JP3298211B2 - Video camera and video playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera and a video reproducing apparatus having a camera shake correction function.

[0002]

2. Description of the Related Art In recent years, as video cameras have become smaller and lighter, the problem of camera shake has become more likely to occur. Therefore, a video camera having a camera shake correction function has appeared.

As such a camera shake correction method for a video camera, there is known a method in which a camera shake is detected by an angular velocity sensor and a cutout position of an image memory is shifted in accordance with an output of the angular velocity sensor. I have.

In such a camera shake correction method for a video camera, the output of the angular velocity sensor is integrated by a low-pass filter, the angular velocity is converted into an angle, and the correction amount is obtained. The screen is shifted based on this correction amount.
A limiter for setting a correction limit value of the output of the low-pass filter is provided so that the correction amount does not exceed the limit value.

[0005]

However, if such a camera shake correction function is added, there has conventionally been a problem that an image pickup screen becomes unnatural during panning shooting. In other words, at the time of panning shooting, the camera is rapidly moved at the start of panning, so that the integral value of the angular velocity sensor rapidly increases and suddenly exceeds the correction limit. For this reason, the shooting screen becomes unnatural.

That is, when panning photography is performed, a detection signal as shown in FIG. 10A is output from the angular velocity sensor. This detection signal is integrated by a low-pass filter.
This integrated value, as shown in FIG. 10B, at time t ₁₁ reaches the correction limit LMT. Conventionally, as shown in FIG. 10C, from the point P11 at the time t ₁₁ to reach the correction limit LMT,
The integral value is suddenly limited.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a video camera and a video reproducing apparatus capable of preventing an unnatural screen movement during panning shooting.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a shake detecting means for detecting a shake amount of a video camera and a shake detecting means are provided.
A filter means for obtaining a correction amount of shake of the video camera by integrating the amount of detected shake, versus the output of the filter means
And the characteristics change according to the panning speed.
And output of the filter means via the limiter means.
Correction means for performing camera shake correction based on
It is a video camera. This invention is a video camera
Shaking detecting means for detecting the shaking amount, and detecting by shaking detecting means
The amount of shaking corrected by integrating the amount of shaking
Filter means for calculating
Limiter means whose characteristics are changed according to the zoom ratio
And the output of the filter means via the limiter means.
And a correction means for performing camera shake correction.
It is a video camera. The present invention provides a screen for input video signals.
Detection means for detecting the amount of vibration of the
Integrates the shake amount issued to determine the amount of screen shake correction
The filter means and the output of the filter means
Limiter means whose characteristics change according to the speed of the
Based on the output of the filter means via the
A video playback device having a correction means for performing shake correction.
It is a raw device. The present invention provides a method for shaking the screen of an input video signal.
The swing detection means for detecting the amount of
To obtain the amount of correction for shaking on the square screen by integrating the shaking
To the zoom ratio for the output of the filter
Limiter means whose characteristics are changed in response to the change, and limiter means
Image stabilization based on the output of the filter means passed through
And a correcting means for performing the correction.
You.

[0009]

In the present invention, the shaking of the video camera is detected and the control amount is obtained by integrating the detected shaking. By using a non-linear limiter as the limiter for setting the control limit value, it is possible to prevent the correction limit from suddenly reaching the correction limit during panning, and to make the screen during panning natural.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of a video camera to which the present invention is applied. In FIG. 1, subject image light having passed through a lens group 1 is imaged on a light receiving surface of a CCD image sensor 3 via an iris 2. Although this video camera performs recording by the NTSC system, the number of lines of the CCD image pickup device 3 is not equivalent to the number of lines of the NTSC system but is set to the number of lines of the PAL system in order to perform camera shake correction. The equivalent is used.

The CCD image pickup device 3 is driven by a driver 4 based on a timing signal from a timing generation circuit 5. The synchronization signal is supplied from the synchronization signal generation circuit 6 to the timing generation circuit 5. Further, the output of the camera shake correction controller 20 is supplied to the timing generation circuit 5. The CCD image pickup device 3 is supplied with a high-speed transfer clock within a vertical blanking period according to the vertical swing of the camera.

The output of the CCD image pickup device 3 is supplied to an A / D converter 9 via a sample hold circuit 7 and an AGC circuit 8.
Supplied to The image signal is digitized by the A / D converter 9. The output of the A / D converter 9 is supplied to a signal processing circuit 10 and also to an optical detector 11.

The signal processing circuit 10 performs necessary camera signal processing to convert the image signal from the CCD image sensor 3 into an NT signal.
A luminance signal and a chroma signal corresponding to the SC system are formed. The output of the signal processing circuit 10 is
Supplied to

The optical detector 11 is for obtaining information necessary for optical control such as exposure control, focus control, and white balance control. A window is set by the optical detector 11, and the light amount level in this window is detected. This light amount level is supplied to the camera controller 13.

The camera controller 13 controls the gain of the AGC circuit 8 and the opening of the iris 2 according to the light amount level. Thus, automatic exposure control is performed. Further, a window is set in the optical detector 11, and the edge component level of the image pickup signal in this window is detected. This edge component level is supplied to the camera controller 13. The camera controller 13 controls the position of the focus lens in the lens group 1 so that the edge component is maximized. Thereby, automatic focus adjustment is performed.

The position of the window of the optical detector 11 can be moved in the horizontal direction by a window generating circuit 12. The position of this window is changed according to the camera shake correction amount.

The image memory 14 is provided for performing an electronic zoom, and is used for performing a camera shake correction with large vibration. The output of the image memory 14 is supplied to an electronic magnifying circuit 15. The electronic magnifying circuit 15 corrects camera shake in the horizontal direction of the camera by shifting the reading position of one line. Also, the electronic magnifying circuit 15 corrects vertical camera shake of one line or less.

The output of the electronic magnifying circuit 15 is supplied to a D / A converter 16. From the D / A converter 16,
An analog video signal is output. This analog video signal is output from the output terminal 17.

The camera shake is detected by pitch and yaw angular velocity sensors 21A and 21B. That is, the vertical swing is detected by the pitch angular velocity sensor 21A. The output of the pitch angular velocity sensor 21A is
It is supplied to the A / D converter 23A via 2A. A
The output of the / D converter 23A is supplied to the camera shake correction controller 20. The output of the yaw angular velocity sensor 21B is supplied to an A / D converter 23B via an amplifier 22B. The output of the A / D converter 23B is supplied to the camera shake correction controller 20.

The camera shake correction controller 20 performs vertical camera shake correction by performing high-speed transfer of electric charges by the CCD image pickup device 3 based on the vertical vibration detected by the pitch angular velocity sensor 21A. Further, a horizontal shift is performed based on the horizontal swing detected by the yaw angular velocity sensor 21B. Thus, horizontal camera shake correction is performed.

That is, as shown in FIG. 2, in one embodiment of the present invention, the CCD image pickup device 3 has the number of lines of the PAL system, for example, the number of effective lines 582. In contrast, the number of active lines in the NTSC system is 49
4. Therefore, of the number of effective lines 582 on one screen of the CCD image sensor 3, only 494 lines are used, and the output of other lines is not used as shown by hatching in FIG. The screen can be moved in the vertical direction by changing the start position ST. Therefore, if the start position ST is moved so as to remove vertical shaking of the screen, vertical camera shake correction can be performed.

As described above, charges are transferred at a normal speed for the number of lines of the NTSC system among the CCD image pickup devices 3 having the number of lines of the PAL system, and charges are transferred at a high speed for the remaining lines. As shown, for example, a circular subject A1 is projected as a vertically extending circular image A2.

Therefore, as shown in FIG. 4A, the signal SL for one line is fetched into the line memory, and as shown in FIG. 4B, the signal is read with the time axis changed. This corrects the aspect ratio of the projected image,
The horizontal screen is enlarged. By shifting the read position of the line memory in accordance with the shake of the video camera in the horizontal direction, horizontal camera shake correction can be performed.

In the video camera to which the present invention is applied,
By moving the zoom lens, optical zoom shooting can be performed, and by using the image memory 14, electronic zoom shooting can be performed. That is, assuming that an imaging screen as shown in FIG. 5A is stored in the image memory 14, a portion indicated by an area B1 is cut out from the screen of the image memory 14 and enlarged interpolation is performed.
As shown in the figure, the screen can be enlarged twice.

The above-mentioned camera shake correction controller 20 performs a filtering process on the outputs of the pitch angular velocity sensor 21A and the yaw angular velocity sensor 21B, and calculates the vertical and horizontal correction amounts.

FIG. 6 shows the configuration of the camera shake correction controller 20.
Is a functional block diagram of the processing in FIG. First, the processing on the pitch side will be described. In FIG.
The input terminal 51A has an angular velocity sensor 21A in the pitch direction.
Output from the multiplication circuit 22A and the A / D converter 23A
(FIG. 1). The signal from the input terminal 51A is supplied to a high-pass filter 53A via an amplifier 52A for adjusting the overall gain. Hyper filter 53
A removes a DC offset included in the angular velocity sensor 21A.

The output of the high-pass filter 53A is supplied to a multiplication circuit 54A for adjusting the variation of the angular velocity sensor. The multiplication circuit 54A is supplied with a gain according to the variation from the input terminal 55A. The output of the multiplying circuit 54A is supplied to a noise removing coring circuit 56A. The output of the coring circuit 56A is supplied to the multiplication circuit 57A.

The coefficient is given to the multiplying circuit 57A from the table 58A. The optical zoom position is given to the table 58A from the terminal 59A. The camera shake correction needs to be increased as the optical zoom magnification increases. Therefore, a coefficient is set by the table 58A so that a larger correction is applied when the zoom lens is on the telephoto side.

The output of the multiplying circuit 57A is supplied to a low-pass filter 61A via a limiter 60A. The low-pass filter 61A converts an angular velocity into an angle. This low-pass filter 61A is configured by an IIR filter, as described later in detail. And
In the low-pass filter 61A, a coefficient is set according to the electronic zoom magnification from the terminal 62A, so that effective correction can be performed even in the electronic zoom region.

The output of the low-pass filter 61A is supplied to a coring circuit 63A. The output of the coring circuit 63A is supplied to a limiter 64A. The output of the limiter 64A is supplied to an output terminal 71 via an offset addition circuit 69A.
And is supplied to a subtraction circuit 65A.
In accordance with the output from the output terminal 71, the read position of the PAL CCD image pickup device 3 is shifted, and vertical camera shake correction is performed.

A correction value exceeding the offset is obtained by the subtraction circuit 65A. The output of the subtraction circuit 65A is supplied to the addition circuit 66A. The addition circuit 66A has a terminal 6
Electronic zoom control data is supplied from 7A. The output of the addition circuit 66A is output to an output terminal 72 via a limiter 68A.
Output from In accordance with the output from the output terminal 72, the readout position of the image memory 14 is shifted, and vertical camera shake correction beyond the correction range is performed. Further, the output of the output terminal 72 is supplied to the electronic magnifying circuit 15 to perform vertical camera shake correction of 0.5 lines or less.

Next, the processing in the yaw direction will be described.
The processing in the yaw direction is the same as the processing in the pitch direction. That is, the output of the yaw direction angular velocity sensor 21B is supplied to the input terminal 51B by the amplifier 22B and the A / D converter 23B.
Is supplied via The signal from the input terminal 51B is supplied to a high-pass filter 53B for removing a DC offset via an amplifier 52B for adjusting the overall gain.

The output of the high-pass filter 53B is supplied to a multiplication circuit 54B for adjusting the variation of the angular velocity sensor. The multiplication circuit 54B is supplied with a gain according to the variation from the input terminal 55B. The output of the multiplication circuit 54B is supplied to a noise removing coring circuit 56B. The output of the coring circuit 56B is supplied to the multiplication circuit 57B. The coefficient is given to the multiplying circuit 57B from the table 58B. The optical zoom position is given to the table 58B from the terminal 59B. The coefficient is set by the multiplying circuit 57B and the table 58B so that a larger correction is applied when the zoom lens is on the telephoto side.

The output of the multiplying circuit 57B is supplied to a low-pass filter 61B via a limiter 60B. The low-pass filter 61B converts an angular velocity into an angle. The electronic zoom magnification is supplied to the low-pass filter 61B from a terminal 62B. Low-pass filter 61
The output of B is supplied to the coring circuit 63B. The output of the coring circuit 63B is supplied to a limiter 64B.
The output of the limiter 64B is output from the output terminal 73 via the offset addition circuit 69B, and the output of the addition circuit 66B.
B. An offset is supplied to the addition circuit 66B from the terminal 70B. The addition circuit 69B has a terminal 67
B supplies the electronic zoom control data. Adder circuit 6
The output of 6B is output from the output terminal 74 via the nonlinear limiter 68B.

The output from the output terminal 73 is supplied to the window generation circuit 12, and the window position of the optical detector 11 is shifted according to the output from the output terminal 73. The output of the output terminal 74 is supplied to the electronic magnifying circuit 15, and the read position of the electronic magnifying circuit 15 is shifted according to the output from the output terminal 74, and the horizontal camera shake is corrected.

As described above, the low-pass filter 61A
And 61B perform conversion from angular velocity to angle to obtain a correction amount. In order to set the limit of the correction amount, a limiter 64A, a limiter 68A, a limiter 64B, and a limiter 68B are provided. Among these limiters, the limiter 68B is a non-linear limiter. This is to prevent the imaging screen from becoming unnatural during panning shooting.

That is, at the time of panning photographing, since the camera is rapidly moved at the start of panning, the integral value of the angular velocity sensor rapidly increases and suddenly exceeds the limit value. For this reason, if a normal limiter is used, an unnatural photographing screen in which the correction limit is suddenly reached and the panning is performed from a screen state in which the movement of the panning is suppressed at the start of the panning is obtained.

On the other hand, in one embodiment of the present invention,
As shown in FIG. 8, a non-linear limiter whose correction amount gradually approaches the limit is used. FIG. 8 shows a table of the nonlinear limiter 68B. In FIG. 8, the horizontal axis is the input value of the nonlinear limiter 68B, and the vertical axis is the output value. The input corresponds to the output of low-pass filter 61B.

As described above, in the embodiment of the present invention, since the nonlinear limiter 68B is used, even if the camera is suddenly moved at the start of the panning, the correction limit is not suddenly reached, and the photographing during the panning is performed. The screen is not unnatural.

That is, when panning photography is performed, a detection signal as shown in FIG. 9A is output from the angular velocity sensor. This detection signal is integrated by a low-pass filter. This integrated value, as shown in FIG. 9B, at time t ₁ reaches the correction limit LMT. Since the non-linear limiter 68B has a non-linear characteristic, it gradually reaches the correction limit LMT as shown by a point P1 as shown in FIG. 9C. For this reason, the shooting screen at the time of panning is not unnatural.

The characteristics of the nonlinear limiter 68B may be fixed, but depending on the panning speed and the zoom ratio,
The non-linear characteristics may be changed. For example, the faster the panning speed and the larger the zoom magnification,
The limiter characteristic is set so that the curve reaching the correction limit becomes gentle.

In the above-described embodiment, the nonlinear limiter is provided only in the horizontal camera shake correction system. However, it is needless to say that the nonlinear camera limiter may also be provided in the vertical camera shake correction system.

The present invention is not limited to a video camera,
The present invention can be similarly applied to a video reproducing apparatus having a camera shake correction function. In other words, the shaking of the screen due to camera shake
When recording, not only do the corrections on the video camera side,
At the time of playback, it can be performed on the playback device side. That is,
During playback, camera shake is detected, and according to the camera shake amount,
The screen is shifted. As described above, when performing camera shake correction during reproduction, camera shake is detected by detecting a motion vector of a reproduced video signal. A low-pass filter is used to determine the actual correction amount from the motion vector.

Also in such a video reproducing apparatus, a nonlinear limiter can be used as in the above-described embodiment.

[0045]

According to the present invention, the limiter for setting the control limit value is set to a non-linear limiter, so that the correction limit is prevented from suddenly reaching the correction limit at the time of panning, and the screen at the time of panning is made natural. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a video camera to which the present invention is applied.

FIG. 2 is a schematic diagram used for describing one embodiment of the present invention.

FIG. 3 is a schematic diagram used for describing camera shake correction according to an embodiment of the present invention.

FIG. 4 is a schematic diagram used for explaining camera shake correction according to an embodiment of the present invention.

FIG. 5 is a schematic diagram used for describing an electronic zoom according to an embodiment of the present invention.

FIG. 6 is a functional block diagram of a camera shake correction controller according to an embodiment of the present invention.

FIG. 7 is a schematic diagram used for describing camera shake correction according to an embodiment of the present invention.

FIG. 8 is a graph showing an example of a table of a nonlinear limiter according to an embodiment of the present invention.

FIG. 9 is a waveform chart used to explain one embodiment of the present invention.

FIG. 10 is a waveform diagram used for explaining a conventional limiter.

[Explanation of symbols]

 3 CCD imaging device for PAL 14 Image memory 20 Camera shake correction controller 21A, 21B Angular velocity sensor 61A, 61B Low pass filter 68B Nonlinear limiter

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/225-5/247

Claims (4)

(57) [Claims] And a shaking detecting means for detecting a shaking amount of the video camera, and integrating the shaking amount detected by the shaking detecting means.
The filter means for obtaining the amount of correction of the shake of the video camera, and the output of the filter means are responded to the panning speed.
And the output of the filter means via the limiter means.
Correction means for performing camera shake correction based on
Video camera. 2. A shake detection system for detecting a shake amount of a video camera.
Means out, by integrating the amount of detected shake in the swing detecting means the
A filter means for obtaining a correction amount of shake of the video camera, the output of the filter means, in accordance with the zoom ratio especially
Limiter means whose characteristics are changed, and an output of the filter means via the limiter means.
Correction means for performing camera shake correction based on
Video camera. 3. The method according to claim 1, wherein the amount of fluctuation of the screen of the input video signal is detected.
And a shaking amount detected by the shaking detecting means.
The filter means for obtaining the correction amount of the surface sway and the output of the filter means correspond to the panning speed.
And the output of the filter means via the limiter means.
Correction means for performing camera shake correction based on
Video playback device. 4. The method according to claim 1, wherein the amount of screen fluctuation of the input video signal is detected.
The swing detected by the swing detecting means, and integrating the
The filter means for obtaining the correction amount of the surface shake and the output of the filter means are specially determined according to the zoom ratio.
A limiter means sex is changed, the output of said filter means interposed said limiter means
Correction means for performing camera shake correction based on
Video playback device.