The Effect of Viewing Angle on Detection of Landmines from Thermal Time Series Images Using Active Thermography

Year 2017, Volume: 4 Issue: 1, 1 - 6, 10.04.2017

Murat Kılınç Osman Torunoğlu Hasan Koçer

Abstract

Use of landmines in soils is a significant
international threat facing the world today. There are no safe and highly
reliable methods or inspection systems capable of detecting landmines in all
situations. The use of infrared thermography is one of the promising methods
for mine detection tasks. In infrared thermography, the investigation is done
in either way: actively or passively. In this study, thermal signatures of the
active infrared time difference images of buried mines and sand are
investigated for different camera angles. It is aimed to find the effects of
shot angles of the thermal camera on the performance of landmine detection. The
experiments are performed at a sandbox emplaced in an indoor laboratory
environment. A metal and a plastic antipersonnel mine are buried at 2 cm depth
in sandbox. The sand surface is initially heated homogeneously by an infrared
heater (2400 W) for 10 minutes on different days. During the cooling phase
of the surface, a sequence of images are captured with an LWIR (8-12 µm band)
camera (FLIR T 650 SC), which is 280 cm away from the detection area at
different angles (90°, 60° and -60°). Images of the size of 480×640 pixels are
taken at 15 seconds intervals during one hour. “Thermal signatures” of the
buried mines and soil in three viewing angles are compared in MATLAB®
environment. The results show that the locations of landmines are easily
detected from the captured images during the cooling phase of the surface since
observable differences develop between temperature signatures of landmines and
sand, but the observation angle of camera has little effects on the detection
performance. In addition, it is found that one hour measurement period is
adequate for the detection of landmines at 2 cm depth in active thermography.

Keywords

Landmine detection, Thermal infrared imagery, Active thermography

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