CCTV Dictionary

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CCTV Dictionary
2012-06-15 16:12:14

CCTV Dictionary
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  1. Image Sensor?
    a device that converts an optical image to an electric signal.
  2. DSP (Digital Signal Processing)
    Conversion of the analog signal from a CCD image sensor into a digital signal through an analog to digital converter. This enables many digital features such as backlight compensation or sensitivity up.
  3. WDR (Wide Screen Display) (aka: ALC (Automatic  Level Control))
    enables the capture and display of both bright and dark areas in the same frame, in a way that there are details in both areas, i.e. bright areas are not saturated, and dark areas are not too dark.
  4. 3D-DNR (Digital Noise Reduction)
    dramatically cleans up the noise in video frames.
  5. DSS (Digital Slow Shuttering)
    DSS basically electronically spreads the light reflected onto the CCD chip of the camera, onto fewer images per second. This leads to drastic increase of the useable illumination LUX.
  6. Privacy Masking
    Privacy masking is a feature found in many IP cameras which is used to protect personal privacy by concealing parts of the image from view with a masked area.
  7. DIS (Digital Image Stabilizer)
    Image stabilization technology uses either hardware or software inside the digital camera to minimize the effects of camera shake or vibration.
  8. OSD (On screen display)
    a menu system within the camera assembly that can be accessed in order to set functions such as Iris levels, AGC on/off and most features of standard and advanced cameras.
  9. Iris (Aperture)
    Adjusts for various lighting conditions.
  10. Lux
    lower the lux, the better the camera is in low light situations.
  11. Focal Length
    what determines how far the camera can see.
  12. Manual Iris
    lenses are adjusted at the camera – not recommended in areas where the light changes.
  13. Auto Iris
    lenses will open and close the iris as needed.
  14. Attenuation
    a decrease or loss in a signal.
  15. Automatic Gain Control
    an electronic circuit used by which the gain of a signal is automatically adjusted as a function of its input or other specified parameter.
  16. Back Light Compensation
    a feature of modern CCD cameras which electronically compensates for high background lighting to give detail which would normally be silhouetted.
  17. Blooming
    the halation and defocusing effect that occurs around the bright areas of the picture (highlight) whenever there is an increase in the brightness intensity.
  18. CCD (imager)
    charged coupled device, converts  image to digital electronically.
  19. Db
    a measure of power ratio of two signals
  20. Distribution Amplifier
    a device that accepts a video signal and sends it out over a number of independent outputs
  21. Duplex (Multiplexer)
    a multiplexer with two frame stores allowing it to show multi-screen pictures while performing time multiplex recording.
  22. Focal Length
    the distance in mm from lens to the surface of the image sensor. The shorter the distance, the wider the view; the longer the distance, the narrower (telephoto) the view.
  23. Foot Candle
    a measurement of light. 1 lumen per square foot.
  24. Format
    the size of the camera’s pickup device (imager). Current standard formats are 1/4”, 1/3”, and 1/2”.
  25. Frame
    a complete picture
  26. F-stop
    a term used to indicate the speed of a lens. The smaller the f-number, the greater is the amount of light passing through the lens.
  27. Gigabyte
    1,024 mb or 1 billion character of information
  28. Gray Scale
    the number of variations from white to gray.
  29. IR
    a range of frequencies lower than visible red light for covert surveillance.
  30. Impedance
    the effective resistance of an electronic circuit to an AC signal.
  31. Insertion Loss
    the signal strength loss that occurs when a piece of equipment is inserted into a line.
  32. Intensifier
    an electronic device that creates an output image brighter than the input of original image.
  33. Matrix Switcher
    a switcher able to route any of its camera inputs to any of its monitor outputs; a name usually reserved for large systems.
  34. Passive
    a non-powered element of a system.
  35. Photocell
    automatically switches on the infra-red lights when light levels fall to a preset level.
  36. Pixel
    picture element. The smallest cell or area of a CCD chip capable of displaying detail on a screen. The greater the number of pixels, the higher the resolution.
  37. Quad
    a device that compresses up to four video signals and simultaneously displays the images onto one monitor.
  38. RF
    signals with a repetition rate above audible range, but below the frequencies associated.
  39. RAID
    the use of two or more disk drives instead of one disk, which provides better disk performance, error recovery, and fault tolerance and includes interleaved storage techniques and mirroring of important data.
  40. Sensitivity
    a camera’s ability to reproduce a given scene with a given amount of light.
  41. Switcher
    a device used to switch the video signals from two or more cameras on a monitor.
  42. Zoom ratio
    the ratio of starting focal length (wide position) to the ending focal length (telephoto position) of a zoom lens. Typically 10x.