Detecting thermal infrared radiation from cave openings using thermography

This research addressed questions regarding the use of thermal infrared sensors for detection of cave openings. The experimentation portion of this research was done in three phases. Phase I used a laboratory scale limestone cave to examine thermal emissions under simulated winter and summer conditions. This initial experiment successfully distinguished the laboratory scale cave opening from the surrounding rock surface based on distinctive thermal emissions. Phase II of the experiment also used the laboratory scale cave to test the potential for thermal interference from various air flow and humidity factors. Results of this second phase experiment revealed no evidence to indicate that air flow or humidity within the ranges tested would adversely affect thermal cave detection. For the third phase of this experiment three actual limestone caves were used in the Texas Hill Country in northern Bexar County Texas. The cave openings were monitored and recorded for a full 24-hour diurnal cycle, and were distinguishable from the surrounding terrain based on their thermal emissions. This research advances the use of thermography for cave opening detection by quantifying thermal emissions from laboratory scale model caves and real caves.