System and method for facilitating reflectometric detection of physiologic activity
Inventors
Gamble, Ronald C. • Weill, Lawrence Randolph • Monacos, Steve Perry
Assignees
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Publication Number
US-9492099-B2
Publication Date
2016-11-15
Expiration Date
Abstract
A method for remotely sensing cardiac-related data of an animal subject includes transmitting a RF signal to impinge on tissue of the subject, receiving a reflected portion of the RF signal, generating baseband data, filtering baseband data (e.g., including high pass filtering), performing waveform phase position determination, performing at least one auto-correlation of the waveform phase position determined data, determining periodicity of the auto-correlated data, and (i) computing heart rate using a maximum periodicity of the periodicity, or (ii) identifying abnormalities in cardiac function, such as may be indicated by temporal variations in heart rate and/or signal amplitude corresponding to cardiac activity. Multiple bandpass filtering schemes may be employed.
Core Innovation
The invention relates to remotely sensing cardiac-related data of an animal subject using radio frequency transmission and reflectometric sensing. A radio frequency signal is transmitted to impinge on tissue of the subject and a reflected radio frequency signal is received as a reflection of the transmitted radio frequency signal impinging on the tissue. Baseband data is generated using the reflected radio frequency signal and processed to derive cardiac-related periodicity information and compute heart rate.
The signal-processing core filters multiple parallel streams of data embodying or derived from the baseband data to produce initially filtered data including a plurality of initially filtered data sets. Each initially filtered data set is obtained by filtering with a different filtering scheme, and each filtering scheme includes high-pass filtering with a cutoff frequency of 10 Hz or greater. Waveform phase position determination is performed on data embodying or derived from the initially filtered data to yield waveform phase position determined data.
At least one auto-correlation of the waveform phase position determined data yields auto-correlated data, and periodicity of data embodying or derived from the auto-correlated data is determined by determining a plurality of periodicity values. Heart rate is computed by selecting a majority or median of the plurality of periodicity values. The system includes a radio frequency transmitter, radio frequency receiver, baseband data generating element, filtering elements, waveform phase position determining element, auto-correlation element, periodicity determining element, and heart rate computing element.
Claims Coverage
The independent claims include two independent claims that share a common processing pipeline: reflectometric RF cardiac sensing followed by multiple parallel filtering with high-pass cutoff frequency of 10 Hz or greater, waveform phase position determination, auto-correlation, periodicity determination from auto-correlated data with a plurality of periodicity values, and heart-rate computation by selecting a majority or median of the periodicity values. The claims cover both a method and a corresponding system implementing the same elements and functions.
Remotely sensing cardiac-related data using RF transmission and reflected RF reception
Transmitting a radio frequency signal to impinge on tissue of the subject; receiving a reflected radio frequency signal comprising a reflection of the transmitted radio frequency signal impinging on the tissue; and generating baseband data utilizing the reflected radio frequency signal.
Multiple parallel filtering streams with high-pass filtering cutoff of 10 Hz or greater
Filtering multiple parallel streams of data embodying or derived from the baseband data to yield initially filtered data including a plurality of initially filtered data sets, wherein each initially filtered data set is obtained by filtering a stream of data of the multiple parallel streams of data with a different filtering scheme, and each filtering scheme includes high-pass filtering with a cutoff frequency of 10 Hz or greater.
Waveform phase position determination and auto-correlation to support periodicity estimation
Performing waveform phase position determination on data embodying or derived from the initially filtered data to yield waveform phase position determined data; performing at least one auto-correlation of the waveform phase position determined data to yield auto-correlated data; and determining periodicity of data embodying or derived from the auto-correlated data, wherein said determining of periodicity comprises determining a plurality of periodicity values.
Selecting a majority or median periodicity value to compute heart rate
Computing heart rate including selecting a majority or median of the plurality of periodicity values.
System architecture matching the method processing pipeline
A radio frequency transmitter adapted to transmit a radio frequency signal for impingement on tissue of the subject; a radio frequency receiver adapted to receive a radio frequency signal comprising a reflection of the radio frequency signal impinged on the tissue of the subject; a baseband data generating element configured to generate baseband data from the received radio frequency signal; at least one filtering element configured to filter multiple parallel streams of data embodying or derived from the baseband data to yield initially filtered data including a plurality of initially filtered data sets with each filtering scheme including high-pass filtering with a cutoff frequency of 10 Hz or greater; a waveform phase position determining element; an auto-correlation element; a periodicity determining element determining a plurality of periodicity values; and a heart rate computing element computing heart rate including selection of a majority or median of the plurality of periodicity values.
The independent claims cover both a method and a system for reflectometric, remotely sensing cardiac-related data using RF transmission and reception, generating baseband data, applying multiple parallel filtering schemes with high-pass filtering cutoff frequency of 10 Hz or greater, performing waveform phase position determination, auto-correlation, periodicity determination from auto-correlated data with a plurality of periodicity values, and computing heart rate by selecting a majority or median of those periodicity values.
Stated Advantages
Not explicitly described in patent.
Documented Applications
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