Research On Deflection Detection Of Moving Guideway Based On Image Processing

Deflection measurement plays a very important role in many different fields. For example, the bridge deflection detection and monitoring, in the course of construction bearing beam deflection monitoring, building beam safety testing, crane girder deflection check etc.. The deflection of the bridge operation, accurate measurement for the construction safety, has very important significance for heavy machinery work smoothly.After analyzing many measurements of deflection, the vision measurement method based on the laser spot center location was studied. Firstly, the deflection range of the moving guide rail was calculated according to the simplified model, and the measuring equipment with appropriate parameters was selected according to the measuring range and accuracy. Secondly, several algorithms of extracting the center of the laser spot were introduced, and various algorithms were simulated by using matlab. After comparison, the gray weighted average method was selected eventually. In the end, the deflection measuring system was built by using semiconductor laser, CCD camera, image acquisition card and PC machine, and wrote the image processing program by using Visual C++. The calibration of the whole system was accomplished by using the least square method, and the corresponding relationship between the center coordinates of the spot center and the deflection value was determined which effectively weakened the systematic error. Stability and repeatability of the system were measured repeatly and he results showed that the system had high stability with the measurement accuracy of 0.1mm, the maximum range of 24mm.