Lepton Spot Meter Code

Lepton® with radiometry provides accurate non-contact temperature measurement data in every thermal image pixel.


What is Radiometry?

Lepton with radiometry simplifies the calibration and external processing required to convert the temperature-stabilized output of Lepton to actual scene temperature.  With minimal work, users are now able to get calibrated scene temperatures directly in the returned buffer.

The Lepton ® with Radiometry includes multiple options for radiometry modes that affect the video output:

  • Radiometry enabled, TLinear enabled
  • Radiometry enabled, TLinear disabled
  • Radiometry disabled

By default, radiometry is enabled and TLinear is disabled. This is advantageous in situations that require an exact temperature measurement, as the spotmeter will need no calibration before outputting the correct values. When running the Lepton, an average of the middle 9 pixels will be taken and output to the screen in Celsius.


Fig. 1: At 24 feet away, the average temperature covers a 1 square foot area.


Fig. 2: The temperature reading of the wall in the center of the frame is outputted to the screen.


Fig. 3: When a hot object is in the center, an accurate average of the middle crosshairs is given.

If you’re familiar with the existing Lepton codebase, there aren’t many changes that need to be made to get Lepton with radiometry up and running. Download the latest codebase here.



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