Operating Notes - Argus 3 User Manual

1.5

Operating Notes

The following information relates to a "white-hot" image.
•
Interpreting The Image – Relative Temperatures
The image displayed is simply a black and white picture of the infrared energy
entering the lens. The camera displays relative temperature differences between
individual objects and their surroundings irrespective of overall ambient
temperature.
The camera is set up to display objects at various shades between black for
cooler items and white for hotter bodies, e.g. in a room at 20 °C a cold drink
would appear black whilst a hot radiator would appear white. However, in a
room at 250 °C, it is possible that the same hot radiator may appear darker than,
for example, burning materials.
•
Identification of Fire and Hotspots
The camera will represent zones of very high temperature as white zones within
the picture. When sufficient heat has been detected, e.g. a large area of fire, the
camera will automatically enter low sensitivity mode. This will extend the
dynamic range of the camera and allow the image of surrounding objects to
remain clearly visible.
•
Hidden Fires
It is possible that fires may be burning or smouldering behind doors, in ducting
or in wall or floor cavities. In such circumstances, the operator should look for
areas that appear whiter when compared with the surroundings.
For example, a fire behind a door will cause the door to appear whiter against
the background. Similarly, a white area on an otherwise dark wall could indicate
an area of fire behind the masonry.
•
Search for Persons and Objects
The camera is not restricted to locating fires. In many cases, the fire-fighter will
be using the camera to search for casualties, to seek out dangerous items such
as fuel tanks or gas cylinders and also as an aid to navigation through unknown
premises.
•
Image Clarity
The sharpness and clarity of the image provided is related to the temperature of
the scene and objects in view. A cold room provides little infrared energy and
less detail is detected than in a warm environment where objects give off
significant energy. In general, the warmer the scene, the more thermal contrast
and hence the greater detail in the picture.
•
Heat Layers in Closed Spaces
In a major fire, a layer of hot gases may build up in the upper region of the
closed space. Attempting to use the camera in this hot layer will cause the
image to become featureless. By bringing the camera down beneath this layer,
the unit is able to provide the fire-fighter with a clearer picture of the scene
ahead.
 e2v technologies (uk) limited 2014
118707 P7030UM version 6, page 10