AERIAL THERMAL INFRARED DETECTION OF PFM-1 PLASTIC BUTTERFLY MINES

Remnant plastic-composite landmines, such as the mass-produced PFM-1, represent an ongoing humanitarian threat aggravated by high costs associated with traditional demining efforts. These particular unexploded ordnance (UXO) devices pose a challenge to conventional geophysical detection methods, due their plastic-body design and small size. Additionally, the PFM-1s represent a particularly heinous UXO, due to their low mass (~25 lb) trigger limit and “butterfly” wing design, earning them the reputation of a “toy mine” – disproportionally impacting children across post-conflict areas. We present results of a field study focused on thermal detection of the PFM-1 anti-personnel landmines from a remotely operated unmanned aerial vehicle (UAV).

We conducted a series of field detection experiments meant to simulate the mountainous terrains where PFM-1 mines were historically deployed and remain in place. In our tests, 18 inert PFM-1 mines along with the aluminum KSF-1 casing were randomly dispersed to mimic an ellipsoidal minefield of 8-10 x 18-20 m dimensions in a de-vegetated rubble yard at Chenango Valley State Park (New York State). We collected multiple thermal infrared imagery datasets focused on these model minefields with the FLIR Vue Pro R attached to the 3DR Solo UAV flying at approximately at 10 m. We identified different environmental variables to constrain the optimal time of day and daily temperature variations to reveal presence of these plastic UXOs. We show that in the early-morning hours when thermal inertia is greatest, the PFM-1 mines can be detected based on their differential thermal inertia. After processing datasets, we found that an increase in moisture content, finer grain sediment and surface laid mines are optimal conditions to detect the PFM-1. We anticipate that following further development, this remote sensing method can aid in significantly reducing the cost and time associated with landmine remediation in post-conflict nations.