JPH0573312B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a video selection device that selects a single video signal from a plurality of video signals and synchronizes it with a reference synchronization signal. It is.

More specifically, video signals are used to select images from multiple cameras in surveillance television camera systems (e.g., monitoring systems for banks, supermarkets, automated production lines, etc.), or to select images when editing video programs. This invention relates to a video selection device used for switching.

[Conventional technology]

Conventionally, the following two methods have been used to select a single video signal from a plurality of video signals and obtain a video signal synchronized with a reference synchronization signal.

A method of selecting a single video signal from multiple video signals and then synchronizing it with a reference synchronization signal (hereinafter referred to as "synchronization"; generally using a device called a frame synchronizer).

A method of selecting a single video signal after synchronizing multiple video signals.

FIG. 4 is a block diagram showing an example of the conventional method described above.

That is, the video signals VS 1 to VS _o output from the television cameras C ₁ to _{C o} that constitute the video signal source ₁ are as follows:
After a single video is selected by the video selection circuit 3 according to the selection information set by the selection information setting circuit 2, a reference synchronization signal is supplied from the video signal processing device 5 by the video synchronization circuit 4. It is synchronized with the signal SY and output to the video signal processing device 5.

FIG. 5 is a block diagram showing an example of the above-mentioned conventional method.

In the figures, the same reference numerals as those mentioned above indicate the same or equivalent parts. Video signal source 1
The video signals VS ₁ to VS _o outputted from the television cameras C ₁ to _{C o} constituting the system are converted to a reference synchronization signal SY supplied from the video signal processing device 5 by video synchronization circuits 4 ₁ to 4 _o . After synchronization, a single video is selected by the video selection circuit 3 according to the selection information set by the selection information setting circuit 2 and output to the video signal processing device 5. Further, the selection in this case is normally performed during the vertical blanking period in synchronization with the synchronizing signal SY so as to prevent discontinuous screens from occurring due to video switching.

Note that the video signal processing device 5 is equipped with, for example, a video recording device (VTR) or a program sending device, and is used to record or send out a video signal converted into a specific format. Further, the reference synchronization signal SY is generated by this device.

[Problem to be solved]

FIG. 6 is a timing diagram showing the flow of video signals according to the method of the prior art (FIG. 4). In order to simplify the explanation and drawings, the case where video signals from three television cameras are selected is shown.
are the video signals VS ₁ to VS ₃ from the respective television cameras C ₁ to C ₃ , are the contents of the video selection signal indicating the video signal to be selected, are the output signal of the video selection circuit 3 , are the output of the video synchronization circuit 4 It's a signal. Here, the Δ mark is a vertical synchronization signal. Furthermore, the video synchronization circuit 4 is activated by the vertical synchronization signal of the input video signal, and if the input video signal is switched during operation, the video synchronization circuit 4 is configured to interrupt the operation and output the previous screen ( same as below).

As is clear from FIG. 6, the video synchronization circuit 4 of
When the video selection signal of the output signal changes, the old and new images are switched in the middle of the screen, resulting in a discontinuous boundary on the screen.

The conventional technique solves the problem of discontinuous boundaries occurring in the conventional technique.

FIG. 7 is a timing diagram showing the flow of video signals according to the method of the prior art (FIG. 5). In order to simplify the explanation and drawings, a case is shown in which video signals from four television cameras are sequentially selected in units of one field, and ~ indicates television cameras C ₁ to _{C 4}
The video signals VS ₁ to VS ₄ , '- are signals obtained by synchronizing the respective video signals by the video synchronization circuits 4 ₁ to 4 ₄ , are the content of the video selection signal, and are the output signal of the video selection circuit 3 .

As is clear from FIG. 7, the video selection circuit 3 of
In the output signal, the video is switched only in the vertical synchronization signal part. However, there is a problem that the same number of video synchronization circuits as the input video signals are required, making the device complicated and expensive.

SUMMARY OF THE INVENTION An object of the present invention is to provide a video selection device having a video synchronization function that switches only in the vertical synchronization signal by using two video selection circuits and two video synchronization circuits. .

[Means for solving problems]

In order to achieve the above object, the video selection device of the present invention includes video selection means for selecting a single video signal from a plurality of video signals, and synchronization with the video signal outputted from the video selection means as a reference. Each system is provided with video synchronization means to synchronize with the signal, and one of the two systems of video signals output from the video synchronization means is provided.
The system is selected based on selection information in accordance with a reference synchronization signal, and is outputted in sequence as a series of output video signals.

The configuration of the device will be explained below using the drawings.

FIG. 1 is a functional block diagram showing the overall configuration of the apparatus of the present invention. As shown in the figure, it can be roughly divided into the following seven parts.

That is, selection information setting means 102 sets video selection information and outputs it to timing generation means 106.
and reference synchronization signal and selection information setting means 102
Video selection means 1 from video selection information input from
03a, 103b, video synchronization means 104a, 10
4b, timing generation means 106 for creating and outputting a timing signal for the system selection means 107;
According to the timing signal from the timing generation means 106, two systems of video synchronization means 104a, 1
A system selection means 107 selects one of the video signals from 04b and outputs an output video signal, and two systems select a single video signal from a plurality of video signal inputs according to the timing signal from the timing generation means 106. video selection means 103a, 103b
and two systems of video synchronization means 104a and 104b for synchronizing video signals according to timing signals from timing generation means 106.

[Effect]

The plurality of input video signals are sent to the video selection means 1.
03a, 103b and synchronized by video synchronization means 104a, 104b. However, if the selected video is changed in this case, discontinuity of the image on the screen will occur and the image will be distorted. Therefore, in the present invention,
By operating the other system one screen or more ahead of the change in the selected video of one system (preparing the next screen to be selected before switching), an image without discontinuity can be created on the screen. By making a selection using the system selection means 107 in advance, generation of boundaries between images on the screen due to changes in image selection can be prevented.

〔Example〕

The present invention will be explained in detail below with reference to Examples.

FIG. 2 is a block diagram showing the configuration of an embodiment of the video selection device of the present invention. A video signal source 1 having a plurality of television cameras C ₁ to _{C o} as shown in the figure
A and B two-system video selection circuit 3a, which selects a single video signal from n video signals sent from
3b, video synchronization circuits 4a and 4b of two systems A and B that synchronize video signals, and a system selection circuit 7 that selects an output signal of either system A or B,
A selection information setting circuit 2 that sets a video signal to be selected, a timing circuit 6 that creates a necessary timing signal, and a video signal processing device that receives the output signal of the video selection device and generates a reference synchronization signal. 5.

Next, the operation of the video selection device having the above configuration will be explained.

Television camera C ₁ configuring video signal source 1
~C _o outputs video signals VS ₁ ~VS _o . The video selection circuits 3a and 3b each receive a video selection signal P3.
Video signal VS ₁ ~ input according to a, P3b
A single video signal of VS _o is output as P1a and P1b.

The video synchronization circuits 4a and 4b are connected to the video selection circuit 3.
Video signals P1a and P1b output from a and 3b
is input, and according to timing signals P4a and P4b from the timing circuit 6, video signals P2a and P2b synchronized with the reference synchronization signal SY output from the video signal processing device 5 are created.

The system selection circuit 7 selects one of the video signals P2a and 2b from the A and B systems in accordance with the system selection signal P6 from the timing circuit 6, and outputs it to the video signal processing device 5 as an output video signal P7.

The timing circuit 6 selects the video selection circuits 3a and 3b according to the reference synchronization signal SY from the video signal processing device 5 and the setting signal P5 from the selection information setting circuit 2.
video selection signals P3a, P3b to the video synchronization circuits 4a, 4b, and timing signals P4a, P4b to the video synchronization circuits 4a, 4b.
Then, a system selection signal P6 to the system selection circuit 7 is created and output.

FIG. 3 is a timing diagram showing the flow of video signals in the embodiment of the present invention. In order to simplify the explanation and drawings, a case is shown in which video signals from four television cameras are sequentially selected in units of one field, and ~ are the output video signals of the television cameras C ₁ to C ₄ constituting the video signal source 1. VS ₁ to VS ₄ are the contents of the video selection signal P3a indicating the video signal to be selected by the A-system video selection circuit 3a, and are the output signal P1a of the A-system video selection circuit 3a, are the A-system video synchronization circuit. is the output signal P2a of the B-system video selection circuit 3b, is the content of the video selection signal P3b indicating the video signal to be selected by the B-system video selection circuit 3b, is the output signal P1b of the B-system video selection circuit 3b, is the B-system video synchronization signal is the output signal P2b of the circuit 4b, is the content of the system selection signal P6 indicating the system to be selected by the system selection circuit 7, and is the output signal P7 of the system selection circuit 7, which is the output signal of the present device. Further, the mark Δ is a vertical synchronization signal.

As shown in FIG. 3, one of system A consisting of a video selection circuit 3a and a video synchronization circuit 4a and system B comprising a video selection circuit 3b and a video synchronization circuit 4b performs processing. When the currently selected video is changed, the other systems that have been inactive start processing the video signal to be newly processed (video selection and synchronization) at least one screen before the selected video is changed. During the vertical blanking period after the preparation of the borderless video on the screen is completed, the system selection circuit 7 is changed to complete the video selection.

By repeating the above series of operations, a synchronized video signal P7 with no discontinuous boundaries on the screen where one field is the minimum video selection unit is generated.
is obtained.

〔effect〕

As explained above, the video selection device equipped with the video synchronization function of the present invention can generate two sets of selected video signals without image boundaries on the screen, which conventionally required the same number of video synchronization circuits as input video signals. Since this is realized using a video synchronization circuit, the device can be simplified and inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing the configuration of the device of the present invention, FIG. 2 is a block diagram of an embodiment of the video selection device of the invention, and FIG. 3 is a block diagram of an embodiment of the video selection device of the invention. 4 and 5 are block diagrams of a conventional video selection device, and FIGS. 6 and 7 are timing diagrams for explaining the operation of a conventional video selection device. FIG. 1... Video signal source, 2... Selection information setting circuit, 3
a, 3b...Video selection circuit, 4a, 4b...Video synchronization circuit, 5...Video signal processing device, 6...Timing circuit, 7...System selection circuit, 102...Selection information setting means, 103a, 103b...Video selection means, 104
a, 104b...Video synchronization means, 106...Timing generation means, 107...System selection means, _C1 to _Co ...
TV camera, SY...Reference synchronization signal.

Claims (1)

[Claims] 1. Two systems of video selection means for selecting a single video signal from a plurality of video signals, and a video system for synchronizing each video signal output from the video selection means with a reference synchronization signal. Two systems of synchronization means, system selection means for selecting one system from the two systems of video signals outputted from the video synchronization means and outputting it as an output video signal, and selection information for setting information on the video signal to be selected. selectively operating the two systems of the video selection means and the two systems of the video synchronization means in units of fields or frames in accordance with a setting means, selection information set in the selection information setting means, and a reference synchronization signal; and timing generation means for creating a timing signal for selection by the system selection means as a series of video signals synchronized with a reference synchronization signal, and setting information of the video signal to be selected in the selection information setting means. When changing the selection information, the selection information set to the timing generation means is supplied from the selection information setting means, and the timing generation means changes the selection information to the video selection means of the system not selected by the system selection means. A video selection signal corresponding to the selection information is supplied to select the set video signal, and a reference synchronization signal is supplied to the video synchronization means of the unselected system to select the output video of the video selection means. Synchronizing the signal with the reference synchronization signal, and supplying a system selection signal from the timing generation means to the system selection means to select the video signal of the unselected system after the synchronization is established. A video selection device equipped with a video synchronization function characterized by outputting a series of video signals synchronized with a reference synchronization signal. 2. The two systems of video selection means and the two systems of video synchronization means are each operated selectively, and when the selected video of one system is changed, the other system is activated by at least one screen. , comprising a video synchronization function according to claim 1, characterized in that by selecting a system by the system selection means, an image without boundaries is created in the video on the screen by changing the video selection. video selection device.