Astronics Max-Viz 1500, Информационное руководство, Страница: 14 / 24

Astronics Max-Viz Max-Viz 1500 3091-00019 Rev M
 The image will re-stabilize after a Non-Uniformity Correction cycle (NUC), described
in Section 4. Operation and Section 6.8 below.
 This process will continue, with the halo encompassing more and more of the image
between NUC cycles until the window reaches a constant temperature across the
surface.
 After approximately 20 minutes (depending upon the temperature of the camera
when the heater was turned on and the ambient operating temperature), there will
be a NUC cycle that creates a clean image and the halo will no longer form.
 To best prevent a halo from occuring during flight, turn the system on during
preflight or run-up to stabilize the window and body heaters prior to flight and allow
thermal stabilization.
6.5. Ice Effects and Body Heaters
During in-flight use, the Sensor uses heaters to keep ice from building up over the
window. If the heaters fail and ice builds up, infrared energy will be unable to pass
through the ice, and the image will begin to fade. (In this situation, ice build up may
first occur around the outside of the image, and eventually close up as a circle of ice
closes in over the circular lens).
If the heaters fail, EVS use should be discontinued and the Sensor should be returned
to the factory for service. (If the Sensor is iced over on a cold winter morning before
start-up, it may take a few minutes before the ice melts off and an image appears).
Please use caution when handling the Sensor during cold weather operation.
Note: the Sensor could be warm to the touch (25 degrees Celsius).
6.6. Image Quality and Interpretation
Independent of the operation of the Sensor, image quality is a function of target size,
target temperature, background temperature, and atmospheric attenuation from
particles or moisture in the air.
As such, it is important to know that the quality
of the image will appear different as these variables change.
If the video
image appears clear in the cool morning and a little “washed out” on a hot/humid
summer afternoon, the difference is probably caused by changes in the infrared
environment, and not from changes in the operation of the system.
6.7. Nitrogen Added to Sensor
The Sensor is sealed at the factory and filled with nitrogen to eliminate moisture. If the
Sensor is opened, the nitrogen will be lost.
Do not open the Sensor during system
installation or maintenance, warranty is void if opened.