Distortion Reduction and Signal Estimation in Doppler Radar Physiological Monitoring Systems
Date: Thu, October 17, 2013
Time: 9 am
Location: Holmes 485
Speaker: Ehsan Yavari, Advisor: Dr. Olga Boric-Lubecke
Cardiopulmonary monitoring can serve as good
prognostics and diagnostics tool for respiratory and cardiac ailments which are
the leading cause of death in United States. Respiratory rate, heart rate,
pulse pressure, and volumetric measurement are important indicators of human
health status. For measuring vital signs Doppler radar can be used to
detect small movements on the chest walls induced by heart and lungs. Being a
non-invasive and non-contact method, numerous researches were conducted for
health monitoring such as: sleep monitoring, home healthcare monitoring, tumor
tracking, baby monitoring, life detection under the rubble, and occupancy
detection. Although Doppler radar is a well-developed field, physiological
monitoring is a rather new application bringing its own challenges. Issues with
low frequency of the physiological motion, quadrature channel imbalance, local
oscillator leakage, DC offset and flicker noise limit the sensitivity and
accuracy of the radar system. The goal of this work is to develop new hardware
and software solutions to address challenges in Doppler radar physiological
monitoring that currently limit practical applications. In particular, this
work focused on improving system performance by reducing the effects of
distortion. New signal processing algorithms are explored to condition the
received signal for better physiological motion extraction, and estimation of
life signs. Numerous experiments with mechanical target simulating chest
motions, and human subjects have been done to explore the effectiveness of the
proposed methods.