JP6306915B2 - Target used in a method for measuring a predetermined position of an object to be measured and distance measurement method using the target - Google Patents

Description

  The present invention relates to a target used for accurately measuring the position of an end of an object to be measured using a laser scanner and a method for measuring a distance on the object to be measured using the target.

  In recent years, in the manufacturing process of large buildings, rather than assembling individual members at the installation site, blocks of a certain size are manufactured at the factory, and the blocks are joined together by welding etc. at the site. ing. In this case, the work accuracy is required to suppress the deviation of the end portions between the blocks to about several mm. In order to satisfy this requirement, there is an increasing need for accurately measuring the shape and dimensions of the end of each block.

The use of a laser scanner is being studied for the above needs. A laser scanner is a device that can acquire the entire shape of a measurement target with a single measurement and can accurately measure a surface by processing the obtained point cloud data. However, the laser scanner can acquire a large amount of point cloud data in a short time, but also acquires data other than the measurement target such as a ceiling, wall, and desk within the set range. In Patent Document 1, a field-limitation window is provided to remove point cloud data indicating unnecessary objects so that only a measurement target can be irradiated with a laser beam.
In a distance measuring device using a laser, a technique for adjusting the position of a detection area by detecting the position of a target is known (Patent Document 2).

JP 2012-47656 A JP 2003-215244 A

Conventionally, as an edge measurement method using a laser scanner, there is a technique of measuring the shape of an edge using a point cloud of the edge. However, this method has the following problems.
・ Measurement error determined by the interval between the laser scanner spots. That is, the end position could not be measured with higher accuracy than the irradiation spot interval.
・ Because the laser scanner must be installed so that the end of the object to be measured can be irradiated with laser, and the position of the laser scanner is limited by the position of the end of the object to be measured, the work efficiency for measurement Was bad.

  A conventional measurement method will be described with reference to an example in which the position of the end portion of a substantially rectangular plate-like object as shown in FIG. 7 is measured using a laser scanner.

  A laser scanner is a non-contact optical sensor, and can digitize the shape of an object as a set of position coordinates. The typical principle is called the time-of-flight method. The laser is irradiated from the scanner to the target object, and the distance to the target irradiation spot is measured by the time it takes to return to the scanner. The shape of the object can be digitized as a collection of points, that is, points having coordinates. In the laser scanner, the irradiation spot interval is the limit of detection in principle.

Next, detection of the end of the object by the laser scanner will be described with reference to FIG.
When the end A of the device under test 1 is to be detected, the laser scanner 2 is placed at a position where the laser beam can be applied to the end A of the device under test 1 and the laser is irradiated while scanning near the end A.
In FIG. 7, the laser beam returns to the scanner 2 from the spots of the objects A1, A2, A4, A5, A7, and A8, but the laser beam does not return to the scanner 2 from the spots of A3, A6, and A9.
In the laser scanner 2, after detecting the laser returning from the spots A1, A2, A4, A5, A7, A8, the spots A1, A2 of the object to be measured based on the time until returning and the laser irradiation direction. , A4, A5, A7, and A8 are digitized as a set of point clouds.

On the scanner 2 side, the approximate position of the end A can be detected from the point cloud data A1, A2, A4, A5, A7, and A8, but each spot interval is the limit of detection. If the irradiation spot interval is reduced, the edge detection accuracy is improved. However, reducing the spot interval means an increase in the number of times of laser irradiation and, consequently, an increase in measurement time. Furthermore, when a laser scanner is installed at the position shown in FIG. 7 and the measurement surface of the object to be measured and the laser incident angle are shallow, even a slight change in the laser emission angle of the laser scanner results in a large spot interval on the measurement surface. There is a problem that the edge detection accuracy is lowered.

  The present invention has been made paying attention to such problems, and by using a new target, the target of interest can be easily determined from point cloud data acquired by a laser scanner. It is possible to measure the end of the non-measurement part with higher accuracy (resolution higher than the irradiation spot interval) than the irradiation spot interval of the laser scanner, and the position of the laser scanner regardless of the end of the object to be measured The object is to provide a very easy-to-use target for measuring the end, which can be any location.

In order to solve the above problems, the target used in the method for measuring a predetermined position of the object to be measured of the present invention is:
Based on point cloud data obtained by scanning a predetermined measurement range with a laser scanner, a target used in a method for measuring a predetermined position of an object to be measured existing in the predetermined measurement range,
The target is an octahedron and a rectangular parallelepiped having a vertex that can be aligned with a predetermined position of the object to be measured, and has a three-dimensional shape composed of a plurality of planar regions that can be scanned by a laser scanner,
By scanning a range including the target with a laser scanner to obtain point cloud data of the target,
Extracting a set of point cloud data constituting a plane area from the acquired point cloud data for a plurality of plane areas ,
Based on the set of point cloud data constituting the extracted plurality of planar regions and known unique data for specifying the three-dimensional shape of the target, the position of one vertex of the rectangular parallelepiped is calculated,
The method is characterized in that it is used in a method for measuring a predetermined position of an object to be measured based on the calculated position of the vertex of the rectangular parallelepiped.
According to this feature, the lower part of the target is a rectangular parallelepiped, and the vertex of the rectangular parallelepiped is aligned with a predetermined position to be measured. Therefore, the alignment operation becomes easy. In particular, when the predetermined position to be measured is the end of the object to be measured, the vertex of the rectangular parallelepiped is matched, so that the target does not protrude from the object to be measured and can be stably placed on the object to be measured.
In addition, the target that is the target of laser irradiation has a shape that makes it easy to detect the irradiated surface regardless of the angle from which the laser is irradiated, and the installation position of the laser scanner can be arbitrarily set.

The target used in the method for measuring the predetermined position of the object to be measured according to the present invention is:
The target is combined in a shape in which a top portion including one vertex of the octahedron is embedded at the center of one surface of the rectangular parallelepiped, and further reaches a vertex opposite to the embedded vertex of the octahedron 2 The octahedron is combined with the rectangular parallelepiped in a form in which a plane formed by two ridge lines is orthogonal to a pair of opposing planes of the four planes of the rectangular parallelepiped that are in contact with the one surface of the rectangular parallelepiped. It is said.
According to this feature, it is possible to easily detect the octahedral and cubic planes constituting the target regardless of the irradiation angle of the laser scan.

The target used in the method for measuring the predetermined position of the object to be measured according to the present invention is:
Based on point cloud data obtained by scanning a predetermined measurement range with a laser scanner, a target used in a method for measuring a predetermined position of an object to be measured existing in the predetermined measurement range,
The target is a combination of an octahedron and a rectangular parallelepiped having a vertex that can be aligned with a predetermined position of the object to be measured, and is composed of a plurality of planar regions that can be scanned by a laser scanner, and further, at the center of one surface of the rectangular parallelepiped. The top including one vertex of the octahedron is combined in an embedded shape, and an imaginary plane formed by two ridge lines leading to the vertex facing the embedded vertex of the octahedron is the rectangular parallelepiped. The octahedron has a three-dimensional shape combined with the rectangular parallelepiped in a form orthogonal to a pair of opposed planes of the four planes of the rectangular parallelepiped in contact with the one surface,
By scanning a range including the target with a laser scanner to obtain point cloud data of the target,
Extract a plurality of planar regions from the acquired point cloud data using a region growth method,
A plane area constituting the octahedron is extracted from the plurality of plane areas based on known unique data for specifying the three-dimensional shape of the target, and further obtained from the extracted plane area constituting the octahedron. A plane region constituting the rectangular parallelepiped is extracted based on known specific data specifying the vertices of the octahedron and the three-dimensional shape of the target,
Calculate the position of the vertex of the rectangular parallelepiped aligned with the predetermined position of the object to be measured from the vertex extracted from the octahedron and the planar area constituting the extracted rectangular parallelepiped,
A predetermined position of the object to be measured is measured based on the calculated position of the vertex of the rectangular parallelepiped.
According to this feature, since the vertices of the octahedron constituting the target are detected and the vertices of the rectangular parallelepiped are calculated based on the vertex positions, the vertices can be accurately calculated.

The target used in the method for measuring the predetermined position of the object to be measured according to the present invention is:
The rectangular parallelepiped is a cube.
According to this feature, since the target mounting surface is a square, there is no need to consider the direction in which the target is mounted when mounting the target object at a predetermined position. The vertex of the cube can be easily calculated from the vertex.

The target used in the method for measuring the predetermined position of the object to be measured according to the present invention is:
Instead of the rectangular parallelepiped, a triangular prism, pentagonal prism, or hexagonal prism is used.
According to this feature, the target can be stably placed according to the shape of the end of the object to be measured.

The target used in the method for measuring the predetermined position of the object to be measured according to the present invention is:
The octahedron is a regular octahedron.
According to this feature, the vertices of a cube can be more easily calculated from the vertices of a regular octahedron that constitutes the target.

The target used in the method for measuring the predetermined position of the object to be measured according to the present invention is:
A fixing means is provided on the bottom surface of the target.
According to this feature, there is no fear that the target moves due to vibration or the like during measurement, and it can be used for measurement of a surface to be measured such as a wall or a ceiling that is not horizontal.

The target used in the method for measuring the predetermined position of the object to be measured according to the present invention is:
The fixing means is a magnetic member.
According to this feature, when the object to be measured is a substance that is adsorptive with a magnet such as iron, it can be easily installed and removed.

Using the target of the present invention, a method for measuring a distance on an object to be measured is
A plurality of points to be measured on the object to be measured are installed by aligning the vertices of the target,
The distance on the object to be measured is measured based on the positions of the vertices of the plurality of targets.
According to this feature, by using the target of the present invention, it is possible to easily measure the distances at a plurality of locations within the measurement range scanned by the laser scanner.

It is a figure which shows the method of measuring the distance of the edge part of the to-be-measured object using the target of this invention. It is a figure which shows the target used for this measuring method. It is a figure explaining the method of calculating the vertex of a cube from the vertex of a regular octahedron. It is a figure which shows the modification of a target. It is a figure which shows the other modification of a target. It is a figure which shows the adhering means of a target. It is a figure which shows the conventional method of measuring the edge part of a to-be-measured object with a laser scanner.

  A target for use in a method for measuring a predetermined position of an object to be measured according to the present invention and a mode for carrying out a distance measurement method using the target will be described below based on examples.

Here, the present invention will be described based on an example in which the distance between the A end and the B end of a substantially rectangular plate-like object as shown in FIG. 1 is measured using a laser scanner.
In the present invention, in order to detect the end portions A and B of the DUT 1 as shown in FIG. 1, the apex of the target 10 is placed in alignment with the end portions A and B, and the position of the target 10 is set. The shape is detected by laser scanning, and the end portions A and B of the DUT 1 are calculated based on the detected shape.
In the present invention, the position of the object to be measured is not directly measured, but indirectly measured using the target 10. For this purpose, the target 10 needs to be accurately aligned with a predetermined position of the object to be measured and placed. At this time, it is easier to align the vertex of the cube bottom surface of the target 10 than to align the center of the cube bottom surface of the target 10 with a predetermined position of the object to be measured. In particular, when the predetermined position to be measured is the end of the object to be measured, the vertices of the cube are aligned, so that the target 10 does not protrude from the object to be measured and can be stably placed on the object to be measured. Therefore, the calculation of the position of the vertex of the target 10 from the data obtained by laser scanning is related to the ease of alignment of the target 10.

First, the target 10 will be described with reference to FIG.
The target 10 used for edge measurement according to the present invention has a shape in which a part of a regular octahedron lower portion 12 is joined to an upper plane of a cube 11 in a shape. Also, a cube including a plane (a plane formed by the vertices 14f, 14a, 14e, and 14c) and an octahedron embedded in the cube of the octahedron 14 and two ridge lines connecting the vertex 14e facing the vertex 14f. The plane (the plane formed by the vertices 11a, 11e, 11h, and 11d and the plane formed by the vertices 11b, 11f, 11g, and 11c) is combined with a cube that contacts one side with the upper plane at an angle of 90 degrees. ing. Similarly, a plane (a plane formed by the vertices 14f, 14b, 14e, and 14d) and a regular octahedron are embedded including the vertex 14f embedded in the cube of the regular octahedron 14 and the two ridge lines connecting the vertex 14e opposite to the vertex 14f. The upper plane of the cube and the plane of the cube that touches one side (the plane formed by the vertices 11a, 11e, 11f, and 11b and the plane formed by the vertices 11c, 11g, 11h, and 11d) are combined at an angle of 90 degrees. Has been.
In order to combine the cube 11 and the regular octahedron 14, a part of the regular octahedron is embedded in the cube. This is performed in order to obtain a predetermined strength in manufacturing the target. Therefore, if the intensity is obtained, the accuracy of detecting the target by laser scanning is improved when the number of the portions to be embedded is small. However, in detecting the plane of the regular octahedron lower part 12, even if about 1/3 of the regular octahedron lower part 12 is embedded, there is no problem in detecting the lower surface of the octahedron by laser scanning.
The size of the target 10 can be set to an appropriate size according to the size of the object to be measured, the scan spot interval of the laser scanner, and the distance between the laser scanner and the target.
The target material may be anything as long as it can reflect the laser, but if it is partly transparent (translucent), the transmitted laser is reflected at the tip of the target, and the laser scanner. Since there is a possibility that the detection of the target surface is adversely affected by returning to, a material that transmits the laser is not suitable.

The shape which combined the cube and the regular octahedron as the target 10 is further demonstrated.
In the edge measuring method of the present invention, the surface information of the target 10 is acquired by a laser scanner, and finally the vertexes of the cube are calculated. Therefore, the shape of the target is preferably a shape that can obtain a lot of surface information regardless of the laser irradiation direction (this is related to the installation position of the laser scanner). In order to obtain the vertices 11a, 11b, 11c, and 11d of the cube, the coordinates of any one of the vertices 14a, 14b, 14c, and 14d of the regular octahedron are obtained, and the vertexes of the cube are calculated by using the vertex coordinates. There is a method of obtaining (the method for calculating the vertex of the cube from the vertex of the regular octahedron is described later). The coordinates of the vertices of the regular octahedron are obtained from information defined by the three surfaces surrounding the vertices. Therefore, it is necessary to acquire point cloud data for at least three surfaces surrounding the vertex by laser scanning. With the shape of the target as shown in FIG. 2, information defining the three surfaces surrounding the apex can be obtained regardless of the direction from which the laser is incident.

  In the present invention, in order to calculate the target vertex, it is necessary to calculate a plane including the vertexes of the cube constituting the lower part of the target. In the case of the target shape as shown in FIG. 2, a planar region having a normal vector most similar to the normal vector from the apex of the regular octahedron to the center is searched as a plane constituting the cube (details will be described later). . This means that the vertex of the octahedron is effective information when the computer automatically searches for a cubic plane. For example, when the shape combined with the cube is not a regular octahedron but a sphere, the center coordinates of the sphere can be calculated from the surface information of the sphere, but the orientation of the plane that forms the base of the cube is known from this center coordinate It is not possible. In other words, it is impossible to know how the plane rotates around the axis connecting the center of the sphere and the center of the cube. As described above, the shape of the target of the present invention has an advantage that it is useful when a computer automatically searches for a plane constituting the cube.

  As shown in FIG. 7, when the incident angle of the laser is shallow with respect to the measurement surface of the DUT 1, the end detection error increases. However, when the target 10 is placed at the end, the cube of the target 10 is obtained. Since the side surface 11 is perpendicular to the measurement surface, the incident angle is deep with respect to the incidence of the laser. Further, each surface of the regular octahedron has an inclination of about 35 ° with respect to the measurement surface, so that the incident angle is much deeper than the incident angle of the laser with respect to the measurement surface. Therefore, sufficient point cloud data can be acquired for the target 10 even when the incident angle of the laser is shallow with respect to the measurement surface of the DUT 1.

An example of a method for measuring an end portion of an object to be measured using the target 10 will be specifically described.
(Target setting)
When measuring the distance between the end A and the end B of the DUT 1 shown in FIG. 1, the vertex of the cube of the target 10 is placed on the end A of the DUT 1 so as to be positioned exactly. As for the end portion B, another target 10 is placed with its apex aligned.
(Acquisition of point cloud data)
Next, a range including the two targets is scanned by a laser scanner installed at a position where the two targets 10 fall within the scanner range, and point cloud data of the target 10 is acquired. The acquired point group data is a set of points having xyz coordinates.

(Plane area search)
A planar region is extracted from the acquired point cloud data using a region growing method.
The region growth method is to search for a planar region by enlarging the planar region, assuming that the region on the surface selected as the seed region and the normal vector of its neighboring points are similar and assuming that they are on the same plane. It is a technique to go. A region growth method is applied to the acquired point cloud data, and a plurality of planar regions are automatically extracted by a computer.

(Search for combinations of planes that make up the target)
A combination of planes constituting the target 10 is determined from the extracted plurality of plane areas.
First, a combination of planes constituting the target octahedron 14 is determined. The angle formed by adjacent faces of the regular octahedron (in FIG. 2, the plane formed by the apexes 14e, 14a, and 14b and the plane formed by the apexes 14f, 14a, and 14b) is 109.5 °. Further, the angle formed by the surfaces that are not adjacent to each other and not parallel (in FIG. 2, the plane formed by the apexes 14e, 14a, and 14b and the plane formed by the apexes 14f, 14b, and 14c) is 70.5 °. From this graphic property, when a plane having two planes with an angle of 109.5 ° and one plane with an angle of 70.5 ° is obtained, the combination of these four planes is the target. This is a combination of planes constituting the regular octahedron 14. With the above operation, the position and orientation of the regular octahedron portion of the target can be specified.
Next, a plane that forms the target cube 11 is searched. A planar region having a normal vector most similar to a vector directed to the center of the regular octahedron is searched from the vertex P including the four planes of the regular octahedron 14 obtained earlier. The search range is an area within a certain distance from the target octahedron 14. By this search, one plane S constituting the target cube 11 can be automatically detected by a computer.
Thereby, the position and attitude | position of the target 10 whole can be specified.

(Extraction of target bottom vertex)
Based on the detected position and orientation of the target, the coordinates of the bottom vertex are automatically calculated by a computer using FIG. As shown in FIG. 3A, the apex P of the regular octahedron is projected onto the plane S which is one surface of the cubic part, and the point P ′ is obtained. Since the dimensions of the target are known, the point P ′ is translated in the vertical direction in the plane S by the height up to the bottom surface and in the horizontal direction by half the length of one side of the cube. Two bottom surface vertices on the side that can be confirmed from the laser scanner measurement point can be calculated (FIG. 3B). From the two obtained vertices, a translation is performed in the normal direction of the plane S by the length of one side of the cube, and the coordinates of the remaining two vertices on the side far from the laser scanner are calculated.

The distance between the end A and the end B of the DUT 1 shown in FIG. 1 is the coordinates of the target bottom vertex placed according to the end A of the DUT among the cube bottom vertices of the target 10. From the bottom vertex of the cube of the target 10, it can be obtained from the coordinates of the target bottom vertex placed according to the end B of the object to be measured.
In this way, the bottom vertex of the target is placed at the position to be measured, and the plane of the target is automatically recognized by the computer by the laser scanner, so that the end of the object to be measured is not detected directly. The position of the end of the object to be measured can be accurately measured.
FIG. 1 shows an example in which the DUT 1 is a flat plate and the distance between the end A and the end B on the same plane is measured, but the DUT 1 is a bent or curved member. Can also be used with the target of the present invention. In this case, one end and the other end of the member are not on the same plane, and the irradiation spot interval to one end and the irradiation spot interval to the other end may differ depending on the installation position of the laser scanner. It may become. However, even in such a case, the target of the present invention has a shape that allows easy detection of the irradiated surface regardless of the direction of the laser irradiation. Can be extracted well.

  In the above-described detection of the end of the cube, first, the vertex of the regular octahedron is obtained from the three planes of the regular octahedron, and the lower vertex of the cube is obtained based on the obtained vertex. The three planes that make up may not be recognized correctly. The target combining the regular octahedron and the cube of the present invention has a structure in which the plane of the cube can be efficiently detected when the laser is irradiated from a direction in which the plane of the regular octahedron is not sufficiently detected. Therefore, when the three planes of the regular octahedron cannot be sufficiently detected, the lower vertex of the cube can be detected in consideration of the plane of the cube.

A modification of the target 10 will be described. As a target, a combination of a cube and a regular octahedron as shown in FIG. 2 is optimal as a shape capable of observing three or more planes regardless of the installation position of the laser scanner. Can be used for edge measurement. For example, instead of a combination of a cube and a regular octahedron, a combination of a rectangular parallelepiped 21 and a regular octahedron 14 may be used as shown in FIG. 4A, or a plane of a cube and an isosceles triangle may be used as shown in FIG. 4B. A combination of octahedrons 24 may be used. Further, it may be a combination of a rectangular parallelepiped and an octahedron composed of planes of isosceles triangles (not shown). Further, when combining octahedrons composed of planes of isosceles triangles, as shown in FIG. 4 (B), the one having the longer distance between the opposite vertices of the octahedron is combined with the lower solid, and FIG. There is a combination of the lower solids with the axis having the shorter distance between the opposite vertices of the octahedron. Further, as shown in FIG. 4D, the triangle forming the upper part 43 of the octahedron is an equilateral triangle, and the triangle forming the lower part 42 is an isosceles triangle. The face body 44 can also be used.
Also, the lower part of the target is not limited to a rectangular parallelepiped, but a triangular prism, pentagonal prism, or hexagonal prism as long as the target can be stably placed on the end of the object to be measured and surface information can be acquired by a laser scanner. There may be.
In the target shown in FIG. 2, the length between the opposite vertices of the regular octahedron is larger than the length of one side of the cube, and is a dimension that protrudes from the cube. It may be smaller than the length of one side.

The above-described target and the measurement method using the target have been described based on a form in which the target is placed on the end of the object to be measured and measured with a laser scanner from a substantially lateral direction with respect to the target.
However, when the target installation position is, for example, a ceiling, the laser from the laser scanner is irradiated to the target from above the lick. In this case, the laser is not irradiated to the lower part of the regular octahedron of the target. Therefore, when such a usage pattern is assumed as the usage pattern of the target, a shape (FIG. 5) in which the lower part of the regular octahedron is entirely embedded in a cube may be used. That is, the cube may be a combination of the pyramidal upper portion 54.
In short, as long as at least three surfaces of the target can be recognized, and if the target installation conditions and the laser irradiation direction are limited, this measurement method uses a target with a shape that can recognize the three surfaces accordingly. it can.

In this measurement method, the target must be placed on the end of the object to be measured. It is desirable that the cube and the object to be measured have some fixing means so that the target placed with its ends aligned due to vibration or the like does not move during measurement. FIG. 6 shows an example of a target provided with such fixing means. When the object to be measured is a substance containing iron, as shown in FIG. 6A, the target cube bottom surface 110 may be a magnet or a magnetic sheet may be attached. Further, instead of attaching the magnetic sheet to the entire bottom surface, the magnetic sheet may be attached only to the peripheral portion 111 of the bottom surface. In addition, when the object to be measured is a metal or wood that is not adsorbable by a magnet, an adhesive sheet may be attached to the bottom of the target cube (FIG. 6A).
Further, as shown in FIG. 6B, bolts 120 may be provided at the bottom of the target cube, or conventional fixing means such as bolt holes may be provided (not shown).

(Other usage forms)
When using the target according to the present invention, the distance between the targets can be easily and accurately measured. Therefore, the target is not only placed on the object to be measured, but also attached to the position to be measured to measure the distance of the object by the laser scanner. can do. For example, if the target is attached to a large structure such as a bridge or a tunnel or a nuclear reactor, the distance of the target location can be measured from a vehicle loaded with a laser scanner. In bridges and tunnels, secular changes and deterioration due to the lapse of years from construction cannot be avoided, and such secular changes can be inferred from measurement of the target part. In the case of nuclear reactors, in addition to secular changes, for example, even when people are not able to approach due to accidents, etc., by measuring the distance of the target location with a remote induction vehicle loaded with a laser scanner, etc. Can be guessed. In either case, the advantage that the position of the laser scanner for measuring the target, which is a feature of the present invention, is not easily restricted by the position and orientation of the target is utilized.
Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and modifications and additions within the scope of the present invention are included in the present invention. It is.

1 DUT
2 Laser scanner
10 Target
11 Cube that forms the target
11a-11h Cube apex 12 Regular octahedron lower part
13 Regular octahedron top
14 Regular octahedron forming the target
14a to 14f A regular octahedron vertex 21 A rectangular parallelepiped constituting a deformation target
24 Octahedrons constituting the deformation target
34 Other octahedrons constituting the deformation target
42 Lower octahedrons constituting the deformation target
43 Upper part of other octahedrons constituting the deformation target
44 Other octahedrons constituting the deformation target
54 Other upper part 110 constituting the deformed target 110 Target fixing means 111 Other target fixing means arrangement 120 Screw for fixing the target

Claims (9)

Based on point cloud data obtained by scanning a predetermined measurement range with a laser scanner, a target used in a method for measuring a predetermined position of an object to be measured existing in the predetermined measurement range,
The target is an octahedron and a rectangular parallelepiped having a vertex that can be aligned with a predetermined position of the object to be measured, and has a three-dimensional shape composed of a plurality of planar regions that can be scanned by a laser scanner,
By scanning a range including the target with a laser scanner to obtain point cloud data of the target,
Extracting a set of point cloud data constituting a plane area from the acquired point cloud data for a plurality of plane areas ,
Based on the set of point cloud data constituting the extracted plurality of planar regions and known unique data for specifying the three-dimensional shape of the target, the position of one vertex of the rectangular parallelepiped is calculated,
A target used in a method of measuring a predetermined position of an object to be measured based on the calculated position of a vertex of the rectangular parallelepiped.   The target is combined in a shape in which a top portion including one vertex of the octahedron is embedded at the center of one surface of the rectangular parallelepiped, and further reaches a vertex opposite to the embedded vertex of the octahedron 2 The octahedron is combined with the rectangular parallelepiped in a form in which a virtual plane formed by two ridge lines is orthogonal to a pair of opposing planes of the four planes of the rectangular parallelepiped that are in contact with the one surface of the rectangular parallelepiped. The target according to claim 1, wherein: Based on point cloud data obtained by scanning a predetermined measurement range with a laser scanner, a target used in a method for measuring a predetermined position of an object to be measured existing in the predetermined measurement range,
The target is a combination of an octahedron and a rectangular parallelepiped having a vertex that can be aligned with a predetermined position of the object to be measured, and is composed of a plurality of planar regions that can be scanned by a laser scanner, and further, at the center of one surface of the rectangular parallelepiped. The top including one vertex of the octahedron is combined in an embedded shape, and an imaginary plane formed by two ridge lines leading to the vertex facing the embedded vertex of the octahedron is the rectangular parallelepiped. The octahedron has a three-dimensional shape combined with the rectangular parallelepiped in a form orthogonal to a pair of opposed planes of the four planes of the rectangular parallelepiped in contact with the one surface,
By scanning a range including the target with a laser scanner to obtain point cloud data of the target,
Extract a plurality of planar regions from the acquired point cloud data using a region growth method,
A plane area constituting the octahedron is extracted from the plurality of plane areas based on known unique data for specifying the three-dimensional shape of the target, and further obtained from the extracted plane area constituting the octahedron. A plane region constituting the rectangular parallelepiped is extracted based on known specific data specifying the vertices of the octahedron and the three-dimensional shape of the target,
Calculate the position of the vertex of the rectangular parallelepiped aligned with the predetermined position of the object to be measured from the vertex extracted from the octahedron and the planar area constituting the extracted rectangular parallelepiped,
A target used in a method of measuring a predetermined position of an object to be measured based on the calculated position of a vertex of the rectangular parallelepiped.   4. The target according to claim 1, wherein the rectangular parallelepiped is a cube.   The target according to claim 1, wherein a triangular prism, a pentagonal column, or a hexagonal column is used instead of the rectangular parallelepiped in the target.   The target according to claim 1, wherein the octahedron is a regular octahedron.   The target according to claim 1, further comprising a fixing means on the bottom surface of the target.   The target according to claim 7, wherein the fixing means is a magnetic member. A method for measuring a distance on an object to be measured using the target according to claim 1,
A plurality of points to be measured on the object to be measured are installed by aligning the vertices of the target,
A method of measuring a distance on an object to be measured based on the positions of the vertices of the plurality of targets.

Images