The Study On The Calibration Technology For The Machine Vision Fatigue Crack Detection Test System

During machine vision fatigue crack propagation test, measurement accuracy of fatigue crack is one of the most system performance index. Meanwhile, the camera calibration is one of the most key factors which affect measurement accuracy of the crack. This paper proposes a camera dynamic calibration method of machine vision fatigue crack detecting system based on summarizing and analyzing the camera calibration technology at home and abroad. This meghod mainly include camera calibration technique, image processing technology of calibration block and camera motion control technology. At the same time, the paper completes the design of hardware and software of the camera dynamic calibration method. At last, modular commissioning and overall performance test are also done. The details of this paper are as follows:1. Seen from image imaging principle, the paper analyses the research history and current developing situation of the camera calibration system at home and abroad, and also Combine with the actual situation, the camera calibration scheme of machine vision fatigue crack propagation test is propsed.2. Study on image processing techniques of the calibration block, which mainly include image preprocessing, subpixel edge detection, corner detection and image mosaics.3. Study on the camera motion control technology based on ARM platform. The hardware of the lower computer is designed and implemented which used ARM7TDMI as the core, and using C language to complete the lower computer machine programming.4. Develop image processing algorithm of calibration block image based on Lab VIEW platform.5. The system hardware and software debugging and related experiments are done, and the results show that the improved Tsai calibration method is more suitable for the system and has achieved the expected function demand and accuracy request.