Patent ID: 6147759
Filing Date: 2000-11-14
Classification: F41J,G01B

Abstract:
An apparatus for detecting the presence and location of at least one object in a field, the apparatus comprising:(a) a rotating arm which spins around the field, the rotating arm including (i) a transmitter and, (ii) an opposing receiver array mounted thereon, the receiver array including a plurality of receivers located horizontally coplanar with each other, the transmitter and receiver array being fixed relative to each other, the transmitter outputting a detection beam that emanates from a single point, overlaps the field, and is simultaneously received at all times by the plurality of receivers of the receiver array, the receivers detecting changes which occur in the field as a result of an object being in the field, wherein the changes which occur in the field are shadows caused by one or more objects being in the field;(b) a position sensor for detecting the angular displacement of the rotating arm relative to a fixed point; and(c) a processor for receiving output signals from the plurality of receivers and angular displacement data corresponding to the output signals, and determining therefrom the presence and location of an object in the field.