FLIR Voyager III Operator's Manual page 93

Voyager III Reference
To clean the JCU, use a soft cloth and clean water. Mild household cleaner such
as Windex can also be used to remove tougher stains or spots.
Caution: Do not use alcohol based cleaners or any type of solvents as this may
discolor or damage the unit.
Video not switching between thermal and visible
The display can be switched between the thermal camera and the visible camera
by pressing and holding the SCENE button. If this does not cause the display to
switch from the thermal camera to the visible-light camera, be sure the proper
input channel is selected on the display.
Noisy image
A noisy image is usually attributed to a cable problem—too long or inferior
quality—or the cable is picking up electromagnetic interference (EMI) from
another device. Although coax cable has built-in losses, the longer the cable is or
the smaller the wire gauge/thickness, the more severe the losses become; and
the higher the signal frequency, the more pronounced the losses. Unfortunately
this is one of the most common and unnecessary problems that plagues video
systems in general.
Cable characteristics are determined by a number of factors such as core
material, dielectric material and shield construction, among others and must be
carefully matched to the specific application. Moreover, the transmission
characteristics of the cable will be influenced by the physical environment through
which the cable is run and the method of installation. Use only high quality cable
and ensure the cable is suitable to the marine environment.
Check cable connector terminations. Inferior quality connections may use multiple
adapters that can cause unacceptable noise.
Image too dark or too light
By default, the Voyager III thermal camera uses an Automatic Gain Control (AGC)
setting that has proven to be superior for most applications. However, a specific
environment may benefit from a different AGC setting. For example, a very cold
background (such as the sky) could cause the camera to use a wider temperature
range than appropriate. You should keep the ocean, and not the sky or the boat,
as the predominant object in the image. Refer to "SCENE Button" on page 17 for
information about how to make adjustments to the image.
Performance varies with time of day
You may observe differences in the way the camera performs at different times of
the day, due to the diurnal cycle of the sun. Recall that the camera produces an
image based on temperature differences.
At certain times of the day, such as just before dawn, the objects in the image
scene may all be roughly the same temperature, compared to other times of the
day. Compare this to imagery right after sunset, when objects in the image may
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432-0005-00-10 Rev 100 — Voyager III Operator's Manual