions, and extract the maximum value from each of the remaining distances.

[0053] Alternatively, for example, the position control unit 82 determines the predetermined amount of movement based on the minimum value of each distance measured by the distance meter of the first position measurement unit 4 in a plurality of different measurement directions, and controls the aviation unit 7 to move the determined predetermined amount of movement. In this embodiment, as described above, since the cross-sectional shape of the orthogonal plane of the hollow columnar structure CB is a square, the intersection of two diagonals is the center position of the hollow columnar structure CB as shown in Fig. 5A, and the length as seen from the center position in the direction perpendicular to each of the two diagonals is the minimum (= (half the length of one side)) and is known from a design drawing, actual measurement, etc. For this reason, first, the length of half of one side is stored in the memory unit 9 as one of the various data as a position control reference value, and the position control unit 82 extracts the minimum value from among the distances measured by the rangefinder of the first position measurement unit 4 in multiple different measurement directions, and calculates the specified movement amount so that the distance (first distance) in the measurement direction (first measurement direction, for example, the direction of line DS3) in which the minimum value of the extracted distances was measured approaches the position control reference value, while determining the specified movement amount so that each of the distance (second distance) in the measurement direction opposite to the first measurement direction (second measurement direction, for example, the direction of line DS11), the distance (third distance) in the measurement direction perpendicular to the first measurement direction at 90 degrees clockwise (third measurement direction, for example, the direction of line DS7), and the distance (fourth distance) in the measurement direction perpendicular to the first measurement direction at 90 degrees counterclockwise (fourth measurement direction, for example, the direction of line DS15) become the position control reference value, and controls the aviation unit 7 to move the specified movement amount determined. The same is true for equilateral triangles and regular polygons with more than one side, such as squares.

[0054] On the other hand, when the hollow columnar structure CB is a cylindrical structure, the distances from the center position to the inner wall surface in a plurality of different measurement directions in the circumferential direction are equal to each other, as shown in Fig. 5B. Therefore, the position control unit 82 determines the predetermined movement amount based on the distances measured by the first position measurement unit 4 in a plurality of different measurement directions in the circumferential direction so that the measured distances become equal to each other, and controls the aviation unit 7 to move by the determined predetermined movement amount. For example, the position control unit 82 determines the predetermined movement amount based on three distances measured by the first position measurement unit 4 at intervals of 120 degrees in the circumferential direction so that the measured distances become equal to each other, and controls the aviation unit 7 to move by the determined predetermined movement amount.

[0055] When the flight unit 7 is controlled based on the distances measured by the first position measurement unit 4 as described above, if the first position measurement unit 4 becomes unable to measure due to, for example, non-reception of the measurement pulse wave, the first position measurement unit 4 is determined to be malfunctioning, and the position control unit 82 controls the flight unit 7 as described above using the measurement result of the second position measurement unit 5 instead of the measurement result of the first position measurement unit 4. Alternatively, for example, since the flight unit 7 is controlled to the central position, the difference between the previous measurement result and the current measurement result is predicted to be small. Therefore, if the difference between the previous measurement result and the current measurement result exceeds a preset threshold, the first position measurement unit 4 is determined to be malfunctioning, and the position control unit 82 controls the flight unit 7 as described above using the measurement result of the second position measurement unit 5 instead of the measurement result of the first position measurement unit 4.

[0056] In this embodiment, the position control unit 82 further controls the aviation unit 7 based on the data acquisition direction (the orientation of the aviation unit 7) of the data acquisition unit 2 obtained by the direction detection unit 3 so that the data acquisition direction faces a predetermined direction. For example, the position control unit 82 controls the aviation unit 7 to rotate the aviation unit 7 at a predetermined angle in the circumferential direction so that the data acquisition direction faces each direction in sequence while hovering the aviation unit 7 at the center position of the hollow columnar structure CB so as to acquire internal data over the entire circumference of the inner wall surface of the hollow columnar structure CB. The predetermined angle is appropriately set according to the data acquisition range of the data acquisition unit 2 and the circumferential length of the inner wall surface of the hollow columnar structure CB, for example, several degrees, 10 degrees, 20 degrees, etc.

[0057] Furthermore, in this embodiment, the position control unit 82 controls the aviation unit 7 so that the aviation unit 7 reaches a predetermined altitude based on the altitude determined by the altitude measurement unit 6. More specifically, the position control unit 82 controls the aviation unit 7 so that the aviation unit 7 reaches a predetermined altitude based on the altitude determined by the altitude measurement unit 6 by instructing the aviation unit 7 to rise a predetermined height in order to reach the predetermined altitude.

[0058] The emergency processor 83 performs emergency processing to avoid collision between the aviation unit 7 and the inner surface of the hollow columnar structure. More specifically, in this embodiment, for example, when the horizontal distance from the aviation unit 7 to the inner wall surface of the hollow columnar structure CB measured by the first and second position measuring units 4 and 5 becomes equal to or less than a predetermined threshold value, the emergency processor 83 transmits a signal (warning signal) for warning the operator of a collision to the emergency operation unit 13 via the communication unit 11. In response to this, when the emergency processor 83 receives a signal (avoidance instruction signal) from the emergency operation unit 13 via the communication unit 11 instructing the aviation unit 7 to avoid the collision, the emergency processor 83 instructs the aviation unit 7 to move by a predetermined movement amount in priority to the instruction of the position control unit 82 in order to move away from the inner surface of the hollow columnar structure CB by a predetermined distance.

[0059] The emergency operation unit 13 is a device that instructs the aircraft unit 7 to avoid a collision. More specifically, the emergency operation unit 13 is configured to include a communication interface circuit that communicates with the communication unit 11, an output unit such as a speaker, an indicator light, and a display device that outputs a collision warning when the warning signal is received from the data acquisition device S via the communication interface circuit, an input unit such as a push button switch that accepts an instruction to transmit an avoidance instruction signal, and a control circuit such as a microcomputer that controls the communication interface circuit, the output unit, and the input unit according to their respective functions.

[0060] Next, the operation of this embodiment will be described. Fig. 6 is a flow chart showing the operation of the data acquisition device with respect to acquisition of internal data of the hollow columnar structure. Fig. 7 is a diagram for explaining the state in which internal data of the hollow columnar structure is acquired by the data acquisition device. Fig. 8 is a diagram for explaining the control of the data acquisition direction in the data acquisition device. Fig. 8A shows the case where the data acquisition direction (first imaging direction) is 0°, Fig. 8B shows the case where the data acquisition direction is 90°, Fig. 8C shows the case where the data acquisition direction is 180°, and Fig. 8D shows the case where the data acquisition direction is 270°.

[0061] When the data acquisition device S having such a configuration is powered on, it initializes each required part and starts its operation. In the control processing unit 8, a control unit 81, a position control unit 82, and an emergency processing unit 83 are functionally configured by executing the control processing program.

[0062] Regarding the acquisition of the internal data of the hollow columnar structure CB, the data acquisition device S operates as follows, and during this operation, the emergency processing unit 83 performs emergency processing to avoid collision between the data acquisition device S and the inner wall surface of the hollow columnar structure CB, as described above. Note that the acquisition interval of the internal data by the data acquisition unit 2 in the circumferential direction is appropriately set as described above, but here it is set to 90 degrees for the sake of simplicity of explanation. Note that the same explanation can be given for other angles.

[0063] Regarding acquisition of internal data of the hollow columnar structure CB, first, a mark MK consisting of a first and a second mark MK1, MK2 is formed (S1) in Fig. 6. More specifically, the mark forming unit 1 is operated, and as shown in Fig. 7, a mark MK is formed on the bottom surface of the hollow columnar structure CB by the mark forming unit 1. For example, an LED tape light is laid on the bottom surface of the hollow columnar structure CB as a first mark MK1 so as to extend in a straight line, and another LED tape light is laid on the bottom surface of the hollow columnar structure CB as a second mark MK2 so as to extend in a straight line from the first mark MK1 at a central position CP in the longitudinal direction of the first mark MK1.

[0064] Next, a predetermined initial setting is performed (S2). For example, in order to facilitate control of the aviation section 7 to its central position, the aviation section 7 is placed on the bottom surface of the hollow columnar structure CB so that the central position of the aviation section 7 coincides with the central position CP of the bottom surface of the hollow columnar structure CB.

[0065] Next, the aviation unit 7 moves a predetermined distance h in the height direction (S3). More specifically, the position control unit 82 of the control processing unit 8 controls the aviation unit 7 based on the altitude calculated by the altitude measurement unit 6 so that the aviation unit 7 reaches a predetermined altitude. For example, in the first (first) ascent, the aviation unit 7 is located in an orthogonal plane of a height position HP1 at an altitude h. Also, for example, in the second ascent, the aviation unit 7 is located in an orthogonal plane of a height position HP2 at an altitude 2h (=h+h). The predetermined distance h is, for example, 0.5 m, 1 m, 1.5 m, etc., and is appropriately set according to the data acquisition range of the data acquisition unit 2, etc. It is preferable that the predetermined distance h is set so that the internal data at adjacent height positions partially overlap at each end. In such a setting, if the aviation section 7 moves in the vertical direction the specified distance h during the initial (first) ascent, internal data of the inner surface from the bottom surface to the distance h / 2 will not be acquired by the data acquisition unit 2, so the aviation section 7 may be controlled to move only half the specified distance h (h / 2) during the first ascent.

[0066] Next, the aviation unit 7 measures the position of the aviation unit 7, moves the aviation unit 7 so that the position of the aviation unit 7 is located at the center position in the orthogonal plane of the hollow columnar structure CB, detects the orientation of the aviation unit 7 (the data acquisition direction of the data acquisition unit 2), and rotates the aviation unit 7 so that the orientation of the aviation unit 7 faces a predetermined direction (S4). More specifically, the position control unit 82 controls the aviation unit 7 to move a predetermined amount based on the position of the aviation unit 7 determined by the first and second position measurement units 4 and 5 so that the aviation unit 7 is located at the center position in the orthogonal plane of the hollow columnar structure CB, and the aviation unit 7 moves according to this control, and the position control unit 82 controls the aviation unit 7 based on the data acquisition direction of the data acquisition unit 2 determined by the direction detection unit 3 (the orientation of the aviation unit 7) so that the data acquisition direction faces a predetermined direction, and the aviation unit 7 rotates according to this control.

[0067] For example, in the orthogonal plane at the height position HP of the altitude h, in the first control, the position of the aviation unit 7 is controlled to be located at the central position, and the second mark MK2 is controlled to extend parallel to the y-axis in the -y direction from the first mark MK1 in a plan view, and the orientation of the aviation unit 7 is controlled to be along the extension direction of the first mark MK1, in order to adjust the orientation of the aviation unit 7 (the data acquisition direction of the data acquisition unit 2) to 0°, as shown in FIG. 8A. In the second control, the aviation unit 7 is controlled to be located at the central position, and by turning counterclockwise (or by turning clockwise), the second mark MK2 is controlled to extend parallel to the x-axis in the +x direction from the first mark MK1 in a plan view, and the orientation of the aviation unit 7 is controlled to be perpendicular to the extension direction of the first mark MK1 (i.e., the orientation of the aviation unit 7 is controlled to be along the extension direction of the second mark MK2), in order to adjust the orientation of the aviation unit 7 to 90°, as shown in FIG. 8B. In the third control, the aviation unit 7 is controlled to be located at the central position, and by rotating counterclockwise (or by rotating clockwise), the second mark MK2 extends parallel to the y-axis in the +y direction from the first mark MK1 in a plan view, as shown in Fig. 8C, in order to adjust the orientation of the aviation unit 7 to 180°, and the orientation of the aviation unit 7 is controlled to be along the extension direction of the first mark MK1. In the fourth control, the aviation unit 7 is controlled to be located at the central position, and by rotating counterclockwise (or by rotating clockwise), the second mark MK2 extends parallel to the x-axis in the -x direction from the first mark MK1 in a plan view, as shown in Fig. 8D, in order to adjust the orientation of the aviation unit 7 to 270°, and the orientation of the aviation unit 7 is controlled to be perpendicular to the extension direction of the first mark MK1 (i.e., the orientation of the aviation unit 7 is controlled to be along the extension direction of the second mark MK2). By rotating in one direction in this manner, the data acquisition direction of the data acquisition unit 2 (the orientation of the flight unit 7) can be set by the asymmetric mark MK consisting of the first and second marks.

[0068] Next, the aviation unit 7 acquires internal data by the data acquisition unit 2 and stores it in the storage unit 9 (S5). More specifically, when the position control unit 82 controls the position and orientation of the aviation unit 7 in process S4, it notifies the control unit 81 of the data acquisition direction of the data acquisition unit 2, the altitude of the aviation unit 7, and an instruction for data acquisition. Upon receiving this notification, the control unit 81 causes the data acquisition unit 2 to acquire the internal data, acquires the internal data from the data acquisition unit 2, and associates the acquired internal data with the notified data acquisition direction of the data acquisition unit 2 and the altitude of the aviation unit 7 (the altitude of the data acquisition unit 2), and stores the acquired internal data in the storage unit 9 as one of the internal data of the structure. For example, in the first (first) instruction, internal data in the 0° direction at the height position HP1 at altitude h is acquired, and the internal data, the data acquisition direction 0°, and the altitude h are associated with each other and stored in the storage unit 9 as one of the internal data of the structure. Furthermore, for example, in response to a second instruction, internal data in a 90° direction at height position HP1 at height h is acquired, and this internal data, the data acquisition direction 90°, and the height h are associated with each other and stored in the storage unit 9 as another piece of internal data of the structure. Furthermore, for example, in response to an eighth instruction, internal data in a 270° direction at height position HP2 at height 2h is acquired, and this internal data, the data acquisition direction 270°, and the height 2h are associated with each other and stored in the storage unit 9 as another piece of internal data of the structure.

[0069] Next, the control unit 81 of the aviation unit 7 determines whether or not the internal data for each direction has been acquired (S6). If the result of this determination is that the internal data for each direction has not been acquired (No), the control unit 81 returns the process to step S4. As a result, steps S4 to S6 are executed in sequence, and the internal data for the next data acquisition direction is acquired in the orthogonal plane at the height position HP of the altitude h, and the internal data for that structure is stored. On the other hand, if the result of the above determination is that the internal data for each direction has been acquired (Yes), the position control unit 82 controls the aviation unit 7 by rotating counterclockwise (or clockwise) so that the orientation becomes 0°, and then executes step S7.

[0070] In this process S7, the control unit 81 of the aviation unit 7 judges whether or not the aviation unit 7 has reached a predetermined altitude, for example, the altitude of the highest imaging position in the hollow columnar structure CB. If the result of this judgment is that the predetermined altitude has not been reached (No), the control unit 81 returns the process to process S3. As a result, each process from process S3 to process S7 is executed sequentially, and each internal data in each direction is obtained in the orthogonal plane at the height position HP of the next altitude h, and each internal data of the structure is stored. On the other hand, if the result of the judgment is that the predetermined altitude has been reached (Yes), the control unit 81 next executes process S8.

[0071] In this process S8, the control unit 81 controls the aviation unit 7 to descend to the bottom surface of the hollow columnar structure CB, and the aviation unit 7 lands on the bottom surface, thereby completing this process.

[0072] When the aviation unit 7 lands, the operator (user) retrieves and acquires the internal structure data stored in the memory unit 9 via the IF unit 10. By referring to the internal data of the acquired internal structure data (in this embodiment, an image of the internal structure), the operator can inspect the inner surface of the hollow columnar structure CB. If an abnormality is found in the internal structure image, the operator can determine the location of the abnormality by referring to the data acquisition direction and altitude associated with the internal structure image in which the abnormality is found. The abnormality is, for example, a crack, a missing inner surface covering member (lining material), or dirt.

[0073] As described above, the data acquisition device S and the data acquisition method implemented therein in this embodiment include the mark forming unit 1, and therefore the data acquisition direction can be found using the first and second marks MK1, MK2 formed by the mark forming unit 1 as landmarks. Therefore, when acquiring internal data of a hollow columnar structure, the data acquisition device S and the data acquisition method can acquire internal data from which the data acquisition direction is known.

[0074] The data acquisition device S and the data acquisition method described above include an aerial unit 7, and therefore can acquire internal data at a plurality of locations (positions) inside the hollow columnar structure without using relatively large-scale temporary structures such as scaffolding or gondolas.

[0075] The data acquisition device S and data acquisition method control the aviation section 7 based on the measured position of the aviation section 7 so that it is positioned at the center of the hollow columnar structure in the perpendicular plane, thereby making it possible to acquire the internal data of the hollow columnar structure with the expected accuracy.

[0076] When the structure of the hollow columnar structure is known, the maximum or minimum value from the central position to the hollow columnar structure can also be obtained in advance. The data acquisition device S and the data acquisition method described above can control the aviation unit 7 so that the distance measured by the first and second position measurement units 4 and 5 becomes the maximum or minimum value, thereby controlling the aviation unit 7 to be located at the central position.

[0077] The data acquisition device S and the data acquisition method described above use the position control unit 82 to control the flight unit 7 so that the data acquisition direction is oriented in a predetermined direction, so that internal data of the hollow columnar structure can be acquired in the predetermined direction.

[0078] In the above embodiment, the data acquisition device S may further include a second direction detector that detects the data acquisition direction of the data acquisition unit 2 by detecting rotational motion, and when it is determined that the direction detector 3 has made an erroneous detection, the second detection result of the second direction detector may be used instead of the detection result of the direction detector 3. Since such a data acquisition device S further includes a second direction detector, it can back up the direction detector 3. FIG. 9 is a diagram for explaining a data acquisition device in a first modified embodiment. FIG. 9A shows an image of the first mark MK1 captured at an altitude where sunlight entering the inside of the hollow columnar structure does not reach, FIG. 9B shows an image of the first mark MK1 captured at an altitude where sunlight entering the inside of the hollow columnar structure reaches, and FIG. 9C is a schematic diagram showing how sunlight enters the inside of the hollow columnar structure. In FIG. 9A and FIG. 9B, the second mark MK2 is omitted for convenience of explanation. For example, if the top of the hollow columnar structure is open, sunlight may penetrate into the hollow columnar structure as shown in Fig. 9C. In such a case, as shown in Fig. 9A, in an image of the first mark MK1 captured at an altitude where the sunlight does not reach, the first mark MK1 is clearly captured and the first mark MK1 is not erroneously detected. However, as shown in Fig. 9B, in an image of the first mark MK1 captured at an altitude where the sunlight reaches, not only the first mark MK1 but also a bright area illuminated by sunlight is captured, so that the optical direction detection unit 3 may erroneously detect the first mark MK1. Even if there is a risk of erroneously detecting such a mark MK, the data acquisition device S can detect the data acquisition direction by further providing a second direction detection unit that backs up the optical direction detection unit 3.

[0079] Such a second direction detector may be configured with a gyro that detects at least one axis of rotational motion, but as described above, the data acquisition device S includes an inertial measurement unit 12 for attitude control when flying autonomously, and therefore this inertial measurement unit 12 is used as the second direction detector. The inertial measurement unit 12 is used for attitude control when flying autonomously, and therefore constantly detects the direction. Whether or not the direction detector 3 has made an erroneous detection is determined by, for example, if the absolute value of the difference between the extension direction of the previous first mark MK1 obtained from the current data acquisition direction, the previous data acquisition direction, and the current extension direction of the first mark MK1, and the extension direction of the previous first mark MK1 itself, is equal to or greater than a preset threshold (erroneous detection determination threshold), the control processing unit 8 determines that the direction detector 3 has made an erroneous detection, and if the absolute value of the difference is less than the erroneous detection determination threshold, the control processing unit 8 determines that the direction detector 3 has not made an erroneous detection. When the attitude of the data acquisition device S (aircraft unit 7) becomes stable after the start of flight, the second direction detection unit corresponds (synchronizes) with the data acquisition direction detected by the direction detection unit 3, and when the control processing unit 8 determines that the direction detection unit 3 has made an erroneous detection, it switches from the detection result of the direction detection unit 3 to the second detection result of the second direction detection unit. The correspondence (synchronization) may be performed periodically at a predetermined time interval or a predetermined altitude interval. Also, after switching from the detection result of the direction detection unit 3 to the second detection result of the second direction detection unit as described above, when the absolute value of the difference between the data acquisition direction obtained by the direction detection unit 3 and the data acquisition direction obtained by the second direction detection unit becomes less than the erroneous detection determination threshold value at each predetermined time interval set in advance, the data acquisition device S returns to the original state and uses the detection result of the direction detection unit 3 instead of the second detection result of the second direction detection unit.

[0080] In the above embodiment, the data acquisition device S may further include a second distance measuring unit 14, as shown by a broken line in FIG. 1, having a measurement direction opposite to the direction toward the inner surface of the hollow columnar structure on which the first and second marks are formed. Since such a data acquisition device S further includes the second distance measuring unit 14, when an obstacle is present in the direction opposite to the direction toward the inner surface of the hollow columnar structure, the obstacle can be avoided. FIG. 10 is a diagram for explaining a data acquisition device in a second modified embodiment. For example, as shown in FIG. 10, the hollow columnar structure CBc may include a first hollow columnar structure CBc1, a second hollow columnar structure CBc2, and a junction structure CBc3 that joins the first and second hollow columnar structures CBc1 and CBc2. The junction structure CBc3 is a structure that joins the fluids flowing in from the first and second inlets and flows them out from one outlet, the first inlet being connected to the top of the first hollow columnar structure CBc1, and the second inlet being connected to the second hollow columnar structure CBc2. When the data acquisition device S ascends inside the first hollow columnar structure CBc1 in order to collect data inside the structure in the first hollow columnar structure CBc1 of such a hollow columnar structure CBc, there is a risk that the data acquisition device S will collide with the inner surface of the junction structure CBc3 because the junction structure CBc3 has a slope at the top of the first hollow columnar structure CBc1. Therefore, by further providing the second distance measuring unit 14, it is possible to detect an obstacle in the direction opposite to the direction toward the bottom surface of the hollow columnar structure CBc where the mark MK is formed (upward in the example shown in FIG. 10), and thus it is possible to avoid the obstacle.

[0081] The second distance measuring unit 14 is configured to include a distance meter that determines distance by a so-called TOF method, similar to the first and second position measuring units 4 and 5, and is connected to the control processing unit 8, measures distance according to the control of the control processing unit 8, and outputs the measurement result to the control processing unit 8. In the example shown in FIG. 2, the second distance measuring unit 14 is disposed on the main body of the flying unit 7 so as to face upward along the vertical direction. When the measurement result of the second distance measuring unit 14 becomes equal to or less than a predetermined threshold (obstacle determination threshold) set in advance, the control processing unit 8 executes a suitable obstacle avoidance process set in advance, such as hovering at that position. The obstacle avoidance process may include a process of transmitting a warning signal to the emergency operation unit 13 via the communication unit 11 to warn the operator of an obstacle, similar to the emergency processing unit 83.

[0082] In the above embodiment, the data acquisition device S controls the aviation unit 7 by the position control unit 82 so as to position the aviation unit 7 at the center of the hollow columnar structure in the orthogonal plane based on the position of the aviation unit 7 determined by the first and second position measurement units 4 and 5. However, the data acquisition device S may measure the distance of the aviation unit 7 from the hollow columnar structure CB, and control the aviation unit 7 by the position control unit 82 so as to position the aviation unit 7 at a predetermined distance from the hollow columnar structure CB in a predetermined direction in an orthogonal plane perpendicular to the extension direction of the hollow columnar structure CB, based on the data acquisition direction of the data acquisition unit 2 determined by the direction detection unit 3 and the measured distance of the aviation unit 7. As described above, the first position measurement unit 4 is configured with a distance measuring device, so that the first position measurement unit 4 can measure the distance of the aviation unit 7 from the inner surface (e.g., the inner surface) of the hollow columnar structure CB in the orthogonal plane. The predetermined direction is appropriately set in advance to, for example, a 0° direction or a 90° direction when each direction of 360° counterclockwise is defined with the extension direction of the first mark MK1 as a 0° direction. The predetermined distance is appropriately set in advance depending on, for example, the cross-sectional size of the hollow columnar structure CB in the orthogonal plane, the assumed area size, etc. In such a data acquisition device S, in the process S4, the data acquisition direction of the data acquisition unit 2 is detected, the distance of the aviation unit 7 is measured, and the aviation unit 7 is controlled so as to be located at a predetermined distance from the hollow columnar structure CB in a predetermined direction. Then, in the next process S5, the aviation unit 7 is controlled so that the data acquisition direction faces a predetermined direction so that internal data can be acquired, and the aviation unit 7 rotates according to this control.

[0083] Such a data acquisition device S controls the aviation part 7 so that it is positioned at a predetermined distance from the hollow columnar structure CB in a predetermined direction on the orthogonal plane, and can acquire internal data of the hollow columnar structure CB with expected accuracy. Since the position of the aviation part 7 is controlled by the direction and distance, the data acquisition device S can be applied to a hollow columnar structure CB having any cross-sectional shape on the orthogonal plane.

[0084] In order to express the present invention, the present invention has been described adequately and sufficiently through the embodiments with reference to the drawings in the above description, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that departs from the scope of the claims described in the claims, the changes or improvements are interpreted as being included in the scope of the claims. [Explanation of symbols]

[0085] S Data acquisition device 1. Mark forming section 2 Data Acquisition Section 3 Direction detection unit 4 1st position measurement section 5 Second position measurement section 6 Altitude measurement section 7 Aviation Department 8 Control processing section 81 Control Unit 82 Position control section

Claims

1. A data acquisition unit that acquires predetermined data representing the internal state of a hollow columnar structure, which is a hollow columnar member; a direction detection unit that determines a data acquisition direction of the data acquisition unit inside the hollow columnar structure based on a predetermined mark; an aviation unit that has the data acquisition unit and the direction detection unit and flies; a position measuring unit that measures the position of the aerial part inside the hollow columnar structure; a position control unit that controls the aviation unit based on the position of the aviation unit measured by the position measurement unit so that the aviation unit is located at a center position of the hollow columnar structure in a plane perpendicular to the extension direction of the hollow columnar structure, the predetermined mark includes a linear first mark extending in one direction on an inner surface of the hollow columnar structure, and a second mark having a predetermined shape in one of one region on one side of the first mark and another region on the other side of the first mark, The aviation unit further includes the position measurement unit and the position control unit, The cross-sectional shape of the hollow columnar structure in the orthogonal plane is a circle, an ellipse, a rectangle, or a regular polygon, the position measurement unit includes a distance measurement unit that measures a distance from the aerial unit to the hollow columnar structure in the orthogonal plane, The position control unit controls the flight unit based on a maximum or minimum value of the distance measured by the distance measuring unit. Data acquisition equipment.

2. A second direction detector is further provided for detecting a rotational motion to determine a data acquisition direction of the data acquisition unit, when it is determined that the direction detection unit has made an erroneous detection, a second detection result of the second direction detection unit is used instead of the detection result of the direction detection unit. The data acquisition device according to claim 1 .

3. a second distance measuring unit having a measurement direction opposite to a direction in which the aerial part moves toward an inner surface of the hollow columnar structure on which the first and second marks are formed; The data acquisition device according to claim 1 or 2.

4. A data acquisition method carried out on a flying aircraft, comprising: a data acquisition step of acquiring predetermined data representing the internal state of a hollow columnar structure, which is a hollow columnar member; a direction detection step of determining a data acquisition direction of the data acquisition step inside the hollow columnar structure based on a predetermined mark; a position measuring step of measuring the position of the aerial part inside the hollow columnar structure; a position control step of controlling the aviation section based on the position of the aviation section measured in the position measurement step so that the aviation section is located at a center position of the hollow columnar structure in a plane perpendicular to the extension direction of the hollow columnar structure, the predetermined mark includes a first mark having a linear shape extending in one direction on an inner surface of the hollow columnar structure, and a second mark having a predetermined shape in one of one region on one side of the first mark and another region on the other side of the first mark, The cross-sectional shape of the hollow columnar structure in the orthogonal plane is a circle, an ellipse, a rectangle, or a regular polygon, the position measuring step includes a distance measuring step of measuring a distance from the aerial part to the hollow columnar structure in the orthogonal plane, The position control step controls the flying unit based on a maximum value or a minimum value of the distance measured in the distance measurement step. Data acquisition method.

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