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Laser

A coherent source of light with a narrow beam and a narrow spectral bandwidth (about 2nm).

Legalised Privacy Masking, LPM

LPM is an advanced dynamic spherical privacy zone masking feature.  It allows unwanted or prohibited areas within an image to be masked precisely and appropriately.  This technology allows masking areas to be interlocked with the camera's pan/tilt/zoom movements regardless of the camera angle. What is unique about this feature as compared to conventional masking is that the masked areas remain covered even when the camera is circling.  In addition, when the zoom is engaged, the size of all masked areas adjusts in proportion to the zoom position.  This feature is essential for dome cameras used in wide-area monitoring applications.  Users can easily set masking areas on the screen simply by positioning each area to be masked in the centre of the viewer (indicated by two intersecting lines), and executing the masking function.  In a dome application for example, if a tracked object moves beneath the camera dome, the image can be inverted to maintain the correct orientation. 

Light Emitting Diode, LED

It is a semiconductor device that emits incoherent light formed by the P-N junction.  Light intensity is roughly proportional to electrical current flow.  Light producing transistors used to display dots, numeric and text in the viewfinder, slowly replacing by LCD display.

Light Sensitivity

Light sensitivity ratings are generally given as the minimum "Lux" levels at which the camera will produce a useable image (1 Lux equals 1/10 Foot Candle). The lower the Lux number, the lower the light levels at which the CCTV camera will produce an acceptable image. In other words, the lower the Lux level rating, the more light sensitive the camera.   Lux level ratings (and the amount of light entering the camera) are inversely proportional to the aperture of the camera iris and so are stated at a specific “F Stop” (Focal Length divided by Aperture).  A camera with a Lux rating of 1.0 at F1.4 will only have a Lux rating of 2.0 at F2.0.  B/W security cameras generally have lower Lux level ratings than color cameras (i.e. B/W cameras will produce acceptable images in lower light conditions than color cameras).  With the adoption of enhanced light sensitivity ExView CCD chips we can now offer exceptionally light sensitive color cameras in CCTV cameras.  Day/Night cameras change from color to B/W when Lux levels drop below about 1.0 and produce useable B/W images down to a Lux level of about 0.03 Lux.  We are also pleased to offer several cameras incorporating "frame integration" such as BC3-971, 951P, 751P,551P,BC-23XP,BS-3451P, BDR-505R-D37C,BR-3151P-D37C and BR-4752P-D312.  This method of electronically boosting the amount of useable light by holding the shutter open for longer, allows our "Starlight" cameras to produce a useable color image in as little as 0.001 Lux (the equivalent of the amount of light available on a starlit but moonless night).

Line-locked

In CCTV, this usually refers to multiple cameras being powered by a common alternative current (AC) source (either 24V AC, 110V AC or 240V AC) and consequently have field frequencies locked to the same AC source frequency (50 Hz in CCIR systems and 60Hz in EIA systems).

Linux
Linux is an open source operating system within the Unix family.  Because of its robustness and availability, Linux has won popularity in the open source community and among commercial application developers.

Liquid Crystal Display, LCD

A type of display used in digital watches and many portable computers. LCD displays utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so that light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light.

Liquid Crystal Display (LCD) panel

An electronically generated text, numeric & symbols.  Before the popularity of the LCD, LED is the most common method.  LCD consume only one fifth (1/5) of the power of the LED and thus have a wider application in photographic line.  The only problem is, it will turn dark at very high temperature (will resume to normal when cool down) and it will fades in extended time.  Used most commonly on cameras that show such information as remaining exposures, flash status and aspect ratio selected.

Local Area Network, LAN

A communications network connecting a group of computers, printers, and other devices located within a relatively limited area (for example, a building). A LAN allows any connected device to interact with any other on the network.

Log file

It is a file that stores messages generated by an application, service or operating system. These messages are used to track the operations performed. For example, web servers maintain log files listing every request made to the server.  Log files are usually plain text (ASCII) files and often have a .log extension.   In Backup, a file that contains a record of the date the tapes were created and the names of files and directories successfully backed up and restored. The Performance Logs and Alerts service also creates log files.

Loss

Energy or signal lost without accomplishing useful work.

LTTS

Lotus Twisted Pair Transmission Solution.

Lux

A measurement of the light intensity.  One Lux in video means light level of a candle light.  Specifications for surveillance cameras often include a minimum illuminance level in lux at which the camera will record a satisfactory image. A camera with good low-light capability will have a lower lux rating.  Still cameras do not use such a specification, since longer exposure times can generally be used to make pictures at very low illuminance levels, as opposed to the case in video cameras where a maximum exposure time is generally set by the frame rate. 0.01 lux.