Object detector for detecting buried objects

摘要

An object detector for detecting metallic or non-metallic objects is disclosed which comprises a sound source such as a speaker (12) for generating impulse short sound bursts. A tube (16) conducts the acoustic signal from the speaker to the ground and at least one microphone M1-M3 is utilised for detecting reflections from the ground. A reflection from a buried object is compared with a reference signal which may be obtained from another microphone M1, M2 or earlier in time from the same microphone M3. The reflected and reference signals are subtracted to provide a difference signal and a difference signal is correlated with the original acoustic signal to provide an indication of an object. Time windows may be set to enable analysis of different depths to be obtained.