JP2015010911A - Airborne survey method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an airborne survey method allowing a three-dimensional shape corresponding to the size of each of various objects and the distance to an object to be acquired only with an airborne survey device, without setting a leveling rod and reference point to a survey object, by using a parallel stereoscopic camera instead of the leveling rod.SOLUTION: In the airborne survey method, a stereoscopic camera 3, a monocular camera 6 for survey having an angle and azimuth meter 7, and an injector of reflective paint are attached to a model aircraft via a vibration-proof mechanism, a survey object is photographed, a survey object of any size is surveyed at a required accuracy by applying an image correlation method to the photographed image without manually setting a leveling rod to the survey object, and an image is pasted without manually setting a reference point to the survey object.

Description

  The present invention relates to a surveying method and apparatus using aerial photography of a three-dimensional shape of a natural object such as a slope or a large structure.

(1) Conventionally, surveying work has been performed using a surveying instrument that measures distance and angle, but in recent years, a method of acquiring three-dimensional shape data of a survey target using laser measurement technology or photogrammetry technology has been used. It came to be able to.
(2) In the acquisition of three-dimensional shape data using a photograph, the position coordinates of a point on the photograph are obtained by a stereo image correlation method using two or more images obtained by photographing the object with parallax.

(3) Taking the case of using two photographs as an example, the technique used in the surveying field is a technique using two photographs taken in two different positions by shifting the photographing position with a monocular camera for surveying. There is a method of using two photographs taken simultaneously by a stereo camera in which two cameras are arranged in parallel so that the position does not change.
(4) The former has the advantage that it is possible to shoot with a general camera and adjust the shooting accuracy by freely setting the distance between the cameras according to the size of the survey target. is there.

(5) In the latter case, since the positional relationship between the two cameras is known, it is easy to obtain the correlation between the two photos, and the size of the object can be obtained without installing a scale or the like on the measurement object. There are benefits.
(6) The former is often applied to vast natural objects such as topographical surveys and large structures, and the latter is often used for surveying of small objects such as dimensional measurements in laboratory experiments.

The inventors of the present application have already developed a non-contact vibration measurement technique using a laser Doppler vibrometer (see Patent Documents 1 to 3 below).
The inventors of the present application have also proposed a radio control aircraft that can form a reflective target on an object (see Patent Document 4 below).

Japanese Patent No. 4001806 JP 2004-184377 A JP 2008-281422 A JP 2012-40975 A

However, in the above surveying with a monocular camera, it is difficult to obtain the exact positional relationship of the camera when shooting in two steps. There is a problem that it is impossible to correctly evaluate the size of. Installation of a staff at a dangerous place such as a high place hinders the safety and efficiency of work.
On the other hand, in surveying with a stereo camera, the distance (baseline length) between the cameras is fixed, so there are restrictions on the shooting distance for each stereo camera. In particular, the measurement accuracy in the depth direction depends on the shooting distance. In order to photograph and evaluate a large object from a long distance, it is necessary to give a long baseline length to the stereo camera, and there is a problem that the photographing apparatus becomes large.

In photogrammetry, if the orientation of the camera at the time of shooting is indeterminate, the vertical or horizontal tilt of the measurement target cannot be detected unless a horizontal or vertical target or a target whose orientation is known is reflected in the photo. There is a problem.
Furthermore, in photogrammetry by aerial photography, the camera may be affected by aircraft vibrations, and the image may be disturbed, resulting in a decrease in survey accuracy. In particular, when a small model aircraft is used, there is a problem that the base line length of the camera is long and mounting on the model aircraft becomes difficult due to an increase in the size and weight of the stereo camera.

  Further, in photogrammetry, it is not possible to measure the position that becomes the blind spot of the camera due to the unevenness of the surface of the measurement object. When the shape of the survey target is obtained in more detail, the shape of the survey target is restored by pasting together the three-dimensional shape data obtained by photographing from a plurality of directions so that a blind spot cannot be formed. Data are similarly pasted when surveying a region wider than the shooting range of the camera. In order to accurately perform this pasting, it is necessary to accurately determine the corresponding points on the image data. At present, a reference point (spherical or circular target) with a clear position is set on the survey target and displayed in the photograph. There are many cases where they are captured, and work such as installation and surveying has occurred.

  In the present invention, in view of the above problems, by using a parallel stereo camera instead of a measuring scale, various sizes of objects can be obtained with only an aerial surveying instrument without installing a measuring scale or a reference point on the surveying target. An aerial surveying method that enables acquisition of a three-dimensional shape according to the distance from an object is provided. That is, using a model aircraft, a surveying monocular camera equipped with a stereo camera and an angle and compass through a vibration isolation mechanism, and a device equipped with a reflective paint spraying device, a photo of the surveyed object is taken, and the photographed image is displayed. By applying the image correlation method, a person does not install a scale on a survey target, and surveys with a precision that requires a survey target of any size, and a person does not set a reference point on the survey target. Provided is an aerial surveying method and apparatus that can easily carry out bonding.

In order to achieve the above object, the present invention provides
[1] In the aerial surveying method, the model aircraft is mounted with a surveying monocular camera with a stereo camera and an angle and direction meter attached via an anti-vibration mechanism, and a reflection paint spraying device, and a photo of the surveying object is taken. By applying the image correlation method to the captured image, a person does not install a scale on the survey target, but surveys with the accuracy required for a survey target of any size, and a person sets a reference point on the survey target. The present invention is characterized in that the images are pasted together.

[2] The aerial surveying method according to [1], wherein the distance between feature points to be surveyed is measured by the stereo camera.
[3] In the aerial surveying method according to [1] above, the tilt and orientation information of the surveying monocular camera at the time of photographing by the surveying monocular camera is simultaneously recorded by the tilt and orientation meter attached to the surveying monocular camera. It is characterized by that.

[4] In the aerial surveying method described in [1] above, when the three-dimensional shape data needs to be pasted together, the model aircraft is brought close to the survey target and a reference point is set on the survey target with the retroreflective paint sprayer. It is characterized by that.
[5] In the aerial surveying method described in [4] above, a reference point is provided so that at least three spots are reflected on a portion of the photograph that is to be overlapped for each photographed photograph.

[6] In the aerial surveying method described in [4] above, when photographing a survey target, a flash is taken into consideration so that at least three spots are reflected in the overlap of two images used for image correlation analysis. It is characterized by shooting.
[7] In an aerial surveying device, a monocular camera in which a stereo camera and an angle and direction meter are attached to a model aircraft via a vibration isolation mechanism, a retroreflective paint spraying device, a steering radio transceiver, and a radio for imaging An aerial surveying aircraft equipped with a transceiver, an aerial surveying aircraft control unit that performs radio communication with the aerial surveying aircraft, and imaging and injection information that performs radio communication with the aerial surveying aircraft And a control unit.

[8] The aerial surveying device according to the above [7], comprising a GPS, an IMU, and a distance meter for operating the aerial surveying aircraft.
[9] In the aerial surveying instrument according to [7], the imaging and ejection information control unit includes an imaging and ejection information wireless transceiver, a control device for the imaging and ejection information wireless transceiver, and a recording device. A display device, an input device, and a three-dimensional shape data analysis unit connected to the recording device.

  [10] The aerial surveying instrument according to [9], wherein the three-dimensional shape data analysis unit includes a storage device, an arithmetic device, an input device, and a display device.

According to the present invention, the following effects can be achieved.
By using a parallel stereo camera instead of a measuring scale, there is no need to install a measuring scale or reference point on the surveying object, and only with an aerial surveying instrument, three-dimensional depending on the size of various objects and the distance to the object. The shape can be acquired. In particular, it is possible to easily carry out surveys of steep slopes and large areas where it is difficult for people to enter. In addition, by directly measuring the tilt of the camera, it is possible to obtain accurate shooting information without error as compared to GPS or IMU attached to the aircraft body.

It is a schematic diagram which shows the aerial surveying method of this invention. 1 is a block diagram of an aerial surveying apparatus showing an embodiment of the present invention. It is a schematic diagram which shows the measurement of the distance between the feature points by the parallel stereo camera which shows the Example of this invention. It is a schematic diagram of imaging | photography of the survey object by the survey camera (one camera of a monocular camera or a stereo camera) which shows the Example of this invention. It is a schematic diagram which shows the remote installation of the reference point to the surveying object using the retroreflection paint which shows the Example of this invention. It is explanatory drawing of the calculation method of the position coordinate from the picked-up image of a parallel stereo camera. It is explanatory drawing of the calculation method of the position coordinate from the picked-up image image | photographed by changing the position with the monocular camera for surveying. It is explanatory drawing of the determination method of the magnitude | size and inclination of a surveying object which shows the Example of this invention. It is a schematic diagram which shows the search of the retroreflection paint spot which shows the Example of this invention, and its centroid position. It is explanatory drawing of the superimposition of the shape data using the reference point which shows the Example of this invention. It is a figure which shows the vibration-proof parallel stereo camera which shows the Example of this invention. It is a schematic diagram of the imaging | photography system which shows the Example of this invention. It is a drawing substitute photograph which shows the surveying work implementation status which shows the Example of this invention. FIG. 3 is a drawing-substituting photograph in which a three-dimensional point group having obtained shape data and color information is two-dimensionally displayed, showing an embodiment of the present invention.

  In the aerial surveying method of the present invention, a monocular camera for surveying in which a stereo camera and an angle and direction meter are attached to a model aircraft via an anti-vibration mechanism, a reflection paint spraying device is attached, and a photograph of the surveying object is taken, By applying the image correlation method to the captured image, a person does not install a scale on the survey target, but surveys with the accuracy required for a survey target of any size, and a person sets a reference point on the survey target. The images were pasted together without any problems.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a schematic diagram showing an aerial surveying method according to the present invention.
In this figure, as shown in FIG. 1A, a model aircraft 1 includes a stereo camera 3 for measuring a distance between feature points to be surveyed, a monocular camera 6 for surveying, an inclination and an orientation via a vibration isolator 2. A total 7 and a collision avoidance distance meter 8 are provided, and information obtained therefrom is received by the ground station 9 by TCP / IP communication via the imaging and communication control PC 4. Reference numeral 5 denotes a reflective paint spotter. FIG. 1B is an example of a stereo image instead of a drawing. FIG. 1C is a schematic diagram of a stereo image correlation method data analysis system. FIG. 1D shows a drawing substitute photograph showing three-dimensional point cloud data. The stereo image correlation method data analysis system will be described in detail (see FIG. 6).

FIG. 2 is a block diagram of an aerial surveying apparatus showing an embodiment of the present invention.
In this figure, 11 is an aerial surveying device, 12 is a model aircraft, 13 is GPS, 14 is an IMU, 15 is a collision avoidance distance meter, 16 is a radio transmission / reception device for steering, and 17 is a distance measurement between feature points to be surveyed. Stereo camera, 18 tilt and direction meter, 19 monocular camera for surveying, 20 retroreflective paint sprayer, 21 control device, 22 recording device, 23 radio transmitter / receiver for photographing, 24 aircraft control unit, 25 is a control information radio transceiver, 26 is a control device, 27 is an input device, 28 is an imaging and ejection information control unit, 29 is an imaging and ejection information wireless transceiver, 30 is a control device, 31 is a recording device, and 32 is a display. 33, an input device, 34, a three-dimensional shape data analysis unit, 35, a recording device, 36, an arithmetic device, 37, an input device, and 38, a display device.

  A parallel stereo camera 17 for measuring the distance between feature points of a survey target whose base line length is not long, a high-resolution survey monocular camera 19 equipped with an inclination and an azimuth meter 18, and a retroreflective paint sprayer 20 (see Patent Document 4). Using the accompanying model aircraft, the survey object is photographed in the following procedure (see FIG. 3). One of the cameras constituting the parallel stereo camera 17 may be used as the monocular camera for surveying.

FIG. 3 is a schematic diagram showing the measurement of the distance between feature points by the parallel stereo camera according to the embodiment of the present invention.
FIG. 4 is a schematic diagram of photographing of a surveying object by a surveying camera (monocular camera or one stereo camera) according to an embodiment of the present invention.
FIG. 5 is a schematic diagram showing remote installation of a reference point on a surveying object using a retroreflective coating material according to an embodiment of the present invention.

Hereinafter, the aerial surveying method will be described.
(1) As shown in FIG. 3, two or more feature points (color, shape) on the survey target 40 from the shooting distance that allows the model aircraft 41 to approach the survey target 40 and to ensure the survey accuracy by the parallel stereo camera 42. A part of the surveying object 40 including a point having a peculiarity such as a position that can be specified on a photographic image is taken several times from a plurality of directions.

(2) As shown in FIG. 4, the model aircraft 41 is moved, and the survey target 40 is photographed by the surveying monocular camera 42 </ b> A from the distance at which the entire survey target 40 is captured.
(3) As shown in FIG. 4, the model aircraft 41 is moved from the first shooting position in consideration of the required survey accuracy, and the second shooting is performed.
(4) The tilt and azimuth information of the camera at the time of camera shooting is simultaneously recorded by the tilt and azimuth meter 18 attached to the camera.

(5) As shown in FIG. 5, when the three-dimensional shape data needs to be pasted, the model aircraft 41 is brought close to the survey target 40, and the retroreflective paint sprayer 43 changes the survey target 40 to the survey target 40. Set a reference point. A reference point is provided so that at least three spots appear in the overlapped portion of the photograph per photograph.
(6) When photographing the surveying object 40, the flash photographing is taken in consideration that at least three spots are reflected in the overlapping portion of the two images used for the image correlation analysis.

(7) When there is no clear feature point in the survey target 40, the reference point by the retroreflective coating 44 in step (5) may be used as the feature point.
Next, an image correlation analysis method will be described.
FIG. 6 is an explanatory diagram of a method for calculating position coordinates from a captured image of a parallel stereo camera.
FIG. 7 is an explanatory diagram of a method for calculating position coordinates from captured images obtained by changing the position with a monocular camera for surveying.

As shown in FIG. 6, the position coordinates are calculated from the captured image of the parallel stereo camera. Here, 51 is a left camera, 52 is a right camera, 53 is a left image, 54 is a right image, 55 is a position P _l (u, v) on the left image, and 56 is a position P _r (u ′ on the right image). , V ′), 57 are position coordinates P (X, Y, Z), X = bu / (u−u ′), Y = bv / (u−u ′), Z = bf / (u−u). ′) Where b is the baseline length and f is the focal length.

(1) As shown in FIG. 6, the distance between feature points on the screen is calculated from the photographing result of the stereo camera (an average value of survey results from at least three directions is used). The position coordinates of the points shown in the two photographs shown in FIG. 6 can be obtained. Since the positional relationship between the two cameras is clear, the dimension of the surveying object 40 can be obtained from the captured image.
(2) As shown in FIG. 7, the position coordinates are calculated from the captured images taken by changing the position with the monocular camera for surveying. As shown in FIG. 7, 61 is the first shooting position on the left side, 62 is the first image, 63 is the position P ₁ (u, v) on the first image 62, 65 is the second shooting position on the right side, and 66 is The second image 67 is a position P _r (u, v) on the second image. Here, f is a focal length.

  Based on the positional relationship, the position coordinates of the points appearing in the two photos are obtained. However, when the positional relationship (distance and orientation) of the camera at the time of the two shootings is unknown, the number of known relationships for obtaining the necessary number of equations for the unknowns that need to be obtained by analysis is insufficient. Therefore, the shape data to be surveyed is obtained by artificially selecting a plurality of points that can be clearly regarded as the same point from the two photographs, and making up for the insufficient equation by utilizing the two points having the same coordinates. Techniques are commonly used.

From the photographed photographs shown in FIGS. 6 and 7, the three-dimensional shape data to be surveyed is obtained.
FIG. 8 is an explanatory diagram of a method for determining the size and inclination of a survey target according to an embodiment of the present invention, and FIG. 8 (a) is a survey target lacking in the size, tilt, and azimuth information measured by a monocular camera for surveying. FIG. 8B is a diagram showing determination of the size of a survey target using the distance between feature points by a parallel stereo camera, and FIG. 8C is an inclination and orientation attached to the monocular camera for surveying. It is a figure which shows determination of the inclination of the survey object using the information of a meter.

In these figures, 71 is a survey target, 72 is a feature point, 73 is a distance between feature points surveyed by a parallel stereo camera, 74 is a correction of the tilt of the survey target, and 75 is a correction of the orientation of the survey target.
FIG. 9 is a schematic diagram showing a search for retroreflective paint spots and their centroid positions according to an embodiment of the present invention.

In this figure, 80 is a surveying object, 81 is a pixel of the surveying object 80, 82 is a retroreflective paint spot, and this retroreflective paint spot 82 is extremely higher than the surroundings by flash photography of the location where the retroreflective paint is attached. Has brightness. The left and right and upper and lower ends of the high luminance image are searched, and the pixel corresponding to the centroid is set as the reference point 83.
FIG. 10 is an explanatory diagram of superposition of shape data using a reference point showing an embodiment of the present invention, and FIG. 10 (a) is a diagram showing a survey target that needs to be divided and photographed due to the influence of size and blind spot, FIG. 10B is a diagram showing the setting of the reference point (black point), FIG. 10C is a diagram showing the calculation of each shape from the divided photograph, and FIG. 10D is a mark of the coordinates of the reference point. The shape data is overlapped as shown in FIG.

In these figures, 91 is a survey target, 91-1 to 91-4 are segmented survey targets, and 92 is a feature point.
Next, the overlay method will be described.
(1) As shown in FIG. 9, the position of the center of gravity of the reflective paint spot 82 is calculated as a reference point 83, and the corresponding pixel 81 on the photograph is determined.
(2) The three-dimensional shape data (three-dimensional point group) is superimposed using the position data of the reference point 83 that exists in common in the two three-dimensional point group data as a mark (FIG. 10). The coordinates of the overlap location are determined by using one data as a representative or by averaging the values of two point group data regarded as the same position.

FIG. 11 is a view showing a vibration-proof parallel stereo camera according to an embodiment of the present invention. That is, it is an enlarged view of the stereo camera unit. One of the cameras may be used for surveying. Separately, when a monocular camera for surveying is used, the camera is provided with a similar vibration isolator.
101 is a parallel stereo camera, and 102 is an anti-vibration mechanism for the stereo camera 101. One of the cameras may be used for surveying. Separately, when a monocular camera for surveying is used, the camera is provided with a similar vibration isolator.

FIG. 12 is a schematic diagram of an imaging system showing an embodiment of the present invention.
(1) Data communication is performed between the ground control notebook PC (personal computer) 111 and the photographing notebook PC (personal computer) 112 on the model aircraft by TCP / IP.
(2) A captured image of the stereo camera is always transmitted to the ground and monitored by the ground control notebook PC (personal computer) 111.
(3) Control the start and stop of stereo camera (moving image shooting) from the ground.
(4) Move the model aircraft while referring to the monitor image and record the images necessary for surveying.
(5) Check the photographed image on the ground, and if necessary images are not photographed, photograph again.

FIG. 13 is a drawing-substituting photograph showing the surveying work implementation status showing an embodiment of the present invention.
Even the surveyed rock mass 121 that is difficult for humans to approach can be easily surveyed by the aerial surveying device 122 of the present invention.
FIG. 14 is a drawing-substituting photograph in which a three-dimensional point group having the obtained shape data and color information is two-dimensionally displayed to show the embodiment of the present invention.

As shown in this figure, a three-dimensional point group having shape data and color information can be displayed two-dimensionally.
In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

  The aerial surveying method and apparatus of the present invention uses a parallel stereo camera in place of a standard measure, so that a variety of object sizes can be obtained using only the aerial surveying instrument without installing a standard or reference point on the survey target. It can be used as an aerial surveying method and apparatus that enables acquisition of a three-dimensional shape according to the distance to the object.

1,12,41 Model aircraft 2 Anti-vibration device 3,17 Stereo camera 4 PC for shooting and communication control
5 Reflective paint spotter 6,19,42A Surveying monocular camera 7,18 Tilt and bearing meter 8,15 Distance meter 9 Ground station 11,122 Aerial surveying device 12 Model aircraft 13 GPS
14 IMU
16 Radio transmission / reception device for control 20, 43 Retroreflective paint sprayer 21, 26, 30 Control device 22, 31, 35 Recording device 23 Radio transmission / reception device for photographing 24 Aircraft control unit 25 Control information radio transmitter / receiver 27, 33, 37 Input Device 28 Imaging and ejection information control unit 29 Imaging and ejection information wireless transceiver 32, 38 Display device 34 Three-dimensional shape data analysis unit 36 Arithmetic device 40, 71, 80, 91 Survey object 42, 101 Parallel stereo camera 44 Retroreflective paint 51 Left camera 52 Right camera 53 Left image 54 Right image 55 Position P _l (u, v) on the left image
56 Position P _r (u ′, v ′) on right image
57 Position coordinates P (X, Y, Z)
b Base line length f Focal length 61 First imaging position on left side 62 First image 63 Position P ₁ (u, v) on first image
65 Second-time shooting position on the right side 66 Second-time image 67 Position P _r (u, v) on the second-time image
72,92 Feature point 73 Distance between feature points measured by parallel stereo camera 74 Correction of tilt of survey target 75 Correction of direction of survey target 81 Pixel of survey target 82 Retroreflective paint spot 83 Reference point (pixel corresponding to centroid)
91-1 to 91-4 Surveyed Objects Taken in Divided 102 Stereo Camera Anti-Vibration Mechanism 111 Ground Control Notebook PC (PC)
112 Notebook PC (computer) for shooting on model aircraft
121 Masses for surveying that are difficult for people to approach

Claims (10)

  A monocular camera for surveying with a stereo camera and an angle and direction meter attached to the model aircraft via an anti-vibration mechanism, and an injection device for reflective paint are attached to take a photo of the survey object, and apply the image correlation method to the captured image By doing this, the person does not install a measuring instrument on the surveying object, but the surveying object of any size is surveyed with the accuracy required, and the person pastes the images without installing a reference point on the surveying object. An aerial survey method characterized by   2. The aerial surveying method according to claim 1, wherein the distance between feature points of the survey target is measured by the stereo camera.   2. The aerial surveying method according to claim 1, wherein the tilting and azimuth information of the surveying monocular camera at the time of photographing by the surveying monocular camera is simultaneously recorded by the tilting and azimuth meter attached to the surveying monocular camera. Aerial surveying method to do.   The aerial surveying method according to claim 1, wherein when the three-dimensional shape data needs to be pasted together, the model aircraft is brought close to the survey target, and a reference point is set on the survey target with the retroreflective paint sprayer. Aerial surveying method to do.   5. The aerial surveying method according to claim 4, wherein a reference point is provided so that at least three spots are reflected on a portion of the photograph that is to be overlapped for each photographed photograph.   5. The aerial surveying method according to claim 4, wherein when photographing a survey object, taking into account that at least three spots are reflected in an overlap portion of two images used for image correlation analysis, and photographing with flash. Features aerial surveying methods. (A) The model aircraft includes a monocular camera in which a stereo camera and an angle and direction meter are attached via a vibration isolation mechanism, a retroreflective coating spraying device, a steering radio transceiver, and a radio transceiver for photographing. Aerial survey aircraft,
(B) an aerial survey aircraft control unit that performs wireless communication with the aerial survey aircraft;
(C) An aerial surveying apparatus comprising an imaging and injection information control unit that performs wireless communication of the aerial surveying aircraft.   8. The aerial surveying device according to claim 7, further comprising: a GPS, an IMU, and a distance meter for controlling the aerial survey aircraft.   8. The aerial surveying instrument according to claim 7, wherein the imaging and ejection information control unit includes an imaging and ejection information wireless transceiver, a control device for the imaging and ejection information wireless transceiver, a recording device, and a display device. An aerial surveying instrument comprising: an input device; and a three-dimensional shape data analysis unit connected to the recording device.   The aerial surveying instrument according to claim 9, wherein the three-dimensional shape data analysis unit includes a storage device, a calculation device, an input device, and a display device.

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