JP2003083745A - Imaging apparatus mounted to aircraft, and aircraft imaging data processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus mounted to an aircraft for performing air triangulation accurately with a small number of reference points, and to provide an aircraft imaging data processing apparatus. SOLUTION: In the imaging apparatus mounted to an aircraft, an image acquired by line sensors 10B, 10N, and 10F and position and attitude information in a camera 10 obtained from a gyro 11, an INS apparatus 15, and a GPS receiver 16 are recorded in a recording means 141 in a pair. In the imaging apparatus mounted to an aircraft, the image of a reference point where spatial position information is stored in a storage means 142 is detected by an image processing section 131. A position/attitude judgment section 132 obtains parameters in the error model of the position/attitude information in a camera 10 so that the deviation between the actual spatial position and image of the reference point and an observation position obtained from the position/attitude information in the camera 1 becomes small, thus correcting the position/attitude information in the camera 10 by the model.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aircraft-mounted image pickup apparatus for obtaining a ground surface image from the sky and an aerial image pickup data processing apparatus for processing the image pickup data. The present invention relates to an aircraft-mounted image pickup device and an aerial image pickup data processing device that collectively acquire position / orientation data of a camera.

[0002]

2. Description of the Related Art As a method for measuring the shape of the terrain, a method using aerial photographs and satellite photographs is known. Patent 280762 as a system for taking such aerial photographs
An aircraft-mounted imaging device disclosed in Japanese Patent Publication No. 2 is known.

This technique uses a three-line sensor camera to store the position / orientation data of the camera and the image data of the continuously photographed surface of the earth as digital data, which enables detailed correction by software later. It was done. Based on the data thus obtained, the spatial position of the ground surface object can be obtained by the principle of triangulation.

[0004]

By the way, since a slight error in the position / orientation data of the camera causes a large deviation in the spatial position of the surface of the ground object, in order to carry out accurate survey, It is necessary to set a reference point and perform correction based on the deviation between the spatial position and the position calculated based on the acquired data (called aerial triangulation). In normal photogrammetry, a two-dimensional image is obtained, so there is only one camera position / orientation data (6 parameters) for the two-dimensional image. Since the posture data exists for each one-dimensional image, there are as many position / posture parameters as there are lines, and they change from moment to moment, so it is enormous to obtain the values of all position / posture parameters. It is necessary to set a reference point, which is not realistic.

Therefore, it is an object of the present invention to provide an airborne image pickup apparatus and an aerial image pickup data processing apparatus capable of performing accurate aerial triangulation from a small number of reference points.

[0006]

In order to solve the above-mentioned problems, an airborne image pickup apparatus according to the present invention has a plurality of line sensors which are mounted on an aircraft and which pick up a ground surface image as a one-dimensional image, if they have different lines of sight. A camera configured by arranging the camera, an attitude information acquisition device that acquires attitude information when the camera captures an image, a position information acquisition device that acquires three-dimensional position information when the camera captures an image, and an acquired one-dimensional In an airborne imaging device that includes an image group and a recording device that records the posture / position information at the time of image capturing as digital data, (1) Corresponds to multiple ground reference points in the acquired one-dimensional image group Pixel detection means for obtaining a pixel to be
(2) A storage unit that stores and stores the position information of each of these reference points, and (3) a model that creates an error model that models the change in the position and position error of the camera during imaging due to time and position. And (4) posture / position information correction for correcting the posture / position information of the camera from the relationship between the position information of the reference point stored in the error model and the storage unit and the corresponding pixel obtained by the pixel detection unit. And means are further provided.

On the other hand, the aerial image pickup data processing apparatus according to the present invention includes a camera mounted on an aircraft and having a plurality of line sensors arranged so as to pick up a ground image as a one-dimensional image with different lines of sight. A posture information acquisition device that acquires posture information when the camera captures an image, a position information acquisition device that acquires three-dimensional position information when the camera captures an image, an acquired one-dimensional image group, and a posture / position information when captured In a aviation imaging data processing device that processes digital data acquired by an aircraft-mounted imaging device that includes a recording device that records as digital data in a set, (1) a plurality of ground surface standards in the acquired one-dimensional image group Pixel detection means for obtaining pixels corresponding to points, (2) storage means for accumulating and storing position information of each of these reference points, and (3) reference stored in the storage means Modeling means for creating an error model that models the change in position and position error of the camera at the time of image capturing, based on the relationship between the position information and the corresponding pixel obtained by the pixel detection means, and (4) And a posture / position information correction means for correcting the posture / position information of the camera by the error model.

According to the present invention, the posture of the camera during image pickup
By modeling the error of the position information, it is not necessary to obtain the pose / position parameter for each image, and only the error parameter in the error model needs to be obtained, so the number of variables can be reduced and the required reference point The number of can also be significantly reduced. As a result, it is possible to reduce the calculation amount and perform accurate aerial triangulation from a small number of reference points.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In order to facilitate understanding of the description, the same reference numerals are given to the same constituent elements in each drawing as much as possible in the drawings, and redundant description will be omitted.

FIG. 1 is a diagram for explaining the configuration of an aircraft-mounted image pickup apparatus 1 according to the present invention. This device 1 is shown in FIG.
As shown in (a), it is attached to the lower part of a flying body 3 such as an aircraft and acquires an image of the ground surface from the sky while the flying body 3 is flying. The flying body 3 is not limited to the fixed-wing aircraft shown in the figure, but includes a rotary-wing aircraft such as a helicopter, an airship, and a balloon.

FIG. 1B is a diagram showing the structure of the image pickup apparatus 1. In the figure, the normal traveling direction of the flying object 3 is shown as leftward. Here, the imaging unit (camera) 10 is a line sensor 1 configured by arranging a large number of pixels one-dimensionally.
0B, 10F, and 10N are arranged in parallel so as to be orthogonal to the normal traveling direction of the flying object 3, and are arranged so that their respective lines of sight intersect. As a result, the line sensor 10F acquires an image below the front of the flying body 3, the line sensor 10N acquires an image immediately below the flying body 3, and the line sensor 10B acquires an image below the rear of the flying body 3.

The camera 10 is arranged in a stabilizer 12 that suppresses the variation of the attitude together with a gyro 11 that detects the attitude (direction) of the camera 10. In addition, the flying body 3
Inertial Navigation System (INS) device 1 for detecting the position of the camera 10, and thus the position of the camera 10.
5, an antenna 17 for receiving a signal from a GPS (Global Positioning System) satellite, and a G connected to the antenna 17.
It is equipped with a PS receiver 16. The control device 13 that controls the entire imaging device 1 includes an image processing unit 131 that performs predetermined image processing on an image acquired by the camera 10, and I
A position / orientation determination unit 132 that determines the position / orientation of the camera based on the outputs of the NS device 15, the GPS receiver 16, and the gyro 11, and an attitude control unit 13 that controls the attitude of the camera.
3. A recording data creation unit 134 for generating recording data by associating the position / orientation of the camera with the acquired one-dimensional image group. The recording device 14 has a recording unit 141 for recording the data created by the recording data creation unit 134, and a storage unit 142 for storing predetermined data used by the image processing unit 131. Here, the recording means 14
1 and the storage means 142 may be the same recording device (for example, hard disk). The recording means 141,
The storage unit 142 may be a magneto-optical disk whose storage medium is removable from the device. Further, the recording unit 141 needs to be a writable recording medium, but the storage unit 1
Reference numeral 42 does not necessarily have to be a writable / erasable recording medium, and is a read-only recording medium such as a CD-ROM.
It may be a DVD-ROM or the like. Also, the storage means 1
The position information stored in 42 may be set based on the data obtained in the past imaging, or the separately obtained data may be manually input.

FIG. 2 is a diagram for explaining the positional relationship between the camera 10 and the object 4 when the object 4 on the ground surface is imaged by the camera 10 from the sky. The image of the arbitrary point P of the object 4 is not simultaneously acquired by the three line sensors 10F, B, and N of the camera 10, and the flying object 3 (not shown in FIG. 2).
Is moving from the right side of the figure to the left side,
First, at a stage where the flying object 3 approaches the sky of the object 4 but has not reached immediately above, the line sensor 10F arranged in the forward direction acquires the image of the point P. And
When the flying object 3 reaches directly above the target object 4, the line sensor 10N arranged downward acquires an image of the point P. Then, when the flying object 3 passes over the object 4 and moves away from it, the line sensor 10B arranged rearward acquires the image of the point P.

FIG. 3 shows a group of images acquired in this way.
FIG. 6 is a diagram illustrating the principle of calculating spatial position information of a subject.
It Here, the ground coordinate system is used as the coordinate system, and the object
The spatial position of P is represented by coordinates (X, Y, Z). Each line
Object position in the images acquired by the sensors 10B, N, F.
Mari image point p_B(X_PB, Y_PB, Z_PB), P_N(X_PN，
Y _PN, Z_PN), P_F(X_PF, Y_PF, Z_PF). Well
During the projection of each line sensor 10B, N, F at this time
Each heart is O_B(X_OB, Y_OB, Z_OB), O_N(X_ON, Y
_ON, Z_ON), O_F(X_OF, Y_OF, Z_OF). here
Then, as shown in FIG. 3, the subject P and the image point p are projected.
Since the hearts O are arranged on a straight line, the following equation is established.

[0015]

[Equation 1]

[0016] Here, the line sensor 10B, N, F projection center O _B of, O _N, spatial coordinate position O _F and image point p _B, p _N, p _F is known from the posture and position information of the camera The position of the subject P is a point where a straight line connecting the corresponding projection center and the image point extends and intersects. In actual calculation, the three straight lines may not intersect due to measurement error or the like. In that case, for example, the least square method may be used to set the point having the smallest distance from these three straight lines as the position P of the subject.

However, since there is an error in the position / orientation information of the camera, the position P of the subject thus obtained (hereinafter, the calculated position is represented by Pc) is the original object. It deviates from the position P. FIG. 4 is a diagram for explaining this shift. Image of the point P being an object of the top of the object 4 is in fact p _f, is obtained at p _n positions. However, there is an error in the position / orientation information of the camera at this time, and it is erroneous that the positions of the image points are _pn 'and _pf ', and when the spatial position Pc is determined as a direction different from the actual direction, Pc
Deviates from the original position P. Especially when the altitude of the flying object 3 is increased, the posture of the camera shifts (that is, the shift in the line of sight).
Greatly influences the shift of the position information calculated as compared with the shift of the position of the camera.

In order to reduce such a displacement of the position information, that is, an error, and perform a highly accurate survey, a plurality of reference points whose spatial position information is known in advance are arranged, and image points Pn and Pf obtained by calculation are calculated. A method called aerial triangulation corrects the error based on the deviation between the image points Pn 'and Pf'.

The aerial triangulation method in the airborne image pickup apparatus according to the present invention will be specifically described below. FIG. 5 is a flowchart showing this aerial triangulation processing. FIG. 6 is a diagram showing the relationship between the reference point and the imaging surface,
FIG. 7 is a diagram illustrating aerial triangulation. This processing is performed by the control device 13 in parallel with the image acquisition by the camera 10.

First, in step S1, the image processing unit 13
2 obtains the pixel positions corresponding to the images 6 _{1 to} 6 ₃ obtained by capturing the reference points 5 _{1 to} 5 ₃ from the acquired images of the line sensors 10B, 10N, and 10F by pattern recognition or the like (see FIG. 6).

In step S2, the position / orientation determination unit 13
1 is stored in the storage unit 142 and the pixel position thus obtained.
Minimum deviation from image point obtained from actual position
Set each parameter of the error model so that. Figure
The pixel position p'observed as shown in FIG.
Observation value O ′ (X_{O '}，
Y _{O '}, Z_{O '}, Ω ', ψ', χ ') contains an error
(Here, ω ', ψ', χ'is the direction of the camera
It is a value that represents the force, and the direction component of each is the axis.
Angle. ) Therefore, the position of the observed reference point is
The position is P ', which is different from the position. During actual camera projection
If we know O, which is the value of the heart and orientation, the pixel in the one-dimensional image
The actual pixel position (image point) p is known from the position, and
The obtained spatial position P should match the position of the reference point.
It In order to reduce this deviation, the observed value O '
A method of modeling an error from the value O is used.

Here, as the error of the position information of the camera, the offset component (X _{of fset} , Y _offset ,
Z _offset) and the reference position due to the measurement by _{GPS (X re f, Y ref} , there is an error component due to the camera position that is proportional to the distance L from the Z _ref). Further, as the error of the posture information of the camera, there are offset components (ω _offset , ψ _offset , χ _offset ) of the posture information and a periodic drift component accompanying the shake of the stabilizer. Therefore,
The following relationships are established between the components O and O ′.

[0023]

[Equation 2]

Here, the unknown variable is the offset component.
(X_offset, Y_offset, Z_offset) And (ω_offset，
ψ_offset, Χ_offset), Ratio of error components with camera position
Example constant k _X, K_Y, K_ZAnd the periodic function f of the drift component
(T), g (t), and h (t). Therefore, multiple groups
Minimize the combination of variables that gives the smallest error for the canonical points
It is calculated using the square method. The actual calculation is, for example,
It may be performed by using the Cux method. Model the error in this way
By converting them to common parameters and handling
Reduce the number of variables to find even if there are many original images
Can be calculated easily and the number of reference points can be increased.
In that case, even if it is not in the same 1D image,
The accuracy of finding the number is also improved.

In step S3, the recording data creating unit 13 is executed by the error model using the parameters thus obtained.
4 updates the position / orientation data of the camera stored in the recording means 141. Instead of directly updating the position / orientation data, the error information obtained by the error model or each parameter of the error model may be recorded.

According to the present invention, aerial triangulation of a one-dimensional image group can be accurately performed with a small number of reference points. Then, by performing the spatial position measurement based on the principle of FIG. 3 using the position / orientation data of the camera corrected by the aerial triangulation, the accuracy of the measurement other than the reference point is also improved.

In the above description, an example in which the processing is performed by the image pickup device mounted on the aircraft has been described. However, aerial triangulation may be performed when the image data including the posture / position information of the camera acquired by the image pickup device is processed. It is also possible. FIG. 8 is a diagram showing the configuration of the aerial image pickup data processing device 2.
This device is equipped with a computer 20 including a personal computer, a workstation, etc., a monitor 23, a keyboard 24 as an input device, and a mouse 25.
0 is a hard disk 22 which is a built-in storage device,
It has a calculation unit 21 including a CPU and a memory. The calculation unit 21 includes a position / orientation information correction unit 211 and an image processing unit 2.
12 and. The position / orientation information correction unit 211 and the image processing unit 212 may be configured as hardware or software.

The data processing device 2 is a device for processing the image pickup data of the aircraft-mounted image pickup device 1 as shown in FIG. 1B, but also the image pickup data obtained by the conventional aircraft-mounted image pickup device. It goes without saying that it is possible.

Since the operation of the data processing device 2 is almost the same as the control of FIG. 5, its detailed description will be omitted. Even when the post-processing is performed as described above, according to the present invention, it is possible to improve the accuracy of aerial triangulation and improve the accuracy of surveying.

[0030]

As described above, according to the present invention, the error of the position / orientation information of the camera is modeled using the parameters and the aerial triangulation is performed, so that the aerial triangulation of the one-dimensional image is small. It is possible to improve the adjustment accuracy at the reference point, which in turn can improve the survey accuracy.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an aircraft-mounted imaging device according to the present invention.

FIG. 2 is a diagram illustrating a manner of acquiring a ground surface image in the apparatus of FIG.

FIG. 3 is a diagram illustrating a principle of measuring spatial position coordinates in the apparatus of FIG.

FIG. 4 is a diagram for explaining the influence of an error in posture / position information on a survey result.

5 is a flowchart showing aerial triangulation processing in the device of FIG.

FIG. 6 is a diagram showing a relationship between a reference point and an imaging surface.

FIG. 7 is a diagram illustrating aerial triangulation.

FIG. 8 is a schematic configuration diagram showing an aerial imaging data processing device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Aircraft imaging device, 2 ... Aviation imaging data processing device, 3 ... Flying object, 4 ... Target object, 5 ... Reference point, 6 ... Image, 7
... image plane, 10 ... camera, 11 ... gyro, 12 ... stabilizer, 13 ... control device, 14 ... recording device, 15 ... IN
S device, 16 ... GPS receiver, 17 ... Antenna, 20 ...
Computer, 21 ... arithmetic unit, 22 ... hard disk, 23 ...
Monitor, 24 ... Keyboard, 25 ... Mouse, 131 ... Image processing section, 132 ... Position / posture determination section, 133 ... Posture control section, 134 ... Data creation section, 141 ... Recording means, 14
2 ... storage means, 211 ... position / orientation information correction unit, 212
… Image processing unit.

Claims (2)

[Claims] 1. A camera configured by arranging a plurality of line sensors mounted on an aircraft to pick up a ground surface image as a one-dimensional image with different lines of sight, and to obtain attitude information at the time of taking the image of the camera. Posture information acquisition device, position information acquisition device that acquires three-dimensional position information when the camera captures images, and recording device that records the acquired one-dimensional image group and the attitude / position information when captured as digital data When,
In an aircraft-mounted image pickup device comprising: a pixel detection unit that obtains pixels corresponding to a plurality of reference points on the ground surface in the acquired one-dimensional image group; and a storage unit that stores and stores position information of each of the reference points, Modeling means for creating an error model that models a change in the position / position information of the camera during the image capturing due to time and position, and the position information of the reference point stored in the error model and the storage means, and An aircraft-mounted image pickup apparatus further comprising: attitude / position information correction means for correcting the attitude / position information of the camera from the relationship with the corresponding pixel obtained by the pixel detection means. 2. A camera configured by arranging a plurality of line sensors mounted on an aircraft to pick up a ground surface image as a one-dimensional image with different lines of sight, and to obtain attitude information at the time of taking the image of the camera. Posture information acquisition device, position information acquisition device that acquires three-dimensional position information when the camera captures images, and recording device that records the acquired one-dimensional image group and the attitude / position information when captured as digital data When,
In an aerial imaging data processing device for processing digital data acquired by an aircraft-mounted imaging device, comprising: a pixel detection unit that obtains pixels corresponding to a plurality of reference points on the ground surface in the acquired one-dimensional image group; Storage means for accumulating and storing the position information of, and modeling means for creating an error model that models a change in position / position information error of the camera at the time of image capturing due to time and position, the error model and the storage A posture / position information correction unit that corrects the posture / position information of the camera from the relationship between the position information of the reference point stored in the unit and the corresponding pixel obtained by the pixel detection unit. Aviation imaging data processing device.