INDUCTIVE METHOD OF DETECTION OF HIDDEN OBJECTS AND INSTRUMENT CONVERTER FOR ITS IMPLEMENTATION Russian patent published in 1998 - IPC

FIELD: metal detectors used in geological prospecting, archeology, criminal investigations, customs inspection, etc. SUBSTANCE: two symmetric opposite alternating magnetic fields interacting along separating plane of symmetry parallel to surface of examined medium are excited in step. Corresponding resulting magnetic fields are recognized separately with the aid of pair of receiving coils spaced apart. Signals induced in receiving coils are compared and difference legitimate signal is extracted. Instrument converter employed for implementation of method has case 13 with working surface 14 housing pair of excitation coils 3, 7 connected in opposition which common axis is normal with reference to working surface 14 and pair of receiving coils 5, 5a; 6, 6a connected in series opposition. They are arranged in pairs in symmetry on both sides of separating symmetry surface. EFFECT: enhanced efficiency in detection of hidden objects thanks to increased level of legitimate signal and its independence from character of distribution of hidden objects in examined medium. 7 cl, 10 dwg