Active modulating element detection

Methods and apparatus for detecting a modulating element of an object in a scene are described in which an element in a scene is illuminated 4 with a modulated light source. A signal is obtained from an optical detector based on light received from the illuminated element. An intermediate frequency...

Full description

Saved in:
Bibliographic Details
Main Authors Jason John Lepley, Mark Edgar Bray
Format Patent
LanguageEnglish
Published 03.03.2021
Subjects
CALCULATING
COMPUTING
COUNTING
HANDLING RECORD CARRIERS
PHYSICS
PRESENTATION OF DATA
RECOGNITION OF DATA
RECORD CARRIERS
Online AccessGet full text

Cover

More Information
Summary:Methods and apparatus for detecting a modulating element of an object in a scene are described in which an element in a scene is illuminated 4 with a modulated light source. A signal is obtained from an optical detector based on light received from the illuminated element. An intermediate frequency signal is derived from the signal, the intermediate frequency signal being related to a frequency of the modulated light source and a frequency of modulation of the element within the scene (e.g. the beat frequency). The modulating element is detected based on the intermediate frequency signal. The object of interest could be an unmanned aerial vehicle (UAV) or drone 3, and the modulating element could be its rotors or blades 5. The intermediate frequency 401 could be the difference between the frequency 402 of modulation of the illumination and the frequency 403 of the modulating element (e.g. a rotor). Further, the signal could be band-width filtered 404 so as to select for the difference frequency.
Bibliography:Application Number: GB20190012327