AN IMPROVED HIGH RESOLUTION VIDEO CAMERA

Abstract: A high resolution video camera (10) is disclosed in which image data is received is compressed and encoded using a wavelet compression algorithm, for example MPEG4 compression standard and which can be interfaced with an ATM network to allow transmission of the image data along the network.

Description: AN IMPROVED HIGH RESOLUTION VIDEO CAMERA This invention relates to an improved high resolution video camera (referred to variously as closed circuit television camera or (CCTV)) for use with an asynchronous transfer mode (ATM) network. High resolution video cameras such as closed circuit video cameras are known and are generally used to provide high resolution, and hence high quality, real time video images for many purposes. For example, such cameras can be used in security systems and surveillance systems. An ATM network is a network along which data is transmitted in short chunks or cells. This allows real time data to be delivered without significant delays. Furthermore, an ATM network can be configured so as to be capable of transmitting video, audio and other data all at the same time rendering it unnecessary to provide a different network for transmission of each of these types of signals. The present invention is based on the realisation that it should be possible to provide a high resolution video camera which is capable of being connected to an ATM network whereby fast transmission of high quality video images can be achieved and such that high quality images can be viewed at any point on the network. Furthermore, as only one network is required for all types of signal, there is a considerable reduction in cabling costs. Still further, it is possible to extend the network particularly simply because only one network is used and therefore only one set of cabling. Thus and in accordance with the present invention there is provided a high resolution video camera which produces an image signal, said camera including means to compress and encode said video signal using a wavelet compression algorithm and means for interfacing with an ATM network whereby said compressed video signal can be transmitted along said network. With this arrangement it is possible to provide a high resolution video camera which is capable of sending video signals over an ATM network. Preferably said compression means is operable to compress said video signal according to an algorithm which is part of the MPEG4 standard. Preferably the camera also includes a connection to an audio input device, for example a microphone, and includes means to convert an analogue audio signal to a digital signal for transmission over an ATM network. Preferably the camera also includes a connection for control data. Preferably the camera also includes means to receive an audio signal from an ATM network and convert this to an analogue signal for a suitable audio output device, for example a loud speaker. The invention will now be described further by way of example only and with reference to the accompanying drawings, the single Figure of which shows a schematic representation of one embodiment of the camera according to the present invention. Referring now to the Figure, there is shown a digital high resolution video camera 10 linked to a compression circuit 1 1 and an ATM interface unit 12. The compression circuit 1 1 is also linked to an audio input device 13. In practice, the compression circuit 1 1 and ATM interface circuit 12 will be contained within the body of the camera 10 but are shown as separate items in the drawing for ease of description. The compression circuit 1 1 comprising a circuit which is operable to compress video signals received from the digital video camera 10 according to a particular image compression algorithm. The preferred algorithm used by the compression circuitry is a wavelet compression algorithm which is part of the MPEG4 standard. The ATM interface device 12 comprises a circuit which is designed to convert the compressed video signals into a form suitable for transmission over an ATM network. Thus the ATM interface device breaks up the compressed video signals into data cells which are transmitted along the network. The audio input device 13 can comprise any suitable audio device for example a microphone. In use, the high resolution video camera 10 produces a video signal which is compressed and encoded by the compression circuitry 1 1 according to the wavelet compression algorithm. The compressed video signal is then converted into data cells by the interface device 12 and is transmitted over the ATM network. The typical rate of transmission of information over the network is approximately 25Mbps. If it is desired that audio signals as well as video signals are transmitted over the ATM network, it is possible for the audio device 1 3, which is for example a microphone, to provide an analogue audio signal which is also converted within the compression circuitry 1 1 into a digital signal and can be transmitted along with the video signals over the ATM network. The camera 10 can also be adapted such that audio signals which are transmitted over the ATM network can be received. In these circumstances, the camera 10 will include circuitry (not shown) which can convert the data cells into a digital signal, and can convert the digital signal, to an analogue signal whereby the audio signal can be played back using a suitable audio device for example a loudspeaker. It will be understood that the present invention will find application in many areas. However, the present Applicants have realised that such a camera will find particular application in the field of security. For example, it will be possible for a number of high resolution video cameras 10 to be linked together, and to a control panel, by a single ATM network whereby images generated by each of the cameras can be viewed at any location on the network and there can be two way communication of data between the control panel and the cameras. Furthermore, it is possible for a video signal and an audio signal, or indeed any number of data signals to be transmitted along the network at the same time. It is of course to be understood that the invention is not intended to be restricted to the details of the above embodiment which are described by way of example only.

Claims: CLAIMS 1 . A high resolution video camera which produces an image signal, said earner, including means to compress and encode said video signal using a wavelet compression algorithm and means for interfacing with an ATM network whereby said compressed video signal can be transmitted along said network. 2. A high resolution video camera according to claim 1 , in which said compression means is operable to compress said video signal according to an algorithm which is part of the MPEG4 standard. 3. A high resolution video camera according to claim 1 or claim 2, further including an audio input device, for example a microphone, and means to convert an analogue audio signal to a digital signal for transmission over an ATM network. 4. A high resolution video camera according to any one of claims 1 to 3, wherein the camera also includes a connection for controlled data. 5. A high resolution video camera according to any one of claims 1 to 4, wherein the camera includes means to receive an audio signal from an ATM network and convert this to an analogue signal for a suitable audio output device, for example a loudspeaker.

Inventors: BEARE PETER, BEARE, PETER
Applicants: BAXALL SECURITY LTD, BEARE PETER, BAXALL SECURITY LIMITED, BEARE, PETER
Application year: 1999
Main classification: H04N5
IPC codes: H04N5, H04N7