System for denoising motion artifact signals and method thereof
The present invention provides a system and a method for denoising motion artifacts from vital signs signals comprising steps of receiving one or more reflected signals from at least one subject, generating a time sequence buffer of reflected signals of predefined duration for vital signals processing, source separation and a component selection, and estimating and tracking vital signs of the source separation and a component selection.
1 . A method for removing noise and motion artifacts from radar-derived vital signs signals, the method comprising steps of:
receiving, by a radar transceiver operating in a THz range of 0.1 THz to 10 THz, one or more reflected radar signals in the THz range of 0.1 THz to 10 THz from at least one subject;
sampling the reflected radar signals and storing, in a signal processor, a time sequence buffer of the reflected radar signals of predefined duration for vital signals processing, wherein the time sequence buffer comprises at least 60 to 120 samples;
performing, by the signal processor, signal processing comprising:
source separation decomposition of pre-processed buffered signals via singular spectrum analysis;
spectral computation of separated components;
component weighting of decomposed components;
forming a probability density function from weighted decomposed components;
forming adaptive harmonic weights of the probability density function; and
computation of vital signs from a weighted probability density function;
estimating and tracking the vital signs, using a tracking filter implemented in the signal processor, to output tracked vital signs compensated for noise and motion artifacts; and
transmitting the tracked vital signs to a display device for observation by at least one of: a subject; a system user; and a caregiver.
2 . The method according to claim 1 , wherein said vital signals are selected from the group consisting of: heart rate (HR); respiratory rate (RR); heart rate variability (HRV); heart rate interval (HRI); respiration amplitude (RA); respiration amplitude variability; respiration rate variability (RRV); ballistocardiogram (BCG); BCG amplitude variability; pulse wave velocity (PWV); blood pressure (i.e. MAP, systolic and diastolic); vascular resistance; body temperature; pulse pressure variability stroke volume; stroke variability; and any combination thereof.
3 . The method according to claim 1 , further comprising the step of pre-processing said buffered signals by at least one step of:
mirroring signals; filtering; and decimation.
4 . The method according to claim 1 , further comprising the step of processing at least one of: at least one phase signal, and at least one amplitude signal, to determine an estimate of fundamental frequency or corresponding harmonics of vital signs signals.
5 . A system for removing noise and motion artifacts from radar-derived vital signs signals, the system comprising:
a radar transceiver, configured to: receive one or more reflected radar signals in a THz range of 0.1 THz to 10 THz from at least one subject, sample the reflected radar signals, and generate a time sequence buffer of the reflected radar signals of predefined duration for vital signs processing, wherein the time sequence buffer comprises at least 60 to 120 samples;
a signal processor, configured to maintain the buffer and to perform signal processing comprising: source separation decomposition of pre-processed buffered signals via singular spectrum analysis; spectral computation of separated components; component weighting of decomposed components; forming a probability density function from weighted components; forming adaptive harmonic weights of the probability density function; and computation of vital signs from a weighted probability density function,
the signal processor comprising an estimation component and tracking filter, configured for estimating and tracking the vital signs, to output tracked vital signs compensated for noise and motion artifacts; and
a transmitter, configured to transmit the tracked vital signs to a display device for observation by at least one of: a subject; a system user; and a caregiver.
6 . The system according to claim 5 , wherein said vital signals are selected from the group consisting of: heart rate (HR); respiratory rate (RR); heart rate variability (HRV); heart rate interval (HRI); respiration amplitude (RA); respiration amplitude variability; respiration rate variability (RRV); ballistocardiogram (BCG); BCG amplitude variability; pulse wave velocity (PWV); blood pressure (i.e. MAP, systolic and diastolic); vascular resistance; body temperature; pulse pressure variability; stroke volume; stroke variability; and any combination thereof.
7 . The system according to claim 5 , wherein said source separation module comprises at least one component selected from the group consisting of:
a decomposition component, configured for decomposing non-mirrored signals data to spectral components; and
a singular spectral analysis (SSA) component, configured for component weighting of said decomposed components.
8 . The system according to claim 5 , wherein said estimation component and tracking filter comprises at least one component selected from the group consisting of:
an estimation component, configured for identifying vital signs from spectral content of the selected decomposed component; and
a tracking component, configured for extracting heart rate (HR) signal and respiration rate (RR) signal output.