CCTV Terms & Definitions

CCTV Terms & Definitions 0 Comments

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  • Analogue CCTV: In the past, all CCTV Cameras were attached to a Multiplexor (A device that will split multiple camera pictures onto an individual CCTV Monitor). The Multiplexor then sends the analogue camera images to a Time Lapse Video Player. These are special CCTV recording devices that can record up to 960 hours of footage on a three hour Video Cassette. This method is still used today for simple CCTV installations but the quality of recording is usually very low (1 Frame Per 12.8 Seconds).


  • Aperture: Aperture is the area of the camera lens that gathers light. The Iris of the cctv lens controls the size of aperture.


  • Auto Iris: Auto Iris Lenses adjust for changing light conditions in a camera view.  If the sun shines on a camera with an auto iris lens, the lens will adjust  the amount of light so the picture remains clear.


  • CCD: Charge Coupled Device – a light sensitive imaging device for almost all cameras. Typical sizes for CCTV cameras – 1/2″, 1/3″, 1/4″.


  • C Mount: Type of screw-on mounting for CCTV Camera Lenses. C Mount lenses need an adapter ring when used with CS Mount camera (see CS Mount).


  • Compression: Compression Techniques are used in Digital CCTV to reduce the file sizes  of recorded video images. Typical compression formats used for video are: MJPEG, MPEG-4 & H.264.


  • CS Mount: More recent type of mounting for CCTV Camera Lenses. Designed for 1/2″, 1/3″ 1/4″ CCD cameras, CS-Mount is the more common lens mount used today in CCTV cameras.


  • Day/Night Camera: A camera that is ‘Day/Night’ means it can capture video in both day and night time.  In low light conditions, the Sony Day/Night chipset switches from colour to black & white at night to enhance the picture quality.


  • Digital CCTV: Digital CCTV, or Digital Closed Circuit Television, is the technology used in modern surveillance systems. Traditional ,VCR, CCTV pictures are sent via cctv cameras to a closed area, e.g. a CCTV Monitor, this type of CCTV is likely to produce lower resolution images and have to be displayed via cabling in the workplace. Modern Digital CCTV Systems can be operated remotely via a pc or mobile phone, can monitor various locations and can be monitored from wherever there is internet or GPRS Access.


  • DSP: Digital Signal Processing – a technique by which video quality can be improved by adjusting parameters of the video signal.


  • DVR: Digital Video Recorder – CCTV Footage is converted to a digital signal and stored on a PC Hard Disk. This is now the standard CCTV recording practice.


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  • ExView: Sony Chipset type that offers very good images in both day and night time. Typically, cameras with Ex-View chipset have good Low Light (LUX) levels.


  • FStop: The Ratio of Focal Length to the diameter of the lens. The smaller the F-Stop number, the more light is passed.


  • Field of View: The view of the camera – in relation to the angle of view and distance of the object from the lens.


  • Frame: A frame consists of 2 interlaces fields. 25 Frames are created every second.


  • Frame Rate: The quality of a Digital Surveillance Systems is often determined by the Total Frame Rate it can record at. The higher the Frame Rate, the higher the quality of recording and the more Real Time your CCTV recording will be – Real Time recording for 1 camera is 25 Frames Per Second (PAL)

 

 

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