Method and apparatus for detecting the presence of an animate body in an

Abstract

The present invention provides a method and detection system for determining whether a person or other animate body is present in a vehicle by analyzing the power of the output signal from a geophone placed in contact with the vehicle structure. First an electrical signal is obtained which is a function of the vibrations emanating from the structure, and this signal is sampled on a contiguous basis over a plurality of time periods of equal duration. From these samples, a determination is then made as to whether a dense accumulation of power exists in the vicinity of the lowest power point of the sampled time periods and whether this lowest power point is above a predetermined minimum level. The system for accomplishing this method may include a seismic transducer used as a sensing device and a micro-computer for processing the output signals from the seismic transducer. The micro-computer will, on a continguous basis, sample about 22/3 seconds of data at a time. The total power from each of these 22/3 second data segments is calculated. If the computer sees that there is a dense accumulation of power at the lowest power point and above and that this is larger than a minimum requirement, then it will signal the presence of one or more concealed persons. There is a variable operating time as the computer continuously accumulates new data and, hence, new power points. It will collect data until it has sufficient information to make a reliable decision. In a quiet environment this may be 6-10 seconds whereas, in a noisy environment it may be two minutes or longer.