Patent ID: 11867848
Assignee: NEATFRAME LIMITED
Field: Audio-visual technology (Electrical engineering)
Classification: CPC G  H | IPC G

Claim 12:
13. A system for detecting a person, the system including:
an emitter, configured to emit an ultrasonic signal including a component at a first frequency, f0;
one or more receivers, configured to receive a reflected signal generated from reflections of the ultrasonic signal; and
one or more processors, configured, in response to the one or more receivers receiving the reflected signal, the reflected signal including components at frequencies greater than and less than the first frequency, including an upper portion of the reflected signal containing a frequency higher than the first frequency and a lower portion of the reflected signal containing a frequency lower than the first frequency, to:
(a) determine a difference between the upper portion of the reflected signal containing the frequency higher than the first frequency, and the lower portion of the reflected signal containing the frequency lower than the first frequency; and
(b) determine, based on the difference between the upper portion and the lower portion, whether a person is present.