1. 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

2. Outline
Introduction
Steps
Experiments

3. Introduction

4. Steps
Camera Calibration
Camera Synchronization
Motion Capture

5. 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

6. 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)

7. Camera Calibration Tensor Voting filter (noise)
Least Squares filter (smooth)
3D surface reconstruction

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

9. Motion Capture
Kinematic Chains
Silhouette Extraction
Pose Estimation

10. Experiments