JPH11194422A - Camera stabilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the sense of incongruity by discontinuity of an image caused at the control switching point of a boundary between an image rotation compensation range and a significant point avoiding range. SOLUTION: Within the image rotation compensation range, a control angle in an RL axis direction given to a gimbal is set to be ϕRL(t)=-θRL(t). Provided that θRL is the angle of a camera in the RL axis direction detected by a horizontal reference gyro. Within the significant point avoiding range where the angle θEL of the camera in an EL axis direction is -90 deg. or near it, the control angle in the RL axis direction is set to be ϕRL(t)=-LMRL(t). Provided that JMRC is the present rotating angle of the gimbal in the RL axis direction detected by a potentiometer incorporated in the gimbal. Besides, a control eclectic range where the control angle ϕRL in the RL axis direction is set to be ϕRL=-a×ϕRL (t)-b×JMRL(t) by using weight coefficients (a) and (b)(a+b=1) is set between the image rotation compensation range and the significant point evading range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera stabilizer, and more particularly to a technique for avoiding singularities in image rotation compensation.

[0002]

2. Description of the Related Art As shown in FIG. 3, a camera stabilizer mounted on a helicopter or the like has an AZ axis (azimat) corresponding to a vertical axis, a roll axis and a pitch axis of an aircraft.
h axis), RL axis (roll axis), and EL axis (eleva)
(tion axis). The functions of the camera stabilizer 1 realized by controlling the three axes include a function of stabilizing the space of the camera, that is, a function of maintaining the camera in the direction in which the camera is directed (a function of maintaining the camera in a tilted state). And the ability to compensate for image rotation so that the image maintains the earth's level.

In order to realize the latter function, as shown in FIG. 4, the camera stabilizer 1 includes a vertical gyro (horizontal reference gyro) having three gyros in each axial direction and three accelerometers. Attached to a gimbal mechanism (simply called a gimbal) 4 together with the camera 3. Camera 3 detected by vertical gyro 2 (gimbal 4)
RL axis direction angle (also referred to as roll angle) θ _RL (t) (t is time) is input to the servo amplifier 5. Servo amplifier 5 sets gimbal 4 to -θ _RL (t)
Only in the direction of the RL axis. At this time, -θ _RL (t)
Is called an RL axis direction control angle, and is represented by _φRL . That is, φ _RL = −θ _RL (t) (1) Thus, the RL axis direction angle (roll angle) θ _RL (t) of the camera 3 (gimbal 4) becomes zero, that is, horizontal The motor 4a of the gimbal 4 is controlled so that

The vertical gyro 2 is shared with a gyro for stabilizing the space of the camera 3. Since the camera stabilizer 1 is fixed to the helicopter 6, for example, as shown in FIG. 6A, if the image rotation compensation function is turned off, the image 7 of the camera 3 will be moved (tilted) by the helicopter 6 as shown in FIG. 6B. Follow. However, when the image rotation compensation function is turned on, the servo amplifier 5 controls the gimbal 4 so that the roll angle θ _RL (t) detected by the vertical gyro 2 is always zero as described above.
By giving a rotation in the L-axis direction, the image (camera) can be kept horizontal.

Next, a process of changing the direction of the camera 3 from a horizontal direction to a downward direction as shown in FIG. 5 with the image rotation compensation function turned on will be considered. That is, this is a case where a downward rotation is given in the EL axis direction. When the camera 3 approaches right below, the horizontal of the image cannot be defined. This is exactly the same as losing the level when you look directly below (the ground) with an ordinary camera. Thus, θ _EL =
The point at −90 ° is called a singular point. At a singular point, the image rotation compensation function cannot operate normally, and the image
The screen turns so close to seeing.

[0006] Therefore, the conventional camera stabilizer 1
In FIG. 5, the servo amplifier 5 detects the angle θ in the EL axis direction.
_ELBut −60 °> θ_EL> -120 ° when the image
(Hence the camera) against the gimbal to keep it level
Stop the rotation drive in the RL axis direction and use the potentiometer attached to the gimbal.
The current rotation angle J of the gimbal in the RL axis direction from the shometer
M _RL(T) is detected and JM_RLReverse the gimbal by (t)
Turn over (-JM at this time_RL(T) is also in the RL axis direction
Control angle), detected by the gimbal potentiometer
The rotation angle in the RL axis direction is maintained at 0 °. That is, φ_RL= -JM_RL(T) (2) Therefore, the EL axis direction angle θ_ELIs θ_EL≧ −60 ° to θ_EL
<60 °, the image held the horizontal of FIG. 7A
From the image, the same inclination as that of the helicopter as shown in Fig. 7B
It will suddenly change to the image you have.

In the conventional example, the angle θ in the EL axis direction shown in FIG.
_EL is; 30 ° ≧ θ _EL ≧ −60 ° and; −180 ° ≦
θ _EL ≦ −120 ° is the image rotation compensation range;
0 ° <θ _EL <−120 ° is called a singularity avoidance range.

[0008]

As described above, the conventional camera stabilizer has an EL axis direction angle θ _EL of −60 °.
When the angle becomes smaller or becomes larger than -120 °, the image suddenly changes from an image in a horizontal state to an image tilted by the same angle as that of the helicopter. Especially when the tilt (roll angle) of the helicopter is large, control is performed. Switching point (θ
_(EL = −60 ° or −120 °), the discontinuity of the image becomes large, and a person looking at the image unfavorably feels strange. SUMMARY OF THE INVENTION It is an object of the present invention to improve control in a servo amplifier so as to reduce a sense of discomfort due to discontinuity of an image at such a control switching point.

[0009]

According to the first aspect of the present invention, RL is set between the image rotation compensation range and the singularity avoidance range.
The axial control angle φ _{RL is set} to φ _RL = −a × θ _RL (t) −b × JM _RL (t) (3) using the weighting coefficients a and b (a + b = 1). A control compromise range is provided.

(2) According to the second aspect of the invention, (1)
The EL axis angle θ of the camera _ELIs α ≦ θ_EL≤β
(Α = 30 ° ± 20 °, β = −60 ° ± 20 °)
Rotation compensation range, θ_EL≒ -90 ° is the singularity avoidance range
And β <θ_EL<-90 ° is a control compromise range. (3) In the invention according to claim 3, in (2), the weight
The coefficient a is calculated as follows: a = (− 90−θ)_EL) / (− 90−β) (5)

[0011] (4) In the invention of claim 4, in claim (1), EL-axis angle theta _EL cameras alpha ≦ theta
_EL ≦ β (α = 30 ° ± 20 °, β = −60 ° ± 10 °)
Is the image rotation compensation range, and γ ≦ θ _EL ≦ δ (γ = −
A range of 80 ° ± 5 °, δ = −100 ° ± 5 °) is defined as a singularity avoidance range, and a range of β <θ _EL <γ is defined as a control compromise range.

(5) In the invention of claim 5, in the above (4), the weighting factor a is set to a = (γ−θ _EL ) / (γ−β) (11) (6) In the invention according to claim 6, in the above (4), the EL
Axial angle theta _{EL is, ε ≧ θ EL ≧ -180 °} (ε = -12
0 ° ± 10 °) as a second image rotation compensation range,
The range of δ <θ _EL <ε is defined as the second control compromise range.

(7) In the invention of claim 7, in the above (6), the weighting coefficient a in the second control compromise range is a = (δ−θ _EL ) / (δ−ε) (14) Set to.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) In the prior art, the vertical gyro 2 detects the angle in the EL axis direction;
When 30 ° ≧ θ _EL ≧ −60 °, the RL axis direction control angle φ _RL of the servo amplifier 5 with respect to the gimbal 4 was φ _RL = −θ _RL (t) (1). Θ _RL (t) in equation (1) is the RL axis direction angle detected by the vertical gyro. On the other hand; -60 °
When <θ _EL <−120 °, the control angle in the RL axis direction was φ _RL = −JM _RL (t) (2). JM _RL (t) in equation (2) is the current rotation angle of the gimbal in the RL axis direction detected by the gimbal potentiometer. Also; -180 ° ≦ θ _EL ≦ −120 °
Then, equation (1) was used as φ _RL .

In the first embodiment of the present invention: α ≧ θ _EL ≧ β
(Α = 30 ° ± 20 °, β = −60 ° ± 20 °)
The conventional equation (1) is used as the L-axis direction control angle φ _RL . For θ _EL ≒ −90 °, the conventional equation (2) is used as φ _RL . ; -180 ° ≦ _EL ≦ γ (γ = −120 ° ± 20 °)
Then, the conventional equation (1) is used again as φ _RL .

When β> θ _EL > −90 °, weights are added to equations (1) and (2), and the sum of the two is used. That is, φ _RL = −a1 × θ _RL (t) −b1 × JM _RL (t) (3) a1 and b1 are weighting coefficients, and a1 + b1 = 1 (b1 = 1−a1) (4) ). For example, a1 = (− 90−θ _EL ) / (− 90−β) (5) is used as a1. That is, if (−90−θ _EL ) occupies 90% of (−90−β), for example, (θ _EL is close to β and −90 °
_RL is 90% of -θ _RL (t) (a1 =
0.9) and 10% of -JM _RL (t) (b1 = 0.1)
And the sum of By doing so, the RL axis direction control angle φ _{RL at}に お け る is obtained as continuity with the expressions (1) and (2), and no abrupt image change occurs.

-90 °> θ _EL > γ (γ = 120 ° ±
20 °), φ _RL = −a2 × θ _RL (t) −b2 × JM _RL (t) (6) is used. Here, a2 and b2 are weighting coefficients, and a2 + b2 = 1 (b2 = 1-a2) (7) If, for example, a2 = (− 90−θ _EL ) / (− 90−γ) (8) is used, the continuity of φ _{RL with} the case of φ2 is maintained.

In the image rotation compensation range, a horizontal image is obtained as shown in FIG. 2A, and in the singular point rotation range, an image having the same inclination as that of the helicopter is obtained as shown in FIG. 2C. ,, An image having a horizontal line having an inclination between A and B is obtained. (Embodiment 2) In Embodiment 1, the singularity avoidance range is set to θ _EL ≒ -9.
Although limited to 0 °, in Example 2, γ <θ _EL <δ
(Γ = −80 ° ± 5 °, δ = −100 ° ± 5 °) is defined as a singularity avoidance range. Therefore, the control angle φ _RL in the RL axis direction is given by equation (2).

Α ≧ θ_EL≧ β (α = 30 ° ± 20 °;
β = −60 ° ± 10 °); and ε ≧ θ_EL≧ -180 °
(Ε = -120 ° ± 10 °) is the image rotation compensation range.
And φ _RLEquation (1) is used. Β> θ_EL> Γ
(Β = −60 ° ± 10 °, γ = −80 ° ± 5 °)
_RLCompromises the value of_RL= −a3 × φ_RL(T) -b3 × JM_RL(T) (9) a3 + b3 = 1 (b3 = 1−a3) (10) a3 = (γ−θ)_EL) / (Γ−β) (11)_RLAnd continuity with
You.

Δ ≦ θ _EL ≦ ε (δ = −100 °)
(± 5 °, ε = −120 ° ± 10 °), φ _RL is a compromise between the values of φ _RL = −a4 × θ _RL (t) −b4 × JM _RL (t) (12) a4 + b4 = 1 (b4 = 1−a4) (13) If a4 = (δ−θ _EL ) / (δ−ε) (14), φ _RL is continuity with Is obtained.

[0021]

As described above, according to the present invention,
Between the image rotation compensation range and the singularity avoidance range, and the control compromise range of setting the RL axis direction control angle φ _RL to a value that compromises between and and maintaining continuity. Because the control compromise range of setting the compromise between the values of
At the control switching point (β, −90 °, γ in FIG. 1A and β, γ, δ, ε in FIG. 1B) of the control switching point of the EL axis direction angle θ _EL of the camera, there is no sharp change of the image as in the related art. Therefore, there is no sense of incongruity due to discontinuity of images.

[Brief description of the drawings]

FIG. 1 is a diagram showing an image rotation compensation range, a singularity avoidance range, and a control compromise range in a camera stabilizer of the present invention.

FIG. 2 is a diagram showing the inclination of a horizontal line of an image in each range of FIG. 1;

FIGS. 3A, 3B, and 3C are a plan view, a front view, and a right side view, respectively, showing the appearance of a camera stabilizer;

FIG. 4 is a block diagram for explaining an image rotation compensation function of the camera stabilizer.

FIG. 5 is a diagram showing an image rotation compensation range and a singularity avoidance range in a conventional camera stabilizer.

6A is a front view showing a posture of a camera stabilizer mounted on a helicopter, and FIGS. 6B and 6C are diagrams showing an example of an image when an image rotation compensation function of the camera stabilizer is turned on or off, respectively.

FIGS. 7A and 7B are diagrams illustrating examples of images in a conventional camera stabilizer in an image rotation compensation range (θ _EL ≧ −60 °) and a singularity avoidance range (θ _EL <−60 °), respectively.

Claims (7)

[Claims] An AZ (azimuth) axis orthogonal to each other, R
A gimbal equipped with an L (roll) axis and an EL (elevation) axis, a camera and a horizontal reference gyro, and an EL axis angle of the camera detected by the horizontal reference gyro when the image rotation compensation function is turned on. θ _EL (t)
When (t is time) is within the image rotation compensation range, the RL axis direction control angle φ _RL given to the gimbal is changed to the RL axis direction angle θ of the camera detected by the horizontal reference gyro.
_{Using RL} (t), φ _RL (t) = − θ _RL (t) (1), whereby the gimbal mechanism is arranged so that the RL axis direction angle θ _RL (t) of the camera becomes zero. When the EL axis direction angle θ _EL (t) is within the singularity avoidance range (−90 ° or near), the RL axis direction control angle φ _RL is determined by a potentiometer built in the gimbal. The detected current rotation angle JM of the gimbal in the RL axis direction
_{Using RL} (t), φ _RL (t) = − JM _RL (t) (2) and setting the rotation angle of the gimbal in the RL axis direction detected by the potentiometer to zero. A servo amplifier comprising: a camera amplifier comprising:
The RL axis direction control angle φ _RL is _calculated by using weighting coefficients a and b (a + b
= 1), and a control compromise range is provided for setting φ _RL = −a × θ _RL (t) −b × JM _RL (t) (3). 2. The camera according to claim 1, wherein the angle θ _{EL in} the EL axis direction of the camera is α ≦ θ _EL ≦ β (α = 30 ° ± 20 °,
β = −60 ° ± 20 °) as the image rotation compensation range, θ _EL ≒ −90 ° as the singularity avoidance range, and β <
A camera stabilizer characterized in that θ _EL <−90 ° is the control compromise range. 3. The camera stabilizer according to claim 2, wherein the weighting factor a is set as follows: a = (− 90−θ _EL ) / (− 90−β) (5) 4. The method of claim 1, EL-axis angle theta _EL of the camera _{α ≦ θ EL ≦ β (α} = 30 ° ± 20 °, β
= −60 ° ± 10 °) as the image rotation compensation range, and γ ≦ θ _EL ≦ δ (γ = −80 ° ± 5 °, δ = −100).
± 5 °) as the singularity avoidance range, and β <θ _EL <
A camera stabilizer, wherein a range of γ is the control compromise range. 5. The camera stabilizer according to claim 4, wherein the weighting factor a is set as follows: a = (γ−θ _EL ) / (γ−β) (11) 6. The method of claim 4, wherein the EL-axis angle theta _{EL is, ε ≧ θ EL ≧ -180 °} (ε = -120 ° ± 10
°) is defined as a second image rotation compensation range, and δ <θ _EL <
A camera stabilizer, wherein a range of ε is set as a second control compromise range. 7. The method according to claim 6, wherein the weighting coefficient a in the second control compromise range is set to a = (δ−θ _EL ) / (δ−ε) (14). Camera stabilizer.