Metal Detection and Classification Technologies

From the detection of buried treasure to the detection of landmines and unexploded ordnance, the history of metal detectors is long and varied. This article reviews the basic technology for detecting metal objects using electromagnetic induction techniques. Working with the U.S. Army Night Vision and Electronic Sensors Directorate and other government agencies, APL has developed a number of advanced metal detection and classification techniques. Several prototype sensor systems have demonstrated capabilities to detect, discriminate from clutter, and classify high- and medium-content metal landmines in addition to some plastic landmines. The prototype sensors have also shown potential for detecting mines with very low metal content because such mines create a void in some types of electrically lossy soils. Compared to conventional electromagnetic induction metal detectors, the APL prototype sensor's discrimination feature results in a lower false alarm rate from metal clutter.