Milestone LPR 1.0 - Manual (Page 43)

Milestone XProtect
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LPR 1.0 Administrator's Manual
www.milestonesys.com 43 Glossary
Keyframe: Used in the MPEG standard for digital video compression, a keyframe is a single frame
stored at specified intervals. The keyframe records the entire view of the camera, whereas the
following frames record only the pixels that change. This helps greatly reduce the size of MPEG files.
A keyframe is similar to an I-frame.
Km/h: Kilometers per hour.
L
License plate library: A license plate library is a set of rules defining license plates of a certain type
and form as belonging to a certain country or region.
License plate list: License plate lists are collections of license plates which an LPR system will treat
in a special way.
LPR: License Plate Recognition, a method for video-based content analysis and recognition of vehicle
license plates.
LPR camera: Defines from where an LPR setup receives video (typically a camera), and how this
video is configured and processed.
M
MPEG: A group of compression standards and file formats for digital video, developed by the Moving
Pictures Experts Group (MPEG). MPEG standards use so-called lossy compression as they store only
the changes between frames, removing often considerable amounts of redundant information:
Keyframes stored at specified intervals record the entire view of the camera, whereas the following
frames record only pixels that change. This helps greatly reduce the size of MPEG files.
Mph: Miles per hour.
N
ND filter: Neutral Density filter. An ND filter (a.k.a. gray filter) basically reduces the amount of light
coming into a camera; effectively working as "sunglasses" for the camera. An ND filter thus affects the
exposure of images.
O
Output: Data going out of a computer. On IP surveillance systems, output is frequently used for
activating devices such as gates, sirens, strobe lights, etc.
Overexposure: Overexposure is when images are exposed to too much light, resulting a in a
burnt-out and overly white appearance.
P
PTZ: Pan/Zoom/Tilt; a highly movable and flexible type of camera.
S
Smear: Smear is an effect leading to unwanted light vertical lines in images; it is frequently linked to
slight imperfections in cameras' CCD imagers (the sensors used to digitally create the images).
T
TCP: Transmission Control Protocol; a protocol (i.e. standard) used for sending data packets across
networks. IP is often combined with another protocol, IP (Internet Protocol). The combination, known
as TCP/IP, allows data packets to be sent back and forth between two points on a network for longer
periods of time, and is used when connecting computers and other devices on the internet.
U