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area of observation. The information from the particle tracking is used for the study of mass transport [11] 
and the interaction of waves [5]. 
6 CONCLUSIONS AND OUTLOOK 
À powerful particle tracking algorithm was described, enabling to track particles over several wave periods at 
particle concentration up to 800 particles per image. Particle tracking for the first time, enters the domain 
of digital particle image velocimetry as described by [4]. In addition PTV yields both the Eulerian and 
Lagrangian flow field. This technique als allows an easy extension to the 3rd dimension, which is currently 
undertaken in cooperation with the BASF [10], by directly correlating the trajectories imaged from different 
camera perspectives. 
ACKNOWLEDGEMENTS 
Financial support for this research from the National Science Foundation (OCE91 15994) and the German 
Science Foundation DFG (Wil029/2-1) is gratefully acknowledged. 
REFERENCES 
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[2] Adrian, R.J.: 1991, ‘Particle-Imaging Techniques for Experimental Fluid Mechanics’, Ann. Rev. Fluid 
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[3] Etoh, T., Takehara, K.: 1992, ‘An Algorithm for Tracking Particles’, Proceedings, 6th International 
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[4] Gharib, M., Willert, C.: 1988, ‘Particle Tracing Revisited’, Proceedings, 1st National Fluid Dynamics 
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