A study on pre-filter design for improving accuracy in heart rate estimation from backside using discrete wavelet transform with mm-wave radar

Abstract

We have been considering applying discrete wavelet transform (DWT) to heart-rate estimation using 77GHz band FMCW radar. The detection accuracy and SNR were improved by using an elliptic High-pass filter (HPF) and a High-pass Chebyshev type II filter. The High-pass Chebyshev Type II filter has less ripple in the passband area, on the other the elliptic HPF has a steeper frequency response compared to the Chebyshev filter. Those filters were used in a pre-processing of DWT for the data acquired from the front and back to reduce respiratory signals and harmonics for comparison. In this letter, the detection accuracy and SNR estimated from the front and back were improved by using two types of filters in DWT pre-processing to decrease respiratory signals.