User's Manual

Achieving a good image14
3. Use the navigation pad to select a different palette.
4. Push the navigation pad to confirm and exit the menu mode.
14.6 Changing the measurement parameters
For accurate measurements, it is important to set the measurement parameters:
• External IR window compensation.
• Object distance.
• Atmospheric temperature.
• Relative humidity.
• Reflected temperature.
• Emissivity.
You can set the measurement parameters globally. You can also change the Emissivity,
Reflected temperature, and Object distance parameters locally for a measurement tool.
For more information, see section 16.5 Changing the measurement parameters, page 64.
14.7 Performing a non-uniformity correction
(NUC)
When the thermal camera displays Calibrating... it is performing what in thermography is
called a ”non-uniformity correction” (NUC). An NUC is an image correction carried out by
the camera software to compensate for different sensitivities of detector elements and
other optical and geometrical disturbances
2
. For more information, see section 34 About
calibration, page 192.
An NUC is performed automatically, for example at start-up, when changing a measure-
ment range, or when the environment temperature changes.
You can also perform an NUC manually. This is useful when you have to perform a critical
measurement with as little image disturbance as possible. You may, for example, want to
perform a manual calibration just before you start recording a video sequence.
14.7.1 Performing an NUC manually
14.7.1.1 Procedure
Follow this procedure:
1. To perform a manual NUC, push and hold down the image archive button
for
more than 2 seconds.
Note You can also assign the function Calibrate to the one of the programmable but-
tons
. For more information, see section 11.12 Assigning functions to the program-
mable buttons, page 34.
14.8 Hiding all overlay
14.8.1 General
The camera overlay consists of overlay graphics and image overlay information. The
overlay graphics include items such as measurement tool symbols, result tables, and
status icons. The image overlay information, which you activate on the Settings menu,
provides additional information such as the date, emissivity, and atmospheric tempera-
ture. For more information, see section 9.6 Image overlay information, page 24.
#T810253; r. AA/42549/42549; en-US
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2. Definition from the European standard EN 16714-3:2016, Non-destructive Testing—Thermographic Testing—
Part 3: Terms and Definitions.