LAN
Local Area Network:
connects different computers so
that they can communicate with each other.
Different connection protocols are possible.
LD
Laser diode:
is a type of light source which
generates a single frequency in the high
end of the infrared spectrum and has a
bandwidth of 1000 MHz. It is used in fibre
optics and infrared links.
Lead
acid battery:
is a type of DC power source
which is similar to a car battery. It
is generally used in temporary installations
with DC cameras.
LED
Light Emitting Device:
is a type of light source which
generates an infrared frequency when stimulated
by electricity. It is used in fibre optics
, infrared links and as an infrared light
source for monochrome cameras.
Lens
calculator:
is a calculator provided by many
lens manufacturers to help calculate the
focal length of the lens that will provide
the required scene.
Lens
hunting:
is a field problem in which the
iris opens and shuts alternatively. A
correct ALC adjustment in the lens could
rectify the problem.
Lens
mount:
see C-mount or CS-mount.
Lens
wheel:
see lens calculator.
Light:
is electromagnetic radiation
between 400 nm and 750 nm which is detectable
by the human eye.
Light
sensor:
is a device which is activated
by a pre-set amount of light falling on
it. It can be used to switch infrared
illuminators On / Off.
Limit
switch:
is a device placed inside or
outside the Pan Tilt head and used to
limit the angles of pan and tilt.
Line:
is the basic unit of a frame
or field containing the charge which is
proportional to the light falling at various
points on the scanning line.
Looping
switcher:
is a type of switcher with looping
outputs. These outputs allow the camera
to be connected to another device without
affecting the usage of the switcher.
Lumen:
is a measurement of light which
indicates the amount of light radiated
by a one candela light source.
Luminous
flux:
is the rate of flow of light.
Luminance
signal:
is that part of the video signal
which contains the information on the
brightness of the picture.
Lux:
is an international unit of illumination.
It is the amount of uniform light falling
on an area of 1 square meter and is measured
in lumen per sq. meter. |
