US 10,376,243 B2
Method and apparatus for low complexity ultrasound based heart rate detection
Sourabh Ravindran, Dallas, TX (US); and Jonathon David Spaulding, Mountain View, CA (US)
Assigned to Texas Instruments Incorporated, Dallas, TX (US)
Filed by Texas Instruments Incorporated, Dallas, TX (US)
Filed on Sep. 25, 2014, as Appl. No. 14/497,295.
Claims priority of provisional application 61/883,563, filed on Sep. 27, 2013.
Prior Publication US 2015/0094592 A1, Apr. 2, 2015
Int. Cl. A61B 8/00 (2006.01); A61B 8/02 (2006.01); A61B 8/08 (2006.01)
CPC A61B 8/5223 (2013.01) [A61B 8/02 (2013.01); A61B 8/488 (2013.01); A61B 8/5207 (2013.01); A61B 8/462 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method comprising:
receiving a demodulated Doppler ultrasound signal;
applying a bandpass filter to the demodulated Doppler ultrasound signal to generate a filtered demodulated Doppler ultrasound signal;
determining a peak in the filtered demodulated Doppler ultrasound signal;
determining, using a first low-pass filter, an average of the filtered demodulated Doppler ultrasound signal;
estimating a signal-to-noise ratio (SNR) based on the peak and average of the filtered demodulated Doppler ultrasound signal;
modifying a lower cutoff frequency of the bandpass filter based on the estimated SNR when the estimated SNR is below a pre-determined SNR threshold;
applying the modified bandpass filter to the filtered demodulated Doppler ultrasound signal to generate a double-filtered demodulated Doppler ultrasound signal;
rectifying the double-filtered demodulated Doppler ultrasound signal to generate a rectified filtered demodulated Doppler ultrasound signal;
applying a second low-pass filter to the rectified filtered demodulated Doppler ultrasound signal to generate a resulting signal;
detecting peaks in the resulting signal; and
computing a heart rate based on the detected peaks.