JP2002156229A - Mobile displacement measuring method and device for structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure displacements of structures extended along a passage by a mobile body in a short time. SOLUTION: Reference targets 8 are fixed at three points or more regarded as immovable on a plurality of planes 51, 52, etc., which intersect the surfaces of the structures 1a and 1b facing the passage 3 at a distance in the direction of movement of the mobile body 4, and a plurality of measurement targets 7 are mounted to the surfaces of the structures 1a and 1b along each of the intersection lines 61, 62, etc., with the plane 51 and 52. A required number of a plurality of image pickup devices 10 are fixed to predetermined locations at predetermined attitudes in the front surface of the mobile body 4, and the mobile body 4 is moved onto the passage 3. Exposure stations Q1, Q2, etc., and attitudes at which all the targets 7 and 8 on the planes 51, 52, etc., are seen in front of each of the planes 51, 52, etc., in the screen of each image pickup device 10 when viewed from the direction of the movement of the mobile body 4 are determined, and forward directions are simultaneously photographed by the plurality of image pickup devices 10. By bundle adjustments based on the two-dimensional coordinates of each image of the targets 7 and 8 in the screen of each image pickup device 10, the location and attitude of each image pickup device 10 when photographed the fixed three-dimensional coordinates of each target 8, and the initial three-dimensional coordinates of each target 7, displacements of the three-dimensional coordinates in photographing and initial three-dimensional coordinates of each measurement target 7, are computed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile displacement measuring method and apparatus, and more particularly to a mobile displacement measuring method for measuring the displacement of a structure extending along a path of a moving body using an image taken from the moving body on the path. The present invention relates to a displacement measurement method and device.

[0002]

2. Description of the Related Art In order to manage the safety of a passage of a moving body, it is sometimes required to measure displacement and deformation of a structure along the passage. For example, in railways, for safe operation of trains,
Management of rails, sleepers, track beds, and other structures (hereinafter, sometimes referred to as rails) laid on the construction base of train tracks is essential, and periodic measurement of rail displacement is required. . Further, in a subway, etc., it is necessary to measure the displacement of the shape of the underground tunnel wall due to settlement or the like. 2. Description of the Related Art Conventionally, displacement of a rail or a tunnel wall shape in a railway has been measured by surveying using a surveying instrument such as a lightwave range finder.

[0003]

However, the conventional displacement measurement using a surveying instrument such as an optical distance measuring device has a problem that it takes a long time to change the relocation and the like, so that the measurement takes a long time. Since it is necessary to measure the displacement of railway tracks and tunnel wall shapes during a limited time period from the last train to the first train, when measuring the displacement of a structure over a long distance along the track, conventional methods are required. The measurement work with the surveying equipment required many devices and many people and man-hours. The time from the last train to the first train tends to be shorter, and it is desired to develop a technology that can measure the displacement of a structure in a short time and with a small number of people while maintaining the measurement accuracy.

An object of the present invention is to provide a mobile displacement measuring method and apparatus capable of measuring the displacement of a structure extending along the path of a moving body in a short time.

[0005]

SUMMARY OF THE INVENTION The present inventor moves a moving body with a camera mounted thereon along a passage, and takes images of structures such as rails and tunnels along the passage according to the movement of the moving body. Attention was paid to photogrammetry of the position and shape of the structure from the captured image. If the position and shape of the structure can be photogrammetrically measured while moving the moving body, it is expected that the work of measuring the displacement of the structure over a long distance can be performed in a short time.

In photogrammetry, as shown in FIG.
And an image point p on the imaging surface and an imaging center (origin) O of the camera are based on a geometric principle that three points exist on one straight line. As shown in the figure, the three-dimensional coordinates of the target point P in the ground coordinate system are (X, Y, Z), and the three-dimensional coordinates of the camera center O in the ground coordinate system are (X ₀ , Y ₀ , Z ₀ ). The focal length of the imaging device is c, the rotation angles of the imaging device around the x-axis, y-axis, and z-axis in the camera coordinate system are ω, φ, κ, and the three-dimensional coordinates of the image point p in the camera coordinate system are (x, y, -c)
The geometric principle can be expressed as a collinear condition expression represented by Expressions (1) to (3). Note in the figure, the three-dimensional coordinates of an image point p on the ground coordinate system (X _p, Y _p, Z _p) is set to. Also,
When considering lens distortion of the image pickup device, the collinear conditional expressions of Expressions (1) and (2) can be modified into Expressions (4) and (5). Δx and Δy in equations (4) and (5) are
This is a correction term determined by the lens distortion coefficient.

The collinear conditional expressions (1) and (2) correspond to the camera position (X₀, Y
₀, Z₀) And camera angles (ω, φ, κ).
No. In general photogrammetry, known three-dimensional
A plurality of target points P of coordinates (X, Y, Z) (hereinafter referred to as reference points)
Sometimes. ) To set an optotype and imprint it on the photograph
Measures the two-dimensional coordinates (x, y) of the target image point p on the surface
To find the unknowns in the collinear condition
You. In photogrammetry with two cameras, one target
Two image points p₁, P_TwoGiven the coordinates of
Is a collinear condition if there are three optotypes in one photo
The six unknowns of (1) and (2) can be located. Collinear condition
When using (4) and (5), the camera position (X₀, Y ₀, Z₀)
Unknown lens distortion coefficient in addition to camera angle (ω, φ, κ)
Because of the number, more reference points are needed for the orientation of the unknown
And If the unknowns in the collinear condition can be located,
Any point on the image plane (hereinafter sometimes referred to as a measurement point)
You. ) By substituting the two-dimensional coordinates of
And calculate the three-dimensional coordinates of the ground coordinate system corresponding to the measurement point.
Can be issued.

[0008]

(Equation 1)

However, since the three-dimensional coordinates (X, Y, Z) of the reference point and the two-dimensional coordinates (x, y) of the target image p include an error,
In practice, it is necessary to provide more targets than necessary and improve the accuracy of the unknown number orientation by the least squares method. In this case, as shown in FIG. 8, a bundle adjustment method has been developed which simultaneously solves the orientation of a plurality of photos by the least squares method, instead of locating the unknown value for each single photo.

In the bundle adjustment method, the reference point and the measurement point
3D coordinates, camera center 3D coordinates, and camera angle
Is calculated as the approximate value (X ', Y', Z ') (X'₀, Y '₀, Z '₀)
(Ω ', φ', κ ') plus the correction amount (X' + ΔX, Y '
+ ΔY, Z '+ ΔZ), (X'₀+ ΔX ₀, Y '₀+ ΔY₀, Z '₀+ ΔZ₀)
And (ω ′ + Δω, φ ′ + Δφ, κ ′ + Δκ), and the reference point
And the true value of the image point of the optotype provided at the measurement point is the measured value
(X ', y') plus error (x '+ Δx, y' + Δy)
You. Multiple approximations with corrections and measured values with errors
Substituting into the collinear conditional expressions (Equations (1) and (2))
After linearizing the collinear condition by Taylor expansion,
Positive quantities (ΔX, ΔY, ΔZ), (ΔX₀, ΔY₀, ΔZ₀), (Δω, Δ
φ, Δκ) and the solution minimizing the error (Δx, Δy)
Obtained as the convergence solution of the recursive method. Collinear condition (4) and (5)
Correction amount of lens distortion coefficient by bundle adjustment method using
It is also possible to find a solution that minimizes Like this van
In the dollar adjustment method, not only the unknown of the collinear condition
The three-dimensional coordinates (X, Y, Z) of the point and the measurement point are also
Sometimes solve.

According to the bundle adjustment method, the three-dimensional coordinates (X, Y, Z) of the reference point are set to known coordinates that can be regarded as immovable in the ground coordinate system, and the accuracy of the approximate value of the reference point is equal to that of the approximate value of the measurement point. Weighting that is higher than accuracy (reference point correction amount (ΔX,
The weighting (ΔY, ΔZ) is infinitely set to 0), whereby the three-dimensional coordinates (X, Y, Z) of each measurement point can be accurately obtained. The inventor of the present invention has completed the present invention as a result of research and development of a technique for applying a bundle adjustment method to a photograph taken while moving a moving object.

Referring to the embodiment of FIG. 1 and the flowchart of FIG. 2, the method for measuring the displacement of a structure according to the present invention comprises the steps of:
In the method for measuring the displacement of the structure 1 (1a and 1b in the illustrated example) extending along the passage 3, a plurality of planes 5 intersecting the surface of the structure 1 facing the passage 3 at a distance in the moving body traveling direction. ₁ , 5 ₂ ,..., Three or more points that can be regarded as immovable are fixed on the reference target 8 and fixed three-dimensional coordinates of each reference target 8 are determined. ₁ ,
A plurality of measurement targets 7 are attached along the respective intersections 6 ₁ , 6 ₂ ,... With 5 ₂ ,. After the machine 10 is fixed at a predetermined position on the front surface of the moving body 4 in a predetermined posture, the moving body 4 is advanced on the passage 3 and the planes are viewed from the moving body traveling direction.
5 _1, 5 _2, said plane 5 ₁ in front of ...., 5 _2, the total target 7,8 on ... is widely distributed to the shooting position of the moving body 4 bleeds through the screen of each imaging device 10 Q ₁ , Q ₂ , ... and posture are determined (Fig. 3
See), at the same time taken forward by the plurality of imaging device 10 upon reaching of the movable body 4 to the photographing position Q _i for the particular plane 5i, when shooting the image pickup device 10 from the photographing position Q _i and orientation of the moving object 4 The position and orientation are calculated, and the two-dimensional coordinates (see FIG. 3B) of the images of the reference optotypes 8 and the measurement optotypes 7 on the specific plane 5i in the screen of each of the imaging devices 10 are calculated. The specific plane 5i is obtained by bundle adjustment based on the shooting position and orientation, the fixed three-dimensional coordinates of each reference target 8 and the initial three-dimensional coordinates of each measurement target 7.
The displacement between the three-dimensional coordinates at the time of photographing of each of the measurement targets 7 and the initial three-dimensional coordinates is calculated, and the cycle from the photographing in front to the calculation of the displacement of each measurement target 7 is calculated according to the progress of the moving object 4. By repeating the measurement, the displacement of the structure 1 is measured.

Referring to the embodiment of FIG. 1, the moving displacement measuring apparatus for a structure according to the present invention comprises
In a device for measuring the displacement of a structure 1 extending along a plane, a plurality of planes 5 ₁ , 5 ₂ ,... Which intersect with the surface of the structure 1 facing the passage 3 at a distance in the moving body traveling direction are immovable, respectively. The reference optotype 8, which is fixed by defining three or more points that can be regarded as, along each intersection line 6 ₁ , 6 ₂ ,... On the surface of the structure 1 with the plurality of planes 5 ₁ , 5 ₂ ,. Storage means 15 for storing a plurality of measurement targets 7 to be attached, fixed three-dimensional coordinates of each reference target 8 and initial three-dimensional coordinates when each measurement target 7 is attached, the front surface of the moving body 4 traveling in the passage 3 , A plurality of required imaging devices 10 to be fixed in a predetermined position at predetermined positions, and all of the planes 5 ₁ , 5 ₂ ,... Before the planes 5 ₁ , 5 ₂ ,. imaging position of the target 7,8 moving body 4 bleeds through and widely distributed in the screen of each imaging device 10 Q _1, Q _2, and identify flat defines ...... and orientation Imaging device control unit 13 to the plurality of imaging device 10 upon reaching of the movable body 4 to the photographing position Q _i against 5i instructing front of simultaneously photographed, the particular plane within each screen enter the screen of each imaging device 10 Optotype image coordinate extracting means 16 for obtaining two-dimensional coordinates of the images of the optotypes 7 and 8 on 5i;
The photographing position and posture of each imaging device 10 are calculated from the photographing positions Q ₁ , Q ₂ ,... And the postures, and the two-dimensional coordinates of the images of the reference visual targets 8 and the measurement visual targets 7 by the coordinate extracting means 16 are calculated. Each imager 10
3D coordinates of each measurement target 7 on the specific plane 5i by bundle adjustment based on the photographing position and orientation, the fixed three-dimensional coordinates of each reference target 8 and the initial three-dimensional coordinates of each measurement target 7 And a bundle adjusting means 17 for calculating a displacement between the coordinate and the initial three-dimensional coordinates.

[0014]

FIG. 1 shows an embodiment in which the present invention is applied to measurement of displacement of a rail 1a and a tunnel wall 1b extending along a train line in a tunnel. However, the present invention is not limited to the rail-shaped passage 3 such as a train track, but is also applicable to a structure extending along the passage 3 such as an automobile road. FIG. 1B is an example of a block diagram illustrating a configuration of the measurement moving body 4 according to the present invention. The measurement moving body 4 is provided with a plurality of required imaging devices 10, imaging device control means 13, optotype image coordinate extraction means 16, and bundle adjustment means 17. In the illustrated example, a computer 11 is provided in the moving body 4, and the imaging device control unit 13, the optotype image coordinate extraction unit 16, and the bundle adjustment unit 17 are programs built in the computer 11.

In the block diagram of FIG. 1B, a digital camera such as a CCD camera is
The digital image data output by 10 is directly input to the optotype image coordinate extracting means 16. However, it is also possible to use a conventional optical film camera as the imaging device 10, in which case a scanner or the like for converting a film image into digital data is provided between the imaging device 10 and the optotype image coordinate extracting means 16. . The plurality of imaging devices 10 are fixed at predetermined positions on the front surface of the moving body 4 in a predetermined posture. Each imaging device on the moving body 4
The fixed position and the posture of 10 are stored in the storage means 15 on the moving body 4 (see FIG. 1B). The fixed position and orientation of each imaging device 10 are used for calculating the imaging position and orientation of each imaging device 10 described below. In addition, it is desirable to fix the lens, for example, so that the focal length and the angle of view (internal parameters) of the imaging device 10 do not change during shooting.

The number M of the imaging devices 10 fixed to the moving body 4 is:
The number of internal parameters Nk (lens distortion coefficient, etc.) of the camera that requires orientation, and the number of measurement and reference targets Nr described below
And can be determined as an integer satisfying the expression (6). However, in the bundle adjustment method, the measurement accuracy is improved as the number of images photographed at the same time is large. Therefore, the number M of the imaging devices 10 is determined so that the required measurement accuracy is obtained.

The installation interval L of the imaging device 10 on the moving body 4 and the number a of pixels when a digital camera is used as the imaging device 10 are also appropriately determined so that necessary measurement accuracy can be obtained. In general, the measurement accuracy in the camera optical axis direction and its vertical direction in photogrammetry is based on the camera resolution a, the shooting distance D between the camera and the target point P, and the camera installation interval L, and the equations (7) and (8) Can be expressed as
As can be seen from the equation, the greater the installation interval of the imaging device 10 and the greater the number of CCD pixels of the imaging device 10, the higher the measurement accuracy. Note that the camera resolution a in equations (7) and (8) is the real space distance per pixel of a CCD in the case of a digital camera, and is the value of one of the scanners that converts a film image of the camera into digital data in the case of a film camera. The real space distance per pixel.

[0018]

[Equation 2] M ≧ 3Nr / (2Nr−Nk−6) (6) Measurement accuracy in the optical axis direction of the camera = a · (D / L) …… (7) Measurement accuracy in the direction perpendicular to the camera optical axis = a ………………… (8)

FIG. 2 shows an example of a flow chart of the processing in the present invention. Hereinafter, the displacement measuring method of the present invention will be described with reference to the flowchart. First, in step 201, the measurement target 7 is attached to a position where displacement measurement of a surface of a structure facing the passage 3 (hereinafter, sometimes referred to as a passage adjacent surface) is required. In the present invention, as shown in FIG. 1, assuming a plurality of planes 5 ₁ , 5 ₂ ,... That intersect with the moving body traveling direction, the planes 5 ₁ , 5 ₂ ,. ... each intersection line ₆₁ between the passage adjacent the surface, 6 _2, along ..., mounting a plurality of measurement optotypes 7. In the illustrated example, a plane 5 ₁ perpendicular to the moving body traveling direction,
Although it is assumed that 5 ₂ ,..., The planes 5 ₁ , 5 ₂ ,... Are sufficient if they intersect with the moving body traveling direction at a distance from each other, and are not necessarily perpendicular to the moving body traveling direction. Is enough.
In the illustrated example, each plane 5 _1, 5 _2, is attached to the measurement visual target 7 on the inner surface of the surface and the tunnel 1b rails 1a intersecting the ....... The number of the measurement targets 7 mounted on the intersection lines 6 ₁ , 6 ₂ ,... Can be appropriately determined so as to obtain necessary measurement accuracy.

In step 202, initial three-dimensional coordinates of the attached measurement target 7 are obtained by, for example, surveying. The initial three-dimensional coordinates of each measurement target 7 are stored in a storage unit on the moving body 4.
Remember at 15. The initial three-dimensional coordinates are used for calculating a displacement of each measurement target 7 described later, and are used as an approximate value of each measurement target 7 in the bundle adjustment method.

Next, in steps 203 to 204, each plane
5 ₁ , 5 ₂ , ... 3 or more points that can be regarded as not displaced in the ground coordinate system are defined on each of the points, and a reference optotype 8
Is fixed so that displacement does not easily occur. It is desirable that the reference target 8 be distinguishable from the measurement target 7. Further, the three-dimensional coordinates of each reference target 8 are obtained by surveying and stored in the storage means 15 on the moving body 4. By providing the reference target 8 in which displacement is unlikely to occur, the reference target 8 can be used as a reference point of the bundle adjustment method. By providing three or more reference points, the collinear conditional expressions (1) and (2), or the expression (3) and
The camera position (X ₀ , Y ₀ , Z ₀ ) and camera angle (ω, φ,
κ) can be determined. FIG. 1 (A)
In the above, the reference target 8 is attached by selecting points on the ground surface that are less likely to be displaced due to the construction of the pile or the like, such as the left and right and the center of the rail 1b. The reference target 8 may be attached to a utility pole or the like that can be regarded as immovable.

[0022] In step 205, the measurement for mobile 4 in which a plurality of imaging device 10 is mounted is allowed to proceed over path 3, ₁ each plane 5 as viewed from the mobile traveling direction, 5 _2, in front of ....,
Each plane 5 _1, 5 _2, the screen includes all measurement optotype 7 and reference optotype 8 provided on ...... shooting with the imaging device 10. FIG. 6 shows an example of a screen shot by the image pickup device 10. In order to increase the measurement accuracy in the bundle adjustment method, each imaging device 10
It is desirable that the images of the targets 7 and 8 in the screen of (1) are widely dispersed. In the present invention, as shown in FIG.
All targets 7 _i1 on plane 5 _i before moving direction of moving body on each plane 5 _i
7 _i10 , 8 _i1 to 8 _{i 3} determine the photographing position Q _i and posture of the moving body 4 on which the image of the image capturing device 10 is distributed over a wide area, and when the moving body 4 reaches the photographing position Q _i Next, a plurality of image pickup devices 10 simultaneously photograph the front (step 206). Photographing position Q _i and orientation of the moving body 4, for example, FIG. 3 (B) as shown in, the total target 7 _i1 to _7-i10 screen peripheral portion of the imaging device 10, 8 _i1 to 8 _i3 so that bleeds through However, if distortion at the periphery of the screen is a problem, all targets 7 _{i1 to} 7 _i10 and 8 _i1 to 8 _i3 should be distributed and _projected within the range where no screen distortion occurs. Determine.

In the block diagram of FIG. 1B, the photographing position calculating means 14 stores the initial three-dimensional coordinates (initial coordinates of the plane 5 _i ) of the targets 7 and 8 stored in the storage device 15 and the , The shooting distance Di between the plane 5i and the moving object 4 that enables the screen including the targets 7 and 8 of each plane 5i to be obtained, and the initial three-dimensional coordinates and the shooting distance Mobile 4 based on Di
And calculates the photographing position Q _i and attitude. Further, to detect the arrival of the moving body 4 to the imaging apparatus control unit 13 is photographed position Q _i, simultaneously instructs the imaging for a plurality of image pickup device 10 when reaching the photographing position Q _i. Reach the photographing position Q _i of the moving body 4 may be detected based on the traveling speed of the moving body 4. If necessary, a position measuring device, a posture measuring device, and the like may be attached to the moving body 4.

In step 207, the image of each imaging device 10 is input to the optotype image coordinate extracting means 16, and the two-dimensional coordinates of the images of the optotypes 7 and 8 in each screen are obtained. For example, optotype 7,
The two-dimensional coordinates of the position of the center of gravity of the image No. 8 are obtained. Each target 7, 8
In order to obtain the two-dimensional coordinates of the image, it is necessary to detect the target image in the screen and to associate each target image with the measurement target 7 or the reference target 8. In the conventional bundle adjustment method, the work of detecting and associating a target image takes time, which has been a problem in reducing the time of the displacement measurement work. In the present invention, as shown in FIG.
From the shooting position Q _i and orientation and the initial three-dimensional coordinates of each measurement optotypes 7 and the fixed three-dimensional coordinates of each reference target 8, the optotypes 7,
It is possible to estimate the range (for example, the outermost part of the screen) in which the optotype image corresponding to 8 exists in the screen of each imaging device 10.

The target image coordinate extracting means 16 extracts a target image corresponding to each of the targets 7 and 8 by scanning the estimated existence range, and automatically obtains two-dimensional coordinates of the target image in a short time. . For example, the outermost optotype images in the screen are extracted as the images of the optotypes 7 and 8 on the specific plane 5 _i immediately before the photographing position Q _i . In addition, as will be described later, by using each of the measurement target 7 and the reference target 8 as a reflective material with an ID, the reliability of the association is increased, and the calculation time of the two-dimensional coordinates of the target image can be further reduced. The two-dimensional coordinates of each target obtained by the target image coordinate extracting means 16 are used as measurement values (x ′, y ′) including errors (Δx, Δy) with respect to the true values in the bundle adjustment method.

In step 208, the photographing position and posture of each image pickup device 10 are calculated from the photographing position Qi and posture of the moving body 4. Since the fixed position and orientation of the imaging device 10 on the movable unit 4 are stored in the storage unit 15, and stores photographing position Q _i and orientation of the moving body 4 obtained by the imaging position calculating unit 14 and the storage means 15 Based on the fixed position and orientation of each imaging device 10, the imaging device position and orientation calculating means 18 (see FIG. 1B) calculates the imaging position and orientation of the ground coordinate system at the time of imaging of each imaging device 10. can do. Each imager
The shooting position and orientation of 10 are based on the bundle adjustment method.
They are used as approximate values (X ′ ₀ , Y ′ ₀ , Z ′ ₀ ) and (ω ′, φ ′, κ ′) of the camera center and the camera angle.

In step 209, the bundle adjustment method
From the three-dimensional coordinates of each measurement target 7 in the ground coordinate system.
calculate. Specifically, first, the three
Let the dimensional coordinates be the approximate coordinates (X ', Y', Z ') of each of the optotypes 7 and 8,
The photographing position and position calculated by the photographing device position and orientation calculating means 18
Camera position and camera angle and camera angle approximation (X '₀, Y ' ₀,
Z '₀) And (ω ′, φ ′, κ ′), and the target image coordinate extracting means 16
2D coordinates of each target extracted from the image of each imager 10
Let the target be the measured value (x ', y') that contains the error, Equation (1) and
(2) or substituting into the collinear condition formulas of formulas (4) and (5),
Make a collinear equation. Next, from each of the collinear equations,
The correction amount (ΔX, に 対 す る) for the approximate coordinates (X ′, Y ′, Z ′) of the targets 7 and 8
ΔY, ΔZ) and approximate values of camera center and camera angle
(X '₀, Y '₀, Z '₀) And (ω ', φ', κ ')
(ΔX₀, ΔY₀, ΔZ₀) And (Δω, Δφ, Δκ) and measured values
A solution that minimizes the error (Δx, Δy) for (x ′, y ′)
Determined by the least squares method. Furthermore, the obtained minimum correction amount and
The error is added to the approximate value and the measured value to obtain the new approximate value and
And the measured value, and minimize the correction amount and error again.
To find a solution. This process is performed with sufficiently small correction amount and error.
By repeating until the measurement target 7 is photographed
Find the convergence solution of the three-dimensional coordinates of.

In the present invention, since the reference target 8 is fixed to a point that can be regarded as immovable, the correction amount (ΔX, ΔY, ΔZ) for the reference target 8 is set to 0 without limitation when calculating the correction amount by the least square method. By fixing the coordinate values of the reference target 8 by weighting, the three-dimensional coordinates of each measurement target 7 in the actual three-dimensional coordinate system (terrestrial coordinate system) defined by the reference target 8 at the time of shooting are calculated. The convergence solution can be calculated accurately.

In step 210, the three-dimensional coordinates of each measurement target 7 calculated by the bundle adjustment method and each measurement target 7
The displacement of the measurement target 7 is calculated as the deviation from the initial three-dimensional coordinates. The calculated displacement of the measurement target 7 is represented by a displacement output unit 19 shown in FIG.
Can be displayed or printed.

[0030] In step 211, whether the displacement measurement of the structure is completed, it is determined whether the displacement measurement of the measurement visual target 7 in this case mounted on all planes 5 _i is completed, the displacement measurement When continuing, it returns to step 205, and repeats steps 205 to 210 described above while further moving the moving body 4. The cycle of steps 205-210, the measurement view all planes target is attached 5 _1, 5 _2, by repeating respect ..., each plane 5 _1, 5 ₂ of the structure 1, exchange with ... Line 6 ₁ ,
6 ₂ ,... Can be measured.

As described above, the computer 11 mounted on the moving body 4
The case where the displacement of each measurement target 7 is measured in real time by the built-in program has been described. However, when the moving object 4 advances, the image of each image pickup device 10 is stored in the computer 11 in step 206, and the processing in steps 207 to 210 is performed. The processing can be performed in another place after photographing. Also step
At 206, an image is taken with a film camera, and the developed image is
And the processing of steps 207 to 210 may be performed.

According to the present invention, a measurement target is attached to a surface adjacent to a passage of a structure, and an image of the measurement target is photographed from a moving body traveling on the passage. Can be calculated by a computer, compared to the conventional displacement measurement method using a lightwave rangefinder, etc.
Significant labor saving on site work can be achieved. In addition, since the displacement of the structure can be automatically calculated by the bundle adjustment method, the displacement measurement time can be significantly reduced. Further, according to the bundle adjustment method of the present invention, since the three-dimensional coordinates of each measurement target can be accurately obtained, improvement in the displacement measurement accuracy of the structure can be expected.

As described above, the object of the present invention is to provide a "movable displacement measuring method and apparatus capable of measuring the displacement of a structure extending along the path of a moving body in a short time".

[0034]

FIG. 4 shows an example of a method of attaching a measurement target 7 to a surface adjacent to a passage of structures 1a and 1b. In general photogrammetry, since the image is taken from various angles with respect to the measurement target,
In many cases, a target is set in parallel with the surface to be measured. However, in the present invention, since the image is taken from the traveling direction of the moving body, if the measurement target 7 is attached in parallel with the plane adjacent to the passage of the structures 1a, 1b, the image of the measurement target 7 is deformed and the target image This may cause an error in the coordinate extracting means 16. In FIG.
Each measurement target 7 is attached by an angle member 9 in the moving body traveling direction. By attaching the measurement target 7 in the moving body traveling direction, the deformation of the target image in the screen of each imaging device 10 can be minimized, and the occurrence of an error in the target image coordinate extracting means 16 can be suppressed. .

Further, in order to further improve the accuracy of the two-dimensional coordinates of the target image in the target image coordinate extracting means 16, it is ideal to take an image so that only the target floats on the screen. For this reason, in the embodiment of FIG. 1, the flash 20 is fixed to the front of the moving body 4, and the measurement target 7 and the reference target 8 are made of a material having a high light reflectance. In this case, when the arrival of the photographing position Q _i of the moving body 4, the imaging apparatus control unit 13 is a flash
At the same time, light emission is instructed to 20, and photographing is simultaneously instructed to each imaging device 10. The above-mentioned angle members 9 are used to attach each reflective material in a direction in which the light emission of the flash is easily reflected, and the aperture of each image pickup device 10 is reduced as much as possible to capture the reflective material, so that only the target appears on the photograph. You can shoot. Note that the shutter speed of each image capturing device 10 is set to be short in order to shoot while moving.

Further, in the embodiment shown in FIG. 1, each of the measurement targets 7 and the reference targets 8 is made of a reflective material having a different ID. By using the reflective material with ID, the target image coordinate extracting means 16 can further facilitate the association of each target image in the image with the measurement target 7 and the reference target 8. FIG. 5 shows an example of a sheet with a reflective material with an ID. The sheet with a reflective material in the illustrated example is different from a sheet to which a normal circular reflective material is attached, in which a plurality of reflective materials 21a to 21h are regularly arranged in a two-dimensional shape, and an ID is assigned according to the arrangement method. It is. For example, by changing the arrangement of the five inner small-diameter reflective materials 21d to 21h shown in FIG. 5 for each of the measurement target 7 and the reference target 8, identification of the target image can be facilitated. ID of measurement target 7 only
A reflective material may be used.

[0037]

As described above, the mobile displacement measuring method and apparatus according to the present invention measure the displacement on each intersection line between the surface of the structure facing the passage and a plurality of planes intersecting at a distance in the traveling direction of the moving body. Attaching the optotype, fixing the reference optotype by defining three or more points that can be regarded as immovable on the plurality of planes, and simultaneously measuring the optotype with the required plurality of imaging devices fixed to the moving body traveling on the passage. Since the reference target is photographed and the displacement between the three-dimensional coordinates of each measurement target and the initial three-dimensional coordinates is calculated by the bundle adjustment from the two-dimensional coordinates of each target image in the screen of each imaging device, the following remarkable: Effect.

(A) Since the displacement of the structure can be measured while moving the moving body along the structure, the measuring operation can be greatly simplified and labor can be saved as compared with the conventional method. (B) Since everything from photographing to displacement calculation can be controlled and processed by a computer, the displacement measurement time can be shortened. (C) By adjusting the resolution of the imaging device, the number of the imaging devices, and the installation interval, the displacement measurement accuracy can be improved as compared with the conventional method. (D) By performing only image shooting at the site and performing work such as image analysis and calculation in another place after shooting,
The on-site work can be further simplified and shortened. (E) Measurement data can be stored in a computer, and the temporal displacement of the structure can be easily referred to. (F) The present invention can be applied to measurement of temporal displacement of various structures extending along a path of a moving body, for example, a railway track, a tunnel, a vehicle road, and the like.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment of the present invention.

FIG. 2 is an example of a flowchart of the measurement method of the present invention.

FIG. 3 is an explanatory diagram of a method of extracting a target image coordinate from a screen of an imaging device.

FIG. 4 is an explanatory diagram of a method of attaching a target.

FIG. 5 is an example of a reflective material with an ID.

FIG. 6 is an example of a screen shot by an imaging device.

FIG. 7 is an explanatory diagram of a collinear conditional expression.

FIG. 8 is an explanatory diagram of a bundle adjustment method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Structure 1a ... Rail 1b ... Tunnel 2 ... Structure surface 2a ... Rail surface 2b ... Tunnel inner surface 3 ... Moving body passage 4 ... Moving body 5 ... Plane 6 ... Intersecting line 7 ... Measurement target 8 ... Reference optotype 9 ... Angle member 10 ... Imaging device 11 ... Computer 12 ... Carriage 13 ... Imaging device control means 14 ... Imaging position calculating means 15 ... Storage means 16 ... Optotype image coordinate extracting means 17 ... Bundle adjusting means 18 ... Imaging machine Position and orientation calculation means 19 ... Displacement output means 20 ... Flash 21 ... Reflective material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) G01C 7/06 G01C 7/06 (72) Inventor Michio Imai 1-2-7 Moto-Akasaka, Minato-ku, Tokyo No. F-term in Kashima Construction Co., Ltd. (reference) 2F065 AA03 AA07 AA65 BB05 CC40 DD06 FF01 FF04 FF09 FF61 GG08 HH02 JJ03 JJ05 JJ09 JJ26 MM07 QQ23 QQ25 SS06 SS13 UU05

Claims (7)

[Claims] In a method for measuring the displacement of a structure extending along a passage by a moving body, the moving body can be regarded as immovable on a plurality of planes which intersect with the surface of the structure facing the passage at a distance in the traveling direction of the moving body. Determine the above points and fix the reference optotypes and obtain fixed three-dimensional coordinates of each reference optotype, attach a plurality of measurement optotypes along the respective intersections with the plurality of planes on the structure surface, and Obtain the initial three-dimensional coordinates at the time of mounting the measurement target, fix a plurality of required imaging devices at a predetermined position on the front surface of the moving body in a predetermined posture, then advance the moving body on the passage, and see from the moving direction of the moving body. In front of each of the planes, all the targets on the plane determine the shooting position and posture of the moving body on which the image is distributed over a wide area of the screen of each imaging device, and the plurality of moving targets reach the shooting position with respect to the specific plane. Simultaneously photograph the front with the imager of The imaging position and orientation of each imaging device are calculated from the imaging position and orientation of the moving object, and the two-dimensional coordinates of the images of the reference and measurement targets on the specific plane in the screen of each of the imaging devices and the respective The three-dimensional photographing of each measurement target on the specific plane by bundle adjustment based on the photographing position and orientation of the imaging device, the fixed three-dimensional coordinates of each of the reference targets, and the initial three-dimensional coordinates of each measurement target. Calculate the displacement between the coordinates and the initial three-dimensional coordinates, and measure the displacement of the structure by repeating the cycle from the photographing in front to the calculation of the displacement of each measurement target according to the progress of the moving object. A mobile displacement measurement method for objects. 2. A structure according to claim 1, wherein an outermost optotype image in a screen of each of said imaging devices is extracted as an image of each of the measurement optotype and the reference optotype on the specific plane. Mobile displacement measurement method. 3. The measurement method according to claim 1, wherein a flash is fixed to a front surface of the movable body, and the reference target and / or
Alternatively, a movable displacement measuring method for a structure, in which a measurement target is made of a reflective material with an ID and a flash is emitted upon reaching the photographing position. 4. A moving displacement measuring method for a structure according to claim 1, wherein the reference target and / or the measurement target is provided in a moving direction of the moving body. 5. An apparatus for measuring the displacement of a structure extending along a path by a moving body, wherein the apparatus can be regarded as immovable on a plurality of planes intersecting the surface of the structure facing the path at a distance in the traveling direction of the moving body. A reference target fixed by defining the above points, a plurality of measurement targets attached on the surface of the structure along each intersection with the plurality of planes, a fixed three-dimensional coordinate of each reference target, and each measurement Storage means for storing initial three-dimensional coordinates at the time of mounting the optotype, a plurality of required imaging devices fixed in a predetermined position at a predetermined position on the front surface of the moving body traveling in the path, before each of the planes as viewed from the moving body traveling direction In this manner, all the targets on the plane determine the photographing position and posture of the moving object in which the image is distributed over a wide range of the screen of each image pickup device, and when the moving object reaches the photographing position with respect to the specific plane, the plurality of image pickup devices Simultaneously indicate forward shooting Imager control means, optotype image coordinate extracting means for inputting the screen of each imager and obtaining the two-dimensional coordinates of each optotype image on the specific plane in each screen, and The photographing position and orientation of the imaging device are calculated, and the two-dimensional coordinates of the image of each reference target and the measurement target by the coordinate extracting means, the imaging position and posture of each imaging device, and the fixed three-dimensional of each of the reference targets are calculated. A bundle adjusting unit that calculates a displacement between the three-dimensional coordinates at the time of shooting of each measurement target on the specific plane and the initial three-dimensional coordinates by a bundle adjustment based on the coordinates and the initial three-dimensional coordinates of each measurement target. Mobile displacement measuring device. 6. The measuring device according to claim 5, wherein said target coordinate extracting means includes a position and a posture at the time of photographing of each of said image pickup devices, initial three-dimensional coordinates of said measured target, and fixed three-dimensional coordinates of said reference target. From the coordinates and the estimated range of the optotype image on the specific plane in the screen of each image pickup device, the optotype image on the specific plane is extracted by scanning the estimated existence range, and the extracted optotype image is extracted. A mobile displacement measuring device for a structure that obtains two-dimensional coordinates of 7. The measuring device according to claim 5, wherein a flash fixed forward is provided on the front surface of the movable body, and the measurement target and / or the reference target is a reflective material with an ID. Displacement measuring device.