| The vector nozzle of engine exhaust nozzle can expand, shrink and deflect. Its spatial dimensions and trajectory are critical to aircraft flight safety, thus the three-dimensional coordinate measurement of vector nozzle plays a pivotal role in the development of the fighter. However, considering the special circumstances, namely it operates under high temperature gas stream and real- time motion environment during testing process of fighter exhaust nozzle, the traditional measurement methods are not already qualified for this job, we have to look for a new modern measuring method which is visual measurements technology.What this thesis researches is cooperation project with the Institute of aero-engine, the geometric parameters of the engine vector tail nozzle are measured by the multi camera vision measurement system for the first time in China, the main line is processing and computing images taken by eight cameras on HALCON software platform, and finally get the spout edge spatial coordinates and other information. This article not only describes some basic theories in machine vision measurement knowledge, but also studies the following elements in detail: Firstly, constitute experimental platform. We focus on the illumination system which plays a very crucial role in whether taking functional images. Secondly, research two practical ways to calibrate, namely the calibration plate respectively cannot be and can be captured completely by eight cameras simultaneously. Thirdly, introduce some principles about the corner detection, especially X-type corner extraction used in our laboratory. And research three-dimensional reconstruction process and approaches how to remove the wrong three-dimensional reconstruction points. Finally, fit round based on three-dimensional coordinates points in the world coordinate system and ca lculate the yaw angle and round radius by MATLAB, meanwhile verify and analysis the two measurement results under the environment of laboratory and experimental site. |
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