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

Introduction

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 Audio signals denotes cross correlation (Fast Fourier Trans.) * convolution

Motion Capture Kinematic Chains Silhouette Extraction Pose Estimation

Experiments