FLIR 72501-0101, User Manual

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Achieving a good image 16
2. Select ( Color ) and push the joystick. This displays a submenu.
3. Use the joystick to select a different palette.
4. Push the joystick to confirm and exit the menu mode.
16.6 Changing the measurement parameters
For accurate measurements, it is important to set the measurement parameters:
• Emissivity .
• Reflected temperature .
• Object distance .
• Atmospheric temperature .
• Relative humidity .
• External IR window compensation .
Emissivity is the most important measurement parameter to set correctly. If the Emissivity
is set to a low value, the Reflected temperature also becomes important. The parameters
Object distance , Atmospheric temperature , and Relative humidity are relevant for longer
distances. The External IR window compensation must be activated if a protective win-
dow or external lens is used.
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 18.5 Changing the measurement parameters , page 73.
16.7 Performing a non-uniformity correction
(NUC)
16.7.1 General
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
3 . For more information, see section 34 About
calibration , page 124.
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.
16.7.2 Performing an NUC manually
16.7.2.1 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 one of the programmable buttons.
For more information, see section 13.11 Assigning functions to the programmable but-
tons , page 36.
#T559954; r. AT/65353/65353; en-US 66
3. Definition from the European standard EN 16714-3:2016, Non-destructive Testing—Thermographic Testing—
Part 3: Terms and Definitions.