It is based on the visualization of a flow with small, neutrally buoyant particles and a stereoscopic recording image sequences of the particles. Due to the fact that particle images cannot be distinguished by features like size, shape or color, the only criterion for the establishment of stereoscopic correspondences is the epipolar line.
Ambiguities occur when multiple candidates are found in a search area defined by the epipolar line.
Ambiguities may also occur in the tracking procedure. Criteria like local correlation and smoothness of the velocity field are employed to solve these criteria. CH-8093 Zurich, Switzerland. Hans-Gerd Maas Institute of Photogrammetry and Remote Sensing Dresden Technical University Helmholzstr.