Equipment for detecting buried non metallic objects - uses cross correlation technique on echoes from loudspeaker at focus of parabolic reflector

摘要

The apparatus detects inhomogeneities using echo and cross correlation technique. A loudspeaker is mounted above a microphone at the focal point of a parabolic reflector. A number of microphones and loudspeakers may be mounted in a row in a single elongated reflector, or the reflector may be of rectangular section with a resonating membrane across its face. The signal processing network produces a timed pulse modulated signal from the loudspeaker. The timing circuit gates out the directly received pulse from the detection networks which include a logarithmic amplifier. It applies a cross correlation algorithm to the transmitted and reflected signals to display any results on a display unit.