Mirror based image de-rotation for aerodynamic rotor measurements

Kurzfassung

The current level of technology allows image based temperature, pressure and skin friction measurements at exposure times in the order of milliseconds. Though CCD and CMOS sensors of increasing sensitivity are continuously under development and being brought into the market, it will take some time before the majority of recording techniques allows for exposure times short enough to avoid motion blur during rotating blade recording. It has been demonstrated that image de-rotation can be achieved with a rotating mirror system. Such a system, which is able to provide very high-speed and easily adjustable image de-rotation, has been described in this article. Problems such as the angular control of the rotating mirror and its synchronization with the camera have been solved successfully. A theoretical model detailed enough to choose appropriate recording parameters for the application of a rotating mirror system has been presented.