JPS62117488A - Television camera changeover device - Google Patents

Abstract

PURPOSE:To automatically decide the presence and the absence of connection of a television camera to changeover by detecting the presence and the absence of connection of the television camera, inputting the result to a memory device and connecting the output of the memory device to the input terminal of the memory device through a latch circuit. CONSTITUTION:The presence and the absence of the connection of the television cameras 1, 2 is detected by detecting circuits 4-6, and the detecting outputs of the circuits 4-6 are inputted to the memory device 11. To the output terminal of the memory device 11, the latch circuit 12 is connected, and data output successively changing according to a latch pulse inputted to a terminal 13 is inputted to the memory device 11. A video signal selecting circuit 9 successively selects the television camera connected according to address data decided by the output of the detectors 4-6 and the output from the latch circuit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a television camera switching device for switching a plurality of television cameras in a surveillance television camera system or the like.

[Summary of the invention]

The present invention is a television camera switching device in which a television camera switching order is recorded in advance in a storage device, and whether or not a television camera is connected is automatically determined and switched.

[Conventional technology]

A conventional camera switching device is shown in FIG. In the figure,
1 to 3 are television cameras, 4 to 7 are television camera detection circuits, 8 is a microcomputer, 9 is a video signal selection circuit,
10 is a video signal output terminal. The operation will be explained using the flowchart in FIG. The microcomputer 8 first sets n, which represents the number of the television camera, to 0. Then add 1 and combine. The result is compared in size with the maximum connectable number m of television cameras (4 in the case of FIG. 2), and if it is larger, the process is restarted from the beginning. Next, it is checked whether the n-th television camera is connected or not, and if it is not connected, the process proceeds to the next numbered television camera. If the nth television camera is connected, a selection signal is output to the video signal selection circuit 9 so that the nth television camera video signal is selected. This state is maintained for a certain period of time, and the operation continues to the next TV camera. In the case of FIG. 2, the video signals of the television cameras 1, 2, and 3 are repeatedly output from the video signal output terminal 10 at regular intervals.

[Problem that the invention seeks to solve]

However, with the above-mentioned conventional technology, since the program contents are written to the ROM (read-only storage device) in the microcomputer, there is an initial cost, and the cost per unit increases when producing small quantities. There is a problem of storage. Furthermore, there is a problem in that the microcomputer malfunctions if it goes out of control due to noise or the like. SUMMARY OF THE INVENTION The present invention aims to solve these problems, and its purpose is to provide a television camera switching device that is inexpensive and resistant to malfunctions.

[Means for solving the problem] In a television camera switching device that includes a detection circuit that detects whether or not a television camera is connected and a video signal selection circuit, the output of the detection circuit is connected to an input terminal of a storage device. , the output terminal of the storage device is connected to the selection circuit, a launch circuit is provided to input the output terminal of the storage device, and the output of the latch circuit is connected to the input terminal of the storage device.

[Effect]

According to the above configuration of the present invention, an EPROM is used as a storage device.
(erasable programmable read-only memory) etc., the presence or absence of a TV camera is input as an address input to the EPROM, and the content of which TV camera was selected last time is stored in the EFROM via a latch circuit. The data in the EPROM is predetermined so that information on which television camera should be selected next is outputted from the EFROM by transmitting the address to the EFROM.

〔Example〕

FIG. 1 shows an embodiment of the present invention. In the figure, 1 to 2
1 is a television camera, 4 to 6 are television camera detection circuits, 9 is a video signal selection circuit, 10 is a video signal output terminal, 11 is a storage device, 12 is a launch circuit, and 13 is a latch timing input terminal. Before explaining the operation, the data contents of the storage device will be explained using FIG. TV camera detection circuit 4 that detects whether the TV camera 1 is connected
The output of is connected to the address input A2 of the storage device 11. Similarly, the output of the television camera detection circuit 5.6 is connected to address inputs A:1 and A4. It is assumed that the television camera detection circuit outputs "1" when the television camera is connected, and outputs "○" when the television camera is not connected. The relationship between address data and data is as follows. Address data (A4, Ao, Az, At, A
o) is (00000), the recorded data (DI,
Do) is (00). This is because (00) is recorded because A2-A4 are all O, and since the television camera is not fully connected, no camera can be selected next. Next, for example, when the address data is (01101), the recorded data is (
10). This means that the first and second TV cameras are connected, and the address data is A+, Ao to 1.
This indicates that the second television camera was previously selected, and if the next selection were to be made, the second television camera would be selected, so the recorded data would be 10). Also, when the address data is (1,0110),
The recorded data is (01). This indicates that the second television camera was previously selected. However, as can be seen from the address data, only the first and third television cameras are connected, so it is thought that some kind of malfunction has occurred. Therefore, in order to return to the original normal state, the recorded data is set to (01). FIG. 4 shows the relationship between address input and data output determined based on the above concept.

The operation in the case of FIG. 1 will be explained using FIG. 4.

Since the first and second cameras are connected, the address data (A4, A3, Az) is (011)
It is. When the launch circuit 12 is reset when the power is turned on, the output becomes (00) and the address data becomes (0
1100). Then, the data output from the storage device 11 becomes (01) from the 13th line of Table 1, and the video signal selection circuit 9 selects the television camera 1.

Next, when a latch pulse is input to the latch timing input terminal 13 of the latch circuit 12, the data output of the launch circuit 12 becomes (01). Then, the address data (01
101), and the data output from the 44a device 11 is (01) from the 14th line of Table 1. Then, the video signal selection circuit 9 selects the television camera 2.

Furthermore, when a latch pulse is input to the latch circuit 12,
The data output of the launch circuit 12 becomes (10). Then, the address data becomes (01110) and the storage device 11
The data output from the 15th line of Table 1 becomes (01), and the video signal selection circuit 9 selects the television camera 1 as before.

As described above, automatic switching is performed in the order of television camera 1 and television camera 2.

Furthermore, consider the case where the launch circuit malfunctions due to noise or the like and outputs the data (11). At this time, the address data becomes (01111) and the data output of the storage device 11 becomes (01). Then, the video signal selection circuit 9 can select the television camera 1 and return to the original state.

〔Effect of the invention〕

As mentioned above, according to the present invention, initialization required for a microcomputer is not required, and it can be realized with a simple circuit configuration, so it is inexpensive and has a recovery function even if it malfunctions. Therefore, it has the effect of being extremely resistant to malfunctions.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a television camera switching device according to the present invention. FIG. 2 is a block diagram of a conventional television camera switching device. FIG. 3 is a flowchart of a conventional television camera switching device. 8...Microcomputer 9...Selection circuit 11...Storage device 12...Latch circuit and above Applicant Seiko Epson Corporation Agent Patent attorney Tsutomu Mogami (1 other person) (] 0) No snoring light Alevi' force / no GH, Kuwa (5 knees)゛0,
Figure 77 Figure 1

Claims (1)

[Claims] (1) (a) A television camera switching device comprising a detection circuit for detecting whether a television camera is connected and a video signal selection circuit, (b) connecting the output of the detection circuit to an input terminal of a storage device. , an output terminal of the storage device is connected to the selection circuit; (c) a latch circuit is provided to input the output terminal of the storage device, and the latch circuit output is connected to the input terminal of the storage device. Features TV camera switching device.