JPH08317278A - Image pickup device - Google Patents

Abstract

PURPOSE: To surely and easily execute exposure control at the time of stroboscopic photographing by executing stroboscopic emission at a timing synchronized with a discharge pulse and controlling a charge accumulation period corresponding to the count value of discharge pulses. CONSTITUTION: This image-pickup device has a CCD 10 for converting an image of a subject into electric charges in an accumulation period and successively outputting the charge based on discharge pulses in a discharge period. A strobe for irradiating the subject with light is emitted with a timing synchronized with a discharge pulse. The accumulation period of charge of the CCD 10 within the light-emitting timing period of the strobe controlled by a timing generation part 22 is set by counting the discharge pulses. In the accumulation period, the supply of discharge pulses to the CCD 10 is inhibited. Since the accumulation period of charge of the CCD 10 can be optionally set in accordance with the count value of discharge pulses, the control for the exposure which cannot be followed only by a stop at the time of strobe light emission can be allowed for each correspondence by controlling the accumulation period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device, and in particular,
The present invention relates to an image pickup device that picks up an image of a subject with an image pickup device such as a CCD.

[0002]

2. Description of the Related Art When recording an image, there is a demand for recording a still image with a still camera in addition to recording a moving image with a video camera or the like. In this case, V from the user
Some people say that it is troublesome to carry the TR and the still camera separately. In order to meet the above requirements, a still camera-integrated video camera in which a still camera and a video camera are integrated has been considered. With a video camera with a built-in still camera, when using each camera to shoot the same subject at the same time using flash, the sensitivity of the silver salt film used in the still camera is lower than the sensitivity of the image sensor used in the video camera. Therefore, there is a problem that the image sensor causes smear and blooming.

FIG. 4 shows a block diagram of a conventional example. Incident light from the lens unit 52 of the video camera unit 51 is converted into an electric signal by the CCD 53, and the CDS circuit 54
After being detected by, the signal is converted into a digital signal by the AD converter 55. Further, this signal is processed by the DSP 56 and then stored in the field memory 57 as necessary.
The DA converter 58 converts the analog signal. At this time, generally, the DSP 56 separates the luminance signal and the color signal into the VTR 6 through the Y filter 59 and the C filter 60, respectively.
Input to 1. CCD53, CDS54, ADC
55, DSP 56, field memory 57, DAC 58
A timing signal and a clock are supplied from the timing generator 62 to the above. In addition, the lens unit 52 is controlled by the camera process controller 63 so that the aperture controller (A
The E controller) 64 controls the diaphragm 65 to control the exposure.

Further, when the shutter button 73 is operated in the still camera section 74, the incident light from the lens section 66 of the still camera section 74 passes through the diaphragm 67 and the shutter 68 to expose the silver salt film 69 to light. At this time, if the subject is dark, the strobe 70 is supplied through the strobe on switch 73 according to the amount of electric charge adjusted by the system controller 72 supplied from the strobe power source 71 to emit light.

In such an apparatus, when the same subject is simultaneously stroboscopically photographed by the video camera and the still camera, the automatic exposure control (AE after A) used in the video camera is performed.
(Expressed as E) indicates that the subject is moving, and if the response is too good, the image will flicker, so the response was set slow, so proper AE based on the exposure data during flash firing cannot be performed. It was A method in which a subject of a video camera emits a strobe only when the subject is backlit (Japanese Patent Laid-Open No. 4-255181) A method in which the shutter speed is switched so that the strobe emits light within the accumulation time of the CCD (Japanese Patent Laid-Open No. 4-5125) No. 326874) was proposed.

[0006]

However, since it is better not to follow abrupt changes of the subject such as an obstacle crossing in front of the AE due to the aperture of the video camera, the time constant is set to be long and stroboscopic photography is performed. When this is done, the flash emission period is as fast as approximately 2 mSEC, so the brightness of the subject actually exposed by the flash light is measured and AE is performed.
Is difficult to carry out, and stroboscopic photography with a video camera cannot be effectively performed.

The present invention has been made in view of the above points, and an object of the present invention is to provide an image pickup apparatus in which exposure control at the time of stroboscopic photography can be performed reliably and easily.

[0008]

According to a first aspect of the present invention, in an image pickup apparatus having an image pickup device for converting an image of a subject into electric charges during an accumulation period and sequentially outputting the electric charges by a discharge pulse during a discharge period, the light is emitted to the subject. Strobe light emission control means for emitting light at a timing that is synchronized with the discharge pulse, and a discharge pulse for the charge accumulation period of the image sensor within the strobe light emission timing period controlled by the strobe light emission control means. The storage period setting means for counting and setting the storage period and the gate means for prohibiting the supply of the discharge pulse to the image pickup device during the storage period set by the storage period setting means.

According to a second aspect of the present invention, there is provided still image recording means for recording a still image of the subject, and the strobe is also used as the still image recording means. According to a third aspect of the present invention, there is provided distance measuring means for measuring the distance to the subject, and the accumulation period setting means sets the accumulation period according to the distance to the subject measured by the distance measuring means. Characterize.

[0010]

According to the first aspect of the present invention, the stroboscopic light emission is performed at the timing synchronized with the discharge pulse for discharging the electric charge according to the image of the subject from the image pickup device, and the electric charge of the image pickup device during the stroboscopic light emission period is reduced. By controlling the accumulation period according to the count value of the discharge pulse, the charge accumulation period of the image sensor during stroboscopic imaging can be set freely according to the value of the discharge pulse. The exposure control, which cannot be followed only by itself, can be easily dealt with by controlling the accumulation period.

According to the second aspect, by providing a still image capturing means for capturing a still image in addition to the image capturing using the image capturing element, it is possible to capture a still image and a moving image using the image capturing element. By sharing a strobe between the image pickup device and the image pickup device, the exposure of the image pickup device can be optimally controlled when the still image is picked up by the still image pickup device using the strobe, and thus the image pickup device is used. It is possible to effectively capture an image with a strobe.

According to the present invention, the distance measuring means is provided, the discharge pulses are counted according to the distance to the object, and the charge accumulating period of the image pickup device during the stroboscopic light emission is controlled. It is possible to take an image with optimum exposure according to the condition.

[0013]

1 is a block diagram of an embodiment of the present invention. In this embodiment, a video camera for converting a moving image of a subject into an electric signal and then recording it on a magnetic tape and a still camera for recording a still image of the subject on a film are integrated into a still camera integrated video camera. An example to which the invention is applied will be described.

The still camera-integrated video camera 1 according to the present embodiment converts a moving image of a subject into an electric signal and then records it on a magnetic tape, and a still camera unit 3 records a still image of the subject on a film 4. 5, a distance measuring unit 6 for measuring the brightness of the subject and the distance to the subject 6, a control unit 7 for controlling the operations of the video camera unit 3 and the still camera unit 5.

In the video camera unit 3, the image from the subject is made incident on the lens unit 8 and condensed, and the CCD is passed through the diaphragm unit 9.
(Charge Coupled Device) 10
Is incident on. The light incident on the CCD 10 is the CCD 10.
Is converted into an electric signal corresponding to the incident light by the correlated double sampling circuit 11 (CDS: Correlated Do
supply to the double sampling).

The electric signal corresponding to the image of the subject converted by the CCD 10 is subjected to processing such as detection amplification in the CDS circuit 11, and an analog-digital converter (ADC: Analog).
gDigital Digital Converter) 12. The ADC 12 converts the signal processed by the analog signal processing circuit 11 into a digital signal, and a digital signal processing circuit (DSP: Digital Signal P) is used.
processor) 13.

The digital signal supplied to the DSP 13 is subjected to preset digital arithmetic processing in the DSP 13, separated into a luminance signal and a color signal, and held in the field memory 14 when the picked-up image is a still image. At this time,
In the case of a moving image, the field memory 14 is bypassed. The digital signal held or bypassed in the field memory 14 is a digital-analog converter (DAC:
Digital Analog Converter)
15 are supplied. The DAC 15 converts the digital signal supplied from the DSP 13 or the field memory 14 into an analog signal to obtain a luminance signal and a chrominance signal.

The luminance signal obtained by the DAC 15 is supplied to the Y filter 16, and the color signal obtained by the DAC 15 is supplied to the C filter 17. DAC 1 for Y filter 16
An unnecessary component is removed from the luminance signal supplied from the circuit 5 and supplied to the recording / reproducing unit 18. Also, in the C filter 17, D
An unnecessary component is removed from the color signal supplied from the AC 15, and the color signal is supplied to the recording / reproducing unit 18 separately from the luminance signal.

The recording / reproducing unit 18 superimposes the luminance signal supplied from the Y filter 16 and the color signal supplied from the C filter 17 and responds to the ambient sound obtained by the microphone 19 and the sound processing unit 20. The audio signal is superimposed and recorded on the magnetic tape 2. An operation instruction signal is supplied from the video camera process controller 23 to the recording / playback unit 18, and the video camera process controller 2
Control of running of the magnetic tape 2, driving of the rotary drum head, etc. is performed in accordance with an operation instruction signal from 3.

The CCD 10 has a timing generator 2
A discharge pulse for discharging charges accumulated in the image of the CCD 10 in response to incident light is supplied from the gate 2 through the gate circuit 21, and the CCD 10, the CDS 11, the ADC 12, the DSP 1 are supplied.
3, various timing pulses are directly supplied from the timing generator 22 to the field memory 14 and the DAC 15. The discharge pulse is output during the horizontal blanking period so as not to be affected by noise. CCD10, AD
C12, DSP13, field memory 14, DAC1
Reference numeral 5 operates in response to the timing pulse supplied from the timing generator 22, and operates in synchronization with each other.

The timing generator 22 is connected to the video camera process controller 23, generates a timing pulse in response to an operation instruction signal from the video camera process controller 23, and outputs the CCD 10, ADC 12,
It is supplied to the DSP 13, the field memory 14, and the DAC 15. A video camera AE controller 24 is connected to the video camera process controller 23, and the video camera AE controller 24 operates according to an instruction from the video camera process controller 23, and a CCD
Exposure control is performed by driving the diaphragm 9 based on the amount of light received at 10. At this time, the video camera AE controller 24 has a long time constant so as not to follow a rapid change in the brightness of the subject, and the diaphragm 9 is not adjusted by a rapid change in the light amount due to a strobe light or the like.

Further, the video camera process controller 23 is supplied from the system control section 7 with information indicating the distance to the subject in the operation instruction signal, and the video camera section is supplied in accordance with the operation instruction signal supplied from the system control section 7. Various operations such as recording / reproducing and exposure control operation of No. 3 are controlled.
In the still camera unit 5, the image from the subject is made incident on the lens unit 26 and condensed, and the image is formed on the film 4. A diaphragm 27 and a shutter 28 are provided between the lens unit 26 and the film 4 to control the exposure of the light supplied to the film 4. The diaphragm 27 and the shutter 28 are connected to the system control unit 7, and the system control unit 7
The aperture amount and the shutter speed are controlled in accordance with the operation instruction signal supplied from the so-called exposure control.

In the still camera section 5, if the brightness of the subject is not sufficient, the film 4 is less likely to be exposed to light and the image of the subject is not well reflected. Therefore, a strobe 29 is provided for irradiating the subject with light. The strobe 29 is the shutter 28.
It is connected to a strobe drive unit 31 via a switch 30 that is turned on in synchronization with the operation of, and emits light by a drive signal supplied from the strobe drive unit 31.

The strobe drive unit 31 is connected to the system control unit 7 and generates a drive signal for causing the strobe 29 to emit light in response to an operation instruction from the system control unit 7. The system control unit 7 controls the operation of the video camera unit 3, the video camera operation unit 32, the shutter button 33 that operates the shutter 28 of the still camera unit 5, the video camera operation unit 3
2. The system controller 34 supplies an operation instruction signal to the video camera unit 3 and the still camera unit 5 in response to the operation of the shutter button 33.

The video camera operation unit 32 has a record button,
A play button, a fast-forward button, a rewind button, etc. are provided. For example, when the record button is operated, the system controller 34 sends an operation instruction signal to the video camera process controller 23 that controls the video camera unit 3 to instruct a recording operation. Supply. Further, when the shutter button 33 is operated, the system controller 34 stops the shutter 28 and closes it.
The shutter 28 is opened for the shutter opening time (shutter speed) corresponding to the aperture amount of 7. At this time,
As a result of measuring the brightness of the subject by the measuring unit 6, if it is determined that the light from the subject is not sufficient, the strobe driving unit 31 is instructed to operate, the strobe 29 is enabled to emit light, and a switch is operated when the shutter button 33 is operated. A strobe trigger ON pulse is supplied to 30 and the gate circuit 21.

The switch 30 is a system controller 34.
When a strobe trigger on pulse is supplied from the strobe, the drive signal is turned on and the drive signal generated by the strobe drive unit 31 is supplied to the strobe 29. The strobe 29 emits light in response to a drive signal from the strobe drive unit 31, and irradiates the subject with light.
Further, the gate circuit 21 controls the timing generator 22 to C in response to the control signal supplied from the discharge pulse counter 35.
The supply of the ejection pulse supplied to the CD 10 is prohibited, and the supply of the camera signal during the light emission of the strobe 29 to the CDS 11 is prohibited only for a time corresponding to the distance to the subject.

The discharge pulse counter 35 is supplied with discharge pulses from the timing generator 22, counts the discharge pulses, and supplies the count value to the gate circuit 21. A count value is supplied from the timing generation unit 35 to the gate circuit 21, and an exposure time (charge storage period) set according to the distance measurement result of the measurement unit 6 is set by a table built in by the video camera process controller 23. Is supplied, the gate circuit 21 compares the count value from the discharge pulse counter 35 with the count value according to the exposure time from the video camera process controller 23, and the count value from the discharge pulse counter 35 is compared. Is equal to or greater than the count value according to the exposure time from the video camera process controller 23,
The ejection pulse supplied from the timing generator 22 is gated to prohibit the supply to the CCD 10.

The distance measuring circuit 6 irradiates infrared rays to measure the distance to the object, drives the lens 9 and the lens 26, and
Perform F (auto focus). Strobe emission period is 2
It is about mS, and the end of the light emission is synchronized with the charge discharge pulse of the CCD 10 and is positioned almost immediately before the discharge pulse. As described above, the emission period of the strobe can be grasped by counting the emission pulses by synchronizing the emission period of the strobe with the emission pulse, and the charge accumulation period that contributes to the photographing by the CCD 10 within the emission period of the strobe is controlled. It becomes possible.

FIG. 2 shows an operation waveform diagram of an embodiment of the present invention. In FIG. 2, (A) is a vertical synchronizing signal, which is generally a CCD
The accumulated charge read pulse from the image sensor is positioned before and after the blanking period of the vertical synchronizing signal, but in the example of the present invention, it is assumed to be immediately after the blanking period of the vertical synchronizing signal. The accumulated charge read pulse from this CCD image pickup device is shown in FIG. That is, in FIG. 2, charges accumulated in the CCD at the timings t0, t3, ..., That is, a camera signal is output. That is, in normal photographing, all the electric charges accumulated in the CCD during t0 to t3 are sequentially output every 1/60 seconds.

FIG. 2- (B) shows the strobe light emission period during the high level period. Further, FIG. 2- (D) is a CCD
This is a discharge pulse for discharging the charge accumulated in 10 to the substrate of the CCD. Now, at t0, after the charge of the CCD 10 is output, new charge starts to be accumulated.
Accumulation and discharge are repeated by the discharge pulse of (D). t2
At time t2, the charge is set to 0, and since there is no discharge pulse after t2, the charge is not discharged and the charge is accumulated.
Accumulation is performed from 2 to t3.

At this time, the required exposure time (t2 to t3)
Is calculated as follows. Now, the distance measurement data supplied from the distance measurement unit 6 refers to and sets the table provided in the video camera process controller 23. FIG. 3 shows a characteristic diagram of the table. Since the reflected light from the subject decreases with the square of the distance as the distance from the subject increases, constant exposure can be obtained by increasing the charge accumulation period at a rate according to the square of the distance as shown in FIG. . For example, in the case of enabling 0.6 ms of the flash emission period of 2 ms, the camera process controller 23
The discharge counter 35 counts only 253 pulses according to the command from, and outputs a discharge pulse through 60 gates during this period. After that, the gate circuit 21 is activated to prohibit the supply of the discharge pulse to the CCD 10, and the discharge pulse is not supplied to the CCD 10 for 9 pulses = 9 horizontal periods. For this reason,
The charge is accumulated in the CCD 10 by the amount corresponding to 9H. That is, 2 mS corresponds to about 31 H, so 0.6 mS is 3 /
10 = approximately 9H.

Thus, depending on the distance to the subject, C
The incident time on the CD 10 is controlled, and the amount of input light is controlled. Therefore, in the case of stroboscopic photography, a table as shown in FIG. 3 for setting the accumulation period (t2 to t3) according to the distance is provided in the camera process controller 23 in advance, and the accumulation period is set by referring to this table. Is possible. At the time of stroboscopic photography, t2 to t3 may be determined based on this table data based on the distance measurement data.
At this time, since the AE control by the diaphragm 9 cannot be performed, the diaphragm 9
The aperture amount of is fixed to a fixed value.

As described in the present embodiment, the charge accumulation period can be set according to the brightness of the object by the CCD 10 when the CCD accumulated charge read pulse is strobe light emission, and the CCD accumulated charge read pulse of the video camera and the strobe light can be set during the strobe light emission period. Since it is possible to capture images without overlapping the light emission in time, it is possible to accumulate charges during strobe light emission, stable exposure control is possible even during strobe light emission, and a complete image can be obtained during strobe light emission. An effective image using a strobe can be obtained.

[0034]

As described above, according to the first aspect of the present invention, the stroboscopic light emission is performed at the timing synchronized with the discharge pulse for discharging the electric charge according to the image of the subject from the image pickup device, and within the stroboscopic light emission period. By controlling the charge accumulation period of the image pickup device in accordance with the discharge pulse count value, the charge accumulation period of the image pickup device at the time of imaging using a strobe can be freely set according to the discharge pulse value. In addition, it has the feature that the exposure control, which cannot be followed only by the aperture during flash firing, can be easily handled by controlling the storage period.

According to the second aspect, by providing the still image capturing means for capturing a still image in addition to the image capturing using the image sensor, it is possible to capture a still image and a moving image using the image sensor. By sharing a strobe between the image pickup device and the image pickup device, when the still image is picked up by the still image pickup device by using the strobe, the exposure of the image pickup device can be optimally controlled, so that the image pickup device is used for image pickup. It has features such as effective image capturing with a strobe even for captured images.

According to the third aspect, the distance measuring means is provided, and the counting control of the discharge pulse is performed according to the distance to the subject.
By controlling the charge accumulation period of the image sensor during stroboscopic light emission, it is possible to perform image capture with optimal exposure according to the distance to the subject.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is an operation waveform diagram of an embodiment of the present invention.

FIG. 3 is an operation waveform diagram of a main part of one embodiment of the present invention.

FIG. 4 is a block diagram of a conventional example.

[Explanation of symbols]

 1 Still camera integrated video camera 2 Magnetic tape 3 Video camera section 4 Film 5 Still camera section 6 Distance measuring section 7 Control section 21 Gate circuit 29 Strobe 34 System controller 35 Emission pulse counter

Claims (3)

[Claims] 1. An image pickup apparatus having an image pickup device for converting an image of a subject into electric charge during a storage period and sequentially outputting the discharge pulse by a discharge pulse, wherein a strobe for irradiating the subject with light is synchronized with the discharge pulse. Strobe light emission control means for emitting light by means of, and a storage period setting means for setting the charge accumulation period of the image pickup device within the strobe light emission timing period controlled by the strobe light emission control means by counting the discharge pulses. An image pickup apparatus, comprising: gate means for prohibiting the supply of the discharge pulse to the image pickup device during the storage period set by the storage period setting means. 2. The image pickup apparatus according to claim 1, further comprising a still image recording means for recording a still image of the subject, wherein the strobe is shared with the still image recording means. 3. A distance measuring unit for measuring a distance to the subject, wherein the accumulation period setting unit sets the accumulation period according to the distance to the subject measured by the distance measuring unit. The image pickup apparatus according to claim 1, which is characterized in that