A closed-circuit television camera is a part of a video surveillance system comprising of CCTV(s) and monitor(s). There could a CCTV transmitting signals to single monitor or to multiple-points. Or multiple cameras could be attached with a single monitor for centralized monitoring. The signals transmitted could be video only or video and audio.
How does a CCTV work?
A video Surveillance Camera has an aperture to capture a light stream and a chip to convert that stream into a continuous stream of images transmitted to a monitor(s) through cables or wireless technology. The signals are recorded for transmission.
The camera comes fitted with Infrared Light Emitting Diodes (IR LEDs) that sense the ambient light level of sources. The sensors detect the light and convert the amount light received into a percentage to calculate the brightness of the light source. Use of digital technology in the recording and processing of data has improved the signal quality and speed of signal transmission.
How are signals recorded?
A video surveillance camera uses either a Digital Video Recorder (DVR) or a Network Video Recorder (NVR) for recording the signals. The data received by DVR is coded, processed and stored in the recorder. But NVR works with IP cameras only and is suitable for remote viewing. It receives signals from a network instead of a device that is the camera.
The DVR is a physical recorder with a limited capacity of recording number of frames but NVR has massive recording capacity. Recordings can be viewed using centralized software of the camera, web browser or a mobile application.
How to choose a CCTV camera?
There are primarily two types of cameras – Analog and IP. Also, the cameras can be further classified according to their range and features like audio recording and two-way communication. A choice for a CCTV can be made after studying needs.