Auto Iris Lense

Auto-Iris
Lenses for CCTV Body cameras are also available
as "Auto-Iris" types. These have a lead that connects
to the camera itself, and provides the camera with the
ability to let in more light in dark conditions, and
less in bright conditions. This helps avoid the common
problem of "sunrise glare", where the rising sun shines
directly into the camera, completely blinding the camera's view.
Auto-Iris lenses are available as two types,
DC-Drive and Video Drive. DC-Drive lenses use a control signal
from the camera to adjust the iris size, whereas video-drive
lenses adjust the iris size based on the brightness of the
image in the video signal.
Lenses are either DC drive or Video Drive, but never both.
Cameras very often support both modes, utilising a mini switch
to select which to use, but not all camera Video Drive
With a video driven lens, the video signal is picked up from
the AI connector, which is connected to the camera. Because the
lens adjust the iris based on the video signal, the lens is
referred to as a video drive lens.

Wide Dynamic Range

Wide dynamic range
The Wide Dynamic Range (WDR) function of a camera
is intended to provide clear images even under back
light circumstances where intensity of illumination
can vary excessively, namely when there are both very
bright and very dark areas simultaneously in the field
of view of the camera. WDR enables the capture and display
of both bright areas 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.
Usage of WDR
WDR cameras are commonly used in surveillance cameras, and
in some medical applications. In surveillance,The WDR allows
a camera to filter the intense back light surrounding a
subject and thus enhances the ability to distinguish features
and shapes on the subject. WDR cameras are usually recommended
for situations where light enters a premise from various angles
such as a multi-window room. A camera placed on the inside of
the room will be able to see through the intense sunlight or
artificial light coming in. If an indoor security camera is
pointed towards a window or an entrance door, you will see
the background washed out during daytime. This is very
common situation in restaurants and stores which have big
glass windows.

IZOD TEST

The Izod Test
The Izod test is has become the standard testing
procedure for comparing the impact resistances of
plastics. While being the standard for plastics it
is also used on other materials.

The Izod test is most commonly used to evaluate the
relative toughness or impact toughness of materials
and as such is often used in quality control
applications where it is a fast and economical test.
It is used more as a comparative test rather than a
definitive test. This is also in part due to
the fact that the values do not relate accurately to
the impact strength of moulded parts or actual
components under actual operational conditions.
What Does the Izod Test Involve?
The Izod test involves striking a suitable test piece
with a striker, mounted at the end of a pendulum. The
test piece is clamped vertically with the notch facing
the striker. The striker swings downwards impacting the
test piece at the bottom of its swing.

Some Izod impact testers are equipped to be able to
utilise different sized strikers, which impart different
amounts of energy. Often a series of stri8kers may be used
to determine the impact energy, starting with small strikers
and working up until failure occurs.


Izod Tests at Different Temperatures
Tests are often performed at different temperatures to more
closely simulate the actual service conditions. In the case of
low temperature tests, specimens may are kept in a freezer
until their temperature has equilibrated. They are then
immediately removed and tested within seconds of removal from the freezer.