Plenary Lecture Dr. Jürgen Kompenhans Title Quantitative visualization techniques for aerodynamics Abstract 　Since two decades technological progress at lasers, video techniques, optoelectronics, computers and evaluation algorithms allow to extract quantitative information from images of flows. Continuous improvement of such image based measurement techniques and decreasing costs of equipment enabled many research groups to exploit these techniques for extraction of 2-dimensional or even 3-dimensional data mainly for fundamental research. Since a decade ago many image based measurement techniques have found interest in aerodynamics and are even used as a matter of routine in industrial applications, especially in large wind tunnels or at in-flight testing. 　Quantitatively measurable values of interest for aerodynamics are pressure (Pressure Sensitive Paint, PSP), velocity (Particle Image Velocimetry, PIV), location of transition lines (Temperature Sensitive Paint, TSP), density (Background Oriented Schlieren Method, BOS), and sound pressure (Acoustic Microphone Array Technique), in parallel with the determination of deformation (Image Pattern Correlation Technique, IPCT) and position of the model in the wind tunnel or of the wing of an airplane in flight (Position and Deformation Measurement System, PDMS). Application of such techniques by the Department Experimental Methods is mainly performed in the scope of large industrial projects in European co-operation. For this purpose mobile measurement systems have been developed, which can be flexibly adjusted to particular testing environments (see http://www.dlr.de/as/en/desktopdefault.aspx/tabid-183/251_read12784/) 　All data is acquired non-intrusively so that no inference of the flow field by the measurement is to occur. In consequence, the methods developed are particularly suited for the aero-dynamical and aero-acoustical analysis of complex, unsteady three-dimensional flow fields measurement techniques in aerodynamics by the Department of Experimental Methods and will describe current problems are future needs.