JP3671972B2 - Video camera equipment - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a video camera apparatus using an image sensor, and more particularly to a video camera apparatus having an electronic camera shake correction function.
[0002]
[Prior art]
In recent years, with the widespread use of video camera devices, development for reducing the size and weight of the devices has been progressing. However, as miniaturization progresses, camera shake tends to occur during shooting, and when a shot image is played back, image shake due to camera shake has become conspicuous.
[0003]
Therefore, various camera shake correction means for video camera devices have been proposed. One of them is, for example, IEEE Trans. on CE, Vol. 35, no. 4, Nov. M. in 1989. Oshima, et. al. As described in a paper entitled “VHS CAMCORDER with ELECTRONIC IMAGE STABILIZer” by the company, a method using an angular velocity sensor is known. In this method, a camera shake detection circuit is provided in a video camera device, and an image sensor and an optical lens are moved by an amount capable of canceling camera shake based on a detection result of the detection circuit. That is, two angular velocity sensors are used as means for detecting vertical and horizontal movement amounts due to camera shake. One angular velocity sensor detects the vertical movement amount due to camera shake, and the other angular velocity sensor uses the same horizontal direction. The image sensor and the optical lens are moved so that the movement of the image due to camera shake is canceled out according to each detection result.
[0004]
[Problems to be solved by the invention]
However, the above prior art has the following problems.
That is, in FIG. 4A, A is a detection axis of the angular velocity sensor, V and H are vertical and horizontal components of movement caused by camera shake, and the angle of the vertical component V of movement with respect to the detection axis A is θ, If the angle of the horizontal component H of the motion with respect to the detection axis A is δ, the detection sensitivity of the angular velocity sensor changes according to the angles θ and δ as shown in FIG. Therefore, for example, if an angular velocity sensor attached to detect a vertical motion component is inclined in the horizontal direction due to an attachment error, it has detection sensitivity also in the horizontal direction, and camera shake occurs only in the horizontal direction. Even if it occurs, motion is detected. At this time, although there is no camera shake in the vertical direction, a false detection that there is camera shake in the vertical direction is performed, and an erroneous camera shake correction is performed, and the image on the screen shakes in the vertical direction. It will be.
[0005]
Even when the angular velocity sensor is mounted at a position where the output gain is lowered, it is not possible to accurately detect the amount of vertical and horizontal movement components due to camera shake.
[0006]
An object of the present invention is to provide a video camera device that can eliminate such a problem and can accurately remove the shaking of an image with respect to a camera shake in an arbitrary direction.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a plurality of shake detectors for detecting shakes in different directions of an image sensor, and a horizontal direction of an image from shake detection signals output from the shake detectors. A shake calculation circuit for calculating vertical shake, and a time for converting the horizontal or vertical time axis of the output video signal of the image sensor in accordance with the horizontal or vertical shake calculated by the shake calculation circuit An axis conversion circuit.
[0008]
[Action]
The detection outputs of the plurality of shake detectors are vector-calculated by a shake calculation circuit to generate shake detection signals representing true vertical and horizontal shake components. The time axis conversion circuit converts the time axis of the output video signal of the image sensor in accordance with these shake detection signals and corrects the shake of the image due to hand shake. The direction of the detection axis of the shake detector is attached to the time axis conversion circuit. Even if the error is deviated from the true vertical and horizontal directions, the influence of the mounting error is canceled out by the vector calculation in the shake calculation circuit, and the shake detection signal not affected by the mounting error is obtained. Therefore, even if there is an attachment error in the shake detector, it is not affected by this, and the shake of the image due to the shake can be corrected accurately.
[0009]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing an embodiment of a video camera apparatus according to the present invention, where 1 is an optical lens, 2 is an image sensor, 3 is a time axis conversion circuit, 4 is a vertical shake detector, and 5 is a horizontal direction. A shake detector 6 is a shake calculation circuit.
[0010]
In the figure, light from a subject (not shown) passes through the optical lens 1 and is incident on the light receiving surface of the image sensor 2, thereby forming a subject image on the light receiving surface. The image sensor 2 captures the subject image and outputs an electrical signal corresponding to the subject image. This electric signal is supplied to a signal processing circuit (not shown) through the time axis conversion circuit 3 and becomes a video signal.
[0011]
On the other hand, a vertical shake detector 4 and a horizontal shake detector 5 are provided, and when a shake due to a hand shake occurs during photographing, the vertical shake detector 4 responds to the vertical component of the shake. A detection signal Mv is output, and a detection signal Mh corresponding to the horizontal component of the fluctuation is output from the horizontal fluctuation detector 5. The detection signals output from the vertical direction shake detector 2 and the vector are calculated by the shake calculation circuit 6 to generate a vertical direction shake detection signal MV and a horizontal direction shake detection signal MH. Thus, when these shake detection signals MV and MH are obtained by vector calculation, even if the vertical shake detector 4 and the horizontal shake detector 5 are mounted at positions shifted due to mounting errors, these shake detection signals MV. , MH accurately represents the amount of shaking in the vertical and horizontal directions, respectively.
[0012]
These fluctuation detection signals MV and MH are supplied to the time axis conversion circuit 3. The time axis conversion circuit 3 converts the vertical and horizontal time axes of the electric signal from the image pickup device 2 so as to cancel the shake of the image due to the hand shake by using the shake detection signals MV and MH.
[0013]
FIG. 2 is a block diagram showing a specific example of the fluctuation calculation circuit 6 in FIG. 1, wherein 7 is a coefficient generator, 8 to 11 are multipliers, and 12 and 13 are adders.
In the figure, a detection signal Mv output from the vertical direction fluctuation detector 4 is supplied to multipliers 8 and 9, and a detection signal Mh output from the horizontal direction fluctuation detector 5 is supplied to multipliers 10 and 11. . The multiplier 8 multiplies the detection signal Mv by the coefficient α1 from the coefficient generator 7, and the multiplier 9 multiplies the detection signal Mv by the coefficient α3 from the coefficient generator 7. The multiplier 10 multiplies the detection signal Mh by the coefficient α2 from the coefficient generator 7, and the multiplier 11 multiplies the detection signal Mh by the coefficient α4 from the coefficient generator 7.
[0014]
Here, the coefficient α1 output from the coefficient generator 7 is equal to the horizontal direction even if the vertical direction fluctuation detector 4 (FIG. 1) is inclined in the horizontal direction due to the mounting error, so that the vertical direction fluctuation is generated. This is a coefficient for correcting the detection as if the shaking occurred. The coefficient α2 output from the coefficient generator 7 indicates that the horizontal shake detector 5 (FIG. 1) is tilted in the vertical direction due to the mounting error, so that even if the horizontal shake is generated, the vertical shake is generated. This is a coefficient for correcting the detection.
[0015]
The coefficients α3 and α4 output from the coefficient generator 7 are used to correct the shake detectors 4 and 5 when they are mounted at positions where these gains are lowered due to the mounting error. It is a coefficient.
[0016]
The outputs of the multipliers 8 and 11 are added by the adder 12, and the outputs of the multipliers 9 and 10 are added by the adder 13. The output of the adder 12 is the vertical shake detection signal MV, and the output of the adder 13 is the horizontal shake detection signal MH. Therefore, these fluctuation detection signals MV and MH are obtained by a vector calculation represented by the following equation.
MH = α1 · Mv + α4 · Mh (1)
MV = α3 · Mv + α2 · Mh (2)
Based on the vertical fluctuation detection signal MV and the horizontal fluctuation detection signal MH thus obtained, the time axis conversion circuit 3 in FIG. 1 converts the vertical and horizontal time axes of the electrical signal from the image sensor 2. , Cancel the shaking of the image due to hand shaking.
[0017]
FIG. 3 is an explanatory diagram showing that the mounting error of the shake detectors 4 and 5 is removed by the vector calculation.
In the figure, the actual vertical direction is V, the actual horizontal direction is H, the detection axis of the vertical direction shake detector 4 is AV, and the detection axis of the horizontal direction shake detector 5 is AH. Further, it is assumed that the detection axes AV and AH are deviated from the vertical direction and the horizontal direction, respectively, due to mounting errors of the vertical direction shake detector 4 and the horizontal direction shake detector 5. Assuming that a shake M occurs in an arbitrary direction in such a state, the vertical shake detector 4 detects a component Mv of the shake M in the direction of the detection axis AV, and the horizontal shake detector 5 detects this shake M. The component Mh in the direction of the detection axis AH is detected. However, since these detection axes AV and AH do not coincide with the vertical direction V and the horizontal direction H, respectively, the component Mv is not the component MV of the swing M in the vertical direction V, and the component Mh is the horizontal direction H of the swing M. Is not the component MH.
[0018]
By the way, assuming these vectors, taking the vibration M, the component Mv, the component Mh, the component MV in the vertical direction V of the vibration M, and the component MH in the horizontal direction H into the absolute value, and taking those directions into account, the calculation of these vectors A component MV in the vertical direction V of M and a component MH in the horizontal direction H can be obtained.
[0019]
That is, when the vibration M and the vector of these components are represented by adding a dash to these codes, as is apparent from FIG. 3, between the vector M ′ and the vector of each component,
M ′ = Mv ′ + Mh ′ = MV ′ + MH ′
The following relational expression can be established. For this purpose, the above formulas (1) and (2) need to be satisfied simultaneously, and the coefficient generator 7 in FIG. 2 is perpendicular to the detection axis AV of the vertical shake detector 4 so that these are satisfied simultaneously. Coefficients α1, α2, α3, α4 corresponding to the amount of deviation from the direction V and the amount of deviation of the detection axis AH of the horizontal shake detector 5 from the horizontal direction H are generated.
[0020]
The coefficients α1, α2, α3, and α4 are obtained from the amount of deviation of the detection axis AV of the vertical shake detector 4 from the vertical direction V and the amount of deviation of the detection axis AH of the horizontal shake detector 5 from the horizontal direction H. However, it can also be obtained by the following method.
Suppose that MV shake is given only in the vertical direction V, and that the detection output of the vertical shake detector 4 at this time is Mvv and the detection output of the horizontal shake detector 5 is Mhv, MH = 0. From the above formulas (1) and (2),
MV = α3 · Mvv + α2 · Mhv (3)
0 = α1 · Mvv + α4 · Mhv (4)
If the MH shake is given only in the horizontal direction V, the detection output of the vertical shake detector 4 at this time is Mvh, and the detection output of the horizontal shake detector 5 is Mhh. Since = 0, according to the above formulas (1) and (2),
0 = α3 · Mvh + α2 · Mhh (5)
MH = α1 · Mvh + α4 · Mhh (6)
Is established. Accordingly, the coefficients α2 and α3 can be obtained from the equations (3) and (5), and the coefficients α1 and α4 can be obtained from the equations (4) and (6).
[0021]
As described above, even when the shake detector is attached with an inclination due to an attachment error, accurate camera shake correction can be performed using the detection output of the shake detector by using the vector calculation.
[0022]
【The invention's effect】
As described above, according to the present invention, even if there is an attachment error in the shake detector by calculating the vector of the shake detection signals output from the plurality of shake detectors, the attachment error is not affected. A shake correction signal can be obtained, and camera shake can be accurately corrected.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a video camera device according to the present invention.
FIG. 2 is a block diagram showing a specific example of a shake calculation circuit in FIG. 1;
FIG. 3 is an explanatory diagram showing vector calculation of the shake calculation circuit shown in FIG. 1;
FIG. 4 is a diagram showing a change in detection sensitivity due to an attachment error of the angular velocity sensor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Optical lens 2 Image pick-up element 3 Time-axis conversion circuit 4 Vertical direction shake detector 5 Horizontal direction shake detector 6 Shake calculation circuit 7 Coefficient generators 8-11 Multipliers 12, 13 Adder

Claims (4)

An image sensor that converts an image formed by the optical lens into an electrical signal;
A plurality of shake detectors for detecting the shake of the image sensor;
A shake calculation circuit that calculates at least one of a horizontal shake amount and a vertical shake amount of the image sensor using detection signals output from the plurality of shake detectors;
A conversion circuit that corrects at least one of a horizontal direction and a vertical direction of an electric signal output from the imaging device in accordance with the amount of shaking in the horizontal direction or the amount of shaking in the vertical direction;
With
Each of the plurality of shake detectors has a detection axis in a different direction, detects and outputs a component of the shake of the image sensor in the detection axis direction,
The shake calculation circuit performs a vector operation on detection signals from the plurality of shake detectors to calculate the horizontal shake amount or the vertical shake amount.
A video camera device. In claim 1,
A video camera device comprising: a coefficient generator that supplies a predetermined coefficient used for vector calculation in the shake calculation circuit to the shake calculation circuit. In claim 1,
The plurality of shake detectors is two,
When the detection signals of the two shake detectors are Mh, Mv, image sensor shake M, the horizontal shake amount MH, and the vertical shake amount MV (however, both are vectors),
M = Mh + Mv = MH + MV
A video camera device characterized in that In claim 3,
A video camera device comprising: a coefficient generator for supplying a coefficient used for vector calculation in the shake calculation circuit to establish the equation to the shake calculation circuit.

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