JPH0556358A - Ccd camera device - Google Patents

Abstract

PURPOSE:To prevent the flicker between fields, in a CCD camera device which operates a variable speed shutter operation by controlling a charge sweeping pulse. CONSTITUTION:The level of a video signal is detected, and converted into a direct current voltage, and the first control pulse having a pulse width equivalent to the direct current voltage is prepared by a pulse preparing part 6 constituted of a timer. Then, the second control pulse is prepared by a pulse preparing part 9 controlled by a binary counter 8 which activates the first control pulse as a trigger, and resets the charge sweeping pulse by counting it in the prescribed number. Those first and second control pulses are switched at each frame, the number of the charge sweeping pulses inputted to a solid-state image pickup element 2 is controlled by controlling a gate circuit 12, and the speed of an electronic shutter is varied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to C with electronic shutter function.
The present invention relates to a CD (Charge Coupled Device) type solid-state imaging device camera (CCD camera) device and relates to speed control of a variable speed electronic shutter.

[0002]

2. Description of the Related Art FIG. 3 shows a configuration example of a speed control of a conventional variable speed electronic shutter of a CCD camera. In the figure, a subject is imaged on the CCD solid-state image pickup device 2 by the optical lens 1, converted into an electric signal, processed by the signal processing circuit 3, and output as a video signal. The level of the video signal is detected by the detector 4, and the detected signal is compared with a predetermined reference voltage by the voltage comparator 5 to obtain a DC voltage corresponding to the level of the video signal. The pulse generator 6 is composed of a timer IC or the like, is activated by a trigger pulse from the timing generator 7 synchronized with the vertical synchronizing signal of the video signal, and has a pulse width corresponding to the level of the output voltage of the voltage comparator 5. Is output. on the other hand,
The charge sweep pulse generator 11 generates a pulse synchronized with the horizontal synchronizing signal of the video signal, is gated by the control pulse from the pulse generator 6 in the gate circuit 12, and is applied to the solid-state image sensor 2 via the drive circuit 13. Is entered. In the solid-state image sensor 2, the accumulated charge is discharged by this charge sweep pulse,
It operates so as to output an electric signal by the accumulated charge during the stop period of the charge sweep pulse. Therefore, the speed of the electronic shutter increases as the number of charge sweep pulses increases, and decreases as the number decreases. Now, when the level of the video signal increases, the output voltage of the voltage comparison unit 5 increases, the pulse width of the pulse signal from the pulse generation unit 6 increases, and the charge sweep that is input to the solid-state imaging device 2 through the gate circuit 11 is performed. The number of discard pulses increases. On the contrary, when the level of the video signal becomes small, the pulse width of the pulse signal becomes small and the solid-state image sensor 2
The number of charge sweep pulses input to is reduced. In this way, the number of charge sweep pulses is controlled according to the brightness of the subject (the level of the video signal), and the speed of the electronic shutter is automatically changed.

As described above, since the speed of the electronic shutter is determined by the number of charge sweeping pulses synchronized with the horizontal synchronizing signal, it is strictly discontinuous and the charge sweeping pulses are generated in the even field and the odd field. May differ in the number of. For example, the error of one charge sweep pulse is about 1/15.
This is equivalent to 000 seconds, and when the speed of the electronic shutter is increased, there is a problem in that the difference in image brightness between the even field and the odd field causes flicker between fields, which is annoying.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a pulse generator controlled by a binary counter for counting the number of charge sweep pulses is provided.
A flicker between fields is generated by generating a control pulse that makes the number of charge sweep pulses in the other field equal to the number of charge sweep pulses in one field and controlling the switching for each field. Prevented C
A CD camera device is provided.

[0005]

In order to solve the above problems, the present invention uses a CCD type solid-state image pickup device with an electronic shutter function to perform a variable speed shutter operation with a charge sweep pulse synchronized with a horizontal sync signal. In the CCD camera device configured as described above, a detector for detecting the level of the video signal output by the solid-state image pickup device, and a voltage comparison unit for comparing and converting the output from the detector with a predetermined reference voltage to output a DC voltage. ,
A first pulse generator that starts with a trigger pulse synchronized with a vertical synchronizing signal of the video signal and outputs a control pulse having a pulse width corresponding to the level of the DC voltage from the voltage comparator, and a first pulse generator. A counter that is started by using a pulse signal as a trigger and that resets after counting a predetermined number of pulses of the charge sweeping pulse that is synchronized with the horizontal synchronization signal, and the counter that is activated by the trigger pulse that is synchronized with the vertical synchronization signal A second pulse generator that outputs a control pulse having a pulse width determined by the resetting of the pulse pulse, and a pulse switcher that outputs the control pulse from the first pulse generator and the second pulse generator for each field of the video signal. ,
A gate circuit that gates the charge sweep pulse with a control pulse from the pulse switching unit, and a drive circuit that variably drives the speed of the electronic shutter based on the number of charge sweep pulses obtained through the gate circuit. A CCD camera device is provided.

[0006]

With the above construction, the CC according to the present invention
In the D camera device, the level of the video signal is detected and converted into a DC voltage, and a pulse generator having a timer circuit produces a first control pulse having a pulse width corresponding to the DC voltage. A second control pulse is generated by a pulse generation circuit which is activated by the control pulse as a trigger, counts and resets the number of charge sweep pulses, and is controlled by a counter. The first and second control pulses are switched for each field of the video signal, input to the gate circuit for the charge sweep pulse, and control the number of charge sweep pulses input to the solid-state image sensor to control the speed of the electronic shutter. To change. At this time, the pulse width of the control pulse of the other field with respect to one field is made by counting a predetermined number of charge sweep pulses so that the number of charge sweep pulses is the same. Flicker does not occur.

[0007]

Embodiments of the CCD camera device according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram of essential parts of an embodiment of a CCD camera device according to the present invention. In the figure, the same parts as those in FIG. In FIG. 1, reference numeral 8 is a binary counter, which is activated by a pulse from the pulse generation unit 6 as a trigger, and counts and resets a predetermined number of charge sweep pulses from the charge sweep pulse generation unit 11. Reference numeral 9 denotes a pulse generator, which is activated by using a pulse synchronized with the vertical synchronizing signal from the timing generator 7 as a trigger pulse, similarly to the pulse generator 6.
A control pulse having a pulse width controlled by resetting the advance counter 8 is output. Reference numeral 10 is a pulse switching unit, which is a pulse generation unit 6
The control pulses from 9 and 9 are output to the switching gate circuit 12 for each field.

Next, the operation of the CCD camera device according to the present invention will be described. FIG. 2 is a time chart for explaining the operation of this device. First, an image of a subject formed on the solid-state image sensor 2 by the optical lens 1 is converted into an electric signal, processed by the signal processing circuit 3, and input to a monitor device or the like. The level of this video signal is detected by the wave detector 4 and guided to the voltage converter 5. The voltage converter 5 is composed of an operational amplifier or the like, and is compared with a predetermined reference voltage to obtain a DC voltage corresponding to the level of the video signal. On the other hand, the pulse generation unit 6 is composed of a timer IC or the like, is activated by a signal from the timing generation unit 7 synchronized with the vertical synchronization signal as a trigger pulse, and has a pulse width (t) control pulse corresponding to the level of the DC voltage. Is output (Fig. 2 (B))
(B)). Next, the binary counter 8 is activated by using the trailing edge of the control pulse having the pulse width (t) from the pulse generator 6 as a trigger pulse, and the predetermined number of charge sweep pulses from the charge sweep pulse generator 11 is set. Count and reset (Fig. 2
(C)). The pulse generator 9 is activated by using the signal from the timing generator 7 as a trigger pulse, and outputs a control pulse that falls when the binary counter 8 is reset (FIG. 2).
(D)). The control pulses from the pulse generators 6 and 9 are
Gate circuit that can be switched for each field by the pulse switching unit
Control 12 (Fig. 2 (e)). If the even field and the odd field are set as shown in FIG. 2 and the even field is controlled by the control pulse of the pulse generator 6,
The odd field is configured to be controlled by the control pulse of the pulse generator 9. FIG. 2F shows the charge sweeping pulse output from the gate circuit 12. Here, the count value (reset value) of the binary counter 8 is determined so that the number of charge sweep pulses in the even field and the odd field is the same.

[0009]

As described above, C according to the present invention
In a CD camera device, the level of a video signal is detected and converted into a DC voltage, and a pulse generator having a timer circuit produces a first control pulse having a pulse width corresponding to the level of the DC voltage. A second control pulse is generated by the pulse generator controlled by the binary counter which is activated by the control pulse as a trigger, counts and resets the number of charge sweep pulses. The first and second control pulses are switched for each field of the video signal, input to the gate circuit for the charge sweep pulse, and control the number of charge sweep pulses input to the solid-state image sensor to control the speed of the electronic shutter. To change.
At this time, the pulse width of the control pulse in one field is made by counting a predetermined number of charge sweep pulses so that the number of charge sweep pulses is the same, so that the electronic shutter There is an effect that flicker does not occur between fields even if the speed of is increased.

[Brief description of drawings]

FIG. 1 is a principal block diagram showing an embodiment of a CCD camera device according to the present invention.

FIG. 2 is a time chart for explaining the operation of the CCD camera device according to the present invention.

FIG. 3 is a block diagram of a main part of a conventional CCD camera device.

[Explanation of symbols]

 1 Optical Lens 2 CCD Solid-State Image Sensor 3 Signal Processing Circuit 4 Detector 5 Voltage Comparison Section 6 Pulse Generation Section 7 Timing Generation Section 8 Binary Counter 9 Pulse Generation Section 10 Pulse Switching Section 11 Charge Sweep Pulse Generation Section 12 Gate Circuit 13 Drive circuit

Claims (1)

[Claims] 1. In a CCD camera device using a CCD type solid-state image pickup device with an electronic shutter function to perform a variable-speed shutter operation by a charge sweep pulse synchronized with a horizontal synchronizing signal, the solid-state image pickup device outputs. A detector that detects the level of the video signal, a voltage comparison unit that outputs a DC voltage by comparing and converting the output from the detector with a predetermined reference voltage, and a trigger pulse that is synchronized with the vertical synchronizing signal of the video signal. Then, the first pulse generator that outputs a control pulse having a pulse width corresponding to the level of the DC voltage from the voltage comparator, and the pulse signal from the first pulse generator is activated as a trigger to synchronize with the horizontal synchronizing signal. A counter that counts and resets the number of charge sweep pulses by a predetermined number, and the trigger pulse that is synchronized with the vertical synchronization signal is used to start the counter. A second pulse generator that outputs a control pulse having a pulse width determined by a set, and a pulse switching unit that switches and outputs the control pulse from the first pulse generator and the second pulse generator for each field of the video signal,
A gate circuit that gates the charge sweep pulse with a control pulse from the pulse switching unit, and a drive circuit that variably drives the speed of the electronic shutter based on the number of charge sweep pulses obtained through the gate circuit. CC characterized by
D camera device.