Heart rate estimation apparatus with state sequence optimization
First Claim
1. A heart rate monitor system to estimate a heart rate of a patient, the heart rate monitor system comprising:
- a light source configured to direct a first light signal toward a patient;
an optical sensor configured to;
detect a second light signal from the patient, the second light signal representing transmission or reflection of the first light signal in the patient; and
generate an analog photoplethysmogram (PPG) signal representing the second light signal;
an analog to digital converter configured to generate a plurality of digital PPG sample values of the PPG signal in a time window; and
a processor circuit configured to;
for the time window;
obtain a frequency domain spectrum according to the digital PPG sample values; and
identify a plurality of heart rate hypothesis states having amplitudes in the frequency domain spectrum greater than a threshold value;
identify a plurality of potential heart rate transition pairs, each representing a respective heart rate transition between;
a corresponding one of the heart rate hypothesis states for the time window; and
one of a plurality of heart rate hypothesis states for a previous time window;
for each potential heart rate transition pair, compute;
a respective heart rate change value; and
a respective branch metric value as a function of the respective heart rate change value and a frequency domain amplitude of the potential heart rate transition pair'"'"'s corresponding one of the heart rate hypothesis states for the time window;
for each heart rate hypothesis state for the time window;
compute a plurality of candidate path metric values, each as a sum of a corresponding branch metric value and a path metric value for a corresponding one of the heart rate hypothesis states for the previous time window; and
select a largest one of the candidate path metric values to be the heart rate hypothesis state'"'"'s respective path metric value; and
determine a heart rate estimate value, representing the heart rate of the patient for the time window, as the heart rate hypothesis state whose respective path metric value is largest.
1 Assignment
0 Petitions
Accused Products
Abstract
Disclosed examples include heart rate monitor systems and methods to estimate a patient heart rate or rate of another pulsed signal, in which rate hypotheses or states, are identified for a current time window according to digital sample values of the pulsed signal for a current sample time window, and a rate change value is computed for potential rate transitions between states of the current and previous time windows. Transition pair branch metric values are computed as a function of the rate change value and a frequency domain amplitude of the corresponding rate hypothesis for the current time window, and the pulsed signal rate estimate is determined according to a maximum path metric computed according to the branch metric value and a corresponding path metric value for the previous time window.
-
Citations
10 Claims
-
1. A heart rate monitor system to estimate a heart rate of a patient, the heart rate monitor system comprising:
-
a light source configured to direct a first light signal toward a patient; an optical sensor configured to;
detect a second light signal from the patient, the second light signal representing transmission or reflection of the first light signal in the patient; and
generate an analog photoplethysmogram (PPG) signal representing the second light signal;an analog to digital converter configured to generate a plurality of digital PPG sample values of the PPG signal in a time window; and a processor circuit configured to; for the time window;
obtain a frequency domain spectrum according to the digital PPG sample values; and
identify a plurality of heart rate hypothesis states having amplitudes in the frequency domain spectrum greater than a threshold value;identify a plurality of potential heart rate transition pairs, each representing a respective heart rate transition between;
a corresponding one of the heart rate hypothesis states for the time window; and
one of a plurality of heart rate hypothesis states for a previous time window;for each potential heart rate transition pair, compute;
a respective heart rate change value; and
a respective branch metric value as a function of the respective heart rate change value and a frequency domain amplitude of the potential heart rate transition pair'"'"'s corresponding one of the heart rate hypothesis states for the time window;for each heart rate hypothesis state for the time window;
compute a plurality of candidate path metric values, each as a sum of a corresponding branch metric value and a path metric value for a corresponding one of the heart rate hypothesis states for the previous time window; and
select a largest one of the candidate path metric values to be the heart rate hypothesis state'"'"'s respective path metric value; anddetermine a heart rate estimate value, representing the heart rate of the patient for the time window, as the heart rate hypothesis state whose respective path metric value is largest. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
Specification