Digital Microscopic Breakdown Of Grating Measurement

Since the fifth of last century, with the development of the technology of grating countermarking and electronics as well as the computer science, metrological grating technique has became a special technology and developed rapidly. For its maturity, the grating measurement system today has been widely used in many regions such as industrial production and national defence. However, as the ceaseless development of metrological technique and higher request of practical application, the new demand for measurement system of grating photoelectric device has appeared. It opens a new path to apply the electronic ocular and computer image processing technology into the metrological grating system.In the paper, a brand new measuring proposal which developed the foundation of conversional grating measurement has been introduced. It applies the electronic ocular (which essential element is CMOS image sensor) to the length measurement and uses the digital image processing technique subdivide the grating image in order to improve the distinguishability and accuracy of the system, and make the data processing, saving and transmission much more easier in the meantime.The dissertation can be divided into four parts. Firstly, the research background is expounded combined with the development of today's general situation of grating technique. Secondly, the hardware of the system is introduced. The particular functions and the impact to the systemic performance of the critical elements such as lighting system, grating, field lens and electronic ocular are analyzed. Thirdly, the software of the system is designed. The implementation method of image processing is also discussed. It innovatively adopts histogram cluster analysis and software subdivision to get the information of parameter and displacement, which advances the image processing precision. Fourthly, the performance of the whole system is tested through experiment and the error analysis is to appraise the system. At the end of the dissertation, it summarizes the content of the whole system, and also discusses the subsistent problems in the experiment and the future improvement for study.