JP2000069322A - Camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a phase locked loop from being configured straddling over devices. SOLUTION: A video signal photographed by an image pickup section of a camera head unit(CHU) 1 is transmitted to a camera control unit(CCU) 2 through a synchronizing signal addition means 11, the transmitted video signal is written in a memory 22 through a format conversion decoder 21 and written to the memory 22 is controlled by a detected synchronizing signal. Furthermore, the CCU 2 is provided with a synchronizing signal generator 25, that is driven by a prescribed reference oscillator 24 and the synchronizing signal from the synchronizing signal generator 25 is fed to a timing generator 26 and read of the memory 22 is controlled by a reset signal synchronously with the synchronizing signal. Moreover, the synchronizing signal, whose phase is advanced by the timing generator 26, is sent to the CHU 1. Then the CHU 1 is controlled by a timing generator 14, this synchronizing signal and the transmitted synchronizing signal are fed to a phase detector 12, and the timing generator 14 is driven by the detected phase difference signal (voltage).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a camera system in which, for example, a camera control unit and a camera head unit are separately operated via a transmission cable. More specifically, the phase of the video signal transmitted from the camera head unit is matched with the reference synchronization signal in the camera control unit.

[0002]

2. Description of the Related Art For example, in a camera system in which a camera control unit (hereinafter abbreviated as CCU) and a camera head unit (hereinafter abbreviated as CHU) are operated separately via a transmission cable, for example, C
It is necessary to match the phase of the video signal transmitted from the HU with the reference synchronization signal in the CCU. In such a case, in a conventional camera system using analog transmission, for example, a configuration as shown in FIG. 4 has been used.

That is, in FIG. 4, a CHU (camera head unit) 100 which is formed separately from each other.
And CCU (Camera Control Unit) 200
And a transmission cable 300 connects between them. The video signal imaged by the imaging unit (not shown) of the CHU 100 is output to the transmission cable 300 through a synchronization signal adding unit 101 described later, and transmitted to the CCU 200 through the transmission cable 300.

The CCU 200 is provided with a synchronization signal generator 202 driven by a predetermined reference oscillator 201.
The horizontal and vertical synchronizing signals H and V from the synchronizing signal generator 202 are taken out together with the transmitted video signal. The horizontal synchronization signal H from the synchronization signal generator 202 is supplied to the phase detector 203. Further, the transmitted video signal is supplied to the synchronization separation circuit 204, and the separated horizontal synchronization signal H ′ is supplied to the phase detector 203.

As a result, the phase difference between the two horizontal synchronization signals is detected, and the detected signal (voltage) is transmitted to the transmission cable 300.
Is transmitted to the CHU 100 through Further CHU10
0, the transmitted phase difference signal is
2, the timing generator 103 is driven by the controlled oscillation signal. Then, the above-described imaging unit is driven by the generated timing signal, and the generated synchronization signal is supplied to the synchronization signal adding unit 101 and added to the captured video signal.

The vertical synchronizing signal V from the synchronizing signal generator 202 and the vertical synchronizing signal V 'in the transmitted video signal are supplied to a phase counter circuit 205. Then, a signal of the detected phase difference between the two vertical synchronization signals is transmitted to the CHU 100 via the transmission cable 300, and the above-described timing generator 103 is reset. Accordingly, the timing generator 103 is driven such that the horizontal and vertical synchronization signals in the transmitted video signal match the reference synchronization signals of the synchronization signal generator 202.

[0007]

However, in this apparatus, a phase locked loop for matching the drive of the timing generator 103 to the synchronization signal generator 202 is provided by the synchronization generator 204, the phase detector 203 and the phase separation loop. , And a voltage-controlled oscillator 102, and is configured to extend over two devices. Here, such a loop formed by straddling a plurality of devices is liable to cause a malfunction in operation.

[0008] Further, in such a loop formed over a plurality of devices, it is difficult to specify the location of the fault once the fault has occurred. For this reason, there is a high risk that the entire device will become unusable due to one failure, and when a failure occurs, there is a risk that both of them must be replaced even though they are separate devices Things.

The present application has been made in view of such a point, and a problem to be solved is that in a conventional device, a phase lock loop for matching driving is provided over a plurality of devices. Therefore, there is a possibility that various problems may occur due to the disadvantages of operation.

[0010]

For this reason, in the present invention, a synchronization signal which is advanced from a reference synchronization signal by a predetermined time is transmitted to a camera head unit, and a memory in which the transmitted video signal is written is provided. And the reading of the memory is reset in accordance with a reference synchronization signal. According to this, a phase-locked loop is not formed across a plurality of devices, and a good operation is always performed. It can be performed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a camera system in which a camera control unit and a camera head unit are separately operated via a transmission cable is provided. Means for transmitting, to the camera head unit, a synchronization signal advanced in phase for a predetermined time from the reference synchronization signal;
A memory having a storage capacity corresponding to a predetermined time in which the video signal transmitted from the camera head unit is written according to the synchronization signal in the video signal transmitted from the head unit, and resetting the memory reading means according to the reference synchronization signal And means for performing the operation.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
FIG. 1 shows a camera to which the camera system according to the present invention is applied.
It is a block diagram which shows the structure of the principal part of an example of each of a control unit (CCU) and a camera head unit (CHU).

In FIG. 1, a CHU (camera head unit) 1 and a CCU (camera control unit) 2 which are separately formed are provided, and these are connected by a transmission cable 3. . And CHU1
The video signal picked up by the image pick-up unit (not shown) is output to the transmission cable 3 through the synchronization signal adding means 11 described later, and is transmitted to the CCU 2 through the transmission cable 3.

The CCU 2 is provided with a decoder 21 for converting the format of the transmitted video signal, and a memory 22 having a storage capacity of, for example, four horizontal periods or more in which the converted video signal is written. Further, the decoder 21
Is supplied to the memory reset signal generation circuit 23, and the writing of the memory 22 is controlled by the write reset signal from the generation circuit 23.

The CCU 2 is provided with a synchronization signal generator 25 driven by a predetermined reference oscillator 24. The horizontal synchronization signal H and the field synchronization signal F from the synchronization signal generator 25 are supplied to a timing generator 26. Supplied. Then, a read reset signal synchronized with the reference signal is formed by the timing generator 26, and the read of the memory 22 is controlled by the reset signal.

As a result, a video signal is extracted from the memory 22. The horizontal synchronizing signal H and the field synchronizing signal F from the synchronizing signal generator 25 are taken out together with the video signal from the memory 22. Further, in the timing generator 26, for example, a field synchronization signal F ″ whose phase is advanced by four horizontal periods is generated and transmitted to the CHU1 through the transmission cable 3 together with the above-described horizontal synchronization signal H.

Further, the CHU 1 is provided with a timing generator 14 driven by a controlled oscillation signal from a voltage controlled oscillator 13. The above-described imaging unit is driven by the timing signal generated by the timing generator 14, and the generated horizontal synchronizing signal and field synchronizing signal are supplied to the synchronizing signal adding means 11 and added to the imaged video signal. Is done.

At the same time, the horizontal synchronizing signal H ″ from the timing generator 14 is supplied to the phase detector 12.
Further, the transmitted horizontal synchronizing signal H is transmitted to the phase detector 1.
2 is supplied. Then, a signal (voltage) of the detected phase difference between the two horizontal synchronizing signals is supplied to the voltage controlled oscillator 13,
The timing generator 14 is driven so that the detected phase difference has a predetermined value.

In this apparatus, the horizontal synchronizing signal H and the field synchronizing signal F are generated from the synchronizing signal generator 25 of the CCU 2 at the timing shown in FIG. In this example, a case of a so-called high-definition television having 1125 horizontal scanning lines in one field is shown. On the other hand, from the timing generator 26,
For example, the horizontal synchronizing signal H and the field synchronizing signal F are generated at the timing shown in FIG.

This signal is delayed by the transmission on the transmission cable 3 and supplied to the phase detector 12 and the timing generator 14 at the timing shown in FIG. 2C, for example, and is added to the video signal at this timing. A horizontal synchronization signal and a field synchronization signal are generated. Further, this signal is delayed by transmission through the transmission cable 3 and supplied to the format conversion decoder 21 at a timing as shown in FIG. 2D, for example, and written into the memory 22 at this timing.

The video signal written in the memory 22 is read out at the timing of the original reference synchronization signal from the timing generator 26, so that the memory 2
For example, as shown in FIG. 2E, a video signal that matches the reference synchronizing signal is extracted from 2. In this example, 1
The latter half of the 124th scanning line and the 1125th scanning line will be missing, but since these scanning lines are located outside the effective screen, this lack does not cause any problem.

The memory 22 is of a type in which writing is performed in order from address 0 and writing is performed in order from address 0 again when writing up to the last address is full. By making the storage capacity of the memory 22 equal to or longer than the delay time of the signal reciprocating between the CCU 2 and the CHU 1 at the data rate of the transmitted video signal, it is possible to always take out a continuous video signal. It is.

Further, in the CHU1, the timing generator 14 is driven in accordance with the synchronization signal transmitted from the CCU2 to output a video signal. In this case, the phase lock loop for performing the synchronous drive is the phase detector 1
2. Since it is composed of the voltage controlled oscillator 13 and the timing generator 14 and is composed only of the inside of the CHU 1, there is a possibility that a problem or the like may occur due to the phase lock loop extending over a plurality of devices in the conventional device. There is no.

Therefore, in this apparatus, a synchronization signal which is advanced by a predetermined time from the reference synchronization signal is transmitted to the camera head unit, and a memory in which the transmitted video signal is written is provided. Reset according to the synchronizing signal, a good operation can always be performed without forming a phase locked loop over a plurality of devices.

That is, in the conventional apparatus, since the phase lock loop for matching the driving is formed over a plurality of devices, there is a possibility that the operation is liable to occur and various inconveniences may occur. According to the present invention, these problems can be easily solved.

Further, in the above-mentioned apparatus, when the video signal written in the memory is read out at the timing of the reference synchronization signal, some of the scanning lines are lost and the image is disturbed. Since the missing scanning line is located outside the effective screen, there is no problem that the displayed image is disturbed due to the missing scanning line.

In the above-described apparatus, the storage capacity of the memory is set to be equal to or more than an arbitrary divisor of the total number of scanning lines of the video signal. That is, in the case of the above-mentioned high definition, the total number of scanning lines is 11
Since there are 25 lines, the capacity is set to be larger than a divisor of, for example, three scanning lines. Then, for example, the reading means of the memory is reset for every three scanning lines.

By doing so, for example, FIG.
As shown in (1), the phase of the video signal can be accurately adjusted to the reference synchronization signal every three scanning lines, whereby a system without any image disturbance can be constructed.

According to the camera system described above,
In a camera system in which a camera control unit and a camera head unit are separately operated via a transmission cable, the camera control unit includes a synchronization signal which is advanced by a predetermined time from a reference synchronization signal. Means for transmitting a signal to the camera head unit, and a storage capacity corresponding to a predetermined time during which the video signal transmitted from the camera head unit is written according to a synchronization signal in the video signal transmitted from the camera head unit And the means for resetting the memory reading means in accordance with the reference synchronization signal are provided, so that a good operation is always performed without forming a phase locked loop over a plurality of devices. Can be done.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0031]

According to the first aspect of the present invention, there is provided a memory for transmitting a synchronization signal which is advanced from the reference synchronization signal by a predetermined time to the camera head unit, and in which the transmitted video signal is written. By resetting the reading of the memory according to the reference synchronization signal, a good operation can always be performed without forming a phase lock loop over a plurality of devices.

That is, in the conventional device, since the phase lock loop for matching the driving is formed over a plurality of devices, there is a possibility that an operational problem is likely to occur and various inconveniences may occur. According to the present invention, these problems can be easily solved.

According to the second aspect of the present invention, the storage capacity of the memory is equal to or more than the delay time of the signal reciprocating between the camera control unit and the camera head unit at the data rate of the transmitted video signal. By doing so, it is possible to always take out a continuous video signal.

According to the third aspect of the present invention, since the phase lock loop for performing the synchronous drive is formed only inside the camera head unit, the phase lock loop is provided to a plurality of devices in the conventional apparatus. There is no danger of inconvenience caused by straddling.

According to the fourth aspect of the present invention, when the video signal written in the memory is read out at the timing of the reference synchronization signal, some scanning lines are lost and the image is disturbed. However, since these missing scanning lines are located outside the effective screen, problems such as disturbing the displayed image due to the missing scanning lines do not occur.

Further, according to the fifth aspect of the present invention, the storage capacity of the memory is set to be at least an arbitrary divisor of the total number of scanning lines of the video signal, and the reading means of the memory is reset for each of the divisors. , The phase of the video signal can be accurately adjusted to the reference synchronization signal for every several scanning lines,
This makes it possible to construct a system with no image distortion.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an example of a camera system to which the present invention is applied.

FIG. 2 is a diagram for explaining the operation.

FIG. 3 is a diagram for explaining the operation.

FIG. 4 is a configuration diagram of a conventional camera system.

[Description of Signs] 1 ... Camera head unit (CHU), 2 ... Camera control unit (CCU), 3 ... Transmission cable, 11 ... Synchronization signal adding means, 12 ... Phase detector, 13
... voltage controlled oscillator, 14, 26 ... timing generator, 2
1 ... format conversion decoder, 22 ... memory, 23 ...
Memory reset signal generation circuit, 24 ... reference oscillator, 25
... Synchronous signal generator

Claims (5)

[Claims] 1. A camera system in which a camera control unit and a camera head unit are separately operated via a transmission cable, wherein the camera control unit has a predetermined synchronization signal based on a reference synchronization signal. Means for transmitting a time-advanced synchronization signal to the camera head unit; and a video signal transmitted from the camera head unit according to the synchronization signal in the video signal transmitted from the camera head unit. A camera system comprising: a memory having a storage capacity corresponding to the predetermined time to be written; and a means for resetting a reading means of the memory in accordance with the reference synchronization signal. 2. The apparatus according to claim 1, wherein the predetermined time is equal to or longer than a delay time of a signal reciprocating between the camera control unit and the camera head unit.
The camera system as described. 3. The camera system according to claim 1, wherein said camera head unit is provided with means for outputting said video signal in accordance with a synchronization signal transmitted from said camera control unit. 4. The camera system according to claim 1, wherein resetting of the memory reading means is performed during a period outside a valid screen of a video signal transmitted from the camera head unit. 5. The storage capacity of the memory provided in the camera control unit is at least an arbitrary sub-multiple of the total number of scanning lines of the video signal. The camera system according to claim 1, wherein reset is performed.