How total digital functionality is enabled by IP Video Surveillance

A video surveillance system consists of four components – Camera, recording, monitor and video network. The CCTV/DVR systems which were employed earlier used the CCD Cameras to record the video which is converted in to analog form for transmission over the co-axial cables and then again digitized in the DVR (Digital Video Recorder) for compression and recording. So, this multiple conversion system (just to carry the video signals over the Co-axial cable) was quite inefficient especially when the digital video signal was converted in to analog signal then back again to digital signal. That’s where the IP Surveillance system comes in to the picture which enables the entire process to be digitized completely. We will take a look at how it is done at the individual component level:

Camera: What was the analog tube camera, was replaced by the digital CCD cameras which generated the image in digital format. Even though the output of a CCD camera was digital, it needed to be converted in to analog for carrying it over the co-axial cable in the component video format. So, these CCD cameras did this conversion. The CCD cameras are replaced by IP Cameras which generates digital video and allows the digital video to be transmitted over the IP network without conversion.

Recording: The analog VCR Tapes of the earlier era was replaced by the DVR – Digital Video Recorder. This was generally a proprietary hardware device which received the analog signals from co-axial cables, digitized it, compressed it and recorded it over disks (which made archiving and searching easier). These Digital Video Recorders (DVR) are replaced by Network Video Recorder (NVR) which receive digital video input from an IP network and record them using recording software’s over any standard computer server.

Monitor: The monitor, which is used to display the video for surveillance, was earlier CRT based. This was converted in to a PC based monitor with DVR. Now, it remains a computer monitor/LCD Display unit and accepts video input directly from a Network Video Recorder (NVR) for displaying the digitized video.

Network: The video network, which was formed using co-axial cables to carry the video signals in analog format is now changed to IP Network which uses twisted pair cables – Catx based, which enables to carry the video signals using digital format. The IP Network, which is already available in most organizations for carrying data can be used with some additions or a new IP network using switches, IP cameras, Catx cables can be created – which could still be less expensive than the analog co-axial cable network. The IP network also enables remote monitoring and control of the IP Video Surveillance system (like over the internet etc). Even the wireless network can be used to connect to the IP Cameras in remote locations or even everywhere to create a total wireless video surveillance system in the campus. This is possible because of the IP Network being employed to carry the digital video signals.

The fundamental difference between a DVR and IP Surveillance concepts:

In a DVR(Digital Video Recorder), the process of digitization and compression of video signals occur in the recorder unit while in the NVR(Network Video Recorder for IP Surveillance), the digitization and compression of video signals occur in the IP Cameras. That enables the IP Cameras to provide intelligent functionalities like motion sensing etc. which partly explains the higher cost of the IP Surveillance Cameras. But the advantages of IP Surveillance are many including scalability, redundancy, single network, additional functionalities etc.

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