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PROCESSING OF TIME-OF-FLIGHT SIGNALS

  • US 20140313376A1
  • Filed: 01/10/2013
  • Published: 10/23/2014
  • Est. Priority Date: 01/10/2012
  • Status: Active Grant
First Claim
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1. A method of determining the presence of aliasing or avoiding aliasing within certain limits in correlation measurements in a time-of-flight system having an imaging sensor and being for use with an illumination unit, the illumination unit being adapted to illuminate a scene with modulated light, the system being adapted to obtain correlation measurements between a correlation signal and modulated light reflected from the scene,the method comprising:

  • a) detecting reflected light from at least one object in the scene;

    b) determining by one or more first correlation measurements a first correlation between a first correlation signal and the reflected light received at the imaging sensor the first correlation signal having a periodic waveform of a first frequency and the first correlation measurement providing a value of a parameter related to a distance from the imaging sensor to the at least one object;

    c) determining by one or more second correlation measurements a second correlation between the reflected light received at the imaging sensor and a second correlation signal, the second correlation signal having a periodic waveform of a second frequency lower than the first frequency;

    d) determining for that value of the parameter the presence of aliasing from the second correlation measurement, andwherein the first and/or second correlation measurements are combined into aliasing indicators, the presence of aliasing is determined from indicators being the sign of the in-phase and/or quadrature components of the detected reflected light.

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