JP3384459B2 - Imaging device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus having a camera shake correction means for correcting a phenomenon in which a shooting screen is largely shaken due to a camera shake generated when a video camera shoots.

[0002]

2. Description of the Related Art It is well known that when a video camera is handheld for shooting, a shake of the screen occurs due to camera shake. Especially, when the zoom lens is set to the telephoto side, the phenomenon becomes remarkable. When such a hand shake phenomenon occurs, a stationary object shakes and moves, which makes it difficult to view a captured image and causes eyestrain. Further, sometimes a problem arises in that a part of the target subject is momentarily removed from the screen, and further, a phenomenon occurs in which the subject blurs due to camera shake.

In order to solve such a problem, there has been proposed a means for correcting camera shake that occurs when a video camera shoots. For example, (1) speed detection by a sensor and direction detection (2) motion vector detection by image processing are generally used as a camera shake detection unit for detecting the degree of the camera shake phenomenon.

Further, when the camera shake phenomenon is detected by the above-mentioned means, as a correction means for correcting the photographed image, (1) means for changing the read position of the image data of the imager such as CCD (2) image data A means for changing the read position of the image data to be stored in the image memory is generally used.

[0005]

By the way, according to the conventional camera shake correction device in a video camera, each of the former camera shake detection means samples the camera shake information at a predetermined timing once in the field and processes it. Then, the correction value of the entire screen is obtained using the latter correction means.

However, in actuality, the camera shake information changes from moment to moment between fields, and in the case of sampling at a predetermined timing once in the field, the optimum correction value is not necessarily obtained for the entire image. Is hard to get.

Further, when camera shake occurs, it is equivalent to the subject moving in small steps.
While the imager such as the above accumulates the electric charge, the subject moves and "blurring" occurs in the image. To avoid this,
It is known to use the image stabilization means and a high-speed shutter together. With the high speed shutter, no charge accumulation occurs in the first fraction of the field and the faster the shutter, the more the center of the image shifts backward. Along with this, it is necessary to shift the timing of capturing the camera shake information backward.

The present invention has been made paying attention to such a point, and the camera shake correction is performed based on the camera shake information of the timing closest to the center of the image calculated according to the shutter speed. An object is to provide a camera shake correction device for a video camera.

[0009]

The image pickup apparatus according to claim 1 of the present invention, which has been made to achieve the above-mentioned object, is an image obtained by an image pickup device in accordance with camera shake detection information provided by the camera shake detection means. An image pickup apparatus having a camera shake correction means for correcting a camera shake by changing a signal read position, wherein an oversampling signal generation means for generating an oversampling signal of a vertical drive pulse based on a vertical drive pulse of an image pickup element, The relationship between the center position of the shutter opening section based on the shutter speed that exposes the image sensor and the plurality of sampling signals provided by the oversampling signal generation means is set.
One sampling signal from the
Comprising a sampling signal extraction means for extracting, based on the over-de, and sampling means for sampling the vibration detection information resulting from the hand shake detecting means based on the sampling signal obtained by the sampling signal extracting means, shake sampled by the sampling means It is characterized in that the read position of the image signal obtained by the image sensor is changed based on the detection information.

According to a second aspect of the present invention, in the image pickup device according to the first aspect, the image pickup element is obtained based on the shake detection information sampled by the sampling means. It is characterized in that the read position of the image signal from the image memory that stores the image signal is changed.

Further, the image pickup device according to claim 3 of the present invention.
In the arrangement according to claim 1, the image pickup device and the image signal read-out position from the image memory for accumulating the image signal obtained by the image pickup device are respectively based on the camera shake detection information sampled by the sampling means. It has a feature in that it is changed.

[0012]

According to the first aspect of the present invention, there is provided an oversampling signal generating means for generating an oversampling signal of a vertical drive pulse based on a vertical drive pulse of the image pickup element, and a shutter speed for exposing the image pickup element. From the table in which the relationship between the center position of the shutter opening section based on the plurality of sampling signals provided by the oversampling signal generating means is set,
One sampling signal based on shutter speed
A sampling signal extracting means for can extract, the sampling signal extraction are provided and a sampling means for sampling the vibration detection information resulting from the hand shake detecting means based on the sampling signal obtained by the means, the hand shake detection sampled by the sampling means Since the read position of the image signal obtained by the image sensor is changed based on the information, the camera shake correction is performed based on the camera shake information at the timing closest to the center of the image calculated according to the shutter speed. You can

Further, in the image pickup device according to the second aspect, in the image stabilizer in the video camera, an image for accumulating an image signal obtained by the image pickup device based on the image pickup detection information sampled by the sampling means. The reading position of the image signal from the memory is changed.

Further, in the image pickup device according to the third aspect, the image pickup device and the image memory for accumulating the image signal obtained by the image pickup device based on the camera shake detection information sampled by the sampling means. The read position of the image signal is changed.

[0015]

The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the image pickup apparatus of the present invention. In this embodiment, it is premised that hand shake is detected during recording (shooting) and is corrected, and therefore FIG. 1 shows only the blocks of the recording system. The embodiment shown in FIG. 1 shows a case where a camera shake sensor is used as the camera shake detection means, and a means for changing the read position of the image data from the image memory is used as the correction means for correcting the photographing screen.

A so-called angular velocity sensor is used as the camera shake sensor 1 as the camera shake detection means. This angular velocity sensor generally includes two sensors that independently detect a vertical sensor 1-1 that detects a vertical (vertical) pitching component angular velocity and a horizontal sensor 1-2 that detects a lateral (horizontal) yawing component angular velocity. It is composed of sensors. As shown in FIG. 3A, the output of the vertical sensor 1-1 is supplied to the A / D converter 1-3, and the horizontal sensor 1-
The output of 2 is supplied to the A / D converter 1-4. These two
Digital outputs from the one A / D converters 1-3 and 1-4 are supplied to the microcomputer 1-5 to calculate the amount of camera shake.

The example shown in FIG. 3B is a vertical sensor 1-1.
Of the output of the horizontal sensor 1-2 and the output of the horizontal sensor 1-2 are supplied to the A / D converter 1-7 via the switch 1-6, which is digitally converted by the A / D converter 1-7. Is supplied to the microcomputer 1-5 to calculate the amount of camera shake. Further, in the example shown in FIG. 3C, the output of the vertical sensor 1-1 and the output of the horizontal sensor 1-2 are supplied to the A / D input terminal of the microcomputer 1-9, and in the microcomputer 1-9, Each is digitally converted and the amount of camera shake is calculated.

Whichever of the examples shown in FIGS. 3A to 3C is adopted, the microcomputer 1 is used.
The outputs from -5, 1-8 and 1-9 are supplied to the sampling and filtering circuit 2.

The sampling and filtering circuit 2 is supplied with a luminance signal provided by an imager 3 which is composed of an image pickup device such as a CCD. Imager 3 to sampling and filtering circuit 2
The luminance signal provided to the image sensor is used to determine the shutter speed at which the imager 3 is exposed in the automatic exposure photographing mode.

The sampling and filtering circuit 2 is also adapted to be supplied with the output from the shutter speed switching circuit 4, which operates in the manual exposure photographing mode at the shutter speed set manually. Output is provided when exposing 3.

On the other hand, the sampling and filtering circuit 2 and the imager 3 are each supplied with a pulse signal from a timing generator 5 which constitutes an oversampling signal generating means. The timing generator 5 supplies a vertical drive pulse for the imager 3, that is, a VD pulse, as a V reset signal to the imager 3 as shown in FIG. 4A, and as shown in FIG. An oversampling signal obtained by oversampling the VD pulse by 8 times is supplied to the sampling and filtering circuit 2.

In the automatic exposure photographing mode, the sampling and filtering circuit 2 detects the luminance signal supplied from the imager 3 and exposes the imager 3 in a cycle of 1/60 second (1 field) according to the luminance signal. The shutter speed (shutter opening time) is determined. In the manual exposure shooting mode,
The sampling and filtering circuit 2 receives the output from the shutter speed switching circuit 4 and fetches the manually set shutter speed information.

Here, the sampling and filtering circuit 2 also serves as sampling signal extracting means,
A sampling signal corresponding to the central position of the shutter opening section is extracted from the plurality of sampling signals provided by the oversampling signal generating means, that is, the timing generator 5 based on the shutter speed.

For example, when the shutter speed is 1/125 second, the shutter opens in about half of the latter half of one field as shown in FIG. 4 (b). The center position of the shutter opening section at this time is shown in FIG.
The sixth sampling signal of the eight times oversampling signal shown in (c) is the closest one. This time,
The relationship between the shutter speed and the sampling signal extracted corresponding thereto can be obtained from the table shown in FIG. As shown in FIG. 5, the shutter speed is coded as a 5-bit shutter speed code, and the shutter speed described on the right side of the shutter speed code is required according to each shutter speed code. Then, the relationship of how much the center of the shutter opening section is delayed from the front end of the field according to the shutter speed is obtained as the center of the image.

For example, when the shutter speed is 1/60 second, the center of the image is "0.5" from the beginning of the field.
The image center shifts to the rear of the field as the shutter speed increases. Then, for example, when the shutter speed is 1/10000 second, the center of the image shifts to the position "0.997" from the beginning of the field. Obtaining the number of the sampling signal closest to the center position of this image is shown in the sample used in FIG.

For example, when the shutter speed is 1/60 second, the fourth sampling signal of the 8 times oversampling signal is located closest to the center of the image, and the shutter speed is 1 / 60th. In the case of 10000 seconds, the 7th sampling signal of the 8 times oversampling signal is located closest to the center of the image.

The sampling and filtering circuit 2 also serves as sampling means, and based on the table shown in FIG. 5, the camera shake detection supplied from the camera shake sensor 1 by the sampling signal located at the position closest to the center of the image. Sample information. FIG. 4D shows camera shake detection information sampled at this time.

FIG. 6 illustrates the relationship between sampling timings when the shutter speed is 1/60 second and 1/125 second. FIG. 6A shows the same VD pulse as that shown in FIG. 4, and A in FIG. 6B shows the same camera shake detection information as that shown in FIG. 4D. The arrow shown in FIG. 6C indicates that the shutter speed is 1
It shows the sampling point in the case of / 60 seconds,
The arrow shown in FIG. 6D indicates that the shutter speed is 1/12.
The sampling point in the case of 5 seconds is shown. As a result, when the shutter speed is 1/60 second, as shown in FIG.
In the case where the camera shake detection information indicated by the solid line B is obtained in (b) and the shutter speed is 1/125 second,
The camera shake detection information indicated by the broken line C in FIG. 6B is obtained.

The camera shake detection information sampled in this way is filtered and supplied from the sampling and filtering circuit 2 to the memory controller 6. The memory controller 6 supplies a read control signal to the image memory 7 and the electronic enlarging circuit 8 based on the sampled camera shake detection information. That is, the image signal obtained by the imager 3 is stored in the image memory 7, and the read position of the image signal stored in the image memory 7 is changed based on the sampled camera shake detection information. It

FIG. 7 illustrates the operation,
FIG. 7A shows the case where there is no camera shake phenomenon and the camera shake correction amount is zero, and FIG. 7B shows the case where the camera shake phenomenon occurs and camera shake correction is performed. First, when there is no camera shake phenomenon and the camera shake correction amount is zero, the central portion E of the effective memory area D supplied from the imager 1 is read from the image memory 7 as shown in FIG. 7A. Then, the central portion E read from the image memory 7
The portion corresponding to is enlarged by the electronic enlargement circuit 8 and an image shown as F is obtained. Further, when a hand shake phenomenon occurs, as shown in FIG. 7B, the read control signal supplied from the memory controller 6 causes the hand shake amount in the vertical direction with respect to the central portion E of the effective memory area D. A portion corresponding to the position E ′, which is formed by adding a corresponding correction amount + v, for example, and by adding a correction amount −h corresponding to the horizontal shake amount, is read out and enlarged by the electronic enlargement circuit 8. An image shown as F'is obtained.

As a result, the image signal obtained from the electronic enlarging circuit 8 is subjected to correction corresponding to the image shake caused by camera shake, and there is almost no change from that in FIG. 7A.
(B) A still screen as shown is obtained.

The image signal thus subjected to the camera shake correction is supplied to the recording system signal processing circuit 9, where it is signal-processed and recorded by the recording head 10 on the magnetic tape 11 which is a recording medium.

With the above configuration, the image memory 7 for accumulating the image signal obtained by the imager 3 based on the camera shake detection information sampled by the sampling and filtering circuit 2 which constitutes the sampling means.
Although the example is shown in which the read position of the image signal from is changed, the configuration as shown in FIG. 2 can also be adopted.

In the configuration shown in FIG. 2, the read position of the image signal from the imager 3 and the image memory 7 for accumulating the image signal obtained by the imager 3 is changed based on the camera shake detection information sampled by the sampling means. The following shows the case. That is, in FIG. 2, the same reference numerals as those in FIG. 1 achieve the same functions, and therefore detailed description thereof will be omitted.

In the example shown in FIG. 2, the camera shake sensor 1
The camera shake detection information supplied by the sampling is sampled by the sampling and filtering circuit 2 at a sampling timing corresponding to the shutter speed, and is supplied from the sampling and filtering circuit 2 to the imager 3 as a read control signal. Here, the sampling and filtering circuit 2 causes the imager 3
The control signal supplied to the image sensor 3 acts as a V reset signal in the imager 3. That is, the V reset signal at the timing corrected for each field based on the vertical shake information is supplied, and the vertical image signal read start position in the imager 3 is corrected by the shake information. As a result, the image signal supplied from the imager 3 to the image memory 7 is one in which the camera shake in the vertical direction has been corrected.

Therefore, the image signal stored in the image memory 7 is one in which camera shake in the vertical direction has been corrected,
The read control signal supplied from the memory controller 6 to the image memory 7 reads the image signal from a position where a correction amount corresponding to the horizontal shake amount is added in order to correct the horizontal shake. Is made.

As described above, in the configuration shown in FIG. 2, the vertical camera shake is corrected by changing the read position of the image signal from the imager 3, and the horizontal camera shake is corrected by the image signal from the image memory 7. The correction is performed by changing the read position of.

Further, as can be easily recalled from the above description, the camera shake in the vertical direction is corrected by changing the read position of the image signal from the image memory 7, and the camera shake in the horizontal direction is corrected by the imager 3. It is also possible to perform correction by changing the signal read position of the image.

Further, as shown in FIG. 8, an image pickup element, that is, an effective screen G of the imager 3, has an image-shake correction area H held in the vertical and horizontal directions as blanking, and this image blanking portion is used to detect an image-shake. If the vertical and horizontal image signal read positions of the imager 3 are changed frame by frame in accordance with information,
As shown in FIG. 1 or 2, the image memory 7 need not be provided in particular.

[0040]

As is apparent from the above description, claim 1
According to the image pickup apparatus described in (1), an oversampling signal generation unit that generates an oversampling signal of a vertical drive pulse based on a vertical drive pulse of an imager, and a center of a shutter opening section based on a shutter speed that exposes the image pickup element. From the table in which the relationship between the position and the plurality of sampling signals provided by the oversampling signal generating means is set, one sampling signal is set.
No. includes sampling signal extracting means for extracting on the basis of the shutter speed, and sampling means for sampling camera shake detection information provided by the camera shake detecting means on the basis of the sampling signal obtained by the sampling signal extracting means, and sampling by the sampling means. The read position of the image signal obtained by the imager is changed based on the detected camera shake detection information.

Therefore, camera shake correction is performed based on the camera shake information at the timing closest to the center of the image calculated according to the shutter speed, and an image with less shaking can be obtained even in a high range camera shake. .

Further, according to the image pickup device of the second aspect, in the image stabilization device in the video camera, an image for accumulating an image signal obtained by the imager based on the image stabilization information sampled by the sampling means. The reading position of the image signal from the memory is changed. For this reason, in addition to the above-described unique effect, most of the pixels possessed by the imager composed of a CCD or the like can be effectively used, so that the image stabilization apparatus does not sacrifice resolution. Can be provided.

Further, according to the image pickup device of the third aspect, the image signals from both the imager and the image memory for accumulating the image signals obtained by the imager are generated based on the camera shake detection information sampled by the sampling means. The reading position is changed respectively. Therefore, for example, the correction for the vertical shake can be corrected at the read-out position of the imager, and the correction for the horizontal shake can be corrected at the read-out position of the image memory, and an image memory having a relatively small capacity can be used. It will be possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an image pickup apparatus of the present invention.

FIG. 2 is a block diagram showing the configuration of another embodiment of the image pickup apparatus of the present invention.

FIG. 3 is a block diagram showing an example of a case in which camera shake detection information is captured from a camera shake sensor.

FIG. 4 is a timing chart showing a state in which camera shake detection information is sampled.

FIG. 5 is a table showing the relationship between shutter speed and used samples.

FIG. 6 is a timing chart showing a situation in which camera shake detection information is sampled according to shutter speed.

FIG. 7 is a schematic diagram illustrating how an image signal is read out from an image memory.

FIG. 8 is a front view showing the configuration of an imager used in another embodiment of the image pickup apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Shake sensor (shake detection means) 2 Sampling and filtering circuit (sampling signal extraction means, sampling means) 3 Imager (imaging device) 4 Shutter speed switching circuit 5 Timing generator (oversampling signal generation means) 6 Memory controller 7 Image memory 8 Electronic expansion circuit 9 Recording system signal processing circuit 10 Recording head 11 Magnetic tape

Claims (3)

(57) [Claims] 1. An image pickup apparatus having a camera shake correction unit for correcting a camera shake by changing a read position of an image signal obtained by the image sensor according to camera shake detection information provided by the camera shake detection unit. Oversampling signal generating means for generating an oversampling signal of a vertical drive pulse based on the pulse, a center position of a shutter opening section based on a shutter speed for exposing the image pickup device, and a plurality of means provided by the oversampling signal generating means. From the table in which the relationship with the sampling signal of
Sampling signal extracting means for extracting a ring signal based on the shutter speed, and sampling means for sampling camera shake detection information provided from the camera shake detecting means based on the sampling signal obtained by the sampling signal extracting means. An image pickup apparatus comprising a camera shake correction unit configured to change a read position of an image signal obtained by the image sensor based on the camera shake detection information sampled by the sampling unit. 2. A camera shake correction means adapted to change a read position of an image signal from an image memory for accumulating an image signal obtained by an image pickup device based on the camera shake detection information sampled by the sampling means. The image pickup apparatus according to claim 1, wherein: 3. A camera shake correction in which an image signal read position from an image sensor and an image memory for accumulating an image signal obtained by the image sensor is changed based on the camera shake detection information sampled by the sampling means. The image pickup apparatus according to claim 1, further comprising means.