JPH0157867B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention provides a video conferencing device that allows a plurality of people located at two separate locations to hold a conference at the same time, that is, a video and audio transmission path. The present invention relates to video equipment in which images of people, documents, etc. are played back on each other's television receivers, and audio is played back from each other's public address systems.

Prior Art This type of conference device is equipped with a plurality of cameras that take pictures of all conference participants, and a camera that takes close-up pictures of a specific number of conference participants. They were used only for this purpose, and it was difficult for them to be used for both purposes for reasons that will be explained later.

Let's consider preparing two cameras and combining the images taken by these cameras to display a large number of people on one screen. If these two cameras are of the same type as described above to photograph all the participants, the vertical center of the screen shot by each camera is extracted and combined to form a single screen. In order to obtain the output video signal, it is necessary to obtain the output video signal. To do this, it is necessary to perform external genlock on both cameras using different synchronization signals, and the external genlock signals are used to
That is, video signals to be transmitted to the ground whose phases are shifted with respect to the reference synchronization signal are used.

On the other hand, when one camera takes close-up shots of one or more people, the transmitted video is a single screen of that camera only, so the external genlock signal used has the same phase as the reference synchronization signal of the transmitted video signal. belongs to. Therefore, during multi-person composite shooting and close-up shooting as described above,
The phase relationships of the external genlock signals used will be different. Therefore, if you try to use one camera for both full-body shooting and close-up shooting, the phase of the synchronization signal will be different in both cases.
If the video signal is sent through a band compression transmission line that thins out and samples the synchronization signal, when switching from an all-person shooting state to a close-up shooting state,
Or, when switching to the opposite, the image would be greatly distorted, making it impractical. As a result, a dedicated camera must be provided for each purpose, making the system more complex.

Purpose of the Invention The present invention provides a synchronization signal for the transmitted video signal when switching from all-person shooting to close-up shooting.
In addition, even in the opposite case, it can be made constant, and the purpose is to eliminate the image disturbance that occurs in the conventional case. The present invention also provides a means for colorizing a composite image when all the members are photographed.

Summary of the Invention In order to achieve the above object, the video conference device of the present invention includes a plurality of cameras that are arranged to separately photograph all conference participants and generate output video signals that do not include a vertical synchronization signal; a reference synchronization signal generation circuit that generates a reference vertical synchronization signal; a control circuit that selectively generates control signals representing first and second operation modes to determine an operation mode of the camera; An external genlock signal for controlling the camera is formed from a reference vertical synchronization signal, and the phase difference of each external genlock signal is made different so that each camera outputs a video signal with a predetermined phase relationship in the first operation mode. An external genlock signal generation circuit that determines the phase of an external genlock signal so that one of the cameras outputs a video signal during a period corresponding to the phase of the reference sync signal in the operating mode, and a reference vertical sync signal and color subcarrier. vertical blanking signal generating means for generating a vertical blanking signal with a color burst signal added to a predetermined position in a vertical period from the above, and each output video signal of the camera and the vertical blanking signal when the control signal is in a first operation mode; outputting a colored composite video signal of all conference participants from and outputting a video signal representing a close-up image from a selected one of the cameras during a second operating mode of the control signal; It is equipped with a video processing circuit and a synchronization signal superimposition circuit that superimposes and adds a reference synchronization signal to the output of the video processing circuit.

Embodiment of the Invention FIG. 1 is a block circuit diagram of a television conference apparatus according to an embodiment of the invention, and FIGS. 2 and 3 are waveform diagrams for explaining the circuit operation of FIG. 1.

The circuit of FIG. 1 shows a case where two cameras 1 and 2 are used, and 3 is a reference synchronization signal generation circuit that generates a synchronization signal to be used as a reference vertical synchronization signal. Reference numeral 4 denotes a control circuit for controlling the switching of the operation mode for transmitting video into a conference mode, that is, between shooting all conference participants and close-up shooting. The control signal obtained from the control circuit 4 is applied to an external genlock signal generation circuit 5 which generates an external genlock signal from the reference synchronization signal, and controls the cameras 1 and 2 to perform external genlock with synchronization signals having different phases. Further, the reference synchronization signal is given to the vertical blanking signal generation circuit 6, and becomes a signal for performing vertical blanking of the composite video signal when photographing all the members. Reference numeral 7 denotes a color subcarrier generation circuit, which supplies a color subcarrier to the color burst adding circuit 8, and uses the vertical blanking signal to plant a color burst in the vertical blanking period. Reference numeral 9 denotes a video processing circuit, which is given the outputs of the cameras 1 and 2 and the output of the color burst addition circuit 8, and takes out a predetermined video signal output depending on the operation mode of the control signal for all-person shooting or close-up shooting. . This signal is transmitted to the synchronization signal superimposition circuit 10
The synchronizing signal applied from the reference synchronizing signal generating circuit 3 is superimposed on the superimposed signal and output from the line terminal 11.

Next, the operation of the circuit shown in FIG. 1 when all conference participants are photographed will be explained with reference to FIG. 2. Figure 2 shows
The waveforms at points A to H in FIG. 1 at this time are shown. When photographing all the members, cameras 1 and 2 are externally genlocked by synchronizing signals A and B of FIG. In other words, the phases of C and D in FIG. 2, which are the video outputs of cameras 1 and 2, are shifted by a predetermined amount with respect to each other and the reference vertical synchronization signal. These camera outputs and the vertical blanking signal E in FIG. 2 are sequentially switched in the video processing circuit 9 based on the control signal from the control circuit 4. F in FIG. 2, which is a composite video signal of predetermined periods of C and D in FIG. 2, which are video outputs of No. 2, and a vertical blanking signal, is output. Incidentally, since both the camera video output and the vertical blanking signal lack a vertical synchronizing signal, the synchronizing signal superimposing circuit 10 converts the synchronizing signal G in FIG. 2 into the second composite video signal. It is superimposed on F in the figure and is sent out from the line terminal 11 to the transmission line as a predetermined signal H in FIG.

Next, the operation of the circuit shown in FIG. 1 during close-up photography will be explained using the waveforms shown in FIG. 3. Third
The figure shows the symbols A, C, F to H in Figure 1 at this time.
This shows the waveform of a point. In this case, the external genlock signal generation circuit 5 outputs the signal A in FIG. 3, which is a signal having the same phase as the reference vertical synchronization signal G in FIG. 3 from the reference synchronization signal generation circuit 3, and the camera given to 1. The camera 1 outputs C in FIG. 3, which is a close-up photographed video signal. The video processing circuit 9 outputs a video signal F in FIG. 3, which is a video signal obtained by close-up photography. This signal is superimposed with the reference vertical synchronizing signal G in FIG. 3 in the circuit 10, and is sent out from the terminal 11 as a predetermined close-up video output H in FIG.

When switching to this photographing mode, since the camera 1 is also used, the phase of the external genlock signal changes significantly before and after, and the output video signal also shifts. However, the synchronization signal of the transmitted video signal does not change before and after this operation. That is, the reference vertical synchronization signal shown in FIG. 3G is used and remains constant regardless of mode switching. As a result, even if a video signal is transmitted through a band compression transmission path in which synchronization signals are thinned out and sampled, there will be no disturbance in the reproduced image when switching the shooting mode.

Furthermore, a color burst is added to the vertical blanking signal by a color burst addition circuit 8, thereby making it possible to colorize the composite image when all the members are photographed. That is, at this time, the color burst of the video section of the output of cameras 1 and 2 is
These are output from cameras 1 and 2, respectively, and the color burst in the vertical blanking section is generated within the apparatus.

Effects of the Invention As described above, according to the present invention, by superimposing a constant synchronization signal when transmitting video and injecting a color burst into the vertical blanking signal, it is possible to use a camera for shooting everyone even when passing through a band compression transmission line. It can also be used as a camera for close-up photography, and it also makes it possible to color composite images when everyone is photographed.

In the above-mentioned embodiment, the case where there are two cameras has been described, but in reality, any number of cameras can be used, and the same operation can be performed with them.

Furthermore, in addition to the color burst in the vertical blanking section, it is also possible to generate a color burst in the video section and to implant this.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of an embodiment of the video conference device of the present invention, FIG. 2 is a waveform diagram for explaining one operation mode of the circuit in FIG. 1, and FIG. 3 is the circuit in FIG. 1. FIG. 3 is a waveform diagram for explaining the other operation mode of FIG. 1 and 2... Camera, 3... Reference synchronization signal generation circuit, 4... Control circuit, 5... External genlock signal generation circuit, 6... Vertical blanking signal generation circuit, 7... Subcarrier generation circuit, 8 ...Color burst addition circuit, 9...Signal processing circuit, 10...
Synchronous signal superimposition circuit, 11...output terminal.

Claims (1)

[Claims] 1. A plurality of cameras are arranged to separately photograph all conference participants and generate output video signals that do not include a vertical synchronization signal, a reference synchronization signal generation circuit that generates a reference vertical synchronization signal, and a first and a control circuit for selectively generating a control signal representing a second operating mode to determine an operating mode of the camera, and forming an external genlock signal for controlling the camera from the reference vertical synchronization signal in response to the control signal. In the first operation mode, each of the cameras outputs a video signal having a predetermined phase relationship by varying the phase difference of each external genlock signal, and in the second operation mode, one of the cameras outputs a video signal having a predetermined phase relationship. an external genlock signal generation circuit that determines the phase of an external genlock signal so as to output a video signal during a period corresponding to the phase of the reference vertical synchronization signal; a subcarrier generation circuit that generates a color subcarrier; and a subcarrier generation circuit that generates a color subcarrier; vertical blanking signal generating means for generating a vertical blanking signal in which a color burst signal is added at a predetermined position in a vertical period from the signal and a color subcarrier; and each output image of the camera when the control signal is in a first operation mode; outputting a colored composite video signal of all conference participants from the signal and the vertical blanking signal; 1. A television conference device comprising: a video processing circuit that outputs a video signal representing an image; and a synchronization signal superimposition circuit that superimposes and adds the reference vertical synchronization signal to the output of the video processing circuit.