Evolution of video surveillance systems
Video surveillance systems have existed for some 25 years, starting out as 100% analog systems and gradually becoming digitized. Today’s systems have come a long way from the early analog tube cameras connected to a VCR. They now use network cameras and PC servers for video recording in a fully digitized system.
However, in between the fully analog and the fully digital systems, there are several solutions which are partly digital; these solutions include a number of digital components but do not represent fully digital systems. In true network video systems, the video is continuously being transported over an IP network, and which are fully scalable and flexible.
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Video motion detection (VMD)
Video motion detection (VMD) is a way of defining activity in a scene by analyzing image data and differences in a series of images. The functionality can either be built-in into a network video product or made available with video management software. In-picture alarm programming allows you to define areas of a screen where you want to detect any visual changes.
Hardware platforms for video administration
There are two different types of platforms for network video management: PC Server platforms and NVR platforms (Network Video Recorder). Both types are based on PCs but there are some noticeable differences.
A PC Server platform solution on the other hand runs on ‘off the shelf’ hardware where hardware components have been selected to obtain the maximum performance. With a PC Server platform solution it is possible to leverage on standard components, such as increased or external storage, additional remote operator stations and to run additional software in parallel to the video application, such as firewalls and virus protection.
The most obvious difference between an NVR platform and a PC Server platform type solution is that an NVR comes as a hardware box with the video management functionality pre-installed. By definition, it is dedicated to its specific tasks of recording, analyzing and playing back of network video. NVRs do not allow for any other applications to reside on them. The NVR hardware itself is "locked" to this application and the unit can very rarely be altered to accommodate anything outside its original specification.
Video management: monitoring & recording
Video management of a network video system includes video monitoring, which can be conducted from a Web browser or specific video management software. Video recording can be conducted from video management software installed on a PC or through the use of a Network Video Recorder (NVR), which is a hardware box with pre-installed video management software.