Applications of Fresnel-Kirchhoff diffraction theory in the analysis of human-motion Doppler sonar grams.
Observed human-gait features in Doppler sonar grams are explained by using the Boulic-Thalmann (BT) model to predict joint angle time histories and the temporal displacements of the body center of mass. Body segments are represented as ellipsoids. Temporally dependent velocities at the proximal and distal end of key body segments are determined from BT. Doppler sonar grams are computed by mapping velocity-time dependent spectral acoustic-cross sections for the body segments onto time-velocity space, mimicking the Short Time Fourier Transform used in the Doppler sonar processing. Comparisons to measured data indicate that dominant returns come from trunk, thigh and lower leg.
National Center for Physical Acoustics, The University of Mississippi, 1 Coliseum Drive, University, Mississippi 38677, USA. rrbradle@olemiss.edu
Marshall
M
Bradley
James M
JM
Sabatier
D000843:Ankle Joint / Q000502:physiology; D005583:Fourier Analysis; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D007596:Joints / Q000502:physiology*; D007719:Knee Joint / Q000502:physiology; D007866:Leg / Q000502:physiology*; D008954:Models, Biological; D009068:Movement / Q000502:physiology; D018608:Ultrasonography, Doppler / Q000379:methods*