Video Surveillance Glossary of Terms [C]

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• » Cable tray [top]
  This tray is installed in many sites, and lays cables out lengthwise for economics and organization.
  
• » Cameo [top]
  A small part of a monitor’s viewing area (1/16^th the screen area) is called a cameo.  Multiplexers create multiple analog signals from security cameras and then combine them into multiple cameos on the screen, which enables simultaneous viewing of up to sixteen different camera pictures. 
  
• » Candela [top]
  A candela is a measurement of luminous intensity and is a replacement to the candle.
  
• » CCD (Charge Coupled Device) [top]
  This is a computer chip that converts the light energy that enters a camera into an electrical charge, which is then converted into an electronic image.  The image is then optimized into a very high quality picture. There are two types of CCD: frame transfer and interline transfer. 
  
• » CCTV (Closed Circuit Television) [top]
  CCTV refers to the use of television cameras for surveillance purposes.  Unlike broadcast television, all devices are linked directly, usually by cables.  CCTV pictures are viewed and/or recorded, but are not broadcast.  Usually involving analog cameras and recorders, CCTV is the precursor to digital network systems.
  
• » CIF (Common Intermediate Format) [top]
  The default frame resolution of 352x288 for DVR systems is known as the CIF. 
  
• » CMOS [top]
  The use of Complementary Metal-Oxide Semiconductors in imagers to sense images improves over CCD technology in resolution, dynamic range, and noise sensitivity.
  
• » C-Mount [top]
  This is a specific type of camera, as well as its corresponding lens mount.  The C-mount lens is found in older versions of security cameras, and has a flange back distance of 17.5mm.  In order to achieve a focused image, a 5mm ring must be inserted between the camera and lens. 
  
• » Coaxial Cable [top]
  A cable with a central conductor that’s surrounded by a shield sharing its same axis is called a coaxial cable.  It’s used primarily for carrying high frequency or broadband signals.  RG59 video coaxial cable is used for digital video recorder (DVR) installations. 
  
• » CODEC [top]
  CODEC means compressor/decompressor and is any technology used to compress and decompress data.  It converts analogue input into digital, and then converts it back to analogue.  CODECS can be either software applications or hardware components, or both.  DVRs use CODECS to compress video streams from security cameras, and then store this compressed data on a hard disk. 
  
• » Composite Video [top]
  This type of video is a combination of different source video signals, usually YUV, field, line, blanking pedestal, color sync, and field equalizing pulses.  The end result is one composite signal, allowing it to be modulated onto a RF carrier.
  
• » Concave [top]
  A concave optical lens has an inward curving surface, causing incoming light to diverge.
  
• » Convex [top]
  A convex lens curves outwards, and is sometimes known as converging.  Light that passes through converges to a focal point.
  
• » Covert [top]
  A CCTV surveillance system that uses hidden cameras and lenses is considered to be covert.
  
• » Crosstalk [top]
  In a multiplex signal, video, audio, or data channels with adjacent signal frequencies can create interference.  This interference produces a noise known as crosstalk.
  
• » CRT (Cathode Ray Tube) [top]
  The CRT is a tube found in most televisions, monitors, and video monitors.  Once heated, it creates images by emitting a beam of electrons that hit a phosphor-coated surface.  The glow of the surface is dependent on the beam’s intensity.  Each CRT uses deflection circuitry to control the beam’s movement. 
  
• » CS Mount [top]
  CS mount lenses offer a longer focal distance than their C mount predecessors.  They have a flange back distance of 12.5mm.  Because they are more practical for compact cameras, CS mounts are used in most modern cameras.  A 5mm spacer ring (known as a C ring) enables CS cameras to also use a C mount lens.

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