Patent ID: 7499150
Filing Date: 2009-03-03
Classification: G01S

Abstract:
1. A distance measurement device, comprising: a light source adapted to provide a beam having at least one beam pulse; a beam splitter aligned to receive said beam and generate an outgoing reference beam and an internal reference beam; an adjustable attenuator aligned to receive said internal reference beam and provide an adjustably attenuated feedback reference beam, said attenuator including a liquid crystal shutter, wherein said feedback beam includes at least one feedback beam pulse derived from said at least one beam pulse; a detector aligned to receive said feedback reference beam and a return beam, wherein said return beam results from a reflection of the outgoing reference beam from an object outside of said distance measurement device, said return beam being unattenuated after reflection from said object, wherein said return beam includes at least one return beam pulse derived from said at least one beam pulse; and a control engine coupled to the attenuator and to the detector and outputting control signals to adjust the attenuator such that the feedback reference beam has a first intensity that substantially matches with a second intensity of the return beam.