Optical Detection of Buried Explosive Hazards

Abstract

Visual detection of soil disturbances is an effective, but imperfect method for detecting buried explosive threats such as landmines and improvised explosive devices (IEDs). Building upon prior studies of optical detection, this study uses signal detection methods to measure observer sensitivity to images of soil disturbances asking “How detectable are disturbed soil signatures recorded in visible (VIS), short-wave infrared (SWIR), and thermal infrared (TIR) bands?” “How effective is each band for detection?” and “How is signature salience in each band effected by extended exposure in the natural environment?” Young adults viewed photos showing either soil disturbed by landmine burial or adjacent undisturbed surfaces and made yes/no decisions about the presence of a disturbance. Stimuli spanned a six-week time period over which VIS, SWIR, and TIR images were collected. Results show that (a) substantial signal strength lasts over the six-week period, (b) generally, SWIR and VIS show consistently strong performance for large anti-tank mines and (c) the soil signatures for the small, anti-personnel mine stay remarkably strong in SWIR. TIR sensitivity lags SWIR and VIS, but shows promising hit rates for anti-tank mine signatures under some conditions. Generally, results show that optical detection, particularly using the SWIR and VIS bands, shows promise for explosive hazards detection, at least under the conditions observed.