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...

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Bibliographic Details
Main Authors Jason John Lepley, Mark Edgar Bray
Format Patent
LanguageEnglish
Published 19.07.2023
Subjects
AIRCRAFT
AVIATION
CALCULATING
COMPUTING
COSMONAUTICS
COUNTING
ELECTRIC DIGITAL DATA PROCESSING
PERFORMING OPERATIONS
PHYSICS
TRANSPORTING
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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