Metal detector with discrimination against metal-mimicking minerals

A pulse-induction type metal detector capable of distinguishing between metal targets and minerals that mimic metals owing to absorption and release of energy. The amount of energy being transferred is measured by comparing the signals generated during specified intervals of a coil energizing pulse train that comprises bipolar current ramps that induce identical signals in metallic targets but differing signals in magnetic minerals. The criterion used to make the distinction between the targets is thus an inherent characteristic of the target and not subject to a particular adjustment of the electronic circuitry, as is the case with conventional metal detectors. This property of the detector makes it usable in industrial applications, where periodic readjustment of the detector is impractical.