Covert and robust facial recognition of individuals is a goal for military check points, law enforcement, and border control. Facial recognition performance in the visible spectrum has greatly improved over the years. There are situations, however, in which visible imagery cannot be used for facial recognition and thermal imaging is required, particularly in dark settings.

Thermal imaging relies on temperature differences to provide contrast in scenes. When scenes don’t have significant temperature differences, recognition or identification cannot be accomplished. Thermal images of human faces rarely provide sufficient facial feature contrast necessary for recognition algorithms.

Polarization enhanced thermal imagery highlights rich geometric and textural features that are hidden in standard thermal imagery. Polaris has shown that facial recognition using our thermal polarimetric imagery yields significantly higher thermal-to-visible match rates than when using standard thermal imagery. This approach enables passive, i.e., no external illumination required, day and night capability.

Polarization addresses the capability gaps in low-light and nighttime scenarios by acquiring naturally emitted radiation in the thermal infrared spectrum from facial skin tissue. The polarimetric images capture key facial details and geometry not available in conventional thermal imagery.

Because facial recognition software uses novel algorithms capable of matching polarimetric thermal facial imagery to visible facial imagery, this approach provides interoperability with existing biometric databases containing visible-only face imagery.