JPH06350911A - Still/movie video camera and its control method - Google Patents

Abstract

PURPOSE:To prevent flicker at reproduction by reading alternately for each field a signal charge stored in a photo diode through interlace scanning for each 1V period at the image pickup at a usual shutter speed and providing an output through the mixing of the charges stored in photo diodes adjacent each other in the vertical direction in the case of a high shutter speed at a CCD vertical transfer path. CONSTITUTION:When an image is picked up at a usual shutter speed in the setting state of still/movie image pickup, interlace scanning is executed and the signal charge stored in photo didoes 60A of odd number lines and the signal charge stored in photo didoes 60B of even number lines are shifted alternately to a vertical transfer path 62 and provided as an output from a horizontal transfer path 63. On the other hand, in the case of the image pickup at a high shutter speed, the signal charge stored in photo didoes 60A of odd number lines and the signal charge stored in photo didoes 60B of even number lines are shifted alternately to the vertical transfer path 62, and the charge of the diodes 60A of the odd number lines and the charges of the diodes 60B of the even number lines adjacent vertically are mixed through the transfer path 62 and the mixed signal is transferred through the transfer path.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a still / movie video camera for performing still reproduction and movie reproduction from a video signal obtained by continuously photographing a subject, and a control method thereof.

[0002]

BACKGROUND ART In general, a video camera shoots at a shutter speed of 1/60 second. For this reason, when trying to perform still reproduction of one frame in the motion of the subject from this movie video signal, only the faint reproduction in which the image flows can be performed.

In order to obtain a clear image of a moving subject at the time of still reproduction, it is necessary to shoot at a high shutter speed, but then, the continuity of each frame of the image is lost at the time of movie reproduction, and the image is reproduced. The movement of the subject in the captured image becomes very unnatural, and the two requirements are incompatible.

Another problem for enabling still reproduction and movie reproduction is a countermeasure against flicker occurring in a reproduced image. When shooting at a high shutter speed for still reproduction, the level of the video signal obtained from the solid-state electronic image pickup device becomes lower than when shooting at a normal shutter speed. Therefore, if the high shutter speed and the normal shutter speed are mixed and photographed, flicker occurs in the reproduced image.

[0005]

DISCLOSURE OF THE INVENTION According to the present invention, it is possible to obtain a clear reproduced still image that is unmistakable due to the movement of a subject, and to perform a movie reproduction of a continuous natural movement without causing flicker. The purpose is to do.

A still / movie video camera control method according to the present invention includes a large number of photoelectric conversion elements arranged in rows and columns, and these photoelectric conversion elements are arranged every other row for the first field and the first field. A solid-state electronic image pickup device, which is defined for two fields and whose exposure time is controllable, is used, and the photoelectric conversion device for the first field and the second photoelectric conversion device for the first field are periodically used for taking one field during continuous photographing of a plurality of fields.
The field photoelectric conversion element and the field photoelectric conversion element are simultaneously exposed at a high shutter speed, and the first field photoelectric conversion element and the second field photoelectric conversion element are alternately exposed for each field at a normal shutter speed. When the exposure is performed and the photoelectric conversion element for the first field and the photoelectric conversion element for the second field are simultaneously exposed by the high shutter speed, the photoelectric conversion element for the first field and the second photoelectric conversion element that are vertically adjacent to each other are exposed. The signal charges accumulated in the field photoelectric conversion element are mixed, a first video signal is generated from the mixed signal charges, and the first field photoelectric conversion element and the second field signal are generated at a normal shutter speed. When the photoelectric conversion element and the photoelectric conversion element are alternately exposed for each field, interlaced scanning is used to perform the first exposure. Reading photoelectric conversion element and the signal charge accumulated in the photoelectric conversion element for the second field for de alternately every field, from the read out signal charges second
Is generated, and the first video signal and the second video signal are recorded on a recording medium.

The still / movie video camera of the present invention includes a large number of photoelectric conversion elements arranged in the row direction and the column direction, and these photoelectric conversion elements are arranged for every other row for the first field and the second field. The photoelectric conversion element for the first field and the photoelectric conversion element for the second field are exposed by a high-speed shutter speed
The above-mentioned solid-state so as to mix the signal charges accumulated in the photoelectric conversion elements for the first field and the photoelectric conversion elements for the second field which are vertically adjacent to each other and output the first video signal from the mixed signal charges. First photographing control means for controlling the electronic image pickup device, the photoelectric conversion device for the first field and the photoelectric conversion device for the second field are alternately exposed by a normal shutter speed, and the first image is converted by the interlace scanning. The solid-state electronic image pickup device so as to alternately read out the signal charges accumulated in the photoelectric conversion device for one image and the photoelectric conversion device for the second image, and to output the second video signal from the read signal charges. Second photographing control means for controlling the above, the photoelectric conversion element for the first field and the second photoelectric conversion element for the first field periodically during photographing of a plurality of consecutive fields.
The field photoelectric conversion element and the photoelectric conversion element for the second field are exposed at a high shutter speed at the same time, and the photoelectric conversion element for the first field and the photoelectric conversion element for the second field are alternately alternated for each field at a normal shutter speed. Control means for controlling the first photographing control means and the second photographing control means so as to perform exposure by means of the first image signal and the second image signal output from the solid-state electronic image pickup device. Is provided on a recording medium.

According to the present invention, exposure is performed at a high shutter speed on a regular basis for one field of the continuous shooting of a plurality of fields, and at other times, exposure is performed at a normal shutter speed. When exposure is performed at a high shutter speed, the signal charges accumulated in the photoelectric conversion element for the first field and the photoelectric conversion element for the second field that are vertically adjacent to each other are mixed and output as the first video signal. . When the exposure is performed at the normal shutter speed, the photoelectric conversion element for the first field and the photoelectric conversion element for the second field are interlaced-scanned, and the signal charges accumulated in the respective photoelectric conversion elements are read out and the second photoelectric conversion element is read out. Is output as a video signal. The first video signal and the second video signal are recorded on the recording medium.

Therefore, a clear image can be obtained by reproducing a still image (creating a print image or displaying it on the screen of a display device) by using a video signal obtained by photographing at a high shutter speed. Further, since shooting at a high shutter speed is performed only once out of a plurality of consecutive times, even when a movie is reproduced, there is no discomfort and the image feels natural.

At a high shutter speed, the exposure time becomes shorter than that at a normal shutter speed, and the level of a video signal obtained by exposure at a high shutter speed is higher than the level of a video signal obtained by exposure at a normal shutter speed. Will be lower. According to the present invention, when the exposure is performed at the high shutter speed, the signal charges accumulated in the vertically adjacent photoelectric conversion elements of the first field photoelectric conversion element and the second field photoelectric conversion element are mixed. Therefore, the level of the video signal becomes high.

When the high shutter speed is twice the normal shutter speed, the level of the high shutter speed video signal and the level of the normal shutter speed video signal are substantially equal to each other, so that flicker is prevented from occurring in the reproduced image. it can.

In the above, the level of the first video signal obtained by exposure at a high shutter speed is set to be substantially equal to the level of the second video signal obtained by exposure at a normal shutter speed. It is preferable to amplify the first video signal and the second video signal.

By thus amplifying, the level of the first video signal obtained by the exposure at the high shutter speed and the level of the second video signal obtained by the exposure at the normal shutter speed are always substantially equal to each other, and the reproduction is performed. It is possible to prevent the occurrence of flicker in the image. Even in this case, since the signal charges are mixed to raise the level of the first video signal, the amplification factor for the first video signal can be made relatively small and the noise component can be made small.

Even if the amplification factor for the second video signal is maximized, it is determined whether the level of the first video signal is different from the level of the second video signal, and the level of the first video signal is When it is determined that the level is different from the level of the second video signal, the amplification rate for the first video signal is amplified to 1/2 of the amplification rate for the second video signal, and the high shutter speed is set to It is preferable that the shutter speed is equal to the normal shutter speed.

Even if the amplification factor for the second video signal is maximized, when the level of the first video signal is different from the level of the second video signal, the flicker cannot be completely removed from the reproduced image. Therefore, the high shutter speed is made equal to the normal shutter speed, and the video signal levels are adjusted to be equal.

It is determined whether or not the first video signal or the second video signal has a flicker due to illumination light, and the first video signal or the second video signal has
When it is determined that there is flicker due to illumination light, the amplification factor for the first video signal is amplified by halving the amplification factor for the second video signal, and the high shutter speed is set to the normal shutter speed. It should be equal to the shutter speed.

If the subject is under illumination light such as a fluorescent lamp, flicker may occur in the reproduced image even if the levels of the first video signal and the second video signal are adjusted in order to prevent the flicker of the reproduced image. There is. Therefore, the exposure at the high shutter speed is stopped, and the exposure is performed at the normal shutter speed.

When the speed of the normal shutter speed can be set, in response to the normal shutter speed being set to a predetermined speed or higher which is faster than the normal shutter speed, the first image is displayed. It is preferable that the amplification factor for the signal is 1/2 the amplification factor for the second video signal, and the high shutter speed is equal to the normal shutter speed.

[0019]

1 is a block diagram showing the electrical construction of a still / movie video camera according to an embodiment of the present invention.

The still / movie video camera shown in FIG. 1 is a high-speed video camera for obtaining a video signal suitable for still reproduction for one field in a continuous multiple field shooting by setting still / movie shooting. Shooting is performed at the shutter speed, and in addition, shooting is performed at the normal shutter speed. Shooting was performed at a high shutter speed of 1/125 second once in 20 fields, and at 1/60 other times.
Shooting is performed at a normal shutter speed of 2 seconds.

The CPU 30 determines a high shutter speed and a normal shutter speed.

When the user of the camera manually sets a high shutter speed for obtaining a video signal suitable for still reproduction, the shutter speed set by the user of the camera is adopted as the high shutter speed.

In a camera having an automatic exposure control (AE) function, the shutter speed is determined based on the brightness of the subject. Since it is extremely difficult to change the aperture for each field, the aperture value of the aperture will be fixed. The aperture value of this diaphragm will generally be set to a value suitable for movie mode. That is, the aperture value is determined in consideration of the normal shutter speed and the subject brightness (shutter speed priority). On the other hand, the high shutter speed for still reproduction will be determined in consideration of the aperture value and subject brightness (aperture priority). In order to simplify the processing in the CPU 30, the relationship between the high-speed shutter speed and the aperture value may be set in advance as a table using the subject brightness value as a parameter.

The CPU 30 gives a command signal representing the high shutter speed thus determined and the normal shutter speed to the timing generation circuit 31. The timing generating circuit 31 is a pulse signal for controlling the zoom lens 2, a pulse signal for controlling the opening and closing of the iris 3, a pulse signal for driving the CCD 5, and sampling in the CDS (correlated double sampling pulse) 6.・ Pulse SP, control signal for switching gain of automatic gain adjustment circuit (hereinafter referred to as AGC) 7, control signal for ON / OFF control of operation of AGC 8, clamp pulse SP for clamp and blanking Blanking pulse BLK is generated.

A pulse signal for controlling the zoom lens 2 is given to the driver 24, and the zoom motor 22 is driven according to the pulse signal given to the driver 24. The zoom motor 22 determines the zoom position of the zoom lens 2.

A pulse signal for controlling the opening and closing of the iris 3 is also given to the driver 24, and the iris motor 23 is driven according to the pulse signal given to the driver 24.
The opening / closing position of the iris 3 is determined by the iris motor 23.

A pulse signal for driving the CCD 5 is a substrate reset signal SUBRST for sweeping unnecessary charges accumulated in the CCD 5 from the substrate, and a signal charge of a vertical transfer path included in the CCD 5 is transferred to a horizontal transfer path. Vertical transfer pulses φV1 to φV4, horizontal drive pulses φH1 and φH2 for driving the horizontal transfer path, and the like.

The substrate reset signal SUBRST is applied to the CCD 5 via the SUB driver 25, the vertical transfer pulses φV1 to φV4 are applied to the CCD 5 via the V driver 26, and the horizontal transfer pulses φH1 and φH2 are applied to the H driver.
It is given to the CCD 5 via 27.

The sampling pulse SP is given to the CDS 6 and correlated double sampling is performed. The gain control signal is given to the first AGC 7. First AGC7
Is for amplifying an input video signal with an amplification factor of 0 dB, 6 dB, or 12 dB, and any one of the amplification factors is determined according to the gain control signal given from the timing generation circuit 31. The gain control signal is also given to the second AGC 8. The second AGC 8 attenuates the input video signal to -6 dB and outputs it when the operation is turned on.
When the operation is off, the input video signal is passed as it is. The gain control signal provided from the timing generation circuit 31 controls the on / off operation in the second AGC 8.

The clamp pulse CL and the blanking pulse BLK are given to the analog signal processing circuit 10.

The image optical system includes a zoom lens 2, an iris 3, an OLPF (optical low pass filter) 4 and a CCD 5.

In this embodiment, a photometry sensor 28 is provided for preliminary photometry, and a range finding sensor 29 is provided for preliminary range finding. The photometry data and range finding data by these sensors 28 and 29 are stored in the CPU 30. Given. CPU30
Controls at least one of the aperture value and the shutter speed on the basis of the photometric data obtained from the photometric sensor 28 so that the exposure amount to the CCD 5 falls within a substantially appropriate range. The CPU 30 also controls the zoom lens 2 via the driver 24 based on the distance measurement data from the distance measurement sensor 29.
Determine the zoom amount of.

After the rough exposure amount adjustment based on the preliminary photometry and the general focusing control based on the preliminary distance measurement, the preliminary photographing is performed. By this preliminary shooting CCD
Using the video signal obtained from No. 5, calculation of the photometric value, precise exposure control, and highly accurate focusing control will be performed. These highly accurate exposure control and focusing control will be described in detail later.

The still / movie video camera includes a switch group 35 for setting various controls of the camera.

The switch group 35 includes a power switch 36 for turning on the power of the still / movie video camera.
A still / movie shooting setting switch 37 for setting still / movie shooting, a gain setting switch 38 for setting an amplification factor in the first AGC 7, and a shutter speed setting switch 39 for manually setting a normal shutter speed are included. Has been.

Depending on the setting of the still / movie shooting setting switch 37, the still / movie shooting operation is performed.

By setting the gain setting switch 38, the amplification factor in the first AGC 7 is selected to be 0 dB, 6 dB or 12 dB. Further, by setting the shutter speed setting switch 39, the normal shutter speed other than the high shutter speed is set to 1/125 seconds or 1/250 seconds.

Signals representing the settings of various switches in the switch group 35 are sent to the CPU 30 via the display CPU 33.
And various control operations according to the settings are performed.

The still / movie video camera includes a liquid crystal display device 34 controlled by a display CPU 33. Various switches 36 included in the switch group 35
The setting statuses in 39 to 39 are displayed on the liquid crystal display device.

In the CCD 5, as will be described later, a photodiode for the first field and a photodiode for the second field are defined every other row.

When still / movie shooting setting switch 37 is set to still / movie shooting, shooting is performed at a high shutter speed once in 20 fields, and at other times, shooting is performed at a normal shutter speed.

In photographing at a normal shutter speed, interlaced photographing is performed, and the signal charge accumulated in the photodiode for the first field and the signal charge accumulated in the photodiode for the second field are every one field period. Are read alternately.

In photographing at a high shutter speed, the signal charges accumulated in the photodiodes for the first field and the photodiodes for the second field which are vertically adjacent to each other are mixed and read.

When shooting at a high shutter speed, the exposure amount is smaller than that when shooting at a normal shutter speed and flicker may occur in a reproduced image. However, the high shutter speed is twice as high as the normal shutter speed. In this case, the exposure amount at the high shutter speed and the exposure amount at the normal shutter speed are equal to each other, and the occurrence of flicker can be prevented.

The video signal output from the CCD 5 is CDS
It is given to the first AGC 7 via 6. First AGC
7, the timing generation circuit 31 to the first AGC 7
The input video signal is amplified in accordance with the gain control signal given to. The amplification factor of the first AGC 7 is set to 0 dB and is not amplified when a video signal obtained by shooting at a normal shutter speed is input. When a video signal obtained by shooting at a high shutter speed is input to the first AGC 7, and the high shutter speed is twice the normal shutter speed, for example, the high shutter speed is 1 /
Even if the shutter speed is 120 seconds and the normal shutter speed is 1/60 second,
The amplification factor of AGC7 is set to 0 dB. The video signal obtained by shooting at a high shutter speed is the first AGC 7
When the high shutter speed is four times the normal shutter speed, for example, the high shutter speed is 1/250 seconds and the normal shutter speed is 1/60 seconds, the first AGC 7 The amplification factor is set to 6 dB. The video signal obtained by shooting at a high shutter speed is the first A
When inputting to the GC7 and the high shutter speed is eight times the normal shutter speed, for example, the high shutter speed is 1/500 seconds and the normal shutter speed is 1/60 seconds, the first AGC7 The amplification factor of is set to 12 dB.

The video signal output from the first AGC 7 is given to the second AGC 8.

The second AGC 8 is responsive to the gain control signal supplied from the timing generation circuit 31 for the first AGC 7
It attenuates the video signal output from -6 dB. The second AGC8 is still / movie shooting setting button 37
When still / movie shooting is set and normal movie shooting is performed, the difference between the high shutter speed and the normal shutter speed is large as described below even if still / movie shooting is set. Even if the amplification factor of the AGC 7 is maximized, when the level of the video signal obtained by shooting at the high shutter speed becomes lower than the level of the video signal obtained by shooting at the normal shutter speed, the flicker detection circuit 21 causes flicker. When detected, the shutter speed setting button 39 causes the normal shutter speed to be higher than a predetermined speed (for example, 1/60 second) (1/125 second,
When set to 1/250 second, etc., it is controlled by the gain control signal output from the timing generation circuit 31 so that the attenuation process is performed, and shooting at a high shutter speed in still / movie shooting is prohibited. The second AGC 8 is set to still / movie shooting by the still / movie shooting setting button 37, and no attenuation processing is performed when still / movie shooting is performed.

The video signal output from the second AGC 8 is applied to the analog signal processing circuit 10.

The analog signal processing circuit 10 includes a gain control circuit, a gamma correction circuit, a clamp and resampling circuit, a blanking circuit, etc.
Color balance adjustment, gamma correction clamp and resampling are performed according to a control signal provided from the timing generation circuit 31, and a blanking signal is added.

In the analog signal processing circuit 10, the video signal is processed into a form recordable on a video tape (not shown), given to the magnetic head 11, and recorded on the video tape.

Prior to the main photographing, precise photometric processing (exposure control) and focusing control are performed as described above. The photometric processing is performed by utilizing the low frequency component of the video signal obtained from the CCD 5 by preliminary photographing, and the focusing control is performed by utilizing the high frequency component of the above video signal.

In order to take out the low frequency component of the video signal representing the image in the photometric area (described later) provided in the photographing area of the CCD 5 for the photometric processing, the Y _L synthesizing circuit 17,
A gate circuit 18, an integration circuit 19 and an amplification circuit 20 are provided. The output signal of the amplifier circuit 20 is given to the CPU 30 via the A / D converter 42.

On the other hand, for focusing control, in order to extract a high frequency component of a video signal representing an image in a distance measuring area (described later) provided in the photographing area of the CCD 5, a gate circuit is used.
12, band pass filter (hereinafter referred to as BPF) 1
3, a detection circuit 14, an integration circuit 15, and an amplification circuit 16 are provided. The output signal of the amplifier circuit 16 is given to the CPU 30 via the A / D converter 41.

Photometric processing, exposure control (control of aperture and shutter) based thereon, and focusing control (zoom lens 2)
The actual shooting is performed after (positioning). The video signal obtained from the CCD 5 by the main photographing is the above-mentioned circuits 6, 7,
It is given to the magnetic head 11 via 8 and 10 and recorded on the video tape.

Of the photometric processing (and exposure control based on it) and the focus control prior to the main photographing, the photometric processing will be described first.

The photometric processing is performed by the Y _L synthesizing circuit 17, as described above.
This is performed using the gate circuit 18, the integrating circuit 19 and the amplifying circuit 20. The output signal of the second AGC 8 is applied to the Y _L combining circuit 17.

The CPU 30 outputs a window signal WIND1 for controlling the gate circuit 18 and a reset signal HLRST1 for resetting the integrating circuit 19. These signals WI
The timing of ND and HLRST will be described later.

The signal output from the second AGC 8 is Y _L
The luminance signal Y _L of a relatively low frequency which is added by the synthesizing circuit 17
(Hereinafter simply referred to as luminance signal Y _L ) is generated. The luminance signal Y _L passes through the gate circuit 18 while the window signal WIND1 is applied during the required horizontal scanning period. The integrating circuit 19 is reset when the reset signal HLRST1 is given, and then integrates the luminance signal Y _L input from the gate circuit 18. The integrated signal of the integrating circuit 19 is amplified by the amplifying circuit 20 and then input to the A / D converter 42 immediately before the integrating circuit 19 is reset.
Converted to digital integration data for photometry by 42 and C
Taken into PU30.

In the photometric processing of this embodiment, average photometry (hereinafter referred to as A
V metering) and spot metering (hereinafter referred to as SP metering) for measuring the brightness of the main subject in the field of view. The SP metering is useful when the brightness of the main subject and the background in the field of view are different and it is necessary to set an appropriate exposure condition accordingly.

Further, in this embodiment, the integration by the integration circuit 19 and the A / D conversion operation and addition processing by the A / D converter 42 are alternately performed every horizontal scanning period.

FIG. 2 shows an AV photometric area and an SP photometric area set in the photographing area 50 of the CCD 5.

The AV photometric area is basically set over almost the entire photographing area 50. In this embodiment, the AV photometric area is set for a period of 40 μs after the lapse of 16 μs from the trailing edge of the horizontal synchronizing signal HD (the start point of the horizontal scanning period) in the horizontal direction, and the 35th horizontal scanning in the vertical direction. 24th from the line
It is set up to the 6th horizontal scan line.

The SP photometric area is set as a small area at an arbitrary position within the photographing area 50. In this embodiment, the SP metering area is set at the center of the photographing area 50, and the horizontal direction is the 87th horizontal scanning line in the vertical direction during the period of 15 μs after 28.5 μs has elapsed from the fall of the horizontal synchronizing signal HD. From the 194th
It is set up to the second horizontal scan line.

The memory associated with the CPU 5 is provided with a photometry area and a distance measurement area. AV metering area data area and SP metering area data
There is an area.

When AV photometry is performed, integration is performed every other horizontal scanning line in the AV photometry area.
The above integration is performed every other horizontal scanning line for A / D conversion, reset integration of the integration circuit, and data addition processing.

As shown in FIG. 3, in AV photometry, between the 34th horizontal scanning line and the 246th horizontal scanning line, the gate circuit 18 is provided with 16 μs after the fall of the horizontal synchronizing signal HD. A window signal WIND1 having a pulse width of 40 μs is applied. Then, the integrating circuit 19
Integration of the luminance signal Y _L , A / D conversion of the integration signal in the horizontal scanning period subsequent to the horizontal scanning period in which this integration operation is performed, reset of the integrating circuit 19 and AV of the memory.
The addition of integrated data to the photometric area data area is alternately repeated for each horizontal scanning period.

When SP photometry is performed, a pulse width rises 28.5 μs after the fall of the horizontal synchronizing signal HD in the gate circuit 18 between the 87th horizontal scanning line and the 194th horizontal scanning line. A window signal WIND1 of 15 μs is provided.

Also in SP photometry, when the window signal WIND1 having a pulse width of 15 μs is given to the integrating circuit 19 to integrate the luminance signal Y _L , the integration is performed in the horizontal scanning period next to the horizontal scanning period in which the integration operation is performed. A / D conversion of the signal, reset of the integrating circuit 19, and addition of the integrated data to the SP photometric area data area of the memory are performed.

When AV photometry is performed, the CPU 30 adds integrated data for one horizontal scanning line obtained based on the window signal WIND1 having a pulse width of 40 μs in the AV photometry area data area for one field period by the procedure described later. Then, the AV photometric value is calculated.

When SP metering is performed, the CPU 30
The integrated data for one horizontal scanning line obtained based on the window signal WIND1 having a pulse width of 15 μs is added in the SP metering area data area for one field period by the procedure described later to calculate the SP metering value.

Next, focusing control will be described.

Referring again to FIG. 1, the output signal of the second AGC 8 is input to the gate circuit 12. The gate circuit 12 is CP
It is controlled by the window signal WIND2 provided from U30. The output signal of the second AGC 8 passes through the gate circuit 12 and is input to the BPF 13 during the period in which the window signal WIND2 is provided in the required horizontal scanning period.

The BPF 13 extracts a high frequency component required for focusing control from the input signal, and the output signal of the BPF 13 is input to the detection circuit 14. The high-frequency signal component output from the BPF 13 is detected by the detection circuit 14, integrated by the integration circuit 15, further amplified by the amplification circuit 16, and then input to the A / D converter 41, which is the A / D converter. Converted to digital data for focus control at 41,
Captured by the CPU 30.

The digital data given from the A / D converter 41 is integrated data obtained by integration over a horizontal scanning period of a focus detection area, which will be described later, set in the photographing area. Is added over the vertical scanning period of the focus detection area to calculate focus detection data, and focus control is performed based on this data. Details will be described later.

In general, when the image is out of focus and the image is blurred, the high frequency component contained in the video signal obtained from the CCD 5 by photographing is small. When the image comes into focus, the high-frequency component of the video signal increases, and the high-frequency component contained in the video signal becomes maximum at the correctly focused position. In this embodiment, focusing control is performed based on such a fact, and B
The PF13 has about 1.5 to extract high frequency components of the video signal.
A pass band of ~ 2.5 MHz is set.

FIG. 4 shows a focus detection area set in the photographing area 50 of the CCD 5. This focus detection area is set at the center of the shooting area 50 where the main subject is highly likely to exist. In this embodiment, the horizontal direction is set as an area smaller than the SP photometric area shown in FIG. Of course, it goes without saying that the focus detection area can be set to any location within the shooting area 50 and to any width.

As shown in FIG. 5, a window signal WIND2 having a pulse width of 10 μs is given to the gate circuit 12 after 31 μs has elapsed from the falling edge of the 87th horizontal synchronizing signal HD, and as described above, this window signal WIND2 is supplied. WIND2
, The gate circuit 12 allows the output signal of the second AGC 8 to pass. The high frequency component signal extracted by the BPF 13 is given to the integration circuit 15 via the detection circuit 14 and integrated. The integrated output signal of the integrating circuit 15 is passed through the amplifying circuit 16, converted into digital data by the A / D converter 41 in the next horizontal scanning period, and given to the CPU 30.
The integrating circuit 15 performs the A / D conversion process and then the reset signal HLR.
It is reset by ST2. The CPU 30 stores this digital data by adding it to the previous data in the distance measuring area of the memory (which is zero because it has been cleared in the first case). The distance measuring area is cleared in synchronization with the 86th horizontal synchronizing signal HD or at the start of the field.

As described above, the high frequency component signal is detected by the BPF 13 on one horizontal scanning line in the focus detection area, the detection and integration of this high frequency component signal, the A / D conversion of the integrated signal, and the horizontal conversion are performed. The addition of integrated data in the scanning period is alternately repeated every horizontal scanning period. Then, this repetition is performed until the 194th horizontal scanning period, that is, over the entire area within the focus detection area.

Therefore, at the time when the scanning in the focus detection area is completed, the focus detection area of the memory shows the focus detection addition indicating the integral value of the high frequency signal passing through the BPF 13 over the entire focus detection area. The data has been stored.

As described above, the approximate distance to the subject is measured in the preliminary distance measurement using the distance measuring sensor 29. Zoom lens 2 based on this preliminary distance measurement data
Is extended to a position slightly before the focus position (referred to as an initial position).

The integration operation of the high frequency component of the video signal output from the CCD 5 over the focus detection area is performed at least 6 times (that is, the B field of each frame period for 6 frame periods) while the zoom lens 2 is moved forward by 10 μm. (During the period). At the initial position (extending amount of the zoom lens 2 = 0 μm), first addition data for focus detection is first obtained. In the next frame period, zoom lens 2 from the initial position to 10 μm
The second addition data for focus detection is obtained at the extended position (zoom lens extension amount = 10 μm). Similarly, the third to sixth focus detection addition data are obtained while the zoom lens 2 is extended by 10 μm. The 6-position addition data thus obtained is stored in a predetermined area of the memory as shown in FIG.

FIG. 7 is a graph showing the in-focus detection addition data at the six positions shown in FIG. zoom·
The initial position of the lens 2 is slightly before the true focus position.
From this position, the zoom lens 2 is extended by 10 μm,
Focusing addition data is obtained. The integrated value of the high frequency signal included in the video signal becomes maximum at the true focus position. Since the unit extension amount of the zoom lens 2 is 10 μm, which is a very small distance, even if the position where the addition data for focus detection shows the maximum value is regarded as the true focus position, the error is extremely small. Therefore, high-precision focusing can be achieved by positioning the zoom lens 2 at the position where the addition data for focus detection shows the maximum value.

Referring again to FIG. 1, the still / movie video camera includes a flicker detection circuit 21.
The flicker detection circuit 21 is supplied with the output signal of the second AGC 8. The flicker detection circuit 21 detects that the video signal contains flicker due to a fluorescent lamp or the like, and the detection signal is converted into digital data by the A / D converter 43 and taken into the CPU 30.

When the subject is under the illumination causing flicker such as fluorescent light, the brightness of the subject varies depending on the flicker, and the brightness of each screen is different. Ie 2 consecutive
The average levels of the video signals of two fields (or two frames) representing the image of one frame are different.

Therefore, the flicker detection circuit 21 can determine whether or not the reproduced image is affected by the illumination light having flicker by comparing the levels of the video signals representing the images of two consecutive frames.

The still / movie video camera includes a battery 32, and power is supplied to each of the above-mentioned units.

FIG. 8 is a schematic diagram of the CCD 5.

As shown in FIG. 8, the CCD 5 is provided with a large number of photodiodes 60A and 60B arranged vertically and horizontally, a vertical transfer path 62 vertically arranged between the photodiodes 60A and 60B, and a signal charge. A horizontal transfer path 63 for transferring in the horizontal direction is included. In FIG. 8, the photodiodes in the odd rows are indicated by the reference numeral 60A, and the photodiodes in the even rows are indicated by the reference numeral 60B. The photodiodes 60A and 60B and the vertical transfer path
A transfer gate 61 for shifting the signal charge accumulated in the photodiodes 60A and 60B to the vertical transfer path 62 is formed between the transfer gate 61 and 62.

When still / movie shooting is set in the still / movie video camera shown in FIG. 1, when shooting is performed at a normal shutter speed,
Referring to FIG. 8, interlaced scanning is performed, and the signal charges accumulated in the photodiodes 60A in the odd rows and the signal charges accumulated in the photodiodes 60B in the even rows are alternately shifted to the vertical transfer path 62, It is output via the horizontal transfer path 63. When still / movie shooting is set and shooting is performed at a high shutter speed, the signal charges accumulated in the photodiodes 60A in odd rows and the signal charges accumulated in the photodiodes 60B in even rows are vertically transferred. The signal charges accumulated in the odd-numbered photodiodes 60A vertically adjacent to each other, which are shifted to the path 62, and the signal charges accumulated in the even-numbered photodiodes 60B are pixel-mixed in the vertical transfer path 62, and the horizontal transfer path 63 Will be output.

FIG. 9 is a time chart showing the reading of the signal charges accumulated in the CCD, and FIG. 10 shows the transfer of the signal charges (shown by hatching) in the vertical transfer path. Readout of signal charges will be specifically described below with reference to these drawings.

CCD photodiodes 60A and 60B
In principle, the signal charges stored in the vertical transfer path 62 are shifted to the vertical transfer path 62 on the basis of 1 V (V is one vertical scanning period).

The transfer gate 61 is synchronized with the vertical reference signal VD.
To field shift pulses FSA and FSB, respectively. Field shift pulse FSA
Is for shifting the signal charges accumulated in the photodiodes 60A in odd rows to the vertical transfer paths 62, and is supplied to the transfer gates 61 in odd rows every 2V. The field shift pulse FSB shifts the signal charges accumulated in the photodiodes 60B in even rows to the vertical transfer paths 62, and is applied to the transfer gates 61 in even rows every 2V. The field shift pulses FSA and FSB are applied to the transfer gate 61 with a delay of 1V. In addition, the substrate extraction pulse for sweeping out the unnecessary charge substrate accumulated in the photodiodes 60A and 60B is C every 1 V in synchronization with the vertical reference signal VD.
Given to CD5.

Referring to FIG. 9, from time t ₁ to time t ₄ , shooting is performed at a normal shutter speed in still / movie shooting. Shooting is performed at a high shutter speed from time t ₅ to time t ₆ . Substrate extraction pulse and field shift pulse FSA and FSB
Determines the shutter speed.

At time t ₁ , the CCD 5 is given a substrate removal pulse to sweep out unnecessary charges accumulated in the photodiodes 60A and 60B.

At the time t ₂ , the field shift pulse FSB is applied to the transfer gates 61 in the even-numbered rows, and the time t
_The signal charges accumulated in the photodiodes 60B in even rows between ₁ and time t ₂ are shifted to the vertical transfer path 62. This state is shown in Fig. 10 (A). Vertical transfer pulses φV1 to φV4 are applied to the vertical transfer path 62, and the signal charges are transferred to the horizontal transfer path 63. Vertical transfer pulses φH1 and φH2 are applied to the horizontal transfer path 63, and signal charges are output.

At time t ₃ , the field shift pulse FSA is applied to the transfer gates 61 in the odd-numbered rows, and at time t ₃ .
_The signal charges accumulated in the photodiodes 60A in the odd rows between ₂ and time t ₃ are shifted to the vertical transfer path 62. This state is shown in Fig. 10 (B). The signal charges are transferred through the vertical transfer path 62 and output through the horizontal transfer path 63.

Referring to FIG. 9, from time t ₅ to time t ₆ , shooting is performed at a high shutter speed in still / movie shooting.

At time t ₅ , the substrate removing pulse is applied to the CCD 5.

At time t ₆ , the transfer gates 61 in the odd rows are
Field shift pulse FSA is applied to the field shift pulse FSB.
Is given. As a result, the signal charges accumulated in the photodiodes 60A and 60B from the time t ₅ to the time t ₆ are shifted to the vertical transfer path 62. This state is shown at the top of FIG. 10 (C). Time t ₆ in the vertical transfer pulses .phi.V1, .phi.V2 and φV3 and a given odd rows of the photodiode 60A to accumulated signal charges and even rows of the photodiode 60B in the accumulated signal charges are mixed (pixel mixing). The pixel-mixed signal charges are transferred vertically
Are transferred and output via the horizontal transfer path 63.

[0100] Fast shutter speed of the exposure time t ₃ ~t ₆ are normal shutter speed exposure time _{t 1 ~t 2, t 2 ~t} 3
Although shorter than the above, signal charges are read out by interlaced scanning at a normal shutter speed, and at high shutter speeds, signal charges accumulated in vertically adjacent photodiodes are mixed. When the high shutter speed is twice the normal shutter speed, the amount of the signal charges output from the CCD 5 becomes substantially equal, and the occurrence of flicker during reproduction is prevented.

FIG. 11 is a flowchart showing another example at the time of still / movie shooting.

At time t ₁₃ , the substrate removal pulse is applied to the CCD 5 and the exposure time at the high shutter speed is from time t ₁₃ to time t ₁₄ . The high shutter speed time is 1/250 second.

When the high shutter speed is four times the normal shutter speed, the first AGC 7 amplifies the video signal obtained by shooting at the high shutter speed by 6 dB. As a result, the level of the video signal obtained by shooting at the normal shutter speed and the level of the video signal obtained by shooting at the high shutter speed are substantially equal to each other, and flicker is prevented from occurring during reproduction.

When shooting at a high shutter speed, C
Since the signal charges accumulated in the photodiode of the CD5 are subjected to pixel mixing, the amplification factor of the first AGC 7 is lower than that when no pixel mixing is performed, and the SN ratio is relatively high.

When still / movie shooting is set by the still / movie setting button 37 and flicker is detected by the flicker detection circuit 21, the subject brightness level measured by the photometric sensor 28 or the like is a predetermined level (for example, 1000 lx) or less, if the normal shutter speed is set to a speed faster than a predetermined speed (for example, 1/125 second, 1/250 second) by the shutter speed setting button 39, still / movie shooting is performed at time t _1. The substrate extraction pulse P (indicated by a chain line at time t ₁₇ ) that should be added at time t ₁₇ is not added and is accumulated in the photodiodes 60A in the odd rows and the photodiodes 60B in the even rows between the times t ₁₆ and t _18. The generated signal charges are shifted to the vertical transfer path 62 at time t ₁₈ . The signal charges shifted to the vertical transfer path 62 are transferred through the vertical transfer path 62 and then transferred to the horizontal transfer path 63.
Is output via.

In this case, the picture is taken at a normal shutter speed,
The amount of signal charges is larger than that when reading signal charges by interlaced scanning, and flicker may occur during reproduction. Therefore, this still / movie video
In the camera, the video signal output from the time t ₁₈ to the time t ₁₉ is attenuated to −6 dB by the second AGC 8. This prevents the occurrence of flicker due to the level difference between the video signals during reproduction.

When reproducing the video signal recorded in this way, a high-precision reproduced image without blur can be obtained by using the video signal obtained at a high shutter speed for still reproduction. Also, since shooting at a high shutter speed is performed once for shooting in a plurality of fields, a movie playback image with smooth motion and no flicker can be obtained even when movie playback is performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a still / movie video camera.

FIG. 2 is a diagram showing a photometric area set within a shooting area.

FIG. 3 is a time chart showing photometric processing.

FIG. 4 is a diagram showing a distance measuring area set within a photographing area.

FIG. 5 is a time chart showing distance measurement processing.

FIG. 6 is a diagram showing a storage area of addition data for focus detection.

FIG. 7 is a graph showing focus detection addition data.

FIG. 8 is a schematic diagram of a CCD.

FIG. 9 is a time chart showing reading of signal charges accumulated in a CCD.

FIG. 10 shows how signal charges are transferred in a vertical transfer path.

FIG. 11 is a time chart showing reading of signal charges accumulated in a CCD.

[Explanation of symbols]

 5 CCD 11 Magnetic head 25 SUB driver 26 V driver 27 H driver 30 CPU 31 Timing generation circuit

Claims (12)

[Claims] 1. A plurality of photoelectric conversion elements arranged in a row direction and a column direction are included, and these photoelectric conversion elements are defined every other row for a first field and a second field,
By using a solid-state electronic image pickup device with controllable exposure time, the photoelectric conversion device for the first field and the photoelectric conversion device for the second field can be operated at high speed periodically for one field during continuous shooting of a plurality of fields. Simultaneous exposure is performed at a shutter speed, and in addition, the photoelectric conversion element for the first field and the photoelectric conversion element for the second field are alternately exposed one by one at a normal shutter speed, and the first and second photoelectric conversion elements are exposed at a high shutter speed. When the 1-field photoelectric conversion element and the 2nd field photoelectric conversion element are exposed at the same time, they are accumulated in the vertically adjacent 1st field photoelectric conversion element and 2nd field photoelectric conversion element. The mixed signal charges are mixed, and the first image signal is generated from the mixed signal charges. When the photoelectric conversion elements for the first field and the photoelectric conversion elements for the second field are alternately exposed for each field, the photoelectric conversion element for the first field and the photoelectric conversion element for the second field are interlaced for scanning. The signal charges accumulated in the conversion element are read alternately for each field, a second video signal is generated from the read signal charges, and the first video signal and the second video signal are recorded in a recording medium. , Still / movie video camera control method. 2. The still / movie according to claim 1, wherein the normal shutter speed is twice the high shutter speed.
Video camera control method. 3. The level of the first video signal obtained by exposure at a high shutter speed is set to be substantially equal to the level of the second video signal obtained by exposure at a normal shutter speed. The still / movie video camera control method according to claim 1, wherein the first video signal and the second video signal are amplified. 4. It is determined whether or not the level of the first video signal is different from the level of the second video signal even if the amplification factor for the second video signal is maximized. When it is determined that the level is different from the level of the second video signal, the amplification factor for the first video signal is set to 1 of the amplification factor for the second video signal.
The still / movie video camera control method according to claim 3, wherein the high-speed shutter speed is made equal to / 2 and the high-speed shutter speed is made equal to the normal shutter speed. 5. It is determined whether or not the first video signal or the second video signal has a flicker caused by illumination light, and the first video signal or the second video signal is illuminated. When it is determined that there is flicker due to light, the first
4. The still / movie according to claim 3, wherein the amplification rate for the video signal of 1 is amplified as 1/2 of the amplification rate for the second video signal, and the high-speed shutter speed is made equal to the normal shutter speed.・ How to control the video camera. 6. The speed of the normal shutter speed can be set, and in response to the normal shutter speed being set at a speed higher than a predetermined speed higher than the normal shutter speed,
The amplification rate for the first video signal is amplified to 1/2 of the amplification rate for the second video signal, and the high shutter speed is made equal to the normal shutter speed. How to control a still / movie video camera. 7. A plurality of photoelectric conversion elements arranged in a row direction and a column direction are included, and these photoelectric conversion elements are defined as a first field photoelectric conversion element and a second field photoelectric conversion element every other row and exposed. A time-controllable solid-state electronic image pickup device, the photoelectric conversion device for the first field and the photoelectric conversion device for the second field are exposed by a high shutter speed, and photoelectric conversions for the first field vertically adjacent to each other are exposed. A first photographing control means for controlling the solid-state electronic image sensor so as to mix the element and the signal charges accumulated in the photoelectric conversion element for the second field and output the first video signal from the mixed signal charge. , The first field photoelectric conversion element and the second field photoelectric conversion element are alternately exposed by a normal shutter speed, and the first field photoelectric conversion element is exposed by interlaced scanning. The solid-state electronic image pickup device is controlled so that the signal charges accumulated in the image photoelectric conversion element and the second image photoelectric conversion element are alternately read, and the second video signal is output from the read signal charges. Second photographing control means, which periodically exposes the photoelectric conversion element for the first field and the photoelectric conversion element for the second field at a high shutter speed for one field in the continuous photographing of a plurality of fields. In addition to the above, the first photographing control means and the photoelectric conversion element for the first field and the photoelectric conversion element for the second field are alternately exposed for each field at a normal shutter speed. Control means for controlling the second photographing control means, the first video signal output from the solid-state electronic image pickup device, and the second image signal. Recording means for recording a signal on a recording medium, the still / movie video camera having a. 8. The still / movie according to claim 7, wherein the normal shutter speed is twice the high shutter speed.
Video camera. 9. The solid-state electronic imaging so that the level of the first video signal obtained by exposure at a high shutter speed is substantially equal to the level of the second video signal obtained by exposure at a normal shutter speed. The still / movie video camera according to claim 7, further comprising: an amplifying unit that amplifies the first video signal and the second video signal output from an element. 10. A determination means for determining whether or not the level of the first video signal does not match the level of the second video signal even if the amplification rate of the second video signal is changed in the amplification means. In response to the determination means determining that the level of the first video signal does not match the level of the second video signal even if the amplification means changes the amplification factor for the second video signal. Then, the amplification factor for the first video signal is 1 / the amplification factor for the second video signal.
The level of the first video signal matches the level of the second video signal even when the gain control means set to 2 and the amplification means change the amplification factor for the second video signal by the determination means. The still / movie video camera according to claim 9, further comprising: shutter speed adjusting means for making the high shutter speed equal to the normal shutter speed in response to the determination that the shutter speed is not set. 11. A flicker detecting means for detecting that the first video signal or the second video signal contains flicker caused by illumination light, and responding to the detection of flicker by the flicker detecting means. And a high-speed shutter in response to the flicker detection by the flicker detection means, and the gain control means for making the amplification rate for the first video signal in the amplification means 1/2 of the amplification rate for the second video signal. The still / movie video camera according to claim 9, further comprising: a shutter speed adjusting unit that makes a speed equal to the normal shutter speed. 12. Setting means for setting the normal shutter speed, wherein the setting means sets the normal shutter speed to a predetermined speed or higher than a shutter speed suitable as the normal shutter speed. The set shutter speed detecting means for detecting, and the amplification factor for the first video signal in the amplifying means in response to the setting of the normal shutter speed by the set shutter speed detecting means to the predetermined speed or more. The high-speed shutter speed is responsive to the normal shutter speed being set to the predetermined speed or higher by the gain control means for halving the amplification factor for the second video signal and the set shutter speed detection means. The shutter speed adjusting means for making the set shutter speed equal to the set normal shutter speed, further comprising: Still / movie video camera.