GB2451751A

GB2451751A - CCTV Network and Camera Control

Info

Publication number: GB2451751A
Application number: GB0814386A
Authority: GB
Inventors: Christopher Hall
Original assignee: TECTON Ltd
Current assignee: TECTON Ltd
Priority date: 2007-08-07
Filing date: 2008-08-06
Publication date: 2009-02-11
Also published as: GB0715316D0; GB0814386D0

Abstract

A CCTV system comprises a camera controller (1, 3) provided with a coax input/output (f), a first coax (4) connecting the input/output (f) to the coax input/output (6) of a local video transmitter/receiver (5), a remote video transmitter/receiver (7) communicating with the local transmitter/receiver by way of an IP network (N), the remote video transmitter/receiver (7) having a coax input/output (9) connected by a second coax (11) to a video camera (12), the local video transmitter/receiver (5) receiving video signals from the network and outputting them to the first coax (4), and receiving camera control signals over coax signals from the first coax and transmitting camera control signals to the network, and the remote video transmitter/receiver receiving video signals from the second coax and to output those to the network, and receiving camera control signals from the network, to reassemble them, and outputting the camera control signals to the second coax. The camera controller unit (1, 3) interacts with the camera such that the camera is controlled as a local camera.

Description

VIDEO TELEMETRY

This invention relates to the field of video telemetry and to CCTV camera systems.

CCTV cameras are commonly mounted on a motorised head to enable the camera to be panned and tilted, by suitable camera control signals, which are often also used to control camera settings such as zoom and focus, and even lighting.

For cameras that are situated close to the camera control centre it is possible to provide a twisted pair for the camera control signals, using RS-485 devices. In order to avoid the need for such a twisted pair, it is well-known to use a camera control down the coax' system, in which the coax is used both to convey the video signals from the camera to the control centre and to convey the camera control signals.

* There are limits to the length of coax that can be employed and, of course, coax can generally only be laid on the premises of the owner of a property or with another property owner's permission. There is *:*::* therefore a need to control a remote camera over an IP (internet protocol) * wireless network, and to be able to receive the video images over the I..

network. * I I I. I

*:*. 20 Although it would be possible to use fibre optics to provide a dedicated long-distance connection between a controller and a remote camera, this would require provision of a specific fibre-optics link.

Whilst it would be possible, but costly, to produce a controller that is dedicated for use just with a particular remote camera via a network, we consider it desirable that a system can utilise one of the camera control over coax inputs/outputs that is provided on a controller for camera control over coax of one or more local cameras. The video signals received from the networked remote camera, and the camera control signals for that camera, can then be handled by the controller in the same way as the video signals and camera control signals of a local camera connected directly by coax.

We have appreciated that there are advantages in providing a transmitter/receiver that is capable of transmitting and receiving both video and camera control over coax signals over an IP network.

According to one aspect of the invention we provide a CCIV camera system comprising a camera controller unit provided with at least one coax input/output, a first coax connecting said coax input/output of the controller to the coax input/output of a local video transmitter/receiver, a remote video transmitter/receiver adapted to communicate with the local video transmitter/receiver by way of an IP network, the remote video * *. transmitter/receiver having a coax input/output connected by a second :::::: coax to a video camera unit, the local video transmitter/receiver being adapted to receive video signals from the network and to output them to *:*::* the first coax, and to receive camera control over coax signals from the *. 20 first coax and to transmit camera control signals to the network, and the remote video transmitter/receiver being adapted to receive video signals from the second coax and to output those to the network, and to receive * camera control signals from the network, to reassemble them, and to output the camera control over coax signals to the second coax.

Thus, we have in effect introduced a pair of transmitters/receivers in the coax line handling camera control over coax signals for the remote camera, the transmitters/receivers being configured to use an IP network for conveying the camera control over coax signals, and the video signals.

Although it would be possible to use dedicated transmitter/receivers for the local and remote locations, preferably the units are dual-purpose transceivers.

The signal protocol for the network signals is preferably a video codec.

According to a second aspect of the invention we provide a local transmitter/receiver unit provided with a coax input/output and with a network input/output, the unit being configured to receive camera control over coax signals at the coax input/output and to convert those signals to a format suitable for conveying over an IP network, and to supply the converted camera control signals to the network input/output, and the unit being configured to receive video signals from an IP network at the network input/output and after re-formatting the video signals to feed the video signals to the coax input/output. *0**

According to a third aspect of the invention we provide a remote *:*::* transmitter/receiver unit adapted to work over an IP network with a local * transmitter/receiver unit in accordance with the second aspect of the *** invention, for handling camera control over coax signals over the **** : 20 network and video signals over the network, the remote *:*. transmitter/receiver unit being configured to receive the camera control signals from the network at a network input/output and to reassemble the camera control signals as camera over coax signals suitable for conveying by coax, the reassembled camera control signals being fed to the coax input/output, and the remote unit being configured to receive video signals at the coax input/output and after re-formatting to transmit those signals to the network input/output for transmission to said local transmitter/receiver over the network.

A CCTV camera system in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawing in which: Figure 1 is a schematic block diagram of the system.

In Figure 1, a conventional controller box 1 is connected to a monitor 2 and to a manually operable camera control 3. The controller box I is configured in well-known manner to transmit camera control over coax signals and to receive video signals from local cameras that can be connected respectively to a plurality of coax connections a to e provided on the controller box. The co-ax connector f, which has precisely the same functionality as the connections a to e, has in this case been connected by a first co-ax 4 to the coax input/output connection 6 of a * 15 novel transmitter/receiver unit 5, which for convenience we are referring :::::: to as a local transmitter/receiver' since it will generally be physically closer to the controller box 1 than a further transmitter/receiver unit 7, *:*::* which we are calling for convenience a remote transmitter/receiver'.

S S.

Various protocols are used for camera control over co-ax signals. A 55..

: 20 commonly used one is that of Building Block Video Ltd in which camera *..: control signals are present on the video signal in the vertical blanking period. Frequencies represent digital data, relating to the camera control signals, where the digit 0 is represented by a frequency of 222KHz and digit 1 is represented by a frequency of 250KHz.

The unit 5 is configured to convert camera control over coax signals received at coax input/output 6 into a format suitable for outputting by network connection 8 to an IF network N. A video codec is employed to compress the video frames derived from the coax signals into a form suitable for transmission over the IF network.

The network N could be the Internet.

The camera control over co-ax signals received from coax 4 are FSK signals of frequencies 222KHz and 250KHz, are converted into digital signals by an FSK demodulator. The resulting sequences of l's and 0's are sampled and stored, and then packetised with a header describing the camera control information, for transmission to IP network N. The remote transmitter/receiver unit 7 similarly has a coax input/output connection 9 via a 1k5 resistor, and a network input/output connection 10. The coax connection 9 is connected by a second coax 11 to a conventional motorised video camera 12 configured in well-known manner for use with camera control over coax signals. The remote * 15 transmitter/receiver unit 7 is conveniently an identical unit to the unit 5 but is suitably configured for its converse function. Unit 7 is configured **** to re-assemble the camera control over coax signals to be output by connector 9 from the corresponding signals received from the network by network connection 10. It will be appreciated that unit 7 is also configured to receive video signals at coax input/output 9 and to convert those using video codec into a suitably compressed format for transmitting to the network at connection 10.

It will be appreciated that the use of the transmitter/receivers 5, 7 simulates what would be achieved if the coax 11 was directly connected to coax 4 so that, in effect, we have interposed the units 5 and 7 into what would otherwise be a local camera control over coax connection to camera 12.

Since the IP neiwork can effectively be of any size, the invention makes it possible to control a remote camera as if it was a local camera, using a conventional controller box 1 as provided for handling the camera control and video signals of local cameras. * ** 0S S * S. * S 1St. * *5 * S S * I*

S Ill

S 5.5. * SI S. I *5 I * a. S.

Claims

1. A CCTV camera system comprising a camera controller unit provided with at least one coax input/output, a first coax connecting said coax input/output of the controller to the coax input/output of a local video transmitter/receiver, a remote video transmitter/receiver adapted to communicate with the local video transmitter/receiver by way of an IP network, the remote video transmitter/receiver having a coax input/output connected by a second coax to a video camera unit, the local video transmitter/receiver being adapted to receive video signals from the network and to output them to the first coax, and to receive camera control over coax signals from the first coax and to transmit camera control signals to the network, and the remote video transmitter/receiver being adapted to receive video signals from the second coax and to output those to the network, and to receive camera control signals from the network, to reassemble them, and to output the camera control over coax signals to the second coax. *s

2. A camera system as claimed in claim I in which the * ISS transmitter/receivers for the local and remote locations, are dual- purpose transceivers. S..

3. A camera system as claimed in claim 1 or claim 2 in which the *1* signal protocol for the network signals is a video codec.

4. A local transmitter/receiver unit provided with a coax input/output and with a network input/output, the unit being configured to receive camera control over coax signals at the coax input/output and to convert those signals to a format suitable for conveying over an IP network, and to supply the converted camera control signals to the network input/output, and the unit being configured to receive video signals from an IP network at the network input/output and after re-formatting the video signals to feed the video signals to the coax input/output.

5. A remote transmitter/receiver unit adapted to work over an IP network with a local transmitter/receiver unit as claimed in claim 4, for handling camera control over coax signals over the network and video signals over the network, the remote transmitter/receiver unit being configured to receive the camera control signals from the network at a network input/output and to reassemble the camera control signals as camera over coax signals suitable for conveying by coax, the reassembled camera control signals being fed to the coax input/output, and the remote unit being configured to receive video signals at the coax input/output and after re-formatting to transmit those signals to the network input/output for transmission to said local transmitter/receiver over the network.

6. A CCTV camera system substantially as described herein with reference to the accompanying drawing Figure 1. * * S...

7. A local transmitter/receiver unit configured for use in the CCTV *:::* camera system substantially as described herein with reference to the accompanying drawing Figure 1. * . S

8. A remote transmitter/receiver unit configured for use in the CCTV camera system substantially as described herein with reference to the accompanying drawing Figure 1.