Building occupancy estimation using microwave doppler radar and time-frequency spectral analysis
OwnerAmy Diane Droitcour, Shekh Md Mahmudul Islaminventors
Life of this patent
Estimating the term…
Abstract
RADAR-based occupancy detection and estimation is provided that is unobtrusive and does not introduce privacy issues. Time-frequency spectral analysis signal processing techniques are used for counting the number of people utilizing microwave Doppler RADAR. A RADAR-based hardware system determines the frequency at which highest amplitude occurs of a segmented portion of the signal obtained. The time-frequency spectral analysis on the signal is used to determine the number of occupants in a room.
Claims17
A method for determining occupancy in a room, comprising:
- operating a RADAR based sensor to detect human movement in a room;
- receiving, by a processor, a baseband signal from the RADAR based sensor;
- extracting, by the processor, a segment of the baseband signal;
- extracting, by the processor, a portion of the segment;
- applying, by the processor, a time-frequency spectral analysis to the extracted segment;
- identifying, by the processor, a distribution of signal over frequencies and time in the extracted segment based on the time-frequency spectral analysis;
- and
- determining, by the processor, a number of occupants present in the room based on parameters associated with the distribution of signal over frequencies and time.
A system for detecting occupancy in a room, comprising:
- a RADAR based sensor;
- and
- computing device connected to the RADAR based sensor, wherein the computing device includes a processor configured to:
- operate a RADAR based sensor to detect human movement in a room;
- receive a baseband signal from the RADAR based sensor;
- extract a segment of the baseband signal;
- extract a portion of the segment;
- apply a time-frequency spectral analysis to the extracted segment;
- identify a distribution of signal amplitude over frequencies and time in the extracted segment based on the time-frequency spectral analysis;
- and
- determine a number of occupants present in the room based on parameters associated with the distribution of signal amplitude over frequencies and time.
A RADAR based sensor system for detecting occupancy in a room, comprising:
- a local oscillator;
- a power splitter;
- a mixer, wherein:
- a radio signal from the local oscillator is split into a first portion of the radio signal and into a second portion of the radio signal,
- the first portion of the radio signal is sent from the local oscillator to an antenna to drive an emitted detection signal and generate a return signal from one or more objects in the room,
- the second portion of the radio signal and the return signal are sent to the mixer, and
- the mixer generates an output of a baseband signal as a product of the second portion of the radio signal and the return signal;
- a baseband signal conditioning circuit is disposed to receive the output baseband signal from the mixer and filter and amplify the baseband signal from the mixer;
- a data acquisition circuit disposed to digitize the output of the baseband signal conditioning circuit and outputting a digitized baseband signal;
- and
- a computing device connected to the baseband signal conditioning circuit, wherein the digitized baseband signal is processed by a processor in the computing device to:
- extract a segment of the baseband signal;
- extract a portion of the segment;
- apply a wavelet transform to the extracted portion of the segment;
- identify a frequency associated with a maximum wavelet coefficient of the extracted portion of the segment based on the wavelet transform;
- determine a number of occupants present in the room based on information in the frequency associated with the maximum wavelet coefficient;
- and
- control an environmental control system of the room based on the determined number of occupants.
Dependencies are inferred from the claim text.