CLOSED CIRCUIT TELEVISION A Closed Circuit Television system is a multipurpose tool. Closed Circuit Television (or CCTV) when properly designed and installed is a most effective tool for purposes of::
A CCTV System consists of a : CCTV Camera and a CCTV Monitor
Enhancements to the CCTV system can include:
Video Time Lapse Recorder
( records up to 960 hours on one VHS tape) Digital Video Recorders
The newest improvement to CCTV system design is the DIGITAL RECORDERS. With these units, the need for VHS tapes is eliminated. The video images (up to 60 pictures-per-second) are stored on a computer hard-drive. Navigation controls are easier than those on a simple VCR. Among the most notable improvements!: No more need for VHS tapes. Most digital recorders come with hardware and software necessary for remote viewing of live and recorded pictures on your home computer. Passive Vs Interactive CCTV Systems A Passive design is made when the cameras are installed at a location with a fixed lens. A recorder is turned on, and that view is captured on the recorder. No operator is necessary, and if the cameras are placed in correct positions and the correct lenses have been chosen, then a proper visual record will be archived. An Interactive design is made when the camera is installed at a location with a pan and tilt motor and possibly a zoom lens or cameras are combined using a sequential switcher. A full time operator is constantly working with the controls to view many areas............ The recorder is recording what the operator is seeing. This is an important weakness in the interactive system. If the operator pan, tilts and zooms onto a suspect at the jewelry counter (for example) the operator is not seeing, and the recorder is not recording the employee 20 feet away (as another example) stealing money out of the cash register. Generally speaking a Passive System is best. If interactive components are added, the system's integrity must be maintained by having enough passive cameras viewing and recording the areas of most critical concern. LENS SELECTION
Above are two views of the beach from the same camera position. The Left picture shows a small part of beach and a close up of the tourists. The Right side picture shows more activity on the beach, but with less detail of individuals. Think in terms of having a detail camera or a wide angle scene camera. You CANNOT have a wide angle lens that will view the whole room and still give you the close up detail to view the denomination of money tendered, or a good face view of the customer. More than likely, your CCTV system will need a combination of scene -type wide angle lenses and detail -type narrow lenses. Switchers, Quad Splitters and Multiplexers When there is more than one camera to be archived on a single recorder or to be viewed on a single monitor then some type of combining device is necessary. The least expensive is the automatic sequential switcher . This device will switch from camera to camera automatically, and will allow recording of each camera (one at a time) on a single recorder. Better, is the quad splitter . This more expensive box will show four cameras on the monitor at the same time, and these four images are recorded in this same format. The only draw back here is that these are four small pictures. Best is the multiplexer . This device will show up to 16 cameras on one monitor at the same time. However, EACH picture is recorded singly, so that on the play-back of the recorded images, you can view any one camera you want "Full sized". Most multiplexers today have built in motion detectors so that only the cameras that are viewing motion are sending a signal to the recorder. SAMPLE OF QUAD SPLITTER Storage Area (rear exit to left) Drive Thru Window+Register
Main Registers Dining Room (Camera over Exit) |
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