JP2778376B2 - Camera viewpoint change method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for changing a camera viewpoint position in an inspection or an operation mainly performed by using a remotely controlled robot arm and a monitoring camera.

[0002]

2. Description of the Related Art Remotely controlled robots are used for work inspections performed in space or nuclear power plants. 2. Description of the Related Art In a work inspection by a conventional remote-controlled robot, a method has been employed in which a master-slave operation method and binocular stereoscopic vision are used to give an operator a sense of realism and assist the operation. In order to perform an inspection or the like, it is necessary to change the viewpoint of the monitoring camera to an appropriate position. In order to facilitate the operation of changing the viewpoint of the surveillance camera, the master arm is operated while watching the stereoscopic display, or the worker wears a head mounted display etc., and the movement of the head is linked with the movement of the camera Such a master-slave method has been used. As the most basic operation method, there is a method of moving a camera by specifying an increment in a camera coordinate system while viewing a single camera image using a joystick or the like.

Further, for the purpose of avoiding occlusion of the viewpoint position of a camera, an automatic determination method based on a geometric model has been studied.

[0004]

In the above-mentioned camera viewpoint operation method, the method of performing a master-slave operation while receiving support such as stereoscopic vision requires a complicated and costly apparatus for performing the operation support. The stereoscopic display has a drawback that it is unsuitable for long-time work due to flickering. Also, the operation of the viewpoint position often depends on the operator's feeling, and it cannot be said that the method is excellent in workability in terms of the arrangement of the viewpoint position. In addition, although the configuration can be simplified for the operation by specifying the increment in the camera coordinate system, it is highly possible that the point of gaze will be out of the screen or the focus will be blurred during the operation, and the posture for the appropriate viewpoint will be determined. There is a drawback that it takes considerable trial and error to do so. The automatic viewpoint arrangement method based on the geometric model under the constraint condition requires a geometric model, and is applicable only when a clear constraint condition is known. There is also a problem that it is necessary to correct an error between the geometric model and the real environment.

An object of the present invention is to provide a camera viewpoint position operation method which solves these problems.

[0006]

According to the present invention, there is provided a camera, a camera operating means for controlling a camera position, a camera image display means, and a gazing point designating means for designating a gazing point on an image. By specifying the same gazing point existing in the field of view of each image from different camera viewpoint positions by the gazing point designating means, the relative position between the specified gazing point and the camera is measured, and the gazing point is determined. With the center as the center, on a spherical surface having a radius of a predetermined distance specified in advance, a position where a currently known camera position intersects with a straight line connecting the specified gazing point and the line of sight direction of the camera and the direction of the specified gazing point. The camera is moved to a posture position where coincides with each other, and the operation of changing the camera position is performed in a spherical coordinate system whose origin is the gazing point.

[0007]

The present invention will be described with reference to the drawings. FIG.
FIG. 1 is a conceptual diagram showing the principle of a camera viewpoint changing method according to the present invention. FIG. 2 shows the flow of processing in that method.

[0008] In FIG. 1, when the camera 1 is in the position of the coordinate system O _R, the coordinates R of the camera image display unit 3 with the fixation point specifying means 4 as a projection point of the target point of interest P
It is assumed that (X _R , Y _R ) is specified. Then move the camera to the coordinate system O _L, the coordinates L (X _L as projected point fixation point P,
Y _L ) is specified. Point of interest P viewed from coordinate system O '
Position relative _{(x p ', y p'} , z p ') by the principle of _{triangulation, x p' = l · (} X L + X R) / (X L -X R) y p '= 2f · l / is determined by _{(X L -X R) z p} '= Y L · y / f. The absolute position of the gazing point P with respect to the reference coordinate system O can be calculated using a coordinate transformation matrix from the coordinate system O to O ′. This coordinate conversion corresponds to the conversion from the origin of the robot arm to the camera 1 and can be known.
Therefore, the position of the gazing point P in the absolute coordinate system O (x
_p, y _p, z _p) are determined.

The camera position is centered on the gazing point P,
Consider the arrangement on a spherical surface of radius R. The distance of the radius R is set in advance in consideration of the camera focal length. As an example of a method for determining the camera position on the spherical surface, the gazing point P
The placing on the intersection of the line segment and a spherical connecting the middle point O 'and P camera position O _R and O _L measured. Since the coordinates of the midpoint O 'are known, the direction of the line connecting O' and P is known in the absolute coordinate system. Therefore, by matching the line-of-sight direction of the camera 1 with this vector direction, the gazing point P is arranged at the center of the camera screen. At this time, rotation around the visual axis is not performed. When a point moved from the point P by a distance R in a direction opposite to the vector is obtained, a camera position Q is obtained. Thereafter, the camera position is changed by designating the azimuth angle A _z , the elevation angle E _l , and the distance R in a spherical coordinate system whose origin is the gazing point. Regarding the change of the posture, the change is always performed so that the camera line of sight and the gazing point coincide.

The initial camera viewpoint on the camera viewpoint sphere 5 is:
Camera position O where the point of interest is first specified according to the work situation
Or as the intersection of a line connecting the O _L and P is specified target point at the intersection and the second after the movement of the straight line connecting the _R and P. Instead of moving the camera 1 for designating the point of gaze P, two cameras may be provided and designated for each camera image. These modifications may be made without departing from the spirit of the present invention, and the above description does not limit the scope of the present invention.

[0011]

FIG. 3 shows an example of pipe inspection as an embodiment of the present invention. In this example, camera 10 and camera 1 are used as camera 1.
A mobile robot 13 equipped with a manipulator 12 as a camera moving means 2 and a host computer 14 and a joystick 1 for manipulator operation.
5, a computer display 16 capable of displaying two camera moving images as the camera image display means 3,
The mouse 17 is used as the gazing point designating means 4. A pipe 20 and a vent 21 on the pipe 20 are considered as work objects. The inspection of a crack in the pipe 20 will be described as an operation example. Since the vent 21 of the pipe 20 is weak in strength, it is a portion where the possibility of existence of a crack is the highest. Therefore, inspection is often performed from these parts. Mobile robot 13
When the vent 21 is observed in the field of view of the cameras 10 and 11, the vent 21 is designated as the gazing point by using the mouse 17 on the display 16. The relative position is measured according to the principle of triangulation. Here, as the viewpoint position, the camera 10 is automatically arranged at the position P ₀ on the viewpoint spherical surface according to the method described in the operation. With this position as the origin, the camera position moves on the viewpoint spherical surface with the gaze point as the origin. The movement operation is performed using the joystick 15,
When allocating the upper and lower operation of the joystick in the elevation angle, it can be easily moved to the position P ₁ lower which is observable in the vent portion 21 by adding as an offset only to the current angle corner E _l. By performing such an operation, the observation of the vent portion where setting the normal viewpoint position is troublesome can be easily performed without fail, and damage to the piping can be quickly found.

[0012]

According to the present invention, when performing a visual inspection or the like by remote control using a manipulator, the target point of interest can be easily located at the center of the camera image and observed from an arbitrary angle. . In addition, since the point of interest can be arbitrarily specified on the camera screen, there is no need for a geometric model in advance, and the distance from the point of interest is constant, so the camera is always in focus even when using a fixed-focus camera. Can be held.

As described above, according to the present invention, it is possible to obtain a camera viewpoint changing method which enables an optimum viewpoint position for an arbitrary point of interest, such as an appearance inspection, to be easily determined.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration and a principle of a camera viewpoint changing method according to the present invention.

FIG. 2 is a diagram showing a flow of processing in a camera viewpoint changing method.

FIG. 3 is a diagram illustrating a configuration in a case of performing a pipe inspection as an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera 2 Camera moving device 3 Camera image display device 4 Point-of-interest designation device 5 Camera viewpoint spherical surface 10 Camera A 11 Camera B 12 Manipulator 13 Moving carriage 14 Host computer 15 Joystick 16 Display 17 Mouse 20 Piping 21 Vent section

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G05D 3/12 G05D 3/12 K W H04N 5/232 H04N 5/232 Z // G02B 7/28 G05D 1/00 B G05D 1/00 G02B 7/11 H

Claims (1)

(57) [Claims] 1. A camera, a camera operation means for controlling a camera position, a camera image display means, and a gazing point designating means for designating a gazing point on an image. By specifying the same gazing point existing in the field of view by the gazing point designating means, the relative position between the specified gazing point and the camera is measured, and the gazing point is set at the center, and a predetermined distance is specified. On a spherical surface having a radius, move the camera to a position at which a currently known camera position intersects a straight line connecting the designated point of interest and a posture position at which the line of sight of the camera coincides with the direction of the designated point of interest. The camera position changing operation is performed in a spherical coordinate system whose origin is the gazing point.