JP2020034296A - Valid distance acquisition method and laser measurement method - Google Patents

Abstract

To provide a valid distance acquisition method and a laser measurement method for enabling measurement with high accuracy while reducing the amount of work.SOLUTION: The valid distance acquisition method includes a scanning step S0, an error acquisition step S1, and a distance acquisition step S2. The error acquisition step includes a step S11 of creating point group data which is a set of reflection points P of laser light, a step S12 of extracting a target point group Ga which is a set of reflection points P corresponding to a reference plane BP of an acquisition structure OC from the point group data, and a step S13 of acquiring a separation distance D between the reflection point P included in the target point group Ga and the reference plane BP as a measurement error. In the distance acquisition step S2, a valid distance is acquired as the distance between the acquisition structure OC and a laser measurement device 1 in which the measurement error is smaller than a first reference value.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an effective distance acquisition method and a laser measurement method.

  Patent Literature 1 describes a measurement operation performed by running a measurement vehicle on a road surface. The measurement vehicle is equipped with a measurement device for mobile mapping. In this measuring operation, various measuring devices such as cameras are repeatedly driven at predetermined intervals or the like as the measuring vehicle travels on the road surface. The captured images and the like obtained thereby are recorded in a storage device mounted on the measurement vehicle. Thus, the omnidirectional direction including the zenith direction is continuously photographed from the road side along the road length, and the laser distance is measured continuously over almost the entire periphery.

JP-A-2017-10082

  By the way, in a mobile mapping system (hereinafter, referred to as “MMS”) for measuring a road surface, a marking such as a lane marking drawn on the road surface or a road incidental object such as a manhole existing on the road surface is measured as a coordinate known point. Accuracy can be improved by using it for data correction.

  On the other hand, it is conceivable to use MMS for measurement of an object far from the road surface, such as a slope of a cut prepared in road construction or the like. In this case, the work of setting a known point on the slope and the work of surveying the slope are required to correct the measurement data, so that the amount of work for high-precision measurement increases.

  Therefore, an object of the present invention is to provide an effective distance acquisition method and a laser measurement method that enable high-accuracy measurement while reducing the amount of work.

  In order to solve the above problem, an effective distance obtaining method according to the present invention is an effective distance obtaining method for obtaining an effective distance for laser measurement, and uses a laser measuring device mounted on a moving body to move the effective distance. With the movement of the body, a scanning step of scanning the area including the structure separated from the moving path of the moving body with the laser light, and after the scanning step, an error obtaining step of obtaining a measurement error of laser measurement, A distance obtaining step of obtaining an effective distance after the obtaining step, wherein the error obtaining step includes: a first step of generating point cloud data that is a set of reflection points of the laser beam; Extracting a target point group, which is a set of reflection points corresponding to the reference plane, and acquiring a separation distance in the normal direction of the reference plane between the reflection point included in the target point group and the reference plane as a measurement error And a third step of In the obtaining step obtains the distance between the laser measuring device and the structure of the measurement error becomes smaller than the first reference value as valid distances.

  In this effective distance obtaining method, first, a laser beam is scanned on an area including a structure separated from a moving path of the moving body by using a laser measurement device mounted on the moving body. Subsequently, point cloud data, which is a set of reflection points of the laser light, is generated, and a target point cloud corresponding to the reference plane of the structure is extracted from the point cloud data. Then, the separation distance between the target point group and the reference plane is acquired as a measurement error. As a result, a measurement error at a position separated from the moving path of the moving body is grasped. Thereafter, a distance at which the measurement error is smaller than the first reference value is acquired as an effective distance. Therefore, at the time of actual laser measurement of the measurement object separated from the moving path of the moving object, the measurement error is made smaller than the first reference value by creating the measurement data using the reflection points within the range of the effective distance. It is possible to do. As described above, according to this effective distance acquisition method, there is no need to install or measure a coordinate known point for a measurement target entering a distant place, that is, to reduce the amount of work and achieve high accuracy. Measurement becomes possible.

  In the effective distance obtaining method according to the present invention, the error obtaining step further includes a fourth step of checking the accuracy of the laser measurement based on the measurement error, and as a result of the fourth step, the accuracy is lower than the second reference value. In this case, the device parameters including the angle of the laser measurement device are calibrated, and the error acquiring step is performed again. As a result of the fourth step, the accuracy is the second reference value or higher than the second reference value. In this case, a distance acquisition step may be performed. In this case, the effective distance can be acquired in a device parameter in which the accuracy of the point cloud data is equal to or higher than the second reference value.

  In the effective distance acquisition method according to the present invention, by performing a scanning step, an error acquisition step, and a distance acquisition step at a plurality of distances between the laser measurement device and the structure, for each of the plurality of distances The effective distance may be obtained. In this case, an effective distance can be acquired for each of a plurality of distances from the laser measurement device.

  In the effective distance obtaining method according to the present invention, while changing the irradiation conditions including the laser irradiation parameters and the moving speed of the moving body in the scanning process, the scanning process and the error obtaining process are performed a plurality of times, so that the irradiation conditions and measurement errors May be obtained. In this case, the relationship between the irradiation condition and the measurement error can be grasped.

  In the effective distance obtaining method according to the present invention, in the scanning step, the scanning of the laser beam may be performed on each of the forward path and the return path of the moving path of the moving body. In this case, the measurement error and the effective distance can be acquired more accurately by performing the scanning with the laser beam under the irradiation conditions different from the forward path and the backward path.

  In the effective distance acquiring method according to the present invention, in the scanning step, the scanning of the laser beam may be performed using each of the plurality of laser measurement devices mounted at different positions on the moving body. In this case, a measurement error and an effective distance can be acquired for laser measurement by each of the plurality of laser measurement devices at different positions.

  In the effective distance acquiring method according to the present invention, the error acquiring step includes, between the first step and the second step, a known point existing on the movement route and a reference point which is a reflection point corresponding to the known point. A fifth step of confirming a reference error which is an error of the following steps: and, as a result of the fifth step, when the reference error is larger than the third reference value, the reference error is equal to or smaller than the third reference value. And a sixth step of adjusting the point cloud data so that is also smaller. In this case, the accuracy of the laser measurement with respect to an actual distant place can be ensured by managing the point cloud data using the error (reference error) between the moving body (laser measuring device) and the known point having relatively close coordinates.

  A laser measurement method according to the present invention includes a preparation step of performing any one of the above-described effective distance acquisition methods, and a measurement step of performing laser measurement of a measurement target separated from a moving path of a moving object, and includes a measurement step. The seventh step of acquiring the measurement point group data, which is a set of reflection points of the laser light, by scanning the measurement object with the laser light in accordance with the movement of the moving object, and includes the measurement point group data. An eighth step of creating measurement data using reflection points whose distance to the laser measurement device is within the effective distance range among the reflection points to be measured. In this laser measurement device, the effective distance is acquired by using any of the effective distance acquisition methods described above. Therefore, highly accurate measurement can be performed while reducing the amount of work.

  ADVANTAGE OF THE INVENTION According to this invention, the effective distance acquisition method and the laser measurement method which enable highly accurate measurement while reducing the amount of work can be provided.

It is a schematic diagram which shows a laser measuring device. FIG. 4 is a diagram for explaining scanning of laser light in the laser measurement device. It is a flowchart which shows the main process of an effective distance acquisition method. FIG. 4 is a diagram for explaining each step shown in FIG. 3. FIG. 3 is a diagram for explaining laser irradiation parameters. It is a figure showing the conventional laser measuring method and the laser measuring method concerning this embodiment.

  Hereinafter, an embodiment will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate description may be omitted.

  FIG. 1 is a schematic diagram showing a laser measurement device. As shown in FIG. 1, the laser measurement device 1 is mounted on a vehicle (moving body) 100. Various devices used for the MMS are mounted on the vehicle 100. Specifically, the vehicle 100 includes an IMU (Inertial Measurement Unit) 3, imaging devices 5 and 7, a DMI (distance measuring instrument) 9, and a GNSS (Global Navigation Satellite System). A machine 11 is provided.

  Although the laser measurement device 1, the IMU 3, and the imaging devices 5 and 7 are installed here on a gantry provided as an example, the gantry need not be used. The IMU 3 acquires the angular velocity and the acceleration of the vehicle 100 (that is, the laser measurement device 1). The imaging device 5 is, for example, an omnidirectional camera, and captures an image of the entire periphery of the vehicle 100. The imaging device 7 is, for example, an HD camera. The imaging device 7 is provided, for example, before and after the vehicle 100, and captures an image in the front-back direction of the vehicle 100. However, the position where the imaging device 7 is provided and the imaging direction are not limited to the front-back direction of the vehicle 100, and may be any of the left, right, up, and down of the vehicle 100. The GNSS receiver 11 acquires the position information of the vehicle 100 (that is, the laser measurement device 1). In this example, two GNSS receivers 11 are provided, but the number of GNSS receivers 11 may be one or three or more. The DMI 9 is provided on a wheel or the like, and acquires information on a traveling distance of the vehicle 100. These various types of information are provided (directly or indirectly) to the laser measurement device 1. The IMU 3, the imaging devices 5, 7, the DMI 9, and the GNSS receiver 11 may not be provided. In other words, at least the effective distance acquisition method described later can be realized without using the IMU 3, the imaging devices 5, 7, the DMI 9, and the GNSS receiver 11.

  FIG. 2 is a diagram for explaining scanning of laser light in the laser measurement device. FIG. 2A is a perspective view, and FIG. 2B is a plan view. As shown in FIGS. 1 and 2, a plurality of laser measurement devices 1 are mounted on a vehicle 100 at different positions. Here, a pair of laser measuring devices 1 are provided apart from each other in the vehicle width direction of the vehicle 100. The laser measurement device 1 outputs the laser beams LA and LB while rotating in a predetermined plane as the vehicle 100 moves. Thereby, the laser measuring device 1 scans the area around the vehicle 100 including the structures OB and OA with the laser beams LA and LB. The number of the laser measuring devices 1 may be one, or three or more. Further, the laser measurement devices 1 are not limited to the vehicle width direction (left-right direction) of the vehicle 100, and may be provided separately from each other in the front-rear direction of the vehicle 100.

  In addition, the laser measurement device 1 receives reflected laser beams LA and LB from areas around the vehicle 100 including the structures OA and OB. Thereby, the laser measurement device 1 acquires information on the point group G including the plurality of reflection points P of the laser beams LA and LB. On the other hand, the laser measurement device 1 inputs various types of information from the IMU 3, the DMI 9, the GNSS receiver 11, and the like. Then, the laser measurement device 1 obtains the three-dimensional position of the reflection point P (that is, the structures OA and OB) from the position and the direction of the laser measurement device 1. Thereby, laser measurement accompanying the movement of the vehicle 100 becomes possible. When the IMU 3 and the GNSS receiver 11 are not used as described above, as an example, the acquisition of the distance of the reflection point P using a clock unit built in the laser measurement device 1 and the point group data by the operator are used. The laser measurement can be performed by setting the coordinates to.

  Subsequently, an effective distance obtaining method according to the present embodiment will be described with reference to FIGS. FIG. 3 is a flowchart showing main steps of the effective distance obtaining method. FIG. 4 is a diagram for explaining each step shown in FIG. The effective distance acquisition method shown in FIG. 3 is a method for acquiring an effective distance for laser measurement by performing laser measurement on a structure for acquiring a predetermined effective distance. In the following, of all the structures that can be measured by laser, the structure for acquiring the effective distance is referred to as “acquisition structure”.

  The acquisition structure OC is, for example, a pier or the like, and is obtained from a structure including a reference plane (reference plane BP: see FIG. 4B) whose position and dimensions are known in advance by surveying for another purpose. Selected. In addition, the structure for acquisition should just be a thing which can obtain a reference surface, and may be an artificial thing or a natural thing. The size and shape of the reference surface are not limited, and may be a flat surface, a curved surface, or a combination of a flat surface and a curved surface. The effective distance is a distance between the laser measurement device 1 and a structure (reflection point) at which a measurement error of the laser measurement becomes smaller than the first reference value. The first reference value can be set arbitrarily, but is, for example, an error value required for work-form measurement in i-Construction defined by the Ministry of Land, Infrastructure, Transport and Tourism.

  The effective distance obtaining method includes a scanning step S0 for performing scanning (scanning) of a laser beam, an error obtaining step S1 for obtaining a measurement error of laser measurement after the scanning step S0, and an effective distance after the error obtaining step S1. And a distance acquisition step S2 for acquisition. In the scanning step S <b> 0, the scanning of the laser beam is performed on an area including the acquisition structure OC separated from the moving path of the vehicle 100 with the movement of the vehicle 100. Here, for example, when the vehicle 100 is traveling on a road as a movement route, a laser beam is directed to an area including the acquisition structure OC provided at a position horizontally (and vertically) away from the road. Light scanning is performed.

  Here, laser light scanning can be performed on each of the outward path and the return path of the moving path of the vehicle 100. However, the scanning of the laser beam may be performed on only one of the forward path and the return path of the moving path of the vehicle 100. Further, when the vehicle 100 reciprocates on the moving path a plurality of times, the scanning of the laser beam may be performed on a plurality of forward paths and a plurality of returning paths of the moving path of the vehicle 100.

  Subsequently, in the error acquiring step S1, data of a point group G (three-dimensional point group data), which is a set of reflection points P of laser light, is created (step S11: first step). Here, the point cloud data is a set of reflection points P in a plurality of structures (including the structure for acquisition) existing in the area. Subsequently, a target point group Ga, which is a set of reflection points P corresponding to the reference plane BP of the acquisition structure OC, is extracted from the point group data created in step S12 (step S12: second step). The reflection point P corresponding to the reference plane BP is, for example, a reflection point included in the reference plane BP when viewed from the normal direction of the reference plane BP.

  Subsequently, a separation distance D between each of the reflection points P included in the target point group Ga and the reference plane BP in the normal direction of the reference plane BP is acquired as a measurement error (step S13: third step). Thereby, for each of the reflection points P included in the target point group Ga, the position and the direction of the reflection point P and the measurement error of the reflection point P are acquired in association with each other. In other words, by linking the distance from the laser measurement device 1 to the reflection point P and the measurement error of the reflection point P, the accuracy of the laser measurement can be grasped.

  Subsequently, the accuracy of the laser measurement is confirmed based on the measurement error obtained in step S13 (fourth step: S14). Here, it is confirmed whether or not the accuracy of the laser measurement is the second reference value or higher than the second reference value. The second reference value can be arbitrarily set in relation to the first reference value. For example, the second reference value can be set as follows. In other words, the second reference value is set such that the target point group Ga includes a certain number of reflection points P at which a measurement error at a measurement distance required in actual laser measurement later becomes smaller than the first reference value. Can be done.

  More specifically, when the measurement distance required in the actual laser measurement later is 100 m and the first reference value is 50 mm, the accuracy is the second reference value or the second reference value. Is higher than 100 m, and the second reference value is set such that the reflection points P whose distance to the laser measurement device 1 is 100 m or more and whose measurement error is smaller than 50 mm are included in a certain number or more of the target point groups Ga. Is set. In this case, at least when the reflection point P whose distance from the laser measurement device 1 is 100 m or more and the measurement error is smaller than 50 mm is not included in the target point group Ga, the accuracy is higher than the second reference value. Is also determined to be low.

  Here, the measurement result of the laser measurement device 1 is obtained using the distance and the angle of the laser measurement device 1 with respect to the IMU 3. For this reason, the device parameters affect the accuracy of laser measurement. Therefore, in the subsequent step, if the accuracy is lower than the second reference value as a result of step S14, calibration of apparatus parameters including the angle of the laser measuring apparatus 1 (boresight calibration) is performed (step S15). . The device parameters include, for example, the distance and angle of the laser measurement device 1 from the IMU 3. After performing the calibration in step S15, the process returns to step S11, and the error acquiring step S1 is performed again.

  On the other hand, as a result of step S14, if the accuracy is the second reference value or higher than the second reference value, the distance acquisition step S2 is performed. That is, the distance between the laser measurement device 1 where the measurement error is smaller than the first reference value and the acquisition structure OC (that is, the reflection point P) is acquired as the effective distance. This will be described in more detail. The target point group Ga includes a plurality of reflection points P at different distances from the laser measurement device 1. In general, the measurement error tends to increase as the reflection point P is farther (farther) from the laser measurement device 1.

  Therefore, for example, by referring to the measurement errors of a plurality of reflection points P at different distances from the laser measurement device 1, it is possible to grasp the threshold value of the distance at which the measurement error exceeds (or falls below) the first reference value. Here, the threshold value of the distance is acquired as the effective distance. By acquiring the effective distance as described above, high accuracy laser measurement can be performed by using only the reflection points within the effective distance range among the reflection points from the measurement target in actual laser measurement later. It becomes possible.

  Here, in the above-described effective distance obtaining method, in the scanning step S0, while changing the irradiation conditions including the laser irradiation parameters and the moving speed of the vehicle 100, the scanning step and the error obtaining step are performed a plurality of times. The relationship between the measurement error and the measurement error may be obtained.

  FIG. 5 is a diagram for explaining laser irradiation parameters. As shown in FIG. 5, first, the laser irradiation parameter is a setting of the laser measurement device 1, for example, a scan frequency and the number of irradiation points. The scan frequency is a frequency of scanning of the laser beams LA and LB in the laser measurement device 1. The laser measurement device 1 repeatedly scans one line, and the higher the scan frequency, the narrower the interval SP between the scan lines SL. The irradiation points indicate the points of the laser beams LA and LB emitted by the laser measurement device 1. As the number of irradiation points increases, point group data including dense reflection points P can be acquired.

  In the above-described effective distance acquisition method, a plurality of distances between the laser measurement device 1 and the acquisition structure are obtained by performing the scanning step S0, the error acquisition step S1, and the distance acquisition step S2. The effective distance may be acquired for each of the distances. In this case, as an example, a plurality of acquisition structures having different distances from the laser measurement device 1 (vehicle 100) are set, and scanning and measurement of a laser beam are performed on an area including each of the plurality of acquisition structures. Acquisition of an error and acquisition of an effective distance can be performed. The plurality of acquisition structures having different distances from the laser measurement device 1 are, for example, a plurality of piers or the like arranged with respect to each other.

  Even when one acquisition structure is set, the relative distance between the laser measurement device 1 and the acquisition structure changes with the movement of the vehicle 100, so that a certain time interval (distance interval) is set. In each case, scanning of a laser beam, acquisition of a measurement error, and acquisition of an effective distance may be performed on an area including one acquisition structure.

  Subsequently, a laser measurement method according to the present embodiment will be described. This laser measurement method is a method of actually measuring the laser of the measurement object after acquiring the effective distance using the above-described effective distance acquisition method. That is, in this laser measurement method, first, the above-described effective distance obtaining method is performed. Note that it is not necessary to perform the effective distance acquisition method once for one laser measurement of the measurement object, and to hold information on the measurement error and effective distance acquired by performing the effective distance acquisition method once. It can be used when performing the laser measurement method a plurality of times.

  As described above, this laser measurement method includes the preparation step of performing the above-described effective distance acquisition method, and the measurement step of performing laser measurement of a measurement target separated from the movement route of the vehicle 100. The measurement step acquires measurement point group data, which is a set of reflection points of the laser light, by scanning the measurement target with the laser light as the vehicle 100 moves (seventh step). As illustrated in FIG. 6, the measurement target is, for example, a slope NS of a cut portion OD separated from a road that is a movement route of the vehicle 100.

  In the measurement step, subsequently, among the reflection points included in the measurement point group data, the reflection points whose distance to the laser measurement device 1 is within the range of the effective distance (already acquired by the previous effective distance acquisition method) are determined. The measurement data is created using the data (8th step). Thereby, highly accurate measurement data in which the measurement error is smaller than the first reference value is created.

  When the measurement data is created, if the measurement point cloud data is acquired under a plurality of conditions, the measurement data can be created by integrating the reflection points of the measurement point cloud data. . In this case, the reflection points of the respective measurement point group data can be integrated by setting the priority according to the conditions. That is, when two or more reflection points are present at a certain position of the measurement target when creating the measurement data, a reflection point with higher accuracy can be adopted according to the priority. .

  Examples of conditions used for setting the priority include parameters such as an incident angle, a measurement distance, and an angular resolution. The incident angle means an angle at which the laser light is incident on the measurement target. As the incident angle becomes shallower (larger), the footprint of the reflected laser light (spot size on the incident surface of the laser light) becomes less uniform, and the accuracy decreases. The measurement distance means a distance from the laser measurement device 1 to a measurement target. As the measurement distance increases, the positional accuracy decreases due to the angle accuracy. The angular resolution means both the angular resolution of the laser beam of the laser measurement device 1 in the irradiation surface and the angular resolution of the IMU 3. The lower the angular resolution, the lower the position accuracy.

  Subsequently, the operation and effect of the above-described effective distance acquisition method and laser measurement method will be described. As described above, in the effective distance acquisition method, first, using the laser measurement device 1 mounted on the vehicle 100, scanning the area including the acquisition structure OC separated from the movement path of the vehicle 100 with laser light. I do. Subsequently, point cloud data, which is a set of reflection points P of the laser light, is generated, and a target point cloud Ga corresponding to the reference plane BP of the acquisition structure OC is extracted from the point cloud data.

  Then, a separation distance D between the reflection point P and the reference plane BP included in the target point group Ga is acquired as a measurement error. As a result, a measurement error at a location separated from the movement route of the vehicle 100 is grasped. Thereafter, a distance at which the measurement error is smaller than the first reference value is acquired as an effective distance. Then, in the laser measurement method, at the time of actual laser measurement of a measurement target separated from the moving path of the vehicle 100, measurement data is created using the reflection point P within the range of the effective distance. As a result, the measurement error can be made smaller than the first reference value. As described above, according to the effective distance acquiring method and the laser measuring method, as in the conventional method shown in FIG. As shown in FIG. 6B, high-precision measurement of a measurement object far away from the vehicle 100 can be performed without requiring a surveying operation and reducing the amount of operation.

  Further, in the effective distance obtaining method according to the present embodiment, the error obtaining step S1 further includes a step S14 of confirming the accuracy of laser measurement based on the measurement error. Then, as a result of step S14, when the accuracy is lower than the second reference value, the device parameters including the angle of the laser measuring device 1 are calibrated, and the error acquiring step S1 is performed again. On the other hand, as a result of step S14, if the accuracy is the second reference value or higher than the second reference value, the distance acquisition step S2 is performed. For this reason, the effective distance can be efficiently acquired in a device parameter in which the accuracy of the point cloud data is the second reference value or higher than the second reference value.

  In the effective distance acquisition method according to the present embodiment, the scanning step S0, the error acquisition step S1, and the distance acquisition step S2 are performed at a plurality of distances between the laser measurement device 1 and the acquisition structure OC. Thus, the effective distance may be acquired for each of the plurality of distances. In this case, an effective distance can be acquired for each of the plurality of distances from the laser measurement device 1.

  Further, in the effective distance obtaining method according to the present embodiment, the scanning step S0 and the error obtaining step S1 are performed a plurality of times while changing the irradiation conditions including the laser irradiation parameters and the moving speed of the vehicle 100 in the scanning step S0. , The relationship between the irradiation condition and the measurement error may be acquired. In this case, the relationship between the irradiation condition and the measurement error can be grasped.

  In the effective distance obtaining method according to the present embodiment, in the scanning step S0, the scanning of the laser beam may be performed on each of the outward path and the return path of the moving path of the vehicle 100. In this case, the measurement error and the effective distance can be acquired more accurately by performing the scanning with the laser beam under the irradiation conditions different from the forward path and the backward path.

  Further, in the effective distance obtaining method according to the present embodiment, in the scanning step S0, scanning of laser light is performed using each of the plurality of laser measurement devices 1 mounted at different positions on the vehicle 100. Therefore, the measurement error and the effective distance can be acquired for the laser measurement by each of the plurality of laser measurement devices 1 at different positions. If there are a plurality of laser measurement devices 1 (scan lines), their characteristics can be considered.

  In the past, in the survey, the range of the error was determined by the scale of the drawing, and the error in an appropriate range remained in the result without being adjusted as a result. However, according to the method according to the present embodiment, even a small systematic error is reduced as much as possible, an error close to the error of the device itself is realized, and the measurement is performed in consideration of the maximum value of the error by further grasping the error range. Can be realized.

  In addition, the method according to the present embodiment realizes efficient and labor-saving on-site work, and enables an appropriate range to be measured with high accuracy to be defined. However, the method can also be applied to quality confirmation and on-site adjustment. And has a wide range of usefulness.

  The above embodiment describes an example of the effective distance obtaining method and the laser measuring method according to the present invention. Therefore, the effective distance acquisition method and the laser measurement method according to the present invention are not limited to the above-described example, and can be arbitrarily modified.

  For example, the error acquiring step S1 can further include another step for managing accuracy. In other words, the error acquiring step S1 is performed between the step S11 and the step S12, the error between the coordinate known point CP existing on the movement route of the vehicle 100 and the reference point which is the reflection point corresponding to the coordinate known point CP. The method may further include a fifth step of checking the reference error. The error acquiring step S1 is performed such that when the reference error is larger than the third reference value as a result of the fifth step, the point cloud data is set so that the reference error is equal to or smaller than the third reference value. May be further included.

  In this case, by managing the point cloud data using the error (reference error) between the vehicle 100 (the laser measuring device 1) and the known coordinates CP relatively close to each other, it is possible to ensure the accuracy of the laser measurement for an actual distant place. That is, in this case, first, it is ensured that the error between the coordinate known point CP existing on the moving route and the corresponding reflection point is the third reference value or smaller than the third reference value. As a result, it is ensured that the error of the laser measurement of the measurement target far from the vehicle 100 (the laser measurement device 1) is also within the error range according to the third reference value.

  As an example, when the accuracy of the laser measurement of the laser measurement device 1 is an error of 10 mm at a nearby position on the moving path, it is assumed that the accuracy is such that the error is 40 mm at a predetermined distant point separated from the moving path. . On the other hand, it is assumed that an actual laser measurement of a distant measurement target is required to have an error range smaller than 50 mm. In this case, if the error in the vicinity is larger than 10 mm, it may not be ensured that the actual laser measurement error of the distant measurement target is smaller than 50 mm.

  On the other hand, as an example, by setting the third reference value to 10 mm and performing the fifth step (and the sixth step), the error of the actual laser measurement of the distant measurement target is smaller than 50 mm. Smallness can be guaranteed. That is, in the fifth step, when it is confirmed that the error (reference error) between the coordinate known point CP existing on the movement route and the corresponding reflection point (reference point) is 10 mm or smaller than 10 mm, Without adjusting the point cloud data, the error of the actual laser measurement of the distant measurement target can be smaller than 50 mm. On the other hand, if the reference error is larger than 10 mm in the fifth step, the point group data is adjusted in the sixth step so that the reference error is 10 mm or smaller than 10 mm. The actual laser measurement error of the object can be less than 50 mm. That is, by managing the point cloud data using the error (reference error) between the vehicle 100 (laser measurement device 1) and the relatively known coordinate point CP, the coordinate point known to the actual distant measurement target is calculated. The accuracy of laser measurement can be ensured without installing a laser beam.

  As an example of the adjustment of the point cloud data, a method of moving the point cloud data using the known coordinates, a method of performing the three-dimensional coordinate conversion of the point cloud data, and a trajectory of the vehicle 100 from the known coordinates are given as examples. Is calculated and the point cloud data is re-created.

  For example, the moving object on which the laser measuring device 1 is mounted is not limited to a vehicle, and may be another object. Examples of the moving body include a ship, a submersible, an aircraft, a railway, an animal, and the like, regardless of whether the vehicle is unmanned or manned. Further, the acquisition structure OC is not limited to a pier, but may be, for example, a building, an apartment building, another building (artificial object) such as a signboard attached to a road, or a terrain and a feature (natural object). You may. Further, the measurement target is not limited to the slope NS of the cut portion OD. That is, the laser measurement method can be applied to any measurement target (for example, the same as the acquisition structure OC).

  1: laser measuring device, 100: vehicle (moving body), Ga: target point group, LA, LB: laser beam, P: reflection point, BP: reference plane, OC: acquisition structure (structure).

Claims (8)

An effective distance obtaining method for obtaining an effective distance of laser measurement,
Using a laser measurement device mounted on a moving body, along with the movement of the moving body, a scanning step of scanning laser light to an area including a structure separated from the moving path of the moving body,
After the scanning step, an error obtaining step of obtaining a measurement error of the laser measurement,
After the error obtaining step, a distance obtaining step of obtaining the effective distance,
With
The error obtaining step includes:
A first step of creating point cloud data that is a set of reflection points of the laser light,
A second step of extracting, from the point cloud data, a target point cloud that is a set of the reflection points corresponding to a reference plane of the structure;
A third step of acquiring, as the measurement error, a separation distance between the reflection point and the reference plane included in the target point group in a direction normal to the reference plane;
Including
In the distance obtaining step, a distance between the laser measurement device and the structure where the measurement error is smaller than a first reference value is obtained as the effective distance,
Effective distance acquisition method. The error obtaining step further includes a fourth step of checking the accuracy of the laser measurement based on the measurement error,
As a result of the fourth step, when the accuracy is lower than a second reference value, while performing calibration of device parameters including the angle of the laser measurement device, again, perform the error acquisition step,
If the result of the fourth step is that the accuracy is the second reference value or higher than the second reference value, the distance acquisition step is performed.
The effective distance acquisition method according to claim 1. At a plurality of distances between the laser measurement device and the structure, the scanning step, the error obtaining step, and the distance obtaining step are performed to obtain the effective distance for each of the plurality of distances. Do
The effective distance acquisition method according to claim 1. The relationship between the irradiation condition and the measurement error is obtained by performing the scanning step and the error obtaining step a plurality of times while changing the irradiation condition including the laser irradiation parameter and the moving speed of the moving body in the scanning step. Do
The effective distance acquisition method according to claim 1. In the scanning step, scanning of the laser beam is performed on each of a forward path and a return path of the moving path of the moving body,
The effective distance acquisition method according to claim 1. In the scanning step, using each of the plurality of laser measurement devices mounted at different positions of the moving body, scan the laser light,
The effective distance acquisition method according to claim 1. The error obtaining step includes:
A step of checking a reference error, which is an error between a coordinate known point existing on the movement route and a reference point that is a reflection point corresponding to the coordinate known point, between the first step and the second step. 5 steps,
As a result of the fifth step, when the reference error is larger than a third reference value, the point cloud data is set so that the reference error is the third reference value or smaller than the third reference value. A sixth step of adjusting;
Further comprising,
The effective distance acquisition method according to claim 1. A preparation step for performing the effective distance obtaining method according to any one of claims 1 to 7,
A measurement step of performing laser measurement of a measurement object separated from the moving path of the moving body,
With
The measuring step includes:
A seventh step of acquiring the measurement point group data, which is a set of reflection points of the laser light, by scanning the measurement target with the laser light along with the movement of the moving body,
Among the reflection points included in the measurement point group data, an eighth step of creating measurement data using the reflection points whose distance to the laser measurement device is within the range of the effective distance,
including,
Laser measurement method.

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