Concerning the further development of gas turbine engines, advances of the aero-thermodynamic design can be achieved most efficiently by cooperative efforts aimed at the improvement of both the numerical simulation methods and the experimental test and measurement techniques. Rapid development of numerical capability is accompanied by increasing demands on experimental data. In this context significant instrumentation research efforts are being conducted to develop the needed measurement technologies. Because of the need for reduced experimental costs planar measurement techniques have undergone a rapid pace of development. Three newly developed quantitative light sheet techniques utilizing the scattered light of tracer particles are described in this paper. First a Doppler global velocimetry (DGV) system optimized for time-averaged three component velocity measurements is presented. The system, which uses a single viewing direction in conjunction with three different illumination directions enables very accurate velocity measurements. Second a quantitative light sheet (QLS) technique for quantitative mass fraction measurements in mixing processes is treated. To apply the technique the inflow of the mixing experiment must consist at least of two separate flows, one of which can be seeded while the other remains unseeded. DGV and QLS results obtained from experimental investigation in a model combuster are presented. Third a method named tracer-based shock visualization (TSV) is described which is capable of determining the shape and structure of shock waves in transonic flows by analysing the sudden increase of flow density across a shock. Results taken in a transonic compressor are presented.

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The behaviour of a surface-micromachined electrostatic microrelay and the influence of the design parameters on the pull-in voltage and the contact force are analysed by means of finite-element method simulations. Three models have been used and compared-a fully three-dimensional coupled electromechanical numerical simulation using CoSolveEM, a two-dimensional coupled simulation, and a simplified semi-analytical model based on the parallel-plate capacitor approximation-and these have shown good conformity. As a new idea, an extension paddle attached to the contact bar is proposed and the positive influence on the pull-in voltage and the contact force is demonstrated.

In this paper we present a system for 3D reconstruction of traffic scenes. Traffic surveillance is a challenging scenario for 3D reconstruction in cases, where only a small number of views is available that do not contain much overlap. We address the possibilities and restrictions for modeling such scenarios with only a few cameras and introduce a compositor that allows rendering of the semi automatically generated 3D scenes. Some of the occurring problems concern camera images, which might show a common background area, but can still differ drastically in lighting effects. For foreground objects nearly no common visual information might be available, as angles between cameras may exceed even 90°

Abstract-Vision-based traffic surveillance systems are more and more employed for traffic monitoring, collection of statistical data and traffic control. We present an extension of such a system that additionally uses the captured image content for 3-D scene modeling and reconstruction. A basic goal of surveillance systems is to get a good coverage of the observed area with as few cameras as possible to keep the costs low. Therefore, the 3-D reconstruction has to be done from only a few original views with limited overlap and different lighting conditions. To cope with these specific restrictions we developed a model-based 3-D reconstruction scheme that exploits a priori knowledge about the scene. The system is fully calibrated offline by estimating camera parameters from measured 3-D-2-D correspondences. Then the scene is divided into static parts, which are modeled offline and dynamic parts, which are processed online. Therefore, we segment all views into moving objects and static background. The background is modeled as multitexture planes using the original camera textures. Moving objects are segmented and tracked in each view. All segmented views of a moving object are combined to a 3-D object, which is positioned and tracked in 3-D. Here we use predefined geometric primitives and map the original textures onto them. Finally the static and dynamic elements are combined to create the reconstructed 3-D scene, where the user can freely navigate, i.e., choose an arbitrary viewpoint and direction. Additionally, the system allows analyzing the 3-D properties of the scene and the moving objects.