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Markerless Motion Capture with Unsynchronized Moving Cameras. N. Hasler , MPI Inf., Saarbrucken, Germany B. Rosenhahn , MPI Inf., Saarbrucken, Germany T. Thormahlen , MPI Inf., Saarbrucken, Germany M. Wand , MPI Inf., Saarbrucken, Germany J. Gall , MPI Inf., Saarbrucken, Germany
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Markerless Motion Capture with Unsynchronized Moving Cameras N. Hasler, MPI Inf., Saarbrucken, Germany B. Rosenhahn, MPI Inf., Saarbrucken, Germany T. Thormahlen, MPI Inf., Saarbrucken, Germany M. Wand, MPI Inf., Saarbrucken, Germany J. Gall, MPI Inf., Saarbrucken, Germany H.-P. Seidel, MPI Inf., Saarbrucken, Germany IEEE 2009
Outline • Introduction • Steps • Experiments
Steps • Camera Calibration • Camera Synchronization • Motion Capture
Camera Calibration • Single Camera Structure from Motion KLT–Tracker or SIFT filter out feature points RANSAC with multi-view constraints minimizes the error of 3D points (Gaussian distribution) • d(….) = Euclidean distance • Pj = 3D object point • Ak = 3x4 camera matrix • p(j,k) = K images J trajectories of 2D feature point
Camera Calibration • Multi camera Structure from Motion • Register N reconstructions into global system (H) find and merge 3D object points (pairwise match) (color intensity , uniqueness constraint)
Camera Calibration • Tensor Voting filter (noise) • Least Squares filter (smooth) • 3D surface reconstruction
Camera Synchronization • Camera Synchronization • Audio signals • denotes cross correlation (Fast Fourier Trans.) • * convolution
Motion Capture • Kinematic Chains • Silhouette Extraction • Pose Estimation