Handheld Metal Detector Characterization Using Spherical Test Objects

The detection performance of handheld and hand-worn metal detectors is based on observing an alarm indication from the metal detector when a test object is brought near the metal detector. These test objects maybe actual threat items or simulated threat items. The detectability of the test object is dependent on the electromagnetic properties of the test object, its shape and size, and its orientation relative to the magnetic field generated by the metal detector. Small misorientations of a test object, relative to a reference orientation, may cause the operator to incorrectly attribute a higher performance to the metal detector than it can provide. Consequently, to support accurate and reproducible characterization of the performance of a metal detector, orientation effects should be minimized or eliminated. Spherical test objects are presented to eliminate these effects for handheld and hand-worn metal detector performance assessments.