JP2713194B2 - CCD TV camera with external trigger function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CCD television camera having an external trigger function which performs an electronic shutter operation by inputting a trigger signal from the outside.

[0002]

2. Description of the Related Art In a production line of a factory, when a visual inspection of a product is automatically performed using a CCD television camera, a sensor for detecting the presence of the product is provided separately from the CCD television camera. The image of the product is obtained by performing a shutter operation of the CCD television camera using the output of the above as a trigger signal. Such a function of capturing an image of a subject using an output of a sensor or the like as a trigger signal is called an external trigger function.

Conventionally, this type of CC with an external trigger function
As a D television camera, one having a configuration as shown in FIG. 3 is known. FIG. 3 shows a conventional C having an external trigger function.
It is a block diagram of a CD television camera. Hereinafter, a conventional CCD television camera with an external trigger function will be described with reference to FIG.

An interline transfer type CCD image pickup device 10
1 (hereinafter referred to as an “IT-type CCD image pickup device”) converts an input optical signal into an electric signal,
As shown in FIG. 4, a light receiving section 110 composed of a photosensor 111 serving as a pixel and a vertical transfer path 112 composed of two stages of CCDs per photosensor 111, and one vertical 4 CCDs per transfer path 112
Is provided. The video signal processing circuit 102 performs video signal processing such as sample hold, clamp, amplification, reset noise elimination, and γ processing on the input signal, and outputs a horizontal synchronization signal (HD signal) output from the synchronization signal generation circuit 104, A synchronizing signal such as a vertical synchronizing signal (VD signal) is added and output as a television signal.

The drive circuit 103 outputs a transfer signal such as a reset signal, a horizontal transfer signal, and a vertical transfer signal to the IT-type CCD image pickup device 101. In addition, IT type CCD image sensor 1
01 is transferred to the vertical transfer path 11
2 is superimposed on the vertical transfer signal and output. VOD (vertical overflow drain)
The electronic shutter circuit 105 accumulates the electric charge for a time corresponding to the shutter time as a signal electric charge, and stores the extra electric charge as I
A charge sweeping signal to be discharged out of the T-type CCD image sensor 101 is output to the IT-type CCD image sensor 101. Since the transfer signal and the charge sweep-out signal need to be in phase with the synchronization signal, the synchronization signal of the synchronization signal generation circuit 104 is transmitted to the drive circuit 103 and the VOD electronic shutter circuit 1.
05 is also input.

The trigger signal input circuit 107 is an interface circuit for receiving a signal output from an externally connected sensor or the like as an external trigger signal. The drive control circuit 106 controls the trigger signal input circuit 107
Controls the operations of the drive circuit 103, the VOD electronic shutter circuit 105, and the synchronization signal generation circuit 104 so as to perform an external trigger operation.

Next, the operation of the CCD television camera with an external trigger function shown in FIG. 3 will be described.

[0008] When no external trigger signal is input, the VOD electronic shutter circuit 105 continuously outputs a charge sweep-out signal every horizontal cycle.
The charge is not accumulated in the CD image sensor 101. Further, the driving circuit 103 stops outputting the charge readout signal superimposed on the vertical transfer signal. With this, IT
No charge is present on the vertical transfer path 112 of the CCD image sensor 101, and the charge stored on the pixel is also discharged every horizontal cycle, and a trigger signal standby state is created. In this state, no video signal is output from the IT-type CCD imaging device 101.

On the other hand, when an external trigger signal from an external sensor or the like is input to the drive control circuit 106 through the trigger signal input circuit 107, the VOD electronic shutter circuit 105 sends a charge sweeping signal according to the control signal of the drive control circuit 106. Is output for only one pulse, and the output of the charge sweeping signal thereafter is stopped. This enables IT type CC
Signal charges start to be accumulated on the pixels of the D imaging element 101 at the same time as the input of the external trigger signal.

Then, when a preset storage time, that is, a shutter time, comes, a drive circuit 103 outputs a charge read signal, and the stored signal charges are stored in the IT type C.
It is held on the vertical transfer path 112 of the CD image sensor 101. This signal charge starts a vertical transfer operation at a predetermined timing within a vertical blank period immediately after being read, and is output from the IT-type CCD image pickup device 101, whereby the output synchronization signal of the synchronization signal generation circuit 102 is output. It is output at the timing that matches. IT type CCD image sensor 1
The output signal from 01 is output as a video signal through the video processing circuit 102.

[0011]

However, in the above-described CCD television camera with an external trigger function, since the vertical transfer path is used as a storage unit for signal charges, only signal charges for one field are stored. Is required, at least two fields are required until all of the exposed signal charges for one field are read out. Therefore, the practical input interval of the external trigger signal is the time interval of two fields (1/30 second interval).
It turns out that. That is, the image output interval is also a time interval for two fields, and there is a problem that it is not possible to sufficiently cope with high-speed image processing in which the number of processings per second is large and where a subject appears continuously. .

If a method of resetting the synchronizing signal of the synchronizing signal generation circuit at the same time as the input of the external trigger signal and immediately outputting the same is used, the input interval of the external trigger signal can be set every field. However, in this case, it is necessary to deal with a signal format in which the synchronization signal is reset halfway on the connected processing device side, so that there is a problem of lack of versatility.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a CCD television camera with an external trigger function which can shorten the input interval of an external trigger signal while having versatility.

[0014]

In order to achieve the above object, a CCD television camera with an external trigger function according to the present invention comprises:
A CCD image sensor that converts an input optical signal into an electric signal and outputs the signal, and a VOD electronic shutter circuit that performs an electronic shutter operation of accumulating and reading signal charges for pixels of the CCD image sensor by input of an external trigger signal has the door, in a CCD TV camera external trigger function for output of the Shutter operation and the electric signal based on the synchronizing signal, as the CCD image sensor, CCD frame interline transfer type having a light receiving portion and the storage portion Using an image sensor, the V signal is set for a preset time in synchronization with the input of the trigger signal.
The electronic shutter operation by the OD electronic shutter circuit is performed, and the signal charge read from the pixel is transferred to the storage unit at a high speed by the shutter operation in a state where no signal charge is present in the storage unit. By the shutter operation in the state where the signal charge is present in the storage section, the signal charge read from the pixel is stored in the vertical transfer path of the light receiving section, and is held in the vertical transfer path and the storage section. A drive control circuit for outputting the signal charge from the CCD image pickup device without resetting the synchronization signal.

The image processing apparatus may further include an image processing circuit that performs predetermined image processing on an output signal from the CCD image pickup device, converts the signal into an image signal, and outputs the image signal.

[0016]

In the CCD television camera with the external trigger function of the present invention configured as described above, when a trigger signal is inputted from the outside, the drive control circuit synchronizes with the trigger signal,
The electronic shutter operation (accumulation and readout of signal charges for the pixels of the CCD image sensor) by the VOD electronic shutter circuit is performed. Further, the drive control circuit causes the signal charges read from the pixels of the CCD image pickup device to be transferred at high speed to the storage section by the electronic shutter operation. The high-speed transfer is performed in a time period of about several horizontal lines, and the next electronic shutter operation becomes possible when the signal charges are transferred to the storage section at a high speed. That is, after the time of the electronic shutter operation and the time of the high-speed transfer operation have elapsed, the next trigger signal can be input.

When the next trigger signal is input while signal charges are present in the storage section, the signal charges read out from the pixels of the CCD image pickup device by the input of the trigger signal are transferred to the vertical transfer section of the light receiving section. Stored on the road. As a result, completely independent signal charges for two fields are stored in the CCD image sensor, and the signal charges for these two fields are output from the CCD image sensor.

Further, since a series of these operations are performed without resetting the synchronization signal, it is necessary for the processing side of the output signal of the CCD image pickup device to cope with a signal format in which the synchronization signal is reset halfway. No versatility is lost.

[0019]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a C having an external trigger function according to the present invention.
FIG. 2 is a block diagram of one embodiment of a CD television camera, and FIG.
Is a frame interline transfer type CCD image pickup device (hereinafter, referred to as a "FIT type CC") of the CCD television camera shown in FIG.
D image sensor ”).

A CCD according to the CCD television camera of the present invention
As the imaging device, a FIT type CCD imaging device 1 is used. The FIT type CCD image pickup device 1 converts an input optical signal into an electric signal and outputs the electric signal to a video signal processing circuit 2, and as shown in FIG. 2, the IT type CCD shown in FIG.
An extension of the vertical transfer path 12 between the light receiving section 10 and the horizontal transfer path 20 having the same configuration as that of the image pickup device is constituted by a CCD,
It has a storage unit 30 that can hold signal charges corresponding to a field screen in a state where it is shielded from external light.

Therefore, the FIT type CCD image pickup device 1 is constructed by combining the vertical transfer path 12 of the light receiving section 10 and the storage section 30 with each other.
Signal charges for two independent fields can be held simultaneously. Normally, the FIT type CCD image pickup device 1 is used for improving smear characteristics in a broadcast / business camera, but in the present invention, the FIT type CC
A major feature is that signal charges for two fields are held by taking advantage of the characteristics of the D imaging device 1.

The video signal processing circuit 2 performs video signal processing such as sample hold, clamp, amplification, reset noise elimination, and γ processing on the input signal, and outputs a horizontal synchronizing signal (output from the synchronizing signal generation circuit 4). HD signal) and a vertical synchronizing signal (VD signal), etc., and output as a television signal.

The drive circuit 3 outputs transfer signals such as a reset signal, a horizontal transfer signal, and a vertical transfer signal to the FIT type CCD image pickup device 1. The charge readout signal for reading out the signal charges stored in the pixels of the FIT type CCD image sensor 1 to the vertical transfer path 12 and the high-speed transfer signal for transferring the signal charges read out to the vertical transfer path 12 to the storage section 30 are vertical The output is superimposed on the transfer signal. The VOD electronic shutter circuit 5 outputs a charge sweeping signal for discharging charges accumulated on the pixels of the FIT type CCD image pickup device 1 and a charge sweeping stop signal for stopping discharge of charges.
To control the charge accumulation on the pixels of the FIT type CCD image sensor 1.

The trigger signal input circuit 7 is an interface circuit for receiving a signal output from an externally connected sensor or the like as an external trigger signal. The external trigger signal is supplied to the drive control circuit 6 through the trigger signal input circuit 7. Is input to The drive control circuit 6 outputs a control signal to the drive circuit 3, the VOD electronic shutter circuit 5, and the synchronizing signal generation circuit 4 for controlling accumulation, readout, and transfer of electric charges of the FIT type CCD image pickup device 1.
The synchronization signal output from the synchronization signal generation circuit 4 is also output to the drive circuit 3, the VOD electronic shutter circuit 5, and the drive control circuit 6 in addition to the video signal processing circuit 2.

Next, C with an external trigger function of the present embodiment
The operation of the CD television camera will be described.

When no external trigger signal is input, a charge sweeping signal is output from the VOD electronic shutter circuit 5 to the FIT type CCD image pickup device 1. Further, the charge transfer signal is not superimposed on the vertical transfer signal output from the drive circuit 3 to the FIT type CCD image pickup device 1. As a result, no signal charges are present in the FIT type CCD image pickup device 1.

In this state, when an external trigger signal for obtaining the exposure timing of the FIT type CCD image pickup device 1 is input to the drive control circuit 6 through the trigger signal input circuit 7 at an arbitrary timing, the VOD electronic shutter circuit 5 outputs the charge sweeping stop signal.
The signal charges are accumulated on the pixels of the D imaging device 1.

After a preset exposure time corresponding to the electronic shutter time has elapsed, the signal charges on the pixels of the FIT type CCD image sensor 1 are changed by the charge readout signal output from the drive circuit 6 to the FIT type CCD image sensor. The data is read out to the vertical transfer path 12 of the light receiving section 10 of the element 1. That is, an electronic shutter operation is performed. The signal charges read out to the vertical transfer path 12 are all transferred to the storage section 30 of the FIT type CCD image pickup device 1 within about 10 horizontal cycles by a high-speed transfer operation of the vertical transfer signal.

After this period has elapsed, exposure by input of the next external trigger signal and the FIT type CCD image pickup device 1
To the vertical transfer path 12, that is, the next shutter operation can be performed. As a result, the interval between the signal charge captured by the first external trigger signal and the signal charge captured by the next external trigger signal is the sum of the exposure time and the high-speed transfer operation time. When the time is short, that is, when the electronic shutter speed is high, the input interval of the external trigger signal can be made sufficiently short. Specifically, the high-speed transfer time is 10
Since the completion can be completed within about the horizontal cycle, the input interval of the external trigger signal can be set within 1 millisecond even if the exposure time is 1/1000 second.

When the next external trigger signal is input while the signal charge is present in the storage section 30 and the shutter operation is performed, the signal charge read out by this is transferred to the vertical transfer path 12 of the light receiving section 10. Is stored in At this point, F
The IT-type CCD image pickup device 1 holds signal charges for two independent fields.

The signal charges for two fields held in the vertical transfer path 12 and the storage section 30 of the light receiving section 10 of the FIT type CCD image pickup device 1 are read out according to the synchronization signal output from the synchronization signal generation circuit 4. The vertical transfer operation is started from a predetermined timing within the vertical blanking period immediately after the start of the operation, and is output from the FIT type CCD image sensor 1. FIT
The output signal of the CCD image sensor 1 is supplied to a video signal processing circuit 2
And output as a television signal. Therefore,
A signal is output from the FIT type CCD image pickup device 1 for each field, and the number of screens per unit time processed by the video signal processing circuit 2 is about twice that of the related art.

Further, since the above-described series of operations is realized without resetting the synchronization signal, there is no need to deal with a signal format in which the synchronization signal is reset halfway on the connected processing device side. As a result, versatility is not impaired, and replacement with a conventional system becomes easy.

[0034]

As described above, the CCD television camera with the external trigger function of the present invention uses a frame interline transfer type CCD image pickup device as the CCD image pickup device, and transfers signal charges for two fields to the CCD image pickup device. By having the drive control circuit for holding, the input interval of the trigger signal from the outside can be extremely shortened.
Further, since this operation is performed without resetting the synchronization signal, the versatility of the CCD television camera is not impaired, and replacement with a conventional system can be easily performed.

Further, the frame interline transfer type CCD image pickup device can simultaneously hold signal charges for two fields and output them for each field.
When an image processing circuit that performs image processing on an output signal from a CCD image pickup device and outputs the processed image is provided, the number of images processed by the image processing circuit per unit time can be increased to about twice that of the related art.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of a CCD television camera with an external trigger function of the present invention.

FIG. 2 is a FIT type C of the CCD television camera shown in FIG.
FIG. 2 is a diagram schematically illustrating a configuration of a CD imaging device.

FIG. 3 is a block diagram of a conventional CCD television camera with an external trigger function.

4 is an IT type CC of the CCD television camera shown in FIG.
FIG. 3 is a diagram schematically illustrating a configuration of a D imaging device.

[Explanation of symbols]

1-frame interline transfer (FIT) type CCD
Image sensor 2 Video signal processing circuit 3 Drive circuit 4 Synchronous signal generation circuit 5 VOD electronic shutter circuit 6 Drive control circuit 7 Trigger signal input circuit 10 Light receiving section 12 Vertical transfer path 20 Horizontal transfer path 30 Storage section

Claims (2)

(57) [Claims] 1. A CCD image sensor for converting an input optical signal into an electric signal and outputting the signal, and an electronic shutter operation for accumulating and reading signal charges to and from pixels of the CCD image sensor by input of a trigger signal from the outside. and a VOD electronic Shutter circuit for performing, in the CCD TV camera external trigger function for output of the Shutter operation and the electric signal based on the synchronizing signal, as the CCD image sensor, a frame inter having a light receiving portion and the storage portion Using a line transfer type CCD imaging device, the VOD electronic shutter circuit performs an electronic shutter operation for a preset time in synchronization with the input of the trigger signal, and in a state where no signal charge exists in the accumulation unit. The signal power read from the pixel by the shutter operation of Is transferred to the storage section at a high speed, and the signal charge read from the pixel is stored in the vertical transfer path of the light receiving section by the shutter operation in the state where the signal charge is present in the storage section thereafter. A drive control circuit for outputting the signal charges held in the vertical transfer path and the storage section from the CCD image pickup device without resetting the synchronization signal. camera. 2. The CCD television camera with an external trigger function according to claim 1, further comprising an image processing circuit for performing predetermined image processing on an output signal from the CCD image pickup device, converting the output signal into an image signal, and outputting the image signal.