JP2005037129A - Surveying method using three-dimensional photogrammetry technique - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring the surface shape of a rut, or the like on a road by using a three-dimensional photogrammetry technique. <P>SOLUTION: In a measurement field, first at least three pieces of reference point equipment for supporting a reference point are installed on a road surface whose shape is measured, and the distance between the reference points is measured. Then, the height of the reference points is adjusted so that the altitudes of the reference points become the same. Further, a plurality of points to be measured are marked on the road surface. Then, photos, where all reference points and all points to be measured are photographed, are photographed from a plurality of directions. After that, the pictures are captured into a computer as image data, a reference point projected to each image data and a point to be measured are equal and are mapped each other, and the coordinates of each point to be measured are calculated by arithmetic processing using information on the distance between reference points and the mapping information. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for surveying surface shapes (that is, uneven shapes) such as a ground surface, a paved surface, and a lawn surface.
[0002]
[Prior art]
There are cases where it is desired to measure the surface shape of the ground, pavement surface, lawn surface, etc. using surveying technology.
[0003]
Hereinafter, a conventional example of such a surveying technique will be described by taking as an example the case of measuring rutting on a road.
[0004]
Rugs are often formed on road surfaces such as roads by long-term use.
Rutting means a road surface undulation formed with the passage of a vehicle or the like. The pavement that has been dug out prevents stable and safe traffic of vehicles. For example, if rainwater accumulates immediately, it may cause a hydroplaning phenomenon. For this reason, it is very important to accurately measure the state of the road in terms of maintenance and management of roads and the like.
[0005]
Conventionally, as a technique for measuring a road or the like, for example, a technique using a cross-sectional unevenness measuring device is known. FIG. 5 is a schematic view showing the external structure of such a cross-sectional unevenness measuring device. As shown in FIG. 5, in this cross-sectional unevenness measuring device, the measurement beam 503 is supported by the support legs 501 and 502, and the measurement unit 504 is placed on the measurement beam 503. The measuring unit 504 is provided with a wheel support bar 505 that can move up and down, and a measurement wheel 506 is provided at the lower end of the wheel support bar 505. The measurement unit 504 moves in the lateral direction along the measurement beam 503. At this time, the measurement wheel 506 moves up and down along the unevenness of the road surface, and accordingly, the wheel support bar 505 also moves up and down. The measuring unit 504 detects a vertical movement of the wheel support bar 505 and creates a log. Thus, according to the cross-sectional unevenness measuring device, the depth of the rut can be measured by detecting the vertical movement of the measuring wheel 506.
[0006]
In addition, as another measuring technique for a child, for example, a technique using an automatic measuring vehicle is known. In this method, for example, a bar to which about 3 to 5 sensors are attached is mounted on an automobile, and the distance between the bar and the road surface is measured using these sensors. According to this method, the depth of the rudder can be measured while driving the automobile. Techniques for measuring a rudder using an automatic measuring vehicle are also disclosed in Patent Documents 1 to 3 below.
[0007]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 09-218028 [Patent Document 2]
Japanese Patent Laid-Open No. 09-287033 [Patent Document 3]
Japanese Patent Laid-Open No. 10-002727
[Problems to be solved by the invention]
However, the cross section unevenness measuring instrument shown in FIG. 5 has the following drawbacks.
[0009]
The cross-sectional unevenness measuring instrument in FIG. 5 is very large and heavy. For this reason, such a cross-sectional unevenness measuring device has a drawback that the cost for transportation to the measurement site is high.
[0010]
Further, in such a cross-sectional unevenness measuring instrument, when measuring a rut along a road width, the measurement beam 503 blocks the entire road or the like. For this reason, there has been a drawback that the vehicle or the like cannot pass on the road or the like during the measurement work.
[0011]
Furthermore, in such a cross-sectional unevenness measuring device, since the measurement is performed sequentially while moving the measuring unit 504, the required time becomes very long when the measurement for the road width is performed at a plurality of locations. For this reason, since time is required for the measurement work, the work cost such as the labor cost increases, and the time during which the vehicle or the like cannot pass on the road also becomes long.
[0012]
On the other hand, when measuring using an automatic measurement vehicle, the measurement vehicle must actually be transported to the measurement site. Furthermore, it is impossible to perform precise measurement with such measurement.
[0013]
In addition, for the following reasons, it is difficult to apply conventional cross-sectional unevenness measuring instruments and measurement vehicles to surface measurements other than road surfaces.
[0014]
For example, when it is desired to finely measure the surface shape of a vast area such as a golf course, it is very difficult to use a cross-sectional unevenness measuring device and a measuring vehicle as shown in FIG. This is because the measurement takes too much time and the measurement accuracy is low.
[0015]
Also, for example, when it is desired to measure the surface roughness of a golf course green, it is not possible to use a cross section unevenness measuring device or a measurement vehicle. This is because the lawn surface hurts or the surface of the lawn becomes uneven.
[0016]
In addition, the above-mentioned cross-sectional unevenness measuring device and measuring vehicle cannot be used even for those having a relatively small area and a large protrusion, such as a Japanese garden or an old burial mound.
[0017]
The present invention has been made in view of such drawbacks of the prior art, and is capable of performing precise measurement at low cost and in a short time regardless of conditions such as the shape and area of the surface to be measured. It aims to provide a method.
[0018]
[Means for Solving the Problems]
The surveying method using the three-dimensional photo measurement technology according to the first invention sets up three or more reference point instruments supporting the reference points on the measurement surface and measures two or more types of distances between these reference points. A reference point setting step, a measurement point setting step for marking a plurality of measurement points on a measurement surface, and a shooting step for photographing a photograph in which some or all of the reference points and measurement points are projected from a plurality of directions And a step of associating a plurality of photographs acquired in the photographing step as digital image data into a computer and associating the same reference point and the same measured point displayed in these image data, and between the reference points A calculation step of calculating coordinates of each measurement point by calculation processing using the distance information, the height information of any reference point, and the association information.
[0019]
In the surveying method using the 3D photo measurement technology according to the second invention, three or more reference point instruments that support the reference points are installed on the surface to be measured and the distance between these reference points is 2 Image data obtained by measuring more than one type, marking a plurality of measurement points on the measurement surface, and shooting a photo in which some or all of the reference points and measurement points are projected from a plurality of directions An input step for inputting measurement data including distance information between reference points and height information of one of the reference points to the computer, and the same reference point and measured point displayed in these image data An association step for associating each other, and an operation step for calculating the coordinates of each measurement point by an operation process using distance information, height information, and association information.
[0020]
According to the surveying method according to the first and second inventions, at the surveying site, it is only necessary to take a photograph of the reference point instrument and the marking, so that the cost is low regardless of the shape and area of the surface to be measured. Precise measurement can be performed in a short time.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a surveying method using the three-dimensional photo measurement technique according to the embodiment of the present invention will be described by taking as an example a case of measuring a rutting of a road. In the drawings, the size, shape, and arrangement relationship of each component are shown only schematically to the extent that the present invention can be understood, and the numerical conditions described below are merely examples. .
[0022]
First, the equipment used at the measurement site and the measurement operation at the site will be described according to the work procedure. FIG. 1 is a conceptual diagram showing such equipment and measurement work.
[0023]
(1) Three or more reference point devices are installed on the road 100 as a measurement site. In the example of FIG. 1, four reference point devices 110, 120, 130, and 140 are installed. Reference points M1, M2, M3, and M4 are attached to the reference point devices 110 to 140. For example, as shown in FIG. 2A, a color cone 220 having a ball 210 as a reference point M1 to M4 attached to the tip can be used as the reference point devices 110 to 140. Two of these reference point devices 110 to 140 are installed on both sides of the road 100 (for example, a shoulder or a sidewalk). In this embodiment, since the reference point devices 110 to 140 are installed on both sides of the road, there is almost no interference with road traffic. The distance between the reference point devices (that is, the reference point devices 110 and 120 and the reference point devices 130 and 140) on the same side of the road 100 is, for example, about 5 to 10 meters. According to the study of the present inventor, in order to obtain sufficient measurement accuracy, it is desirable that the interval between the reference point instruments is 10 meters or less. The interval between the reference points is measured using, for example, a convex. Further, it is necessary to measure two or more kinds of intervals between the reference points, but it is not necessary to measure all the distances between the reference points (described later).
[0024]
(2) Next, the heights of the reference points M1 to M4 are adjusted so that the reference points M1 to M4 have the same altitude. This height adjustment can be performed, for example, using a water pipe 230 as shown in FIG. That is, when the both sides 231 and 232 of the transparent water pipe 230 are lifted and water is put therein, the elevations of the water surfaces A and B at the both ends 231 and 232 are the same. Therefore, the heights of the reference points M1 to M4 may be sequentially adjusted so as to coincide with the positions of the water surfaces A and B.
According to such a method, even when the road surface of the road 100 is inclined, the altitudes of the reference points M1 to M4 can be matched. Thereafter, the height of any reference point device (for example, reference point M1) is measured using a convex or the like.
[0025]
In addition, the measuring method at the time of height adjustment is not specifically limited, For example, you may use the measuring method etc. which used the laser beam.
[0026]
(3) Subsequently, a plurality of measurement points are marked on the road surface of the road 100. In the example of FIG. 1, a total of 35 measured points P1, P2,..., P35 are marked (in FIG. 1, the measured points are indicated by “X”). The interval between the measurement points P1 to P35 is arbitrary, but in this embodiment is about 1 meter. The shorter the interval between the measurement points P1 to P35, the more accurate measurement can be performed. Note that the positions of the measurement points P1 to P35 need not be measured. The marking is performed, for example, by drawing measured points P1 to P35 on the road surface using chalk or the like. Further, the measurement points P1 to P35 may be marked by sticking a seal or the like on the road surface. By marking with chalk or seals, it is possible to reduce the time that obstructs road traffic to a very short time, and it may be difficult to see the marking even if vehicles etc. pass through the road 100 after marking. No.
[0027]
(4) Thereafter, the reference points M1 to M4 and the measured points P1 to P35 are photographed by a camera. Shooting with a camera is performed from at least two directions. In the example of FIG. 1, digital image information G1, G2, and G3 for three images is acquired by photographing from three directions D1, D2, and D3. Each photographing is preferably performed so that all the reference points M1 to M4 and all the measured points P1 to P35 are captured. According to the study of the present inventor, in order to improve the measurement accuracy, it is desirable to also perform photographing from the right lateral direction (direction orthogonal to D2), and to make the association processing described later as easy as possible. It is desirable to shoot from a high position. As will be described later, digital image information G1, G2, and G3 acquired by a photographer is taken into a computer or the like as a digital image. Therefore, it is desirable to use a digital camera as the camera. However, an image taken with a film-type camera or a video camera may be converted into digital image information G1, G2, G3.
[0028]
As described above, the distance between the reference points, the reference point height, and the digital image information G1, G2, and G3 are acquired.
[0029]
Next, a method of calculating the rudder shape data using such information will be described.
[0030]
(5) First, the digital image information G1, G2, G3 described above is input to the computer.
[0031]
(6) Next, the operator performs a process of associating the reference points M1 to M4 and the measured points P1 to P35 on the computer screen. For example, the operator inputs to the computer that the reference points M1 displayed in the images G1, G2, and G3 are the same point. For example, the association can be performed by moving the pointer to the reference point M1 of the images G1, G2, and G3 and clicking the mouse. Similar processing is performed on the other reference points M2 to M4 and the measurement points P1 to P35 on the screen.
[0032]
(7) Subsequently, the operator inputs the coordinates of the reference points M1 to M4. For example, the reference point M1 is the origin (0 0 0), the direction of the reference point M1 → M2 is the X direction, the direction orthogonal to the X direction is the Y direction, and the height direction (vertical direction) is the Z direction. What is necessary is just to determine the coordinate of the points M2-M4. At this time, since the altitudes of the reference points M1 to M4 are the same (see the above process (2)), the Z coordinates of these reference points M1 to M4 are the same.
[0033]
Further, the distance between the reference points measured in the above process (1) is input as data for converting the distance between the reference points on the photographic image into an actual distance. Since the distance between the reference points is used for conversion of the X-axis coordinate and the Y-axis coordinate, two or more types of reference point distances having different directions on the XY plane are required. Further, the measured value of the height of the reference point M1 (see the above process (2)) is input as data for converting the Z coordinate of each of the reference points M1 to M4 into the actual height.
[0034]
(8) Thereafter, the three-dimensional coordinates of the measurement points P1 to P35 are calculated by executing a calculation process by a computer. As a method for calculating the three-dimensional coordinates of the points displayed in the digital image, a known three-dimensional computer graphics method can be used (for example, “Two-dimensional CG made from photographs” Modern Science Co., Ltd., 2001 (Refer to the first edition issued on January 30), and computer software for such arithmetic processing is also sold. Therefore, it will be briefly described here.
[0035]
In this calculation process, first, the X axis, the Y axis, and the Z axis are set in the computer based on the coordinate information of the reference points M1 to M4. Then, the three-dimensional coordinates of the measured point P1 projected on the digital image information G1 and the three-dimensional coordinates of the measured point P1 projected on the digital image information G2 in correspondence with the X axis, Y axis, and Z axis. And the three-dimensional coordinates of the point P1 to be measured displayed on the digital image information G3.
[0036]
Subsequently, these three types of three-dimensional coordinates are compared. In many cases, these three types of three-dimensional coordinates do not coincide with each other due to an optical error in the digital image information G1 to G3, an input error during the association process (see the above process (6)), and the like. For this reason, for example, a coordinate point that minimizes the sum of squares of the Euclidean distance to these three-dimensional coordinate points is determined to be the measurement point P1. That is, if three types of three-dimensional coordinates are (X1, Y1, Z1), (X2, Y2, Z2), (X3, Y3, Z3), (X1 ² + Y1 ² + Z1 ² ) + (X2 ² + Y2 ² + Z2) ² ) + (X3 ² + Y3 ² + Z3 ² ) The coordinate point (X, Y, Z) that minimizes is obtained, and this is set as the final coordinate of the measurement point P1. Similarly, the coordinates of other measurement points P2 to P35 are obtained from the digital image information G1 to G3.
[0037]
The coordinates of the measurement points P1 to P35 thus obtained become data indicating the position and depth of the rut. Then, if an appropriate Z coordinate value is set as a reference depth (that is, a depth of zero) and the Z coordinate of each measurement point is converted, data on the depth of each other can be obtained.
[0038]
FIG. 3 is a table comparing the groove depth obtained by the measuring method according to this embodiment and the groove depth measured by a conventional cross-sectional unevenness measuring device (see FIG. 5). The table in FIG. 3 compares both measurement results on the assumption that the difference between the measurement points P11 is zero. As can be seen from FIG. 3, the difference between the table data is within ± 5 mm. Generally, the system required for rutting measurement is about 10 mm. Therefore, according to the measuring method according to this embodiment, it can be said that sufficient accuracy comparable to that of the cross-sectional unevenness measuring device can be obtained.
[0039]
FIG. 4 shows a contour map created by using the rudder depth obtained by the measurement method according to this embodiment. This contour map is created as one function of the software used in step (8). Thus, according to the measuring method according to this embodiment, a very detailed contour map can be obtained using the three-dimensional coordinates obtained in step (8).
[0040]
According to the measurement method according to this embodiment, only small and lightweight equipment such as a reference point device and photographic equipment are transported to the measurement point. In addition, the passage of vehicles and the like is obstructed mainly when marking the measurement point, but for a very short time.
In addition, since the three-dimensional coordinates of the point to be measured are calculated, a precise measurement result can be obtained. Therefore, according to this embodiment, it is possible to carry out highly accurate rudder measurement at a low cost while reducing the influence on traffic such as roads.
[0041]
In addition, according to the measurement method according to this embodiment, since the reference point device for obtaining the reference coordinates is installed separately from the point to be measured, the reference point has little influence on the traffic on the road or the like. Can be measured with high accuracy. In the generally used three-dimensional computer graphics technique, there is no distinction between a reference point and a point to be measured, and three-dimensional coordinates of each target point are obtained by associating a large number of target points. Therefore, if this technique is applied to measurement directly, it is necessary to mark the measurement points as target points on the road surface and to measure the distances and depths between some measurement points. As a result, the working time at the measurement site becomes longer, and the disturbance of road traffic becomes significant. Furthermore, this method cannot measure the slope of the road surface. On the other hand, in this embodiment, since the reference point device is installed and the distance between the reference points and the reference point height are actually measured, the work time at the measurement site is short and there is almost no interference with road traffic. . In addition, since the height of each reference point is adjusted so that the altitude is the same, it is possible to measure not only the rudder but also the slope of the road surface.
[0042]
As described above, the embodiment of the present invention has been described by taking the case of measuring the rutting of the road as an example. However, the present invention is not limited to surveying road surface shapes. For example, it is clear that the present invention can be applied to surface shapes such as bridges, aircraft runways, and unpaved roads. Also for golf course course and green surface shape, pitcher's mound projection shape of baseball stadium, ground surface for artificial turf laying, projection shape of Japanese garden, etc., projection shape of tomb The surveying method of the present invention can be applied.
[0043]
Here, when measuring the course surface shape of a golf course, for example, reference points may be scattered at predetermined intervals (for example, within 10 meters) in the measurement region or in the vicinity of the outer periphery of the measurement region. . In other words, since there is no problem in road traffic, it is not necessary to arrange them at both ends of the measurement area as in the example shown in FIG. 1, and even if the reference point device and the measurement point are mixed in the measurement area. Good. By applying the present invention to such surveying, a wide area can be measured accurately in a short time.
[0044]
Further, when measuring the shape of a protrusion such as a pitcher's mound, a mountain or a tomb in a baseball field, for example, a reference point device may be arranged along the outer periphery of the surface to be measured (projected area). Arranging the reference point device along the outer periphery of the protruding region facilitates the work of matching the altitude of the reference point device. In addition, when it may be assumed that the altitudes of the reference point device installation locations are all the same, adjustment of the height of the reference point device may be omitted. In this case, if the height of the reference point device in the standard state is known in advance, it is not necessary to measure the height of the reference point device. In addition, not all reference point devices and measurement points may be captured in each digital image. However, in order to increase the measurement accuracy, it is desirable that each reference point device and measurement target point appear in as many digital images as possible. As described above, the present invention can accurately measure even a relatively small area and a large protrusion, and hardly damages lawn or moss on the measurement surface. In addition, when a Japanese garden or the like is temporarily removed and then reconstructed or relocated to the original location, the reproducibility can be improved by using the surveying technique of the present invention.
[0045]
【The invention's effect】
As described above in detail, according to the surveying method of the present invention, accurate measurement can be performed at low cost and in a short time regardless of conditions such as the shape and area of the surface to be measured.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram for explaining measurement equipment and measurement work of a road surface shape measurement method according to an embodiment.
FIG. 2A is a perspective view schematically showing a structure example of a reference point device, and FIG. 2B is a conceptual diagram showing a structure example of a water pipe.
FIG. 3 is a table showing an example of a measurement result of the embodiment.
FIG. 4 is a contour map showing an example of a measurement result of the embodiment.
FIG. 5 is a conceptual diagram schematically showing a conventional road surface shape measuring instrument.
[Explanation of symbols]
100 Road 110, 120, 130, 140 Reference point 210 Ball 220 Color cone 230 Water pipe 231, 232 Both ends of water pipe

Claims (6)

A reference point setting step for installing three or more reference point devices that support the reference point on the measurement surface and measuring two or more types of distances between these reference points;
A measurement point setting step for marking a plurality of measurement points on the measurement surface; a photographing step for photographing a photograph in which a part or all of the reference point and the measurement point are projected from a plurality of directions;
Associating step of associating a plurality of photographs acquired in the photographing step with a computer as digital image data and associating the same reference point and the measured point projected on these image data;
A calculation step of calculating coordinates of each of the measurement points by calculation processing using distance information between the reference points, height information of any of the reference points, and the association information. A surveying method using a three-dimensional photo measurement technique characterized by including. Install three or more reference point instruments that support the reference points on the surface to be measured, measure two or more distances between these reference points, and mark multiple points to be measured on the surface to be measured And image data obtained by photographing a photograph in which a part or all of the reference point and the measured point are projected from a plurality of directions, distance information between the reference points, and any one of the reference An input step for inputting measurement data including point height information to a computer;
An associating step for associating the same reference point and the measured point projected on the image data;
A calculation step of calculating coordinates of each of the measurement points by a calculation process using the distance information, the height information, and the association information. Surveying method. The height information is obtained by measuring the height of any of the reference points after adjusting the heights of these reference points so that the elevations of the reference points are the same. A surveying method using the 3D photo measurement technique according to claim 1. The 3D photo measurement technique according to claim 1, further comprising a drawing step of creating a contour map of the measurement point using the 3D coordinates calculated in the calculation step. Surveying method used. The surveying method using the three-dimensional photo measurement technique according to claim 1, wherein the reference point device is installed on both sides of the surface to be measured. The surveying method using the three-dimensional photo measurement technique according to claim 1, wherein the reference point device is arranged so that the distance information is 10 meters or less.

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