Handheld metal detector with online visualisation and classification for the humanitarian mine clearance

Today for clearing areas from landmines, beside dogs and searching needles, almost only metal detectors are used. Metal detectors for mine clearance are high sensitive inductive sensors which react also on small metal parts. Nevertheless, they give no further information about the buried object (depth, size, shape, material). Besides, the high false alarm rate (up to 1000 per mine) makes the mine clearance a protracted and cost-intensive process. Reasons for the false alarms are "uncooperative" soils, harmless metallic objects and the low metal content in newer anti-personnel mines. In this paper a method is described which provides more information about the buried object by using image processing and signature classification, which works also in the presence of "uncooperative" soil. Based on an algorithm for soil compensation and object classification, this paper describes a handheld system with online visualization and classification. Therefore a commercial metal detector was enhanced with additional signal processing and an ultrasonic position reference system.