<title>Buried object remote detection technology for law enforcement</title>

Abstract

We have developed a precise airborne temperature-sensing technology to detect buried objects for use by law enforcement. Demonstrations have imaged the sites of buried foundations, walls and trenches; mapped underground waterways and aquifers; and been used to locate underground military objects. Our patented methodology is incorporated in a commercially available, high signal-to-noise, dual-band infrared scanner with real-time, 12-bit digital image processing software and display. Our method creates color-coded images based on surface temperature variations of 0.2°C. Unlike other less-sensitive methods, it maps true (corrected) temperatures by removing the (decoupled) surface emissivity mask equivalent to 1°C or 2°C; this mask hinders interpretation of apparent (blackbody) temperatures. Once removed, we are able to identify surface temperature patterns from small diffusivity changes at buried object sites which heat and cool differently from their surroundings. Objects made of different materials and buried at different depths are identified by their unique spectral, spatial, thermal, temporal, emissivity and diffusivity signatures. We have successfully located the sites of buried (inert) simulated land mines 0.1 to 0.2 m deep; sodcovered rock pathways alongside dry ditches, deeper than 0.2 m; pavement covered burial trenches and cemetery structures as deep as 0.8 m; and aquifers more than 6 m and less than 60 m deep. Our technology could be athpted for drug interdiction and pollution control. For the former, we would locate buried tunnels, underground structures built beneath typical surface structures, mof-tops disguised by jungle canopies and covered containers used for contraband. For the latter, we would depict buried waste containers, sludge migration pathways from faulty containers and the juxtaposition of groundwater channels, if present, nearby. Our precise airborne temperature-sensing technology has a promising potential to detect underground epicenters of smuggling and pollution. BACKGROUND AND TECHNICAL APPROACHThe first successful demonstration of the precise temperature survey technology recently adapted for buried land mine detection was for geothermal resource investigations in 1977. Predawn surface temperature patterns were spatially correlated with sub-surface heat flow anomalies, soil moisture differences and variations in solar heat retained by near-surface rock tcroJ2 A 2 square km aquifer was depicted by the corrected thermal imagery. The aquifer was covered by more than 6 m of soil and was less than 60 m deep. See Figure 1 and Figure 2.Other applications of the technology were conducted at the Mercury Nevada Test Site for treaty verification. We investigated the surface temperature signatures near "ground zero" before and after an underground nuclear explosion. Soil "fluffmg" changed the soil thermal diffusivity and consequently the heating and cooling properties of near-surface materials near "ground zero." All else being equal, the ground nearby had a different temperature variation with...

The DTIC Review. Volume 2, Number 1: Land Mine Warfare: Detection and Clearance

“…Notwithstanding that such detection capabilities have been reported, little measurements have been performed (and published [7, 8, 9]) to evaluate quantitatively the apparent contrast in temperature that can be expected from buried mines when observed with an IR imager. The work done by Del Grande [7,8] shows impressive results about the temperature contrasts of buried objects, filled holes and grass-covered sites with a dual-band IR imaging system. The work presented in this report aims to complete this research by evaluating the apparent temperature contrasts of buried mines over a 24-hour interval for different burial depths and types of soil.…”

“…These results describe the apparent temperature contrast at the soil surface where mines are buried. The measuring instrument is an IR camera (8)(9)(10)(11)(12) and acquisitions are made over 24-hour periods. Furthermore, these acquisition periods are achieved for 3 types of anti-tank mine and 3 types of soil: top s0il, clay, and masonry sand.…”

Acoustic Characterization of Prosthetic Heart Valves

“…The acoustic heart valve data was processed to recognize trends and correlations between SLS (single leg separation) and INT (intact) valves. The features investigated included: frequency spectra, coefficients from spectral models (including lattice parameters, predictor parameters, and correlation coefficients), first-order statistical features, second-order texture features, and other representations of the data [2,3,4,5,6,7,8,9,10] .…”

Dual-Band Infrared Imaging Applications: Locating Buried Minefields, Mapping Sea Ice and Inspecting Aging Aircraft

“…California A helicopter-borne demonstration of DBIR imaging was conducted at a pasture in Byron, California (about 15 miles north ofLLNL). [5,6] Our goal was to locate buried surrogate mines and distinguish them from surface targets or clutter. The test area, measured approximately 100 m 2 and, apart from clutter (e.g., squirrel tunnels, a coiled cable), consisted mostly of grass-covered sandy loam soil.…”

“…[5] We first use physical principles to compute ratios of physical measurements (temperature and emissivity) and then apply them to the images. Temperature in I(d) and emissivity-ratio in I(e) images differ for natural soil and surface objects (e.g., the markers and perimeter metal strip).…”