Thermal Imaging

A top-down view of a point cloud colored by surface temperature in celsius.

The HALO utilizes a heavily modified Tau 2 thermal imaging sensor constructed by FLIR. The modifications result in an integrated and precise thermal imaging payload. An external frame has been built around the base imager, which, along with additional software enhancements, allows each exposure to be timestamped precisely, a necessity for georectification the thermal data. Vignetting, a common issue for thermal imagery, is corrected using a mechanical shutter built into the frame that replaces the rolling shutter built into the sensor body. The critical issue of thermal drift is corrected for using a NUC/FFC calibration that is performed multiple times per flight. Other additional components, such as cooling fans, have also been added to the sensor to solve common issues with thermal remote sensing. In tests post modification, the sensor was able to measure object temperatures within 1.5 degrees C of truth on structured surfaces and has an estimated performance of 3 degrees C of truth on unstructured surfaces with correct calibration. While precise temperature mapping is not usually required for animal identification or the identification of features that show clear temperature differences within landscapes, the ability to measure absolute temperature allows a nuanced understanding of how temperature drives animal decisions and enables the construction of models to delineate landscape features more precisely than non-imaging thermal cameras allow.