Measurement device and method

Abstract

To provide a measurement deice and method, which enable accurate and speedy remote measurement of a target.SOLUTION: A measurement device described herein measures a distance to and the shape of a target object by scanning light over the target object, and comprises a focus adjustment unit for adjusting the focus of the light, and a processor. The processor controls the focus adjustment unit when scanning in a sub-scanning direction to focus the light on the target object.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a measurement device and method, and more particularly to a measurement device and method for scanning light on an object to measure the distance to or the shape of the object. [Background technology]

[0002] There is known a technique for scanning a target object with light to measure the distance to the target, its shape, etc. In particular, LiDAR (Light Detection and Ranging or Laser Imaging Detection and Ranging) is known as a technique for irradiating a target object with laser light while scanning it, and measuring the distance to the target, its shape, etc. based on the reflected light (for example, Patent Document 1, etc.).

[0003] Patent Document 2 describes a shape measuring device that scans the surface of an object with light to measure the shape of the object, and performs scanning while adjusting the focus for each measurement point. The shape measuring device described in Patent Document 2 uses the measurement result from the previous measurement point to adjust the focus for the next measurement point. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-1787 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-95261 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, LIDAR technology has made great strides, with on-board LIDAR now capable of instantly measuring distances up to approximately 200 meters. However, there have been issues with accuracy.

[0006] On the other hand, the technique described in Patent Document 2 has the drawback that it takes a long time to perform measurement because focus adjustment is performed for each measurement point.

[0007] An object of one embodiment of the technique of the present disclosure is to provide a measurement device and method that can remotely measure an object with high accuracy and high speed. [Means for solving the problem]

[0008] (1) A measuring device that scans light onto an object to measure the distance to or shape of the object, comprising a focus adjustment unit that adjusts the focus of the light, and a processor, wherein the processor controls the focus adjustment unit to focus the light on the object when scanning in the sub-scanning direction. (2) The measurement device described in (1), wherein the processor focuses light on the object at a specific position set on a scanning line in the main scanning direction. (3) The measuring device according to (2), wherein the specific position is set at a midpoint of scanning in the main scanning direction. (4) The measurement device according to any one of (1) to (3), wherein the processor fixes the focus and scans the light in the main scanning direction.

[0009] (5) The measurement device according to any one of (1) to (4), further comprising a moving body that displaces the measurement position, the moving body moving along a direction intersecting the sub-scanning direction.

[0010] (6) The measurement device according to any one of (1) to (5), wherein the scanning speed of the light in the main scanning direction is faster than the scanning speed in the sub-scanning direction.

[0011] (7) The measuring device according to (5), wherein the scanning speed in the sub-scanning direction is faster than the moving speed of the moving body during measurement.

[0012] (8) The measurement device according to any one of (1) to (7), wherein the processor acquires design data of the object and controls the focus adjustment unit based on the design data.

[0013] (9) A measurement device according to (8), wherein the processor sets a target reference surface on which light is focused based on design data and controls the focus adjustment unit so that the light is focused on the target reference surface.

[0014] (10) The measurement device according to any one of (1) to (7), wherein the processor controls the focus adjustment unit based on the measurement result of the main scan performed earlier.

[0015] (11) A measurement device according to (10), wherein the processor sets a target reference surface on which the light is focused based on the measurement results and controls the focus adjustment unit so that the light is focused on the target reference surface.

[0016] (12) The measurement device according to any one of (1) to (7), further comprising a distance measurement unit, wherein the processor controls the focus adjustment unit based on the distance measurement result of the distance measurement unit.

[0017] (13) A measurement device according to (12), wherein the processor sets a target reference surface on which the light is focused based on the distance measurement result, and controls the focus adjustment unit so that the light is focused on the target reference surface.

[0018] (14) The measurement device according to any one of (1) to (13), wherein the light emitting unit rotates around an axis intersecting the sub-scanning direction to perform scanning in the sub-scanning direction.

[0019] (15) A measurement device according to any one of (1) to (14), in which light from a light source is scanned in the main scanning direction by a polygon mirror, a galvanometer mirror, or an MEMS mirror, and scanning in the sub-scanning direction is performed by rotating the polygon mirror, the galvanometer mirror, or the MEMS mirror around an axis intersecting the sub-scanning direction.

[0020] (16) The measurement device according to any one of (1) to (15), which scans with light whose frequency is periodically modulated.

[0021] (17) The measurement device according to any one of (1) to (16), wherein the object is a tunnel structure, and the sub-scanning direction is a circumferential direction of the tunnel structure.

[0022] (18) The measurement device according to (5), wherein the processor acquires information on the measurement positions and generates three-dimensional shape data of the object based on information on the measurement results for each measurement position.

[0023] (19) The measuring device according to (18), which, when moving along a preset route to make measurements, measures the amount of movement of the moving body and the amount of deviation from the route to obtain information on the measurement position.

[0024] (20) The measurement device according to (18), which acquires information about the measurement position using self-position estimation by SLAM.

[0025] (21) A measurement method for measuring the distance to or shape of an object by scanning light on the object, in which the light is focused on the object during scanning in the sub-scanning direction. [Effects of the Invention]

[0026] According to the present invention, an object can be measured remotely with high accuracy and high speed. [Brief explanation of the drawings]

[0027] [Figure 1] A diagram showing an example of the configuration of a three-dimensional measurement device. [Figure 2] A diagram showing an example of the configuration of a three-dimensional measurement device. [Figure 3] A diagram showing an example of the configuration of a measurement unit consisting of an FMCW lidar [Figure 4] Conceptual diagram of scanning by the scanning unit [Figure 5] Diagram showing how measurement light is incident on a polygon mirror [Figure 6] FIG. 1 is a diagram illustrating an example of a hardware configuration of a control unit. [Figure 7]Block diagram of the main functions of the control unit regarding measurement control [Figure 8] Conceptual diagram of focus control [Figure 9] Conceptual diagram of focus control [Figure 10] Conceptual diagram of focus control [Figure 11] Measurement concept diagram [Figure 12] FIG. 10 is a diagram illustrating the change in separation distance during sub-scanning. [Figure 13] FIG. 10 is a diagram showing another example of a change in the distance to the wall surface during sub-scanning. [Figure 14] Conceptual diagram of measurement results [Figure 15] Conceptual diagram of focusing method using target reference plane [Figure 16] FIG. 10 is a diagram showing another example of focusing in the sub-scanning direction; [Figure 17] FIG. 10 is a diagram showing another example of focusing in the sub-scanning direction; [Figure 18] Diagram showing the schematic configuration of a 3D measurement device [Figure 19] Flowchart showing an example of a measurement procedure DETAILED DESCRIPTION OF THE INVENTION

[0028] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] Here, we will explain an example in which the present invention is applied to a device (three-dimensional measurement device) that uses a lidar to measure the shape of a concrete structure in three dimensions. In particular, we will explain an example in which the present invention is applied to a device that measures the shape of a concrete structure in three dimensions for the purpose of diagnosing deterioration based on lift.

[0030] Here, "floating concrete" refers to the condition in which the concrete near the surface is floating. Floating concrete refers to a state in which the concrete near the surface is losing its integrity with the concrete inside due to continuous cracks inside the concrete, etc.

[0031] Floating areas are detected using the following procedure. First, a height image is generated from the results of 3D measurement of the object. The height image is generated by calculating the height as the difference between the 3D measurement results and a reference plane. The reference plane may be based on previous measurement results, design data for the object (design drawings, etc.), or a curved surface estimated from the 3D measurement results. The generated height image is then analyzed to extract the floating areas. Specifically, the height image is binarized, and the contours are extracted from the binarized image to extract the floating areas. The area, height (average, maximum, etc.), volume, etc. of the extracted floating areas are then calculated.

[0032] Detecting floating requires measuring the object with an accuracy of submillimeter order (approximately 0.5 mm to 0.5 m). To measure the shape of an object remotely with high accuracy using LIDAR, it is necessary to focus the laser light on the surface of the object to be measured, increase the power locally, and increase the scattered light.

[0033] On the other hand, when measuring a large area such as a concrete structure, it is necessary to be able to measure the target quickly.

[0034] In this embodiment, a three-dimensional measuring device is provided that can perform measurements with high precision and high speed even when the distance (separation distance) to the surface to be measured varies greatly.

[0035] [First embodiment] [Configuration of 3D measurement device] FIG. 1 is a diagram illustrating an example of the configuration of a three-dimensional measurement apparatus.

[0036] FIG. 1 shows an example in which a three-dimensional measuring device 100 is installed on a cart 10, and a wall surface (surface) 2 of a tunnel structure 1 is measured from above the cart 10. The cart 10 is manually pushed by a person and moves on rails 11. In this embodiment, the tunnel structure 1 is an example of a concrete structure. Furthermore, the tunnel structure 1 is an example of an object to be measured, and its wall surface 2 is an example of a surface to be measured. Furthermore, the three-dimensional measuring device 100 is an example of a measuring device.

[0037] FIG. 2 is a diagram illustrating an example of the configuration of a three-dimensional measuring device.

[0038] As shown in FIG. 2, the three-dimensional measuring device 100 includes a measuring unit 110, a light source unit 120, a power supply unit 130, a control unit 140, and the like.

[0039] [Measurement unit] The measurement unit 110 scans light onto an object to measure the distance to the object. In this embodiment, the measurement unit 110 is configured as an FMCW (Frequency Modulated Continuous Waves) LIDAR (FMCW LIDAR). The FMCW LIDAR continuously irradiates the object with laser light while modulating the frequency, and calculates the distance to the object from the frequency of the received wave reflected by the object and returned.

[0040] FIG. 3 is a diagram showing an example of the configuration of a measurement unit configured with an FMCW lidar.

[0041] As shown in FIG. 3, the measurement unit 110 includes a beam splitter 111, a reference mirror 112, a focus adjustment unit 113, a scanning unit 114, a light detection unit 115, and the like.

[0042] The beam splitter 111 splits the laser light supplied from the light source unit 120 into a reference light and a measurement light. The reference light is emitted toward a reference mirror 112, and the measurement light is emitted toward a focus adjustment unit 113. The reference light is reflected by the reference mirror 112 and enters the beam splitter 111 again. The measurement light enters the scanning unit 114 via the focus adjustment unit 113.

[0043] The focus adjustment unit 113 adjusts the focal position of the measurement light. As an example, in this embodiment, the focus lens is moved back and forth along the optical axis to adjust the focal position of the measurement light. The focus adjustment unit 113 includes a focus lens and an actuator that drives the focus lens. Note that the focus adjustment method is not limited to this. Alternatively, for example, the focus lens may be configured as a liquid lens, and the focal position may be adjusted by changing the curvature of the lens.

[0044] The scanning unit 114 polarizes the measurement light that has passed through the focus adjustment unit 113 and causes the measurement light to scan the object.

[0045] FIG. 4 is a conceptual diagram of scanning by the scanning unit.

[0046] As shown in FIG. 4, in this embodiment, a polygon mirror (polygonal mirror) PM is used to scan the measurement light onto the object. The polygon mirror PM rotates around the θ axis, reflecting and deflecting the incident light in a direction around the θ axis (θ direction). In this embodiment, the polygon mirror PM is further rotated around the φ axis to deflect the incident light in a direction around the φ axis (φ direction). The φ axis passes through the center of the polygon mirror PM and is orthogonal to the θ axis. Note that the meaning of the term "orthogonal" here includes not only completely orthogonal but also "almost orthogonal," which includes allowable tolerances in design and manufacturing.

[0047] FIG. 5 shows methods of incident measurement light onto a polygon mirror. Two incident methods are shown in FIG. 5. FIG. 5(A) shows a first incident method, and FIG. 5(B) shows a second incident method. The first incident method shown in FIG. 5(A) is a method in which the measurement light is incident onto the polygon mirror PM via two mirrors M1 and M2. The second incident method shown in FIG. 5(B) is a method in which the measurement light is incident directly onto the polygon mirror PM. Either incident method may be used. The incident position of the measurement light also rotates around the φ axis in conjunction with the rotation of the polygon mirror PM around the φ axis.

[0048] According to this configuration, by rotating the polygon mirror PM around the θ axis, the measurement light is scanned in the θ direction. Furthermore, by rotating the polygon mirror PM around the φ axis, the position scanned in the θ direction is displaced in the φ direction. Therefore, by rotating the polygon mirror PM around the θ axis while also rotating it around the φ axis, the measurement light can be scanned onto the object. Scanning in the θ direction is defined as main scanning, and the θ direction is defined as the main scanning direction. Furthermore, scanning in the φ direction is defined as sub-scanning, and the φ direction is defined as the sub-scanning direction. In this embodiment, the polygon mirror PM is an example of a light emission portion. Furthermore, the φ axis is an example of an axis intersecting the sub-scanning direction.

[0049] The polygon mirror PM is driven by a θ-axis motor 114A to rotate around the θ-axis. The polygon mirror PM is also driven by a φ-axis motor 114B to rotate around the φ-axis. The speed Vθ at which the polygon mirror PM rotates around the θ-axis is faster than the speed Vφ at which the polygon mirror PM rotates around the φ-axis (Vθ>Vφ). That is, in this embodiment, the scanning speed of the measurement light in the main scanning direction (Vθ) is faster than the scanning speed in the sub-scanning direction (Vφ).

[0050] 3, the measurement light that is irradiated toward the object and reflected by the object is incident on the beam splitter 111 via the scanning unit 114 and the focus adjustment unit 113. The reflected light of the measurement light that has entered the beam splitter 111 is combined with the reflected light of the reference light and output to the light detection unit 115 as interference light.

[0051] The light detection unit 115 converts the interference light output from the beam splitter 111 into an electrical signal. This electrical signal contains a signal component with a frequency corresponding to the difference between the frequency of the measurement light and the frequency of the reference light. This signal component is called a beat signal. The frequency of the beat signal is also called the beat frequency. There is a correlation between the beat frequency and the distance to the object. Therefore, the distance to the object can be calculated based on the beat frequency.

[0052] [Light source unit] The light source unit 120 supplies measurement laser light to the measurement unit 110. As described above, in this embodiment, the measurement unit 110 is configured with an FMCW LIDAR. Therefore, the light source unit 120 supplies laser light whose frequency is periodically modulated. As an example, in this embodiment, an FSF laser (Frequency-Shifted Feedback Laser) is supplied as the measurement laser light.

[0053] [Power supply unit] The power supply unit 130 includes a battery and supplies power to each component of the three-dimensional measuring device 100 .

[0054] [Control unit] The control unit 140 controls the overall operation of the three-dimensional measuring device 100. The control unit 140 also processes the data measured by the measuring unit 110.

[0055] FIG. 6 is a diagram illustrating an example of a hardware configuration of the control unit.

[0056] The control unit 140 has a configuration as a general computer, that is, it includes a processor 141, a main memory unit 142, an auxiliary memory unit 143, an operation unit 144, a display unit 145, an interface unit (I / F) 146, and the like.

[0057] The processor 141 executes programs and functions as various processing units. As an example, in this embodiment, the processor 141 is configured as a CPU (Central Processing Unit). Various programs and data executed by the processor 141 are stored in the main memory unit 142 and / or the auxiliary memory unit 143. The program is synonymous with software.

[0058] The main storage unit 142 includes a RAM (Random Access Memory) and a ROM (Read Only Memory). The RAM is used as a work area for the processor 141. The ROM stores a basic input / output program and the like.

[0059] The auxiliary storage unit 143 is configured by, for example, a hard disk drive (HDD), a solid state drive (SSD), or the like.

[0060] The operation unit 144 is composed of, for example, a keyboard, a mouse, and the like.

[0061] The display unit 145 is configured by, for example, a liquid crystal display (LCD), an organic electroluminescence diode display (OLED display), or the like.

[0062] The interface unit 146 includes various connection interfaces for connecting the measurement unit 110, the light source unit 120, the power supply unit 130, and the like.

[0063] [Control unit functions] FIG. 7 is a block diagram of the main functions of the control unit regarding measurement control.

[0064] 7, with regard to measurement control, the control unit 140 has functions of a scan control unit 140A, a focus control unit 140B, a signal processing unit 140C, and a recording control unit 140D, etc. The functions of each unit are realized by the processor 141 executing a predetermined program.

[0065] [Scanning control section] The scanning control unit 140A controls the scanning of the measurement light by the measurement unit 110. The scanning control unit 140A controls the scanning unit 114 of the measurement unit 110 to control the scanning of the measurement light. As described above, in this embodiment, the polygon mirror PM is rotated around the θ axis and the φ axis to scan the measurement light onto the object. The scanning control unit 140A controls the driving of the θ axis motor 114A and the φ axis motor 114B to control the scanning of the measurement light.

[0066] [Focus control] The focus control unit 140B controls the focusing of the measurement light. In this embodiment, the focus of the measurement light is adjusted during scanning in the sub-scanning direction.

[0067] 8 to 10 are conceptual diagrams of focusing control. FIG. 8 shows the state of scanning of the measurement light by the three-dimensional measuring device 100 of this embodiment. FIG. 9 shows the state of focusing of the measurement light during scanning in the main scanning direction. FIG. 10 shows the state of focusing of the measurement light during scanning in the sub-scanning direction. FIG. 10 corresponds to the 10-10 cross section of FIG. 9.

[0068] As described above, in the three-dimensional measuring apparatus 100 of this embodiment, the measuring light is focused during scanning in the sub-scanning direction. As an example, in this embodiment, the measuring light is focused when the measuring light is emitted perpendicular to the φ axis. That is, focusing control is performed so that the measuring light emitted perpendicular to the φ axis is focused on the target surface. As a result, as shown in FIG. 10 , the measuring light emitted perpendicular to the φ axis is focused on the target surface. That is, the measuring light is condensed on the target surface. In this way, in the three-dimensional measuring apparatus 100 of this embodiment, the measuring light is focused when the measuring light is emitted perpendicular to the φ axis. That is, focusing is performed only at specific positions in the main scanning direction (in this embodiment, the positions where the measuring light is emitted perpendicular to the φ axis). In this way, the measuring light is focused during scanning in the sub-scanning direction. On the other hand, since focus adjustment is not performed during scanning in the main scanning direction, the degree of condensation of the measuring light decreases as it approaches both ends in the main scanning direction. That is, in scanning in the main scanning direction, the focus is fixed and scanning is performed, so the degree of light concentration decreases as one approaches both ends.

[0069] By focusing the measurement light on the target surface, increasing the power locally, and increasing the scattered light, high-precision measurement is possible even from a distance. As described above, the degree of focusing decreases in the main scanning direction as one approaches both ends. Therefore, the measurement range in the main scanning direction is set within a range that ensures a predetermined level of precision. In other words, the measurement range is set within a range in which light can be focused below a threshold value.

[0070] The focus control unit 140B controls the focus adjustment unit 113 to control the focusing of the measurement light in the sub-scanning direction. Specifically, focusing control is performed at the timing when the measurement light is emitted perpendicular to the φ axis. At this time, focusing is performed using the distance measurement result obtained in the previous main scanning. As an example, focusing is performed using the distance measurement result obtained in the immediately previous main scanning. That is, in this embodiment, focusing in the next main scanning is performed using the distance measurement result obtained in the immediately previous main scanning. The amount of displacement of the scanning position in the sub-scanning direction is minute. Therefore, it can be used as distance measurement information for focusing in the next main scanning. This allows the measurement light to be continuously focused on the target surface in the sub-scanning direction.

[0071] In this embodiment, the position where the measurement light is emitted perpendicular to the φ axis is an example of a specific position set on a scanning line in the main scanning direction. In this embodiment, the specific position is set at the midpoint of scanning in the main scanning direction. That is, the specific position is set at the center of the measurement range (scanning range) in the main scanning direction. More specifically, the measurement range in the main scanning direction is set around the position (specific position) where the measurement light is emitted perpendicular to the φ axis. This allows the measurement range in the main scanning direction to be expanded. Note that the meaning of the terms "center" and "center" here includes not only the meaning of exactly center or center, but also the meaning of "almost center" or "approximately center," which includes tolerances allowed in design and manufacturing.

[0072] The focus control unit 140B acquires information on the distance measurement result obtained in the previous main scan from the signal processing unit 140C and controls focusing in the sub-scanning direction. That is, it adjusts the focus position in the next main scan by referring to the measurement result of the previous main scan. For the measurement result of the previous main scan, for example, the measurement result at the position where the measurement light is emitted perpendicular to the φ axis is used.

[0073] [Signal processing section] The signal processing unit 140C processes the beat signal for each scanning position output from the light detection unit 115, and calculates the distance for each scanning position.

[0074] [Recording control section] The recording control unit 140D records the distance information for each scanning position calculated by the signal processing unit 140C in the measurement data storage unit 140E. The measurement data storage unit 140E is configured by the auxiliary storage unit 143, for example.

[0075] [Measurement operation using a 3D measurement device] Three-dimensional measurement of an object by three-dimensional measurement apparatus 100 of this embodiment configured as described above is performed as follows.

[0076] Fig. 11 is a conceptual diagram of measurement, showing an example of three-dimensional measurement of a wall surface 2 of a tunnel structure 1 having an arc-shaped cross section.

[0077] The axial direction of the tunnel structure 1 is set as the main scanning direction, and the circumferential direction is set as the sub-scanning direction, and the wall surface 2 of the tunnel structure 1 is scanned with measurement light for three-dimensional measurement. The axial direction of the tunnel structure 1 is the same as the laying direction of the rails 11 and the same as the moving direction of the bogie 10. Note that "same" here does not mean completely identical, but means that they can be regarded as the same. In other words, it is a concept that includes a range of almost identical.

[0078] As shown in Fig. 11, the measurement is performed up to the boundary with the ground surface 3. With one boundary as the start point P0 and the other boundary as the end point P1, sub-scanning is performed in the circumferential direction, and the wall surface 2 is measured in three dimensions within a predetermined measurement width.

[0079] In this embodiment, the main scan is performed by rotating the polygon mirror PM around the θ axis, and the sub-scan is performed by rotating it around the φ axis. Therefore, the φ axis is set to be approximately parallel to the axis Tz of the tunnel structure 1, and the wall surface 2 is scanned.

[0080] During scanning, the focus of the measurement light is adjusted. In this embodiment, the focus is adjusted so that the wall surface 2 is in focus during scanning in the sub-scanning direction.

[0081] In the case of a tunnel structure, even if it has an arc-shaped cross-sectional shape, if the position of the axis Tz of the tunnel structure 1 does not coincide with the position of the φ axis, the distance (separation distance) r to the wall surface 2 will fluctuate greatly during secondary scanning.

[0082] FIG. 12 is a diagram illustrating the change in the separation distance during sub-scanning.

[0083] FIG. 12(A) is a diagram showing the relationship between the emission position and irradiation position of the measurement light. In the diagram, the symbol EP indicates the emission position of the measurement light ML, and SP indicates the irradiation position of the measurement light ML. The distance r from the emission position EP to the irradiation position SP is calculated using the equation in the diagram. The angle Φ corresponds to the rotation angle of the polygon mirror PM around the φ axis. Note that the angle is set to 0° when the measurement light ML is emitted horizontally.

[0084] Fig. 12(B) is a graph showing the relationship between the angle Φ and the distance r when the radius R of the tunnel structure 1 is 4350 mm and the emission position EP of the measurement light ML is x1 = 1750 mm, y1 = 1050 mm. As shown in Fig. 12(B), the distance r changes as the angle Φ changes. In other words, the distance to the target surface (wall surface) changes during sub-scanning.

[0085] FIG. 13 is a diagram showing another example of the change in the distance to the wall surface during sub-scanning.

[0086] FIG. 13 shows an example in which the cross section of the tunnel structure 1 is rectangular. FIG. 13(A) is a diagram showing the relationship between the emission position and the irradiation position of the measurement light. FIG. 13(B) is a graph showing the relationship between the angle Φ and the distance r when the width X of the tunnel structure 1 in the x-axis direction (horizontal direction) is 1700 mm, the width Y in the y-axis direction (vertical direction) is 4230 mm, and the emission position EP of the measurement light ML is C = 1700 mm, y1 = 685 mm. In this case, the distance r also changes with the change in the angle Φ. That is, the distance to the target surface (wall surface) changes in the sub-scanning direction. In the case of a rectangular cross section, even if the position of the axis of the tunnel structure and the position of the φ axis are aligned, the distance to the target surface changes in the sub-scanning direction.

[0087] In the three-dimensional measuring apparatus 100 of this embodiment, when the distance to the target surface (wall surface) changes in the sub-scanning direction, the focus of the measuring light is adjusted to follow the change in the distance.

[0088] The focus adjustment is performed using the distance measurement results obtained in the previous main scan. That is, the focus adjustment in the next main scan is performed using the distance measurement results obtained in the previous main scan. This allows the measurement light to be continuously focused on the target surface in the sub-scanning direction.

[0089] As described above, according to the three-dimensional measuring device 100 of this embodiment, focusing is performed by scanning in the sub-scanning direction. This allows for highly accurate measurement of the object even if the distance to the object surface changes due to the sub-scanning. In other words, since the measurement light can be focused on the object surface, highly accurate measurement is possible even from a distance. Furthermore, since focusing is not performed during scanning in the main scanning direction, high-speed measurement is possible. In other words, since scanning is performed with a fixed focus in the main scanning direction, high-speed scanning is possible, thereby increasing the measurement speed.

[0090] FIG. 14 is a diagram showing a conceptual diagram of the measurement results.

[0091] FIG. 14 shows an example of a measurement result when a wall surface 2 of a tunnel structure 1 having an arc-shaped cross section is measured in three dimensions.

[0092] By scanning the wall surface 2 of the tunnel structure 1 once in the circumferential direction, three-dimensional measurement data of the wall surface 2 can be obtained with a width (measurement width) corresponding to the measurement range in the main scanning direction. The data obtained is distance data for each scanning position. Data on the three-dimensional shape of the wall surface 2 (three-dimensional shape data) can be obtained from the three-dimensional measurement data of the wall surface 2. Furthermore, in the case of the tunnel structure 1, data on the three-dimensional shape of the internal space (three-dimensional shape data) can be obtained.

[0093] [Variations] [Modification of focusing in the sub-scanning direction] [Method using the results of a previous main scanning measurement] In the above embodiment, the measurement result of the previous main scan is used to perform focusing in the next main scan. In particular, in the above embodiment, the measurement result of the previous main scan is used to perform focusing in the next main scan, and the measurement result at the position where the measurement light is emitted perpendicular to the φ axis is used. However, the method of using the measurement result is not limited to this.

[0094] It is also possible to use the measurement results of the main scan that have been performed previously to set a reference surface (target reference surface) for the object to be focused on, and to adjust the focus on that target reference surface.

[0095] FIG. 15 is a conceptual diagram of a focusing technique using an object reference plane.

[0096] The target reference surface RP is set as a surface parallel to the φ axis, for example. Therefore, at the position (specific position) where focusing is performed by scanning in the main scanning direction, the measurement light is perpendicular to the target reference surface RP. Note that the meaning of the term "parallel" here includes not only the meaning of completely parallel, but also the meaning of "almost parallel" which includes tolerances allowed in design and manufacturing. The same applies to "orthogonal."

[0097] The target reference surface RP is set, for example, by finding the average value or median value of the measurement range. As an example, the target reference surface RP is set by finding the average value of the measurement range in the immediately preceding main scan. Alternatively, the target reference surface RP is set by finding the median value of the measurement range in the immediately preceding main scan. Focusing control is performed so that the measurement light is focused on the set target reference surface RP at a position where it is emitted perpendicular to the φ axis (= a position where it is emitted perpendicular to the target reference surface RP).

[0098] When measurements are performed densely in the sub-scanning direction, the measurement results of the previous main scanning can be used as is for the target reference surface RP. In this case, as described in the above embodiment, the measurement results at the position where the measurement light is emitted perpendicular to the φ axis may be used, or the average value or median value of the measurement range may be calculated and used. When measurements are performed densely, for example, the focus at a specific position between the previous main scanning and the target is within the depth of field.

[0099] Furthermore, if the measurement target surface 2 has specific irregularities, it is preferable to set the target reference plane RP excluding the irregularities. For example, in the case of a concrete structure, specific irregularities include damaged areas on the concrete surface, such as concrete peeling marks. In addition, electrical equipment installed on the wall surface also falls under the category of irregularities that should preferably be excluded.

[0100] [Method of using distance measurement results from another distance measurement unit] In the above embodiment, the measurement results of the previous main scan are used to perform focusing for the next main scan, but the method of focusing in the sub-scanning direction is not limited to this.

[0101] Fig. 16 is a diagram showing another example of focusing in the sub-scanning direction, which shows an example of focusing in the sub-scanning direction using the distance measurement results of a separately provided distance measurement unit.

[0102] As shown in FIG. 16 , the three-dimensional measuring device of this example is equipped with a ranging unit 150 separate from the measuring unit 110. The ranging unit 150 measures the distance to the target surface in the sub-scanning direction. Note that the distance measurement here is intended to assist in focusing. Therefore, it is sufficient to measure with an accuracy appropriate for that purpose. Therefore, the accuracy can be lower than that of the measurement by the measuring unit 110, and a rougher measurement is also acceptable. The ranging unit 150 is an example of a ranging section. When the target is a tunnel structure, the sub-scanning direction is set to the circumferential direction. Therefore, when the target is a tunnel structure, the ranging unit 150 measures the distance to the target surface (wall surface) along the circumferential direction. The measurement method is not particularly limited. As an example, a ToF (Time Of Flight) lidar (ToF lidar) can be used. Other methods, such as a method using radio waves such as millimeter waves, a method using ultrasonic waves, or a method using infrared rays, can also be used.

[0103] Note that the distance measuring unit 150 does not necessarily need to measure the distance across the entire measurement width (measurement range in the main scanning direction) of the measurement unit 110. It is sufficient to be able to measure the distance at the position where focusing is performed in the sub-scanning direction. For example, when the measurement light is focused at a position where it is emitted perpendicular to the φ axis, it is sufficient to be able to measure the distance at least at the position where the measurement light is emitted perpendicular to the φ axis. Therefore, it is sufficient to be able to measure the distance at at least one cross section.

[0104] When the distance measuring unit 150 measures the distance across the entire measurement width of the measurement unit 110, the measurement results can be used to set a target reference surface and focus on the target reference surface. As described above, the target reference surface is configured as a surface parallel to the φ axis, for example, and is set by finding the average value or median value of the measurement range. If the surface to be measured has specific irregularities, it is preferable to set the target reference surface excluding the irregularities.

[0105] Furthermore, the distance measurement unit does not necessarily have to be provided integrally with the measurement unit 110. In other words, it does not necessarily have to be mounted on the same cart as the measurement unit 110. It is sufficient as long as it is configured to measure the distance or shape of the target in advance. Therefore, for example, it may be configured to use data measured by a distance measurement means separate from the three-dimensional measurement device.

[0106] Furthermore, the method of this example can be combined with a method that utilizes the results of a previous main scanning measurement. That is, a configuration can be adopted in which focusing in the sub-scanning direction is performed using both the results of a previous main scanning measurement and the results of distance measurement by a separate distance measurement unit. For example, a configuration can be adopted in which a target reference surface is set using both the results of a previous main scanning measurement and the results of distance measurement by a separate distance measurement unit, and then the focus is adjusted relative to the target reference surface. Furthermore, for example, a configuration can be adopted in which the results of a previous main scanning measurement are offset from the results of distance measurement by a separate distance measurement unit, and the target reference surface is set.

[0107] [Method of using design data of the object] Fig. 17 is a diagram showing another example of focusing in the sub-scanning direction, which shows an example of focusing in the sub-scanning direction using design data of the object.

[0108] As shown in FIG. 17, in the three-dimensional measuring apparatus of this example, a control unit 140 has the functions of an information acquisition unit 140F, a distance calculation unit 140G, and the like.

[0109] The information acquisition unit 140F acquires various information necessary for measurement, including information about the object (object information), information about the measurement position (measurement position information), and the like.

[0110] The object information includes information such as the shape and size of the object. The information such as the shape and size of the object is, for example, composed of design data of the object. The design data is, for example, composed of drawing data, CAD (Computer Aided Design) data, etc.

[0111] The measurement position is information about the relative position of the object relative to the three-dimensional measuring device 100. When the object is a tunnel structure, the position of the three-dimensional measuring device 100 within the tunnel corresponds to the measurement position.

[0112] Distance calculation unit 140G calculates the distance to the target surface (wall surface) in the sub-scanning direction based on information about the measurement position and information about the shape and size of the target.

[0113] The focus control unit 140B controls the focusing of the measurement light in the sub-scanning direction based on the information about the distance calculated by the distance calculation unit 140G.

[0114] In this example, too, a target reference plane can be set and the focus can be adjusted to the target reference plane.

[0115] [Other Modifications for Focusing in the Sub-Scanning Direction] In the above embodiment, the measuring light is focused at the timing when the measuring light is emitted in the direction perpendicular to the φ axis, but the position where the focusing is performed is not limited to this. For example, the focusing may be performed at the end position on one side of the main scanning direction (the start point or end point of the main scanning).

[0116] Furthermore, the position where the focus is set on the measurement target surface or target reference surface does not necessarily have to coincide with the position where the focus is actually changed. For example, in the above embodiment, the focus position is set so that the target surface or target reference surface is in focus at a specific position (the position where the measurement light is emitted in a direction perpendicular to the φ axis), and the focus position is changed at that specific position, but the focus position may also be changed at another position. For example, the focus position may be changed at the start position of scanning in the main scanning direction. In this case, the target surface or target reference surface is in focus at least at the specific position (the position where the focus is set).

[0117] Alternatively, the focal point may be changed continuously in the sub-scanning direction. For example, the focal point position of the measurement light may be changed during the main scan to control the focal point position so that the measurement target surface or target reference surface is in focus at a specific position.

[0118] Furthermore, in the above embodiment, the measurement results obtained in the immediately preceding main scan are used to adjust the focus for the next main scan, but the measurement results used do not necessarily have to be those from the immediately preceding main scan.

[0119] In the above embodiment, focusing in the sub-scanning direction is performed every time a main scan is performed, but focusing in the sub-scanning direction may be performed every n main scans. For example, in a configuration in which main scans are performed using a polygon mirror, focusing in the sub-scanning direction may be performed every n rotations of the polygon mirror.

[0120] [Variations of measurement method] In the above embodiment, the measurement unit 110 is configured as an FMCW LIDAR, but the measurement unit 110 can also be configured as a ToF LIDAR. However, to measure distances with high accuracy, it is preferable to use an FMCW LIDAR.

[0121] [Variations of scanning method] In the above embodiment, a polygon mirror is used as a means for deflecting the measurement light in the main scanning direction, but the means for deflecting the measurement light in the main scanning direction is not limited to this. Alternatively, a deflection means such as a galvanometer mirror or a MEMS (Micro Electro Mechanical Systems) mirror may be used to deflect the measurement light in the main scanning direction.

[0122] In the above embodiment, the polygon mirror is rotated around the φ axis to deflect the measurement light in the sub-scanning direction, but the means for deflecting the measurement light in the sub-scanning direction is not limited to this. For example, the position or direction of the light incident on a deflector such as a polygon mirror may be changed along the sub-scanning direction to deflect the measurement light in the sub-scanning direction.

[0123] Furthermore, deflection in the sub-scanning direction may be configured to be continuous or intermittent. When deflected intermittently, for example, the scanning position is displaced in the sub-scanning direction for each main scan. In the configuration of the above embodiment, the polygon mirror PM is rotated by a predetermined angle around the φ axis for each main scan to deflect the measurement light in the sub-scanning direction.

[0124] [Second embodiment] Here, a configuration for continuous three-dimensional measurement of a tunnel structure along its axial direction will be described, that is, a configuration for three-dimensional measurement of the entire length of the tunnel structure will be described.

[0125] FIG. 18 is a diagram showing a schematic configuration of a three-dimensional measuring device.

[0126] To measure a tunnel structure in three dimensions over its entire length, it is necessary to measure while changing the position along the axial direction of the tunnel structure. When measuring while changing the position, it is necessary to identify the measurement position.

[0127] As shown in FIG. 18, the three-dimensional measuring apparatus 100 of this embodiment includes a position measuring unit 160 in order to identify the measurement position by the three-dimensional measuring apparatus 100.

[0128] The configuration of the three-dimensional measuring device 100 of the first embodiment is substantially the same as that of the three-dimensional measuring device 100 of the first embodiment, except for the inclusion of the position measurement unit 160. Therefore, only the position measurement unit 160 and the measurement method for a tunnel structure using the three-dimensional measuring device 100 will be described here.

[0129] [Position measurement unit] The position measurement unit 160 measures the position (measurement position) of the three-dimensional measuring device 100. As described above, the measurement position is the relative position of the three-dimensional measuring device 100 with respect to the object. When the object is a tunnel structure 1, the position of the three-dimensional measuring device 100 inside the tunnel is measured.

[0130] In this embodiment, the three-dimensional measuring device 100 is installed on a cart 10, and the measurement position is displaced by moving the cart 10. The cart 10 is an example of a moving body.

[0131] In this embodiment, a carriage 10 moves on rails 11. That is, in this embodiment, a three-dimensional measuring device 100 moves (displaces) along a specified route within the tunnel. If the position of the rails 11 relative to the tunnel structure 1 is known, the measurement position can be identified by the movement distance from a reference position. The reference position can be, for example, the end (opening) of the tunnel structure 1.

[0132] In this embodiment, the position measurement unit 160 has a travel distance measurement unit 160A that measures the travel distance of the bogie 10. The travel distance measurement unit 160A measures, for example, the number of rotations of the wheels of the bogie 10 to measure the travel distance of the bogie 10. Specifically, the number of rotations of the wheels is measured, and the travel distance of the bogie 10 is measured based on the known circumference or outer diameter of the wheels.

[0133] In this embodiment, in order to perform position detection with higher accuracy, the amount of lateral deviation of the bogie 10 on the rail 11 is measured. That is, the amount of deviation in a direction perpendicular to the traveling direction is measured. The position measurement unit 160 has a lateral deviation measurement unit 160B that measures the amount of lateral deviation of the bogie 10. The lateral deviation measurement unit 160B measures, for example, the amount of deviation of the bogie 10 in the lateral direction (the axial direction of the wheels) relative to the rail 11. The measurement method is not particularly limited.

[0134] The position measurement unit 160 outputs a set of information on the movement distance measured by the movement distance measurement section 160A and information on the amount of lateral displacement measured by the lateral displacement measurement section 160B to the control unit 140 as information on the measured position.

[0135] The control unit 140 associates information about the distance at each scanning position measured by the measurement unit 110 with information about the measurement position measured by the position measurement unit 160, and records the information in the measurement data storage unit 140E.

[0136] [3D measurement of tunnel structures] Here, an example will be described in which design data of the tunnel structure 1 exists and the shape, size, etc. are known. In this case, the design data of the tunnel structure 1 can be used to perform focusing in the sub-scanning direction.

[0137] In this example, a case will be described in which measurement and movement are repeated to perform three-dimensional measurement over the entire length of the tunnel structure 1. That is, the movement is stopped during measurement, and after measurement of one circumference is completed, movement to the next measurement position is repeated to perform measurement over the entire length.

[0138] FIG. 19 is a flowchart showing an example of a measurement procedure.

[0139] First, object information is acquired (step S1). Here, information including design data of the tunnel structure is acquired. As described above, the information necessary for focusing in the sub-scanning direction can be acquired from the design data. In addition, it becomes possible to identify the measurement position and the scanning position from the design data.

[0140] Next, information on the measurement position is acquired (step S2). The measurement position is identified from the movement distance from a predetermined reference position and the amount of lateral displacement.

[0141] Next, the scanning position is calculated (step S3). That is, the position where the wall surface 2 of the tunnel structure 1 is scanned is calculated.

[0142] Next, the focusing position is calculated (step S4). That is, the focusing position in the sub-scanning direction is calculated. When measuring the tunnel structure 1, the sub-scanning direction is set to the circumferential direction of the tunnel structure 1. Therefore, the main scanning direction is the axial direction of the tunnel structure 1. The axial direction of the tunnel structure 1 is essentially synonymous with the movement direction (travel direction) of the carriage 10.

[0143] After calculating the focusing position, three-dimensional measurement is performed (step S5). That is, the wall surface 2 is scanned with the measurement light, and the wall surface 2 is measured in three dimensions. At this time, the measurement light is focused by scanning in the sub-scanning direction. This makes it possible to measure the distance to the wall surface 2 with high accuracy even if the separation distance changes.

[0144] The measurement is performed up to the boundary with the ground (see FIG. 11). Sub-scanning is performed in the circumferential direction from the boundary on one side to the boundary on the other side, and the wall surface 2 is measured in three dimensions.

[0145] The measured distance information at each scanning position is associated with the information on the measurement position and recorded in the measurement data storage unit 140E (step S6).

[0146] After completing the measurement for one circumference, it is determined whether the measurement position is the measurement end position (step S7), that is, whether the measurement for the entire length has been completed.

[0147] If the end position has been reached, the measurement is terminated. On the other hand, if the end position has not been reached, the measurement is performed by moving (step S8) and measuring at the next measurement position. The movement is performed by an amount corresponding to the measurement width. At this time, to prevent measurement omissions, the measurement ranges are moved so that they overlap between adjacent measurement positions.

[0148] In this way, by repeating the movement and measurement, the entire length of the tunnel structure 1 can be measured in three dimensions.

[0149] By integrating the measurement data for each measurement position (measurement data for the distance at each scanning position), measurement data for the entire length can be obtained. The measurement data for the entire length constitutes data that shows the three-dimensional shape of the wall surface 2 of the tunnel structure 1. In addition, this data constitutes data that shows the three-dimensional shape of the internal space of the tunnel structure 1.

[0150] The measurement results are used for diagnosing floating as a concrete deterioration diagnosis, as well as for measuring displacement inside a tunnel, measuring concrete peeling, spalling, and spalling marks. In other words, they are used for measuring and diagnosing things that can be correlated with surface displacement. In other words, the three-dimensional measuring device 100 of this embodiment is suitable for use in these measurements, diagnoses, etc.

[0151] [Variations] [Variations of measurement method] In the above embodiment, the movement of the carriage 10 is stopped during measurement, but it may be configured to measure while moving. That is, it may be configured to scan while moving. In this case, it is preferable to set the scanning speed in the sub-scanning direction to be faster than the movement speed of the carriage 10 during measurement. That is, it is preferable to set the movement speed of the carriage 10 to be slower than the scanning speed in the sub-scanning direction. This makes it possible to prevent measurement omissions.

[0152] Furthermore, when performing a sub-scan, the polygon mirror PM may be configured to rotate continuously around the φ axis, or to move back and forth within the measurement range in the sub-scanning direction (measurement range in the circumferential direction). In other words, the polygon mirror PM may be configured to rotate around the φ axis within a predetermined rotation angle range to perform a sub-scan.

[0153] [Variations of the method for identifying measurement positions] In the above embodiment, the moving distance and lateral deviation of the carriage 10 moving on the rail 11 are measured to identify the measurement position, but the method for identifying the measurement position is not limited to this. For example, a configuration can be adopted in which the measurement position is identified using a self-position estimation technique using SLAM (Simultaneous Localization and Mapping). The SLAM technique itself is well known, so a detailed description thereof will be omitted. SLAM using a lidar, SLAM using a camera, etc. can be adopted.

[0154] Other configurations for positioning include a positioning system using a beacon, IMES (Indoor Messaging System), Wi-Fi (registered trademark), or UWB (Ultra-Wideband), etc. Also, various sensors such as an acceleration sensor, a magnetic sensor, and an angular velocity sensor may be installed on the cart 10 or the three-dimensional measuring device 100, and the measurement position may be estimated based on the values ​​obtained from each sensor.

[0155] In addition, in a configuration in which the moving distance and the amount of lateral deviation of the carriage 10 are measured to identify the measurement position, the amount of lateral deviation may be obtained using the measurement results of the three-dimensional measuring device 100.

[0156] [Variations of the method for changing the measurement position] In the above embodiment, the three-dimensional measuring device 100 is installed on a cart 10 that is manually pushed by a person and moves on rails 11, and the measurement position is changed by the movement of the cart 10. However, the method for changing the measurement position of the three-dimensional measuring device 100 is not limited to this. The three-dimensional measuring device 100 may be installed on an automatically traveling cart, and the measurement position may be changed. Furthermore, the three-dimensional measuring device 100 may be installed on an automobile, train, or the like, not limited to a cart, and measurement may be performed thereon. Furthermore, the three-dimensional measuring device 100 may be mounted on a self-propelled robot, unmanned aerial vehicle (drone), or the like, and measurement may be performed thereon. Note that when a cart is used as the moving body, the cart does not necessarily have to run on rails, and a cart configured to run directly on the ground can also be used. Furthermore, a cart that is manually pushed by a person and moves thereon may be equipped with a so-called electric assist mechanism.

[0157] [Other embodiments] [Hardware configuration] In this embodiment, each process is executed by a computer. The computer may execute these processes by a processor, a program, or a combination thereof. The computer may be a general-purpose computer, a computer for specific purposes, a system such as a workstation, or other hardware element capable of executing a program.

[0158] The processor may be composed of one or more pieces of hardware, and the type of hardware is not limited. For example, the processor may be composed of hardware such as a programmable logic device such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or an FPGA (Field Programmable Gate Array), a dedicated circuit for executing specific processes such as an ASIC (Application Specific Integrated Circuit), a GPU (Graphic Processing Unit), or an NPU (Neural Processing Unit). The processor also has units or means for executing various processes in the present embodiment. The type of hardware may also be a combination of different types of hardware. When multiple pieces of hardware are configured to execute one or more processes of a certain processor, the multiple pieces of hardware may exist in devices physically separated from each other or in the same device. In any of the embodiments, the order of the processes performed by the processor is not limited to the order described above and may be changed as appropriate. The hardware may be composed of an electric circuit or the like, which is a combination of circuit elements such as semiconductor devices.

[0159] Furthermore, the present embodiment may be realized by hardware, software, firmware, microcode, or a combination thereof. Software, firmware, and microcode are configured by a program. A program may also be, for example, a group of program modules, each function of which may be implemented by a processor configured to execute the respective function. The program may be, for example, a program code and / or multiple code segments stored in one or more non-transitory computer-readable media (e.g., storage media and other storages). The program may be stored in multiple non-transitory computer-readable media that reside in physically separate devices. The program code or code segment may represent a procedure, a function, a subprogram, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. The program code or code segment may be connected to another code segment or a hardware circuit by sending or receiving information, data, arguments, parameters, or memory contents.

[0160] [Measurement target] In the above embodiment, the 3D measuring device 100 is used to measure a tunnel structure, but the object to be measured is not limited to this. The device can be used for 3D measurement of concrete structures such as bridges and buildings.

[0161] Furthermore, as described above, the measurement results can be suitably used for diagnosing the floating of concrete as a deterioration diagnosis, as well as for measuring displacement inside tunnels, and measuring peeling, spalling, and traces of peeling of concrete.

[0162] [others] The above-described embodiments and their modifications can be used in appropriate combinations. [Explanation of symbols]

[0163] 1 Tunnel structures 2. Wall 3 ground 10 carts 11 Rail 100 3D measuring device 110 Measurement Unit 111 Beam Splitter 112 Reference Mirror 113 Focus adjustment section 114 Scanning unit 114A θ-axis motor 114B φ-axis motor 115 Light detection unit 120 Light Source Unit 130 Power Supply Unit 140 Control Unit 140A Scanning control section 140B Focus control unit 140C Signal processing section 140D Recording control section 140E Measurement data storage unit 140F Information acquisition department 140G distance calculation part 141 processors 142 Main memory 143 Auxiliary storage 144 Operation section 145 Display section 146 Interface section 150 Ranging Unit 160 Position Measurement Unit 160A Travel distance measurement unit 160B Horizontal displacement measurement unit M1 mirror M2 mirror ML measurement light PM Polygon Mirror EP Measurement light emission position SP Measurement light irradiation position Tz Axis of tunnel structure RP target reference plane

Claims

1. A measurement device that scans light on an object to measure a distance to or a shape of the object, a focus adjustment unit that adjusts the focus of the light; a processor; Equipped with the processor controls the focus adjustment unit to focus the light on the object during scanning in the sub-scanning direction; Measuring equipment.

2. the processor focuses the light onto the object at a specific position set on a scan line in the main scanning direction; The measurement device according to claim 1 .

3. the specific position is set at a midpoint of scanning in the main scanning direction; The measurement device according to claim 2 .

4. the processor causes the light to scan while fixing a focus in the main scanning direction; The measurement device according to claim 3 .

5. further comprising a moving body that displaces the measurement position; The movable body moves along a direction intersecting the sub-scanning direction. The measuring device according to any one of claims 1 to 4.

6. the scanning speed of the light in the main scanning direction is faster than the scanning speed in the sub-scanning direction; The measuring device according to any one of claims 1 to 4.

7. the scanning speed in the sub-scanning direction is faster than the moving speed of the movable body during measurement; The measurement device according to claim 5 .

8. The processor: acquiring design data of the object; controlling the focus adjustment unit based on the design data; The measuring device according to any one of claims 1 to 4.

9. The processor: setting a target reference surface on which the light is focused based on the design data; controlling the focus adjustment unit so that the light is focused on the target reference plane; The measurement device according to claim 8.

10. the processor controls the focus adjustment unit based on a measurement result obtained in a previous main scan. The measuring device according to any one of claims 1 to 4.

11. The processor: Based on the measurement result, a target reference surface is set on which the light is focused; controlling the focus adjustment unit so that the light is focused on the target reference plane; The measurement device according to claim 10.

12. Further comprising a distance measuring unit, the processor controls the focus adjustment unit based on the distance measurement result of the distance measurement unit. The measuring device according to any one of claims 1 to 4.

13. The processor: setting a target reference plane on which the light is focused based on the distance measurement result; controlling the focus adjustment unit so that the light is focused on the target reference plane; The measurement device according to claim 12.

14. the light emitting portion rotates around an axis intersecting the sub-scanning direction to perform scanning in the sub-scanning direction; The measuring device according to any one of claims 1 to 4.

15. The light from the light source is scanned in a main scanning direction by a polygon mirror, a galvanometer mirror, or a MEMS mirror; The polygon mirror, the galvanometer mirror, or the MEMS mirror is rotated around an axis intersecting the sub-scanning direction to perform scanning in the sub-scanning direction. The measuring device according to any one of claims 1 to 4.

16. scanning the light whose frequency is periodically modulated; The measuring device according to any one of claims 1 to 4.

17. the object is a tunnel structure, The sub-scanning direction is the circumferential direction of the tunnel structure. The measuring device according to any one of claims 1 to 4.

18. The processor: Obtain information on the measurement location, generating three-dimensional shape data of the object based on information of the measurement results for each measurement position; The measurement device according to claim 5 .

19. When measuring by moving along a preset route, measuring the amount of movement of the moving object and the amount of deviation from the path, and acquiring information on the measured position; The measurement device according to claim 18.

20. acquiring information about the measured position using self-position estimation by SLAM; The measurement device according to claim 18.

21. A measurement method for measuring a distance to or a shape of an object by scanning light on the object, comprising: In scanning in the sub-scanning direction, the light is focused on the object and measured. Measurement method.

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