JP2019015631A - Three-dimensional measuring device - Google Patents

Abstract

To solve the problem in a measuring system using a laser scanner that the shape of a terrestrial object whose thickness is thin, such as a sign board installed beside a railway track, cannot be captured with certain accuracy.SOLUTION: A three-dimensional measuring device 1, mounted on a vehicle capable of traveling on a railway track, includes laser scanners 2a, 2b for acquiring a laser point group. Regarding the widthwise position of a railway track, the laser scanner 2a is at the position of one rail 32a and the laser scanner 2b is at the position of the other rail 32b. Regarding the extensional position of the railway track, the laser scanners 2a, 2b are at mutually different positions. The extensional component of direction vector of laser beams radiated in the same direction as seen from the extension direction of the railway track is in opposite directions between the laser scanner 2a and the laser scanner 2b.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a three-dimensional measuring apparatus that measures the shape of a track and surrounding features from a vehicle that can travel on a railroad track.

  In order to ensure the safety of railway operation, a range where no building or the like that can hinder train operation is set around the railway track is defined as a railway building limit. In addition, the inspection and maintenance of the track conditions are of course important for ensuring the safety of railway operations. In order to efficiently grasp railway building limits and track conditions in railways that are generally long distances, the status of the track and its surroundings while running on the track using a test vehicle equipped with a measuring device or a railroad vehicle, etc. A grasp is being made.

  In recent years, a measurement system including a laser scanner is mounted on a vehicle to grasp the three-dimensional shape of a feature.

Japanese Patent Laid-Open No. 10-038568 JP-A-11-325820

  In a measurement system using a laser scanner, a thin feature such as a sign board provided on the side of a track is difficult to accurately capture the shape, and the accuracy and reliability of judgment on the railway building limit are not ensured. In addition, when laser is irradiated to the rail from diagonally above in the cross section, the bottom of the rail is likely to be a shadow of the head or abdomen of the rail, and it may be difficult to accurately grasp the rail cross-sectional shape and posture. .

  The present invention has been made to solve the above-mentioned problems, and enables the inspection work of railway building limits to be efficiently performed while suitably grasping the state of thin features and rails. An object is to provide a dimension measuring apparatus.

  (1) A three-dimensional measuring device according to the present invention is mounted on a vehicle capable of traveling on a railroad track, and the vehicle is caused to travel along with the motion state of the vehicle, from the surface of the track and its surrounding features. An apparatus for acquiring a laser point group, comprising first and second laser scanners for acquiring the laser point group, wherein the first laser scanner constitutes the line with respect to a position in the width direction of the line. The second laser scanner is at the other position of the pair of rails, and the first and second laser scanners are different from each other with respect to the position of the line in the extending direction. The components in the stretching direction of the direction vector of the laser beam irradiated in the same direction as viewed from the stretching direction are the first laser scanner and the second laser scanner. It is opposite in the.

  (2) In the three-dimensional measurement apparatus described in (1) above, each of the first and second laser scanners may be configured to form the laser beams in a plurality of directions within one plane.

  (3) In the three-dimensional measuring apparatus described in (1) or (2) above, the first and second laser scanners may be configured to emit the laser beam from the same height.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to perform the inspection work of a railway building limit efficiently, grasping | ascertaining the state of a thin feature and a rail suitably.

It is a block diagram which shows the schematic structure of the three-dimensional measuring apparatus which concerns on embodiment of this invention. It is a typical side view of the three-dimensional measuring apparatus which concerns on embodiment of this invention. It is a typical top view of a three-dimensional measuring device concerning an embodiment of the present invention. It is a schematic diagram which shows the positional relationship of the laser scanner and rail seen from the extending | stretching direction of the track | line. It is a schematic diagram which shows the laser point group of the rail surface acquired by a laser scanner.

  Hereinafter, a three-dimensional measurement apparatus 1 according to an embodiment of the present invention (hereinafter referred to as an embodiment) will be described with reference to the drawings. The three-dimensional measuring apparatus 1 is mounted on a vehicle that can travel on a railroad track, and measures the shape of the surface of the track and its surrounding features while the vehicle is traveling.

  FIG. 1 is a block diagram illustrating a schematic configuration of a three-dimensional measurement apparatus 1 according to the embodiment. The three-dimensional measuring apparatus 1 basically has a configuration of a mobile mapping system (Mobile Mapping System: MMS), specifically, a laser scanner 2 and a global navigation satellite system (GNSS) receiver 4. , An inertial measurement unit (IMU) 6, a laser Doppler distance meter 8, a camera 10, and a computer 12.

  The laser scanner 2 emits a laser beam to the surroundings, and the angle and distance of the laser reflection point on the object surface as viewed from the laser scanner 2 is determined based on the emission angle and the time from the laser emission to the reception of the reflected light. measure. The laser scanner 2 sequentially changes the direction of the laser beam to acquire a laser point cloud from a wide range of object surfaces around the track. In the present embodiment, the laser scanner 2 performs a scanning operation of irradiating a laser beam in a plurality of directions shifted by minute angles within a range of 360 ° around the central axis. Each laser beam is emitted, for example, in a direction orthogonal to the central axis, and thus in the coordinate system fixed to the laser scanner 2, the laser beam group forms one plane. Here, the plane is referred to as a scanning plane. As will be described later, the three-dimensional measuring apparatus 1 has two laser scanners 2.

  The GNSS receiver 4 receives radio waves from the satellites constituting the GNSS and acquires the position of the three-dimensional measurement apparatus 1. For example, a global positioning system (GPS) can be used as GNSS.

  The IMU 6 measures the three-dimensional angular velocity and acceleration of the three-dimensional measuring apparatus 1. The measurement data of the IMU 6 is used for grasping the position / posture of the three-dimensional measurement apparatus 1 as a supplementary means when the GNSS reception situation is unstable.

  The laser Doppler distance meter 8 irradiates the rail surface with laser light and measures the moving distance of the three-dimensional measuring apparatus 1. In the MMS used on the road, an odometer is used to measure the rotation distance of the wheel to determine the moving distance. However, in a railway vehicle, the wheel slips and idles on the rail, so the three-dimensional measuring device 1 uses a laser Doppler instead of the odometer. A distance meter 8 is used to ensure distance measurement accuracy.

  The camera 10 is a digital camera, and captures, for example, a color image, an infrared thermography, a monochrome image, and the like around the three-dimensional measurement apparatus 1.

  The computer 12 includes a CPU (Central Processing Unit) 20 and a storage device 22, and receives and records data output from the laser scanner 2, the GNSS receiver 4, the IMU 6, the laser Doppler rangefinder 8, and the camera 10. The data recorded in the measurement work is processed after the measurement work is finished, for example. In the process, the measurement data of the laser scanner 2 is integrated with the motion state of the vehicle equipped with the three-dimensional measurement device 1 or the device equipped with the device, obtained from the measurement data of the GNSS receiver 4, the IMU 6 and the laser Doppler distance meter 8, The coordinate value of the laser point group in the coordinate system set on the ground is obtained. Furthermore, the process which analyzes the shape and arrangement | positioning of the feature around a rail or a track | line can be performed using the said laser point group.

  FIG. 2 is a schematic side view of the three-dimensional measuring device 1, and FIG. 3 is a schematic plan view of the three-dimensional measuring device 1, particularly mounted on a vehicle 30 that can run on a railroad track. The arrangement of the laser scanner 2 of the three-dimensional measuring apparatus 1 is shown.

  The vehicle 30 has wheels 34 that ride on two rails 32 (32a, 32b) of the track. Although the vehicle 30 may have power and can be self-propelled, the figure shows a configuration in which the vehicle 30 is connected to the power vehicle 36 and moves.

  As described above, the three-dimensional measuring apparatus 1 includes the two laser scanners 2a and 2b. These two laser scanners 2a and 2b are arranged obliquely on the vehicle 30 in a plan view as shown in FIG. That is, regarding the position in the width direction of the line, the laser scanner 2a is at the position of one rail 32a constituting the line, the laser scanner 2b is at the position of the other rail 32b, and the position of the line in the extending direction. The laser scanners 2a and 2b are at different positions. For example, if the side connected to the power vehicle 36 in the vehicle 30 is defined as “front”, the laser scanner 2a is positioned on the front side of the vehicle 30 and the laser scanner 2b is positioned on the vehicle in this embodiment with respect to the position in the extending direction of the track. 30 on the back side.

  Further, the laser scanners 2a and 2b are arranged so as to be able to scan the space around the track from the front and from the rear. That is, of the laser beams of the laser scanners 2a and 2b, the components along the line extending direction of the direction vector of the laser beam irradiated in the same direction as seen from the line extending direction are the laser scanner 2a and the laser scanner 2b. The direction is reversed. For example, the scanning plane of the laser scanner 2 of the present embodiment described above is the scanning plane 38a that intersects the rail 32 at a position before the laser scanner for the laser scanner 2a, and the rear side of the laser scanner for the laser scanner 2b. It can be a scanning plane 38b that intersects the rail 32 at a position. With this arrangement, the laser scanner 2a emits a laser beam obliquely forward to a lower position and emits obliquely rearward to a higher position. Conversely, the laser scanner 2b emits a laser beam obliquely backward to a lower position and emits obliquely forward to a higher position. For example, the inclination angle of the scanning plane can be 45 ° from the horizontal position with respect to the extending direction of the track.

  With the configuration of the above-described three-dimensional measurement apparatus 1 in which the laser scanners 2a and 2b are arranged so that the space around the track can be scanned in two ways, from the front and from the rear, the object can be measured by the vehicle 30 traveling. A laser point group scanned from the front and a laser point group scanned from the rear are obtained, and the shape of the object can be suitably grasped. In particular, even if the object has a thin thickness in the direction of travel, such as a sign board, laser point clouds can be obtained from the surfaces on both sides thereof, and the thickness and shape of the object can be easily grasped.

  Here, for example, it is also possible to acquire a laser point cloud by moving a vehicle equipped with a laser scanner that scans only from either the front or the rear, reciprocating in the forward and return directions, Depending on the date of acquisition, the arrangement of the satellites may not be the same, so even if the position is obtained by combining multiple measurement data such as the GNSS receiver 4, IMU 6, and laser Doppler rangefinder 8, the forward and return paths It is difficult to eliminate the displacement of the position, and as a result, the error of the object shape grasped from the laser point cloud can be large. In this respect, since the three-dimensional measuring apparatus 1 acquires both the laser point group irradiated from the front and the laser point group irradiated from the rear in one run, the measurement error of the object shape can be reduced.

  The laser scanners 2 a and 2 b are arranged so that the rail 32 is irradiated with a laser beam, and the laser point group acquired from the rail 32 can be used for grasping the shape and posture of the rail 32. This point will be described below.

  FIG. 4 is a schematic diagram showing the positional relationship between the laser scanners 2a and 2b and the rails 32a and 32b as seen from the extending direction of the line. As shown in FIG. 4, the rail is a flat bottom rail as shown in FIG. 4. In many cases, the rail is a head 42 h that comes in contact with the wheel, a bottom 42 b that extends on both sides in the width direction around the head 42 h, And an abdomen 42m that secures the height of the head 42h.

  As described above, regarding the position in the width direction of the line, the laser scanner 2a is arranged corresponding to the position of the rail 32a, and the laser scanner 2b is arranged corresponding to the position of the rail 32b. Specifically, the laser scanners 2a and 2b are basically disposed so as to be directly above the rails 32a and 32b, respectively, as shown in FIG. 4 when the vehicle 30 is on a straight line portion of the track.

  By arranging the laser scanner 2 directly above the rail 32 in this way, the laser beam of the laser scanner 2 can be easily irradiated on the upper surfaces of the bottom portions 42b located on both sides of the head portion 42h of the rail 32, It is easy to acquire a sufficient number of laser point clouds to enable the shape and orientation of the bottom to be grasped with high accuracy. Specifically, the laser beam 40a of the laser scanner 2a is likely to be irradiated to the bottom portions 42b on both sides of the rail 32a, and the laser beam 40b of the laser scanner 2b is likely to be irradiated to the bottom portions 42b on both sides of the rail 32b.

  On the other hand, the laser scanner 2b is difficult to acquire a laser point group from a portion of the bottom portion 42b of the rail 32a located obliquely below and on the outer side of the line on the back side when viewed from the laser scanner 2b.

  Similarly, the laser beam 40b of the laser scanner 2b makes it easy to obtain the laser point cloud on the upper surface of the bottom part 42b on both sides of the rail 32b, but the laser point cloud is obtained from the part outside the line in the bottom part 42b of the rail 32a. Hateful.

  FIG. 5 is a schematic diagram showing laser point groups on the surfaces of the rails 32a and 32b acquired by the laser scanners 2a and 2b. In the figure, “x” marks indicate laser point groups acquired by the laser scanner 2a, and “◯” marks indicate laser point groups acquired by the laser scanner 2b.

  Here, in order to grasp the inclination (falling down) of the rail 32 in the width direction, it is preferable to use the shape of the bottom portion 42b that is less likely to be deformed due to wear than the top surface of the head 42h whose shape changes due to wear or the like. The shape can be determined with higher accuracy as the number of laser point groups acquired from the bottom 42b is larger. In this regard, as described above, the laser scanner 2 is arranged directly above each of the rails 32a and 32b so that the laser beam can be easily irradiated to the bottoms on both sides of each rail 32, thereby ensuring the number of laser point groups. Thus, it is possible to grasp the shape of the bottom portion 42b with high accuracy and to evaluate the inclination of the rail 32 with high accuracy.

  When grasping the shape of each rail 32, the laser point groups of both the laser scanners 2a and 2b can be used. For example, the point cloud of the bottom part 42b of the rail 32a obtained by the acquisition by the laser scanner 2a and the point cloud of the abdominal part 42m of the rail 32a obtained by the laser scanner 2b are used in the evaluation of the inclination of the rail 32a. The accuracy of the evaluation can be improved.

  In order to grasp the shape and posture of the rail 32 with the same accuracy between the rail 32a and the rail 32b, it is preferable that the density of the laser point group is the same between the rail 32a and the rail 32b. In this regard, on the premise that the specifications of the laser scanners 2a and 2b themselves are equivalent, the heights of the laser scanners 2a and 2b may be aligned so that both laser scanners emit laser beams from the same height. it can. In addition, assuming that the inclination angles of the scanning planes of both laser scanners are the same, the distance from the laser scanner 2a to the irradiation position on the rail 32a is the same as the distance from the laser scanner 2b to the irradiation position on the rail 32b. It is preferable to do.

  1 3D measuring device, 2 laser scanner, 4 GNSS receiver, 6 IMU, 8 laser Doppler rangefinder, 10 camera, 12 computer, 20 CPU, 22 storage device.

Claims (3)

A three-dimensional measurement device mounted on a vehicle capable of traveling on a railroad track, which travels the vehicle and acquires a laser point cloud from the surface of the track and its surrounding features along with the motion state of the vehicle. ,
Having first and second laser scanners for acquiring the laser point cloud;
Regarding the position in the width direction of the line, the first laser scanner is at one position of a pair of rails constituting the line, and the second laser scanner is at the other position of the pair of rails,
Regarding the position in the extending direction of the line, the first and second laser scanners are at different positions,
The component in the stretching direction of the direction vector of the laser beam irradiated in the same direction as viewed from the stretching direction is opposite in the first laser scanner and the second laser scanner;
A three-dimensional measuring device characterized by The three-dimensional measurement apparatus according to claim 1,
Each of the first and second laser scanners forms the laser beam in a plurality of directions within one plane, and is a three-dimensional measurement apparatus. In the three-dimensional measurement apparatus according to claim 1 or 2,
The three-dimensional measuring apparatus, wherein the first and second laser scanners emit the laser beam from the same height.

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