Extraction of the velocity of walking human's body segments using ultrasonic Doppler

The focus of this paper is to experimentally extract the Doppler signatures of a walking human's individual body segments using an ultrasonic Doppler system (UDS) operating at 40 kHz. In a human's walk, the major contribution to Doppler velocities and acoustic scattering is from the foot, lower leg, thigh (upper leg) and torso. The Doppler signature of these human body segments are extracted experimentally. The measurements were made by illuminating one of these body segments at a time and blocking the remaining body segments using acoustic screens. The results obtained in our experiment were verified with the results published by Bradley using a physics-based model for Doppler sonar spectrograms.