JP2652632B2 - How to measure arbitrary spatial coordinates - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring arbitrary spatial coordinates, and more particularly to a method for measuring a distance between a certain object and another arbitrary object along a certain path and a position of the certain object. It relates to a measurement method suitable for obtaining data.

Conventional technology Conventionally, for maintenance management of transmission line routes, periodically monitor the transmission line route to measure the distance between the transmission line running in the hills and the trees, and discover areas requiring attention in maintenance. I needed to. For example, as shown in FIG. 11 of the accompanying drawings,
The distance L between the power transmission line 13 stretched between the tower 11 and the tower 12 and the trees 14 growing in the mountains changes year by year as the trees grow. If the separation distance L becomes too small, the possibility of occurrence of an accident such as a power outage due to a fire accident due to discharge or a tree sway due to strong wind being cut off increases. Therefore, in order to prevent such an accident from occurring, it is necessary to periodically monitor the location along the transmission line route to search for such a danger point and appropriately remove high or large growing tree branches. It is necessary to work such as lowering. For this purpose, it is necessary to know the position of the dangerous place.

Conventionally, as an example of such a patrol monitoring method of a transmission line, a method based on aerial photogrammetry has been considered. According to this conventional aerial photogrammetry method, in order to create a three-dimensional image from the two photographs taken, the airplane flies in parallel to the power transmission line 13 and photographs about 60% of the overlapped photographs at shifted positions. . FIG. 12 shows an example of the photographing range of these two photos shifted from each other. In FIG. 12, the shooting range 31 of the first photograph is the shooting range when the center of the lens of the camera mounted on the airplane is at the point 21, and the shooting range 32 of the second photo is the shooting range 32 on the airplane. This is the shooting range when the center of the lens of the selected camera is at the point 22. Here, the distance between the points 21 and 22 is referred to as a distance b between the principal points. Aerial photograph 3 taken by an airplane in this way
FIG. 13 shows a principle diagram from which distances between points in the photograph can be obtained from 1 'and 32'. In one set of photographs 31 'and 32' where the images overlap, the position of the same image is shifted by the shooting position of the camera. The moving lengths ΔP ₁ ′ and ΔP ₂ ′ are called parallax on a photograph. The difference in height between two points in the same photograph is represented by the difference between the respective parallaxes in the horizontal direction, that is, ΔP ₁ ′ −ΔP ₂ ′, and this is called parallax.

Conventionally, to measure the distance between certain points in a photograph taken based on such a principle, it is necessary to use the above-described method.
A stereoscopic image was created from the set of photographs 31 'and 32' using an analytical plotter, and the parallax of the photographs was determined. In this case, 1 / 10000-1 / 1
The relative position of each point is grasped from a photograph taken at about 5000 (aerial triangulation), these data are transferred to a photograph of about 1/5000 to 1/6000, and the three-dimensional coordinate value of the position of each point ( xyz coordinate values), and the distance between the two points was measured from the difference between the coordinate values.

The procedure of measuring a three-dimensional coordinate by such a conventional analytical plotting machine is shown in a flowchart of FIG. As shown in FIG. 14, in the conventional procedure, first, in step 41, internal orientation in a photograph is performed. In photogrammetry,
A condition in which a line connecting a projection center (lens of a camera), an image on a photograph, and an object is connected by a straight line, that is, a collinear condition is fundamental. When this condition is used, the image on the photograph must be represented by the coordinate system of the photograph in which the positional relationship with the projection center is accurately defined. The internal orientation operation is an operation for converting a coordinate system measured by the machine into a coordinate system of a photograph. Next, in step 42, mutual orientation is performed. As can be seen from FIG. 13, the three-dimensional coordinates of the target object are obtained as a result of the forward intersection in which the light passing through the projection center of the stereoscopic photograph intersects with each other. When this photograph is reproduced in the state when it was taken, the light connecting the two corresponding images on the photograph and the projection center intersects in real space to obtain a three-dimensional image. This stereoscopic image is called a model in photogrammetry.
This model may be formed as long as the relationship between the position and the inclination at the time of photographing is relatively the same. The mutual orientation operation is an operation for creating a model similar to such a real space.

After the mutual orientation is completed in step 42, the absolute orientation is performed in step 44. Eventually, a model under the three-dimensional coordinate system in which the object is defined is required. Therefore, it is necessary to further convert the model obtained by the mutual orientation into a necessary coordinate system. The absolute orientation operation is an operation for performing such coordinate conversion. Conventionally, in order to perform absolute orientation, as shown in step 43, a point whose coordinates appear on a photograph is known, that is, a reference point is input and coordinate conversion is performed using the reference point. They needed a rotation and scale to do so. Conventionally, in an analytical plotting machine, at least three reference points in a model, usually six or more points are measured, and their coordinates are given to perform absolute orientation. In step 45, the model whose absolute orientation has been completed measures arbitrary three-dimensional coordinates in the model. When measuring the separation distance L between the transmission line 13 and the tree 14 (see FIG. 11), first measure the three-dimensional coordinates of the transmission line 13 and then measure the three-dimensional coordinates of the top of the tree 14. .
Based on these measured coordinates, the shape of the transmission line is analyzed by the computer of the analytical plotter in step 46,
The minimum separation distance L between the object and the tree 14 is calculated and output.

Problems to be Solved by the Invention In the conventional aerial photogrammetry method as described above,
It is necessary to know and input the coordinates of a certain reference point as data that is the basis of spatial coordinate values, such as the distance between principal points, the shooting altitude (the position of the lens), and the position of a certain point. Therefore, in the conventional method, as the means for knowing the coordinates of the reference point, the national coordinates photographed in the photograph, that is, triangular points and the like are used. Therefore, in the conventional method, since it is necessary to take a photograph in a range including the triangular points and the like,
Flying altitudes are high altitudes between 1000m and 2000m, and are generally 1/10 scale
I had to take about 000 to 1/15000 photos. And since it is difficult to read individual trees with such a small-scale photograph, it is troublesome to take a photograph of about 1/5000 to 1/6000 in a similar way and measure the position of each tree. It was hanging.

An object of the present invention is to provide a method for measuring arbitrary spatial coordinates which can solve such a problem of the related art.

Means for Solving the Problems According to one feature of the present invention, arbitrary spatial coordinates are obtained in order to obtain data such as the distance between a certain subject along a certain path and another arbitrary object and the position of the subject. In the measuring method, a helicopter equipped with two normal cameras and a panoramic camera arranged at an interval of a fixed baseline length along a horizontal direction substantially perpendicular to the flight direction along the path While flying, perform stereo photography centering on the subject with the two normal cameras and perform panorama photography along the route with the panoramic camera, and obtain a stereo photograph and the panorama photography obtained by the stereo photography. An arbitrary spatial coordinate data can be obtained by reading the panoramic photograph obtained by the above using an analytical plotter and performing a computer processing.

Embodiment Next, an embodiment of the present invention will be described in more detail with reference to the accompanying drawings, particularly, FIG. 1 to FIG.

FIG. 1 is a schematic perspective view showing an example of a helicopter used to carry out the method for measuring arbitrary spatial coordinates of the present invention. As shown in FIG. 1, the helicopter 50 is composed of two ordinary cameras 61 and 62 supported on a gantry so as to protrude on both sides, and a panoramic camera 63 supported so as to protrude on one side. It is installed.
Also, in the window on one side of the cockpit of this helicopter 50,
It is preferable to provide an aiming mark 64 to be described later.

Fig. 2 shows a helicopter equipped with
FIG. 11 schematically shows a state in which a transmission line route including the transmission line 13 as shown in FIG. 11 is being measured. FIG. 3 shows two normal cameras 61 and 62 mounted on the helicopter 50, and 1
A control system for operating the two panoramic cameras 63 from inside the aircraft and confirming the operation thereof is schematically shown. As shown in FIG. 3, the control system 70 includes a control unit 71, and cords from the cameras 61, 62, 63 are connected to the control unit 71. The control unit 71 is provided with shutter buttons 72 and 73. By pressing one of these shutter buttons inside the machine, each camera can release the shutter at the same time. The control unit 71 is provided with operation status confirmation lamps 74 corresponding to the respective cameras. Therefore, the operating status of the camera in the aircraft can be grasped by flashing the corresponding lamp when the camera is operating cleanly, and when a problem occurs, the corresponding lamp remains lit. It can be understood by becoming.

Next, a case where the helicopter 50 measures the spatial coordinates of the transmission line route will be described in detail.

In order to perform such a measurement, first, while flying the helicopter 50 at an altitude of about 100 m along the transmission line path, the shutter button 72 or 73 at a desired position.
Is pressed in the machine, and stereo photography is performed by the two normal cameras 61 and 62, and panorama photography is performed by the panorama camera 63. Each of such stereo shooting and panorama shooting will be described in detail below.

Stereo shooting, as shown in Figure 4, helicopter
The measurement is performed by two normal cameras 61 and 62 arranged at a fixed base line length b ', for example, at a distance of 3.2 m in a direction substantially perpendicular to the flight direction of 50. In this case, since the photographing at the flight position during the patrol is considered in principle, it is necessary that these separation measuring cameras 61 and 62 have a declination θ on the transmission line side. An appropriate angle in this case is 20 ° to 25 °. FIG. 5 shows the ranges 81 and 82 of the stereo photography performed by the cameras 61 and 62 in the state set as described above. FIG. 6A shows a photograph 81 ′ taken by the camera 61.
FIG. 6B illustrates a photograph taken by the camera 62. A method is also conceivable in which the cameras 61 and 62 are mounted before and after the helicopter 50. This makes it possible to increase the length of the fixed base line, which is advantageous in terms of accuracy, but makes transmission lines difficult to read.

On the other hand, in the panoramic photographing, as shown in FIG. 7, the panoramic camera 63 is set so that the lens position can be photographed at the outermost position (in this case, the result is the same as when the camera is swung about 20 degrees to the track side). ) I fix it on the track side of the helicopter,
The lens is set directly above as shown by arrow A (as shown by arrow B, the lens is turned 180 ° and turned directly below). In such a helicopter aerial photogrammetry,
Since there is no external absolute value such as a triangular point, the coordinates of a certain point are set as (0,0,0) and the coordinates of each point are specified as a three-dimensional correlation. Although it is possible to measure the distance between each point in the photograph by taking a picture, the absolute relationship with the one not shown in the photograph cannot be understood. For this reason, it is necessary to consider, as a separate problem, things related to the outside of the photograph, such as where the subject is located between the towers, how much the photographed picture is tilted, and the like. In the embodiment, this is solved by panoramic photography using a panoramic camera.

Therefore, the principle of determining the position of the subject between the towers using the panoramic photograph by the panoramic camera 63 as described above will be described. FIG. 8 illustrates the relationship between the panorama photographing position and the subject. In FIG. 8, χ indicates the distance to the tower 11, and S indicates the distance to the tower 11.
Indicates the span length between the tower 11 and the tower 12.
Δχ indicates an error, and Δh indicates a steel tower.
The height difference between the tree 11 and the tree 14 is indicated, and H indicates the height of the panorama photographing position. In this case, the distance from the tower 11 to the tree 14, that is, χ, is obtained by the following equation.

H · tan θ ₁ + H · tan θ ₂ = S−h · tan θ ₂ H · (tan θ ₁ + tan θ ₂ ) = S−h · tan θ ₂ χ = H · tan θ ₁ −H · tan Δθ = H · (tan θ ₁ −tan Δθ) (b) Substituting (a) for (b) Since the error Δχ in this case is represented by Δχ = Δh · tan Δθ, the larger the value of Δh or Δθ,
That is, the error increases as the subject (tree or the like) is not directly below and the difference between the height of the subject and the tower is greater.

Next, a method of determining a shooting range by such a helicopter will be described. Since the camera is mounted outside the aircraft, it is not possible for a patrolman inside the aircraft to look into the viewfinder to determine the shooting range. Therefore, the following two methods are conceivable as a method for determining the photographing range in the machine.

1) A method of setting up something like a monitor / TV instead of a viewfinder in the aircraft to project the shooting range.

(2) A method in which an aiming mark as indicated by reference numeral 64 in FIG. 1 is installed in the window of the helicopter 50 so that the center of the shooting range can be confirmed.

According to the method (1), the shooting range projected on the monitor / television is accurate, but it is difficult to grasp the position of the subject in the whole. For example, it is conceivable that there are only trees around and it is not clear which place the projected video itself is. On the other hand, in the method (2), it is easy to confirm the position of the subject in the whole image, but the photographing range is roughly grasped as this range. Therefore, when these two methods were compared and examined, the size of the shooting range was about 76m x 76m at an altitude of 70m, which was quite wide. Since it is considered more important to be able to easily grasp the position of the subject, the method of setting the aim 64 is more preferable. This aim 64 has a depression angle of 0
It is preferable from the viewpoint of accuracy that the camera is installed below the door where the subject can be checked by setting the angle to °. In this case, the area that can be seen in the lower half of the front seat side door of the helicopter almost falls within the shooting range,
The aiming mark 64 is used to indicate which part of the lower half of the door the subject should pass through when pressing the shutter button. That is, when the patrol member sits on the co-pie seat and the subject normally comes to the aiming mark 64 and presses the shutter, the subject appears in the middle of the photograph.

Next, how many photographs are appropriate for one subject will be described. This is related to the problem of when to press the shutter, but since the photographed image has a considerable shooting range,
If the shutter is pressed in the vicinity of the aiming mark 64 by the method (2), the subject is almost certainly photographed by one image (one set). However, in the case of camera shake or the like, it is more reliable to take about three shots. Basically, the subject should appear in the middle of the second of the three shots. An aiming mark 64 is preferably provided. It is sufficient that the panorama photograph is rotated by one rotation during this time. Therefore, it is preferable that the mechanism be such that once the shutter is pressed, three photographs for distance measurement are automatically taken, and one panorama photograph can be taken.

In addition, the degree of overlap between the photographs before and after the separation measurement by the cameras 61 and 62 differs depending on the speed and altitude of the helicopter,
At a normal altitude at a patrol speed (50km / h), it is about 80%. The time required for this photographing is about 3 seconds for the photograph for distance measurement and about 2 seconds for the panoramic photograph.

FIG. 9 is a flowchart showing a procedure for measuring using such a helicopter 50. As shown in FIG. 9, in step 90, each device mounted on the helicopter 50 is inspected, and each camera is loaded with a film. Step 100 shows a part of the flight operation by the helicopter 50. As described above, stereo photography is performed in step 101, and panoramic photography is performed in step 102 at the same time. After this shooting work, step
At 110 and 111, each photograph is developed and printed. Step 120 shows the part of the work of reading and computer processing by the analysis plotter. In this step 120,
From the stereo photograph obtained as described above, data such as the separation distance of a desired portion of the subject can be obtained by the coordinate calculation in step 121 and the separation distance calculation in step 122. In step 123, the photographing position of the subject is calculated from the panoramic photograph. Each data obtained in each of these steps is submitted in step 130.

FIG. 10 shows the aforementioned steps in the measuring method of the present invention.
6 is a flowchart showing details of a procedure of coordinate calculation of 121 and a separation distance calculation of step 122. As shown in FIG. 10, in the measuring method of the present invention, the internal orientation of a stereo photograph is performed in step 141, and then the mutual orientation is performed in step 142. This is the same as the above-described conventional method. However, in the method of the present invention, the absolute orientation based on the fixed baseline length is performed in step 144. Therefore, in step 143, data indicating the fixed base line length b 'is input, and in step 144, absolute orientation is performed. This is completely different from the conventional absolute orientation using a reference point. Such an absolute orientation based on the fixed base line length b 'can be realized by appropriately reconfiguring a computer program.
The model for which the absolute orientation based on the fixed base length has been completed can measure arbitrary three-dimensional coordinates in the model in step 145. When measuring the separation distance between the transmission line and the tree, first measure the three-dimensional coordinates of the transmission line, and then measure the three-dimensional source coordinates of the top of the tree. Based on these measured coordinates, in step 146, the shape of the transmission line is analyzed by the computer of the analytical plotter, and the minimum separation distance between the electric line and the tree can be calculated.

According to the measurement method of the present invention, as described above, since a stereo photograph does not need to include an image such as a triangular point to be a reference point, a stereo photograph taken from a helicopter flying at a low altitude is used. Can measure arbitrary spatial coordinates with sufficient accuracy. Therefore, as in the past, using an airplane, at a high altitude of 1000 m to 2000 m, and generally at a scale of 1/10000 to 1/1
There is no need to take about 5,000 pictures and about 1/5000 to 1/6000 pictures separately in the same manner.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an example of a helicopter used to carry out the method for measuring arbitrary spatial coordinates of the present invention, and FIG. 2 is a diagram showing a helicopter of FIG. FIG. 3 is a schematic diagram showing a state in which surveying is being performed.
Two regular cameras mounted on the helicopter shown,
FIG. 4 is a schematic diagram showing a control system for operating one panoramic camera from inside the aircraft and confirming the operation thereof.
FIG. 5 is a diagram for explaining stereo shooting by the helicopter shown in FIG. 5, FIG. 5 is a diagram showing a range of stereo shooting by the helicopter of FIG. 1, and FIG. 6 is a stereo shot in each shooting range of FIG. FIG. 7 shows an example of a photograph.
FIG. 8 is a view for explaining panoramic photography by the helicopter shown in FIG. 8, FIG. 8 is a schematic view for explaining the principle of measuring the position of the subject from the panoramic photography by the helicopter of FIG. 1, and FIG. FIG. 10 is a flowchart showing a measurement procedure according to the method of the present invention, FIG. 10 is a flowchart showing the procedure of calculating the separation distance in the flowchart of FIG. 9, and FIG. Schematic diagram illustrating the state of FIG. 12, FIG. 12 is a diagram illustrating the range of stereo photography in conventional aerial photogrammetry,
FIG. 13 is a diagram showing the principle of measuring the separation distance or the like of a subject by conventional aerial photogrammetry, and FIG. 14 is a flowchart showing a procedure for obtaining the separation distance in conventional aerial photogrammetry. 11, 12 ... tower, 13 ... transmission line, 14 ... trees, L ... ... separation distance, 50 ... helicopter, 61, 62 ... normal camera, 63 ... panoramic camera, 64 ... aiming mark, 70 ……
Control system 71 Control unit 72, 73 Shutter button 74 Operating status confirmation lamp b '
Fixed baseline length.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeshi Ogawa 4-3-6 Ginza, Chuo-ku, Tokyo Inside New Japan Helicopter Co., Ltd. (72) Inventor Hidenori Ito 13 Natsumizu, Atsugi-shi In the center (56) References JP-A-60-7318 (JP, A) JP-A-57-108618 (JP, A) JP-A-61-155810 (JP, A) JP-A-61-209315 (JP, A) )

Claims (1)

(57) [Claims] 1. A method for measuring arbitrary spatial coordinates in order to obtain data such as a distance between a certain subject and a certain other object along a certain route and a position of the certain subject.ヘ リ While flying a helicopter equipped with two normal cameras and a panoramic camera arranged at an interval of a fixed baseline length along a horizontal direction perpendicular to the two normal cameras while flying along the path, And performs panoramic photography along the path by the panoramic camera with the panoramic camera, and analyzes a stereo photograph obtained by the stereo photographing and a panoramic photograph obtained by the panoramic photographing. A method for obtaining arbitrary spatial coordinate data by reading and computer processing.