Research For The Measurement Method Of Curvature Radius Of Leading Edge Of Aero Engine Blade Base On CCD Image Processing

With the rapid development in semiconductor industry and the microelectronics technology, the photo-electricity measurement technology becomes a novel technology combining with optics and electronics. Using CCD to acquire images, using the image processing technology to obtain the required parameters, the modern photo-electricity measurement method has been widely applied in almost all kinds of fields.The quality of aero engine blade affects some factor that is tied up with engine safety and engine dependability directly, such as blade fatigue, engine accelerator and engine oil consuming. The radius of curvature of blade tip is the most important factor that affects the quality of blade. So it is very important to test it.Today, level of testing the quality of aero engine blades in China fall behind the developed country greatly. In order to satisfy the need of aero engine blades producing companies and improve the efficiency and precision in the testing process, an aero engine blade image testing system was designed in this paper. Blade is rooted on the light-section microscope stage. Image of the tested is put into computer through a CCD, and the image is analyzed in order to obtain special information of the tested by digital image processing as follows: edge detecting, data analysis and so on. In this paper, firstly decreasing noise which was produced in the process of image collecting is studied, and changed structure of light-section microscope light path, selected the proper methods of image filter, edge detecting and sub-pixel edge location, emphatically studied edge detecting operator by experiment, secondly studied ellipse-edge fitting process. At last presented system check and measure precision was not only analyzed in theory but also was tested by experiments.