JPH06245135A - Video camera and video reproducing device - Google Patents

Abstract

PURPOSE:To obtain a video camera and a video reproducing device by which a camera shake correction quantity is effectively utilized in an electronic zoom area and a camera shake correction capability is improved. CONSTITUTION:The shake of a video camera is detected by an angular velocity sensor. Low pass filters 61A, 61B obtain a correction quantity from an output of the angular velocity sensor. Coefficients of the low pass filters 61A, 61B are changed by an electronic magnification. The correction capability is improved by increasing the electronic magnification and the correction capability is sufficiently utilized by changing the coefficients of the low pass filters 61A, 61B by the electronic magnification.

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 an image stabilizing function.

[0002]

2. Description of the Related Art In recent years, as the size and weight of video cameras have been reduced, the problem of camera shake is becoming more likely to occur. Therefore, video cameras equipped with an image stabilization function have been introduced.

As a camera shake correction method for such a video camera, a camera shake is detected by an angular velocity sensor,
It is known that the cutout position of the image memory is shifted according to the output of the angular velocity sensor.

Further, in a video camera provided with an image memory, the screen stored in the image memory can be enlarged and interpolated. This is called electronic zoom. On the other hand, zoom for moving the zoom lens is called optical zoom.

In the case of a camera shake correction method in which the movement of the camera is detected by the angular velocity sensor and the correction is performed according to the cut-out position of the image memory, in the optical zoom area, the larger the zoom magnification, the larger the shaking of the screen. It is necessary to increase the correction amount in proportion to the zoom magnification.

On the other hand, in the electronic zoom area, the correction gain may be constant. This is because, in the electronic zoom region, for example, in the case of double electronic zoom, if there is a shake of n lines, the read position of the image memory is shifted by n lines. Then, the content of the image memory is doubled and read out. In this way, when the data is shifted by n lines and interpolated and read out twice, it means that the correction for 2n lines has been performed.

Such a camera shake correction device is provided with a low-pass filter for converting an angular velocity based on camera shake detected by an angular velocity sensor into an angle. Since the correction gain may be constant in the electronic zoom region, conventionally, the gain of this low-pass filter is the same as the control at the tele end of the zoom lens in the electronic zoom region.

[0008]

As the electronic zoom magnification increases, the area that cannot be read out from the image memory increases, so that the camera shake correction capability originally increases. However, conventionally, the low-pass filter that integrates the output of the angular velocity sensor is similar to the control at the tele end of the zoom lens in the electronic zoom region. Therefore, the camera shake correction function cannot be fully exerted even in a place where the electronic zoom magnification, which is originally high in camera shake correction capability, is high. Therefore, the object of the present invention is to effectively use the correction amount in the electronic zoom region,
An object of the present invention is to provide a video camera and a video playback device with improved correction capability.

[0009]

The shake of the video camera is detected by the angular velocity sensor, and the correction amount of the image is calculated from the detection result and the zoom magnification. At that time, the coefficient of the low-pass filter for converting the angular velocity into the angle is changed by using the electronic magnification. As a result, the correction amount in the electronic zoom region can be effectively used, and the correction capability is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall structure of a video camera to which the present invention is applied. In FIG. 1, subject image light that has passed through the lens group 1 is imaged on the light receiving surface of the CCD image pickup device 3 through the iris 2. Although this video camera records by the NTSC system, the number of lines of the CCD image pickup element 3 does not correspond to the number of lines of the NTSC system but is 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 the driver 4 based on the timing signal from the timing generation circuit 5. A 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 the vertical blanking period according to the vertical shake of the camera.

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

The signal processing circuit 10 carries out necessary camera signal processing and outputs the image pickup signal from the CCD image pickup device 3 to NT.
The luminance signal and the chroma signal corresponding to the SC system are formed. The output of the signal processing circuit 10 is the image memory 14
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. As a result, 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 this edge component becomes maximum. As a result, automatic focus adjustment is performed.

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

The image memory 14 is provided to perform electronic zooming, and the image memory 14 is used to perform camera shake correction with large vibration. The output of the image memory 14 is supplied to the electronic expansion circuit 15. The electronic enlarging circuit 15 shifts the reading position of one line to correct the camera shake in the horizontal direction of the camera. Further, the electronic enlargement circuit 15 corrects the vertical shake of one line or less.

The output of the electronic expansion circuit 15 is supplied to the 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 the pitch and yaw angular velocity sensors 21A and 21B. That is, the pitch angular velocity sensor 21A detects the vertical swing. The output of the pitch angular velocity sensor 21A is the amplifier 2
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 the A / D converter 23B via the 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 camera shake correction in the vertical direction by performing high-speed transfer of charges by the CCD image pickup device 3 based on the vertical shake detected by the pitch angular velocity sensor 21A. In addition, the horizontal shift is performed based on the horizontal shake detected by the yaw angular velocity sensor 21B. As a result, horizontal shake correction is performed.

That is, as shown in FIG. 2, in one embodiment of the present invention, as the CCD image pickup device 3, the number of lines of the PAL system, for example, the number of effective lines 582 is used. On the other hand, the number of effective lines in the NTSC system is 49
It is 4. Therefore, of the number of effective lines 582 on one screen of the CCD image pickup device 3, only 494 lines are used, and as shown by hatching in FIG. 2, outputs of other lines are not used. 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 the vertical shake of the screen, the shake correction in the vertical direction can be performed.

As described above, when the charges are transferred at the 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 the charges are transferred at high speed on the remaining lines, FIG. As shown, for example, the circular subject A1 is displayed as a vertically extending circular image A2.

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

In the video camera to which the present invention is applied,
Optical zoom photography can be performed by moving the zoom lens, and electronic zoom photography can be performed by using the image memory 14. That is, assuming that the image pickup screen as shown in FIG. 5A is stored in the image memory 14, the portion shown by the region B1 is cut out from the screen of the image memory 14 and enlarged and interpolated to obtain the image shown in FIG.
As shown in, the screen can be enlarged twice.

The above-described 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 vertical and horizontal correction amounts.

FIG. 6 shows the camera shake correction controller 20.
This 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 a pitch-direction angular velocity sensor 21A.
Is supplied via the amplifier 22A and the A / D converter 23A (FIG. 1). The signal from the input terminal 51A is supplied to the high-pass filter 53A via the multiplication circuit 52A for overall gain adjustment. Hyper filter 53
A removes the DC offset contained in the angular velocity sensor 21A.

The output of the high pass filter 53A is supplied to the multiplication circuit 54A for adjusting the variation of the angular velocity sensor. A gain corresponding to the variation is supplied to the multiplication circuit 54A from the input terminal 55A. The output of the multiplication circuit 54A is supplied to the coring circuit 56A for noise removal. The output of the coring circuit 56A is supplied to the multiplication circuit 57A.

Coefficients are given to the multiplication circuit 57A from the table 58A. An optical zoom position is given to the table 58A from a terminal 59A. The larger the optical zoom magnification, the larger the shake correction needs to be corrected. Therefore, the coefficient is set by the table 58A so that a larger correction is applied when the zoom lens is on the tele side.

The output of the multiplication circuit 57A is supplied to the low-pass filter 61A via the limiter 60A. The low-pass filter 61A is for converting an angular velocity into an angle. The low pass filter 61A is composed of an IIR filter, as will be described later. And
The coefficient of the low-pass filter 61A is set according to the electronic zoom magnification from the terminal 62A so that effective correction can be performed even in the electronic zoom area.

The output of the low pass filter 61A is supplied to the coring circuit 63A. The output of the coring circuit 63A is supplied to the limiter 64A. The output of the limiter 64A is output to the output terminal 71 via the offset addition circuit 69A.
And is supplied to the subtraction circuit 65A.
According to the output from the output terminal 71, the read-out position of the CCD image pickup device 3 for PAL is shifted, and the shake correction in the vertical direction 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 adder circuit 66A is output to the output terminal 72 via the limiter 68A.
Is output from. In accordance with the output from the output terminal 72, the read position of the image memory 14 is shifted, and the camera shake correction in the vertical direction exceeding the correction range is performed. Further, the output of the output terminal 72 is supplied to the electronic enlarging circuit 15, and the shake correction in the vertical direction of 0.5 line or less is performed.

Next, the processing in the yaw direction will be described.
The processing in the yaw direction is similar to the processing in the pitch direction. That is, the input terminal 51B receives the output of the angular velocity sensor 21B in the yaw direction from the amplifier 22B and the A / D converter 23B.
Is supplied via. The signal from the input terminal 51B is supplied to the high-pass filter 53B for DC offset removal via the multiplication circuit 52B for overall gain adjustment.

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

The output of the multiplication circuit 57B is supplied to the low pass filter 61B via the limiter 60B. The low-pass filter 61B is for converting an angular velocity into an angle. The electronic zoom magnification is supplied to the low-pass filter 61B from the 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 the limiter 64B.
The output of the limiter 64B is output from the output terminal 73 through the off-add circuit 69B and the add circuit 66
Supplied to B. An offset is supplied from the terminal 70B to the adder circuit 66B. The addition circuit 69B has a terminal 67.
Electronic zoom control data is supplied from B. Adder circuit 6
The output of 6B is output from the output terminal 74 via the non-linear 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 enlarging circuit 15, the read position of the electronic enlarging circuit 15 is shifted in accordance with the output from the output terminal 74, and horizontal camera shake correction is performed.

As described above, the low pass filter 61A
And 61B convert the angular velocity into the angle to obtain the correction amount. Here, considering the electronic zoom magnification and the correction ability, when the optical zoom magnification is increased, the unused portion of the screen stored in the image memory 14 is increased and the correction ability is increased.

That is, FIG. 7A shows a screen in the optical zoom area. In such an optical zoom area,
The image of the area indicated by C1 is used. Then, camera shake correction in the vertical direction is performed in the range indicated by C2A and C2B,
Image stabilization is performed in the horizontal direction within the range indicated by C3A and C3B. The camera shake correction in the range indicated by C2A and C2B is achieved by shifting the readout position of the CCD image sensor 3. Further, the horizontal shake correction in the range indicated by C3A and C3B is achieved by shifting the horizontal read position by the electronic enlargement circuit 15.

FIG. 7B shows a screen stored in the image memory 14 in the electronic zoom area. In such an electronic zoom area, the image of the area indicated by C11 is used. Then, in the range indicated by C12A and C12B, the CCD
By shifting the read-out position of the image sensor 3, the camera shake correction in the vertical direction is performed, and the camera shake correction in the horizontal direction is performed in the range indicated by C13A and C13B. Further, an unused area C14 is generated on the image memory. This unused area C
14 can be used for camera shake correction.

8 and 9 show a low pass filter 61A.
And 61B. FIG. 8 shows the structure in the optical zoom region, and FIG. 9 shows the structure in the electronic zoom region. 8 and 9, the signal from the input terminal 101 is supplied to the adder circuit 102. The output of the adder circuit 102 is output from the output terminal 103 and is also supplied to the delay circuit 104.

In the optical zoom area, as shown in FIG.
The output of the delay circuit 104 is supplied to the multiplication circuit 105 and the table 107. The coefficient is read out from the table 107 and set in the multiplication circuit 105. The output of the multiplication circuit 105 is supplied to the addition circuit 102.

In the electronic zoom area, as shown in FIG.
The output of the delay circuit 104 is supplied to the multiplication circuit 105 and the attenuator 106. The electronic zoom magnification k is supplied to the attenuator 106 from the input terminal 108. The coefficient is read out from the table 107 and set in the multiplication circuit 105. Multiplication circuit 105
Is supplied to the adder circuit 102.

A signal according to the shake of the video camera is supplied to the input terminal 101, and the addition circuit 102 adds and outputs the feedback amount, and the multiplication circuit 105 multiplies it by an appropriate coefficient and feeds it back. It

In the optical zoom area, this coefficient is determined by the output of the delay circuit 104 as shown in FIG.
07. In the electronic zoom region, as shown in FIG. 9, the output of the delay circuit 104 is supplied to the table 107 via the attenuator 106 and obtained by referring to the table 107. The attenuation of the attenuator 106 is set to be inversely proportional to the electronic zoom magnification k.

FIG. 10 shows the relationship between the integral value and the coefficient in the electronic zoom area. In FIG. 10, the horizontal axis represents the integrated value and the vertical axis represents the coefficient. Attenuator 106
Is set so as to be inversely proportional to the electronic zoom magnification k. Therefore, when the electronic zoom magnification is increased, the line showing the relationship between the integrated value and the coefficient changes like M1, M2, M3, .... I will do it. Therefore, the larger the electronic zoom magnification, the larger the correction range can be.

The present invention is not limited to the video camera,
The same can be applied to a video playback device having a camera shake correction function. In other words, the shaking of the screen due to camera shake is
When recording, not only the correction on the video camera side,
It can be performed on the reproducing device side during reproduction. That is,
During playback, camera shake is detected, and depending on the amount of camera shake,
The screen is shifted. In this way, when performing camera shake correction during reproduction, camera shake is detected by detecting the motion vector of the reproduced video signal. A low-pass filter is used to obtain the actual correction amount from this motion vector. An image memory is used to perform the correction. Further, by using this image memory, it is possible to form an electronic enlarged screen. When forming the electronic enlargement screen in this manner, the correction range can be widened by changing the coefficient of the low-pass filter according to the enlargement ratio.

[0046]

According to the present invention, the coefficient of the low-pass filter for converting the angular velocity into the angle is set according to the electronic zoom magnification. For this reason, the larger the electronic zoom magnification, the larger the correction range, and the camera shake correction capability is improved.

[Brief description of 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 to describe an embodiment of the present invention.

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

FIG. 8 is a block diagram used for explaining a low-pass filter according to an embodiment of the present invention.

FIG. 9 is a block diagram used for explaining a low-pass filter according to an embodiment of the present invention.

FIG. 10 is a graph used to explain a low-pass filter according to an embodiment of the present invention.

[Explanation of symbols]

 3 CCD image sensor for PAL 14 Image memory 20 Image stabilization controller 21A, 21B Angular velocity sensor 61A, 61B Low-pass filter 106 Attenuator 107 Table

Claims (5)

[Claims] 1. A shake detecting means for detecting a shake of a video camera, a filter means for obtaining a correction amount from an output of the shake detecting means, and a correcting means for correcting a shake based on an output of the filter means. A video camera, wherein the coefficient of the filter means is changed according to an electronic magnification. 2. The video camera according to claim 1, wherein the shake detecting means is an angular velocity sensor. 3. The video camera according to claim 1, wherein the shake detecting means is a means for detecting a motion vector of an image pickup screen. 4. A shake detecting means for detecting a shake of a screen from an input video signal, a filter means for obtaining a correction amount from an output of the shake detecting means, and a correcting means for correcting a shake based on the output of the filter means. A video reproducing apparatus comprising: a video reproducing apparatus, wherein the coefficient of the filter means is changed according to an electronic enlargement ratio. 5. The video reproducing apparatus according to claim 4, wherein the shake detecting means is means for detecting a motion vector of a reproduction screen.