JPH07191363A - Camera stabilizer - Google Patents

Abstract

PURPOSE:To improve the directivity accuracy of a camera in the pitching direction without largely changing the weight and the size of a camera stabilizer. CONSTITUTION:Agyro 12 at least measuring a pitch angle and a roll angle is mounted on a 1st gimbal mechanism 10; the sensor part 16 of a camera is held in a 2nd gimbal mechanism 14 attached to be rotated only around a pitch axis Jtheta to the frame 12F of the gyro; and an angle sensor 18 detecting the rotational angle of the mechanism 14 around the pitch axis to the frame 12F of the gyro and an actuator 20 driving the mechanism 14 around the pitch axis are installed. While the mechanism 14 is confirmed by the angle sensor to the position of an angle having the same size as the pitch angle outputted from the gyro and in a reverse direction to the pitch angle, it is driven by the actuator 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera stabilizer for mounting a camera on a vehicle such as an airplane, a train or an automobile to take a strict photo of the ground surface. Therefore, it can be used for aerial photogrammetry etc. for map making.

[0002]

2. Description of the Related Art In aerial photogrammetry for map making, a camera and a gyro are placed on a gimbal mechanism, which is mounted on an aircraft to control the direction of the camera during flight, and to keep track of changes in the attitude of the aircraft. Instead, the camera takes a picture in a predetermined direction (horizontal) with respect to the ground surface. However, when shooting on a silver salt film, it is necessary to digitize the image by using a digitizer later, which is very troublesome.

Therefore, a method has been adopted in which a two-dimensional CCD array is used instead of film to digitize an image at the time of photographing. However, the two-dimensional CCD array is, for example, 700 ×
The thing of about 700 is used and the resolution is low. In recent years, high resolution is often required, and CCD
It is difficult to arrange the chips in a two-dimensional state at a high density so as to have a low cost and a high resolution.

Therefore, it is considered that a one-dimensional CCD array having a high-density array (for example, about 5000 to 10000) is used as a scanning camera sensor, and scanning is performed at intervals of, for example, about 1 millisecond to make one-dimensional scanning. Image one after another on the CCD line
A method of recording on a digital recorder is being used.

[0005]

However, due to the above-described rigidity and response speed of the gimbal mechanism, there is a limit in the pointing accuracy of the camera with respect to the object to be photographed.
It is about 0.1 degree, and is not oriented with an accuracy of 0.01 degree. Therefore, if each member of the gimbal mechanism is enlarged to improve rigidity and the drive motor is changed to one with large power, theoretically the pointing accuracy of the camera can be improved.
A camera stabilizer such as a gimbal mechanism is too heavy to obtain imaging data at a low cost with a small airplane such as a Cessna aircraft.

Therefore, it is necessary to construct the camera stabilizer with the same weight as the conventional gimbal mechanism and motor. Under these conditions, for example, in order to obtain data with the same degree of accuracy as the mapping obtained by imaging with the above-described pointing accuracy of 0.01 degrees, the rolling, yawing, and pitching conditions of the camera on the gimbal mechanism due to flight fluctuations of the airplane should be set. The measurement is performed by a gyro, which improves the accuracy of the imaging data by correcting the error of the one-dimensional imaging data group caused by the pointing accuracy (about 1 to 0.1 degrees above) of the camera stabilizer by the gimbal mechanism or the gyro. (However, as described later, the amount of pitching cannot be corrected).

Referring to FIG. 2, as shown in FIG. 2A, an error (imaging disorder) caused by rolling causes each one-dimensional image data to move in a direction orthogonal to the flight direction F of the airplane corresponding to the rolling angle. (This result is shown in (a ')), and the turbulence due to yawing shown in (b) shows each one-dimensional imaging data in the flight direction F.
It is possible to correct the imaging data at the time of yawing by rotating the imaging data according to the yawing angle (the result is shown in (b ′)). However, in the turbulence due to the pitching shown in (c), each imaged data largely deviates from the one-dimensional shape (linear shape), and correction is generally difficult.

Therefore, an object of the present invention is to improve the pointing accuracy of the camera in the pitching direction without significantly changing the weight and size of the camera stabilizer.

[0009]

In view of the above object, the present invention has a gyro for measuring at least a pitch angle and a roll angle mounted on a first gimbal mechanism, and only a gyro is arranged around a pitch axis with respect to a frame of the gyro. An angle sensor that holds a sensor unit of a camera on a rotatably mounted second gimbal mechanism and detects a rotation angle of the second gimbal mechanism around a pitch axis with respect to the gyro frame, and the second gimbal mechanism. An actuator for driving the gyro around a pitch axis, and the actuator while checking the second gimbal mechanism by the angle sensor up to an angular position having a direction opposite to the pitch angle output by the gyro and having the same size. A camera stabilizer characterized by being driven by.

[0010]

The directivity angle of the camera with respect to the object to be imaged changes due to the change in the traveling state of the vehicle. By using the pitch angle and roll angle measured by the gyro mounted on the first gimbal mechanism (in some cases, the yaw angle is also measured and this is also used), the camera can be operated via the first gimbal mechanism. Point at the subject. However, as described above, this pointing accuracy is only a predetermined accuracy due to the rigidity of the gimbal mechanism.

Among these, the image data of the imaging data due to the limitation of the pointing accuracy of the camera caused by rolling (and yawing) excluding pitching can be improved in accuracy by correction using the measured value of the gyro. Since the pointing accuracy of the first gimbal mechanism due to the remaining pitching cannot be expected to improve the accuracy of the imaging data due to the correction, the pointing accuracy is improved by the second gimbal mechanism attached to the gyro frame. That is, the second gimbal mechanism is attached so as to be rotatable only around the pitch axis, and except for a heavy part such as the electronics of the camera, the second gimbal mechanism has a sensor part, that is, a lens and a one-dimensional CCD.
Only the scanning sensor part such as a row is mounted,
It is extremely lightweight, and the weight and size of the second gimbal mechanism can be light.

There is a limit to the pointing accuracy of the first gimbal mechanism, and this pointing error in the pitching direction is accurately captured by the gyro, and the rotation angle of the second gimbal mechanism with respect to the frame of the gyro about the pitch axis is determined. Only the angle of the same magnitude as the direction opposite to the pitch angle which is the pitching direction pointing error obtained by the output of the gyro by the actuator that drives the second gimbal mechanism around the pitch axis while confirming with the angle sensor that can be detected The second gimbal mechanism is driven by the actuator. This improves the pointing accuracy in the pitching direction of the sensor unit of the camera held by the second gimbal mechanism.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail based on the embodiments shown in the accompanying drawings. FIG. 1 shows a block diagram of a camera stabilizer according to the present invention. Reference numeral 10 denotes a conventional gimbal mechanism. Based on the output value of the gyro 12 mounted here, the controller C1 drives and controls the gimbal mechanism 10 to set the pointing direction of the camera to a predetermined direction.

The gimbal mechanism 10 is referred to as a first gimbal mechanism 10 in relation to a second gimbal mechanism 14 which will be described later. A sensor portion of the gyro is shown as a gyro 12, and a box body holding the sensor portion 12 and a frame portion integrated with the box body are schematically shown as a gyro frame 12F. The second gimbal mechanism 14 attached to the gyro frame 12F is configured to be rotationally movable around the pitch axis Jθ when driven by a driving force of an actuator 20 described later.

The second gimbal mechanism 14 is preferably supported by a torsion spring so as to be rotatable about the pitch axis Jθ. The reason for this will be described later. Only the sensor portion 16 of the camera is held by the second gimbal mechanism, which is extremely lightweight. Therefore, the servo control by the control unit C2, which will be described later, can be driven with substantially no delay.

The sensor unit 16 of the camera is a scanning type sensor unit such as a lens and a one-dimensional CCD array, excluding weight bodies such as a control unit of the camera. Therefore, it is very lightweight. Further, the remaining control parts and the like may be mounted on the first gimbal mechanism 10 as they are, as in the conventional case, but may be mounted on the vehicle itself such as a photographing airplane on the ground surface for map making.

The second gimbal mechanism 14 is a gyro 12
It is driven by the first gimbal mechanism 10 integrally with the first gimbal mechanism 1, but as described above, the first gimbal mechanism 1 by the control unit C1 is used.
Since the pointing accuracy at 0 has a certain limit, if the pointing error in the pitching direction is + Δθ, the second gimbal mechanism 14 is also pointing in the pointing error direction around the pitch axis Jθ, and the camera sensor 16 Has a pointing error of + Δθ in the pitching direction angle. In order to correct this and improve the pointing accuracy of the camera sensor 16, another controller C2, the angle sensor 18 and the actuator 20 are provided.

The angle sensor 18 and the actuator 20 are mounted on the first gimbal mechanism 10 and are provided close to the second gimbal mechanism 14. As described above, the pointing error in the pitching direction angle is about 1 to 0.1 degree, and when the second gimbal mechanism 14 is corrected and rotationally driven, the amount of movement also affects the mounting position of the angle sensor 18. However, the movement is generally within about 1 mm. Therefore, a gap sensor is used as the angle sensor 18.
The use of two gap sensors 18 as in this embodiment is for improving accuracy and is not an essential item. An electromagnet or the like can be used as the actuator 20.

The origin of the gap sensor 18, which indicates the pitching direction angle of the second gimbal mechanism 14, is matched with the reference of the pitch direction of the gyro 12, and the pitch direction of the first gimbal mechanism 10 is equal to the pitch angle + Δθ shown by the gyro 12. Since there is a pointing error, in order to correct this, the second gimbal mechanism 14 may be driven around the pitch axis Jθ to the angular position of −Δθ. Therefore, while monitoring the output of the gap sensor 18 by the control unit C2,
Pitch angle + Δθ obtained from the output value of the gyro 12
In the opposite direction, and up to the same angular position -Δθ,
The actuator 20 is used to rotate the second gimbal mechanism 14 about the pitch axis Jθ.

In order to make the rotation around the pitch axis smooth, it is preferable that the second gimbal mechanism 14 be supported by a torsion spring or the like. This is because a simple bearing cannot be accurately driven when it is rotationally driven by the actuator 20 due to the presence of friction and a gap.

In this way, the presence of the second gimbal mechanism 14 significantly improves the pointing accuracy in the pitching direction with respect to the object to be photographed only by the sensor portion 16 of the camera without changing the weight and size of the conventional camera stabilizer.

The first gimbal mechanism 10 can also be replaced by a vehicle such as an airplane. That is, when the vehicle itself has a stabilizer for correcting rolling and pitching using a gyro, this vehicle corresponds to the first gimbal mechanism.

Even a gyro in a narrow sense for measuring an angular velocity is considered as a gyro in a broad sense in which an integrator is attached to the gyro, and this is integrated to output an angle, which is referred to as a gyro in this specification.

[0024]

As is apparent from the above description, according to the present invention, the gyro frame mounted on the first gimbal mechanism with respect to the directional control of the camera with a certain accuracy by the first gimbal mechanism. The second gimbal mechanism is small and lightweight because it only holds the lightweight sensor part of the camera on the second gimbal mechanism which is attached to the second gimbal mechanism which is attached to the second gimbal mechanism so as to be rotatable only around the pitch axis. When the two-gimbal mechanism is monitored by the angle sensor and rotated by the actuator in accordance with the gyro output value, the pointing accuracy of the camera sensor unit in the pitching direction is improved.

Even if the directional accuracy of other rolling or yawing is inferior to that of the pitching direction, the image data can be easily corrected by the post-processing according to the output value of the gyro, which causes the influence of the rolling or yawing. The accuracy of the imaging data is improved, and the pointing accuracy in the pitching direction is considerably high, and the accuracy of the imaging data is improved. In this case, since the second gimbal mechanism is lightweight, the weight of the camera stabilizer as a whole is almost the same as that of the conventional camera stabilizer, and is easy to use.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a camera stabilizer according to the present invention.

FIG. 2 is an explanatory diagram of correction of an influence of rolling, yawing, and pitching of one-dimensional data captured by a scanning sensor.

[Explanation of symbols]

 10 First Gimbal Mechanism 12 Gyro 12F Gyro Frame 14 Second Gimbal Mechanism 16 Camera Sensor 18 Angle Sensor 20 Actuator Jθ Pitch Axis

Claims (1)

[Claims] 1. A gyro for measuring at least a pitch angle and a roll angle is mounted on a first gimbal mechanism, and a camera is mounted on a second gimbal mechanism rotatably attached to a frame of the gyro only around a pitch axis. An angle sensor that holds the sensor part of the second gimbal mechanism and detects a rotation angle of the second gimbal mechanism around the pitch axis with respect to the gyro frame.
An actuator for driving the second gimbal mechanism around a pitch axis, wherein the second gimbal mechanism is driven by the angle sensor up to an angular position of the same magnitude in a direction opposite to the pitch angle output by the gyro. A camera stabilizer driven by the actuator while checking.