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PHOTOGRAMMETRIC EVALUATION OF FLUID MOTION 
J. Becker 1 W. Bósemann 2 L. Gatti > T. Hau * 
1 ESTEC, P. O. Box 299, 2200 AG Nordwijk zh / Netherlands, Phone: ++31-1719-84198 , Fax: ++31-1719-17400 
AICON Industrial Photogrammetry and Image Processing GmbH, Bültenweg 23, 38106 Braunschweig / Germany 
Phone: ++49-531-344501, Fax: ++49-531-344504 
? Alenia Spazio, Corso Marche 41, 10146 Torino, Italy, Phone: ++39-11-71 80 714, Fax: ++39-11-723 307 
Institute for Photogrammetry and Image Processing, Technical University Braunschweig, 
Gaußstraße 22, 38106 Braunschweig / Germany, Phone: ++49-531-3912897, Fax: ++49-531-3915839 
KEY WORDS: multi media path, fluid motion, object reconstruction 
ABSTRACT 
For an investigation of the phenomenon of Marangoni convection it is necessary to determine the velocity of a liquid body 
and / or the change of it's shape in time. To demonstrate the performance of photogrammetric methods concerning the 
study of those phenomena a demonstration breadboard of a photogrammetric diagnostic tool is developed and built in 
cooperation between AICON and the Institute of Photogrammetry and Image Processing. 
1. INTRODUCTION 
Tangential tension between two media which are not mixable cause motion of part of the liquid on the boundary of 
surfaces. Due to friction these motions will be transmitted to the surrounding area of the liquid. The consequence is a flow 
field. This effect is called Marangoni convection [Wozniak 1986]. Conclusions can be drawn out to those tensions on the 
boundary surfaces by measuring the change of the position and / or the shape of liquid bodies in time. These phenomena 
can be much better studied in space as gravity forced convections no longer cover the smaller effects of Marangoni 
convection. 
Two different scenes are selected for the first demonstration of the performance of photogrammetric methods, here a 
model of a drop or a fluid column can be placed and moved within a fluid matrix in a fluid cell. 
The photogrammetric front end consists of three CCD cameras which take image sequences for the determination of the 
motion or the change of the shape of the liquid bodies. The evaluation of motion and / or shape via photogrammetry has 
to take into account three major topics: 
e The complete imaging chain for the data flow concerning the photogrammetric measurement on microgravity 
experiments consists of calibration procedures, image acquisition, image storage, evaluation, storage and 
representation of measurement results 
e The determination of the multi media path of the image rays (e.g. air, glass, air, glass, liquid) 
^ The determination of the position and shape of the fluid bodies as a function of time. 
IAPRS, Vol. 30, Part 5W1, ISPRS Intercommission Workshop "From Pixels to Sequences", Zurich, March 22-24 1995 
  
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