Definition
A calibration process applied to an infrared imaging system, such as a forward-looking infrared (FLIR) sensor or enhanced vision system, that adjusts the output of each detector element so all elements respond uniformly to the same level of incoming radiation. This compensates for small manufacturing differences between detectors and removes the fixed-pattern noise that would otherwise appear in the displayed image.
Plain English
A built-in correction that evens out the response of every tiny sensor in a thermal or infrared camera, so the picture shown to the pilot is clean and consistent rather than speckled or uneven.
Context Anchor
Seen in discussions of infrared cameras, enhanced flight vision systems, and maintenance or calibration of electronic imaging equipment.
Derivation
Non-uniformity simply means 'not the same across all parts.' In an infrared sensor, each individual detector element reacts slightly differently to the same heat source. The 'correction' is the calibration applied to make their responses match.
Why Pilots Care
Without this correction, an infrared display would show a grainy or patchy image that could mask terrain, traffic, or runway features. A clean image is essential when the system is being used as a visibility aid.
Analogy
It is like adjusting a screen so all its pixels show the same shade when they are supposed to. Without the adjustment, the screen may look patchy even when the scene itself is not.
Intuition Check
Do not read “non-uniformity correction” as correcting the outside scene or the aircraft’s path. It corrects uneven response inside the imaging system so the picture better represents what the sensor is seeing.
Example Sentence 1
The enhanced vision system performs a non-uniformity correction during startup to ensure the infrared image is clear before flight.
Example Sentence 2
Before flight the avionics self-test applied non-uniformity correction to the infrared sensor to ensure consistent temperature readings across the display.