Cmos Grating Measurement System

As the development of the technique of grating score and digital technology as well as the computer science, metric gratings technique has been an special technique and has developed rapidly. At present, metric grating technique has been mature, the measurement of displacement using gratings has been used widely in many fields such as industrial production and national defence. However, as the ceaseless development of metric technique and higher request of practical application, the new demand for measurement system of photo-electric displacement with higher resolution has appeared . From this point, a new interpolating method using CMOS as image incepting device has been put forward in this paper. A new method by software based on the image of grating incepted by CMOS was also studied.The interpolating method was based on the essential theory of physical optics and according to the variation of spectra energy during the motion of scale grating in a period's separation to realize measurement, CMOS image sensor (pixel array was also introduced as receiving device. In the mean time, method by software to process the image of grating was studied.The paper introduces the theory of measurement system using gratings, analyzes various methods and system for the moment, developing current situation and the trend of the photo-electric fine displacement measurement system was also expatiated at first. The testing method and the hardware and the software of the proposed interpolating system according to the variation of spectra energy are expatiated. The hardware mainly includes light, slit, gratings, image sensor. The captured images are demonstrated, existent problems are analyzed and how to improve on the project is also discussed. At last, the software interpolating method based on the images of the grating is introduced, the design of the system and the experimental outcome are introduced in detail. 250 times interpolation has been realized.The paper also discusses the shortage of the theoretic analysis, existent problems and the factors which influence the resolution and precision, in the mean time prepares for the farther study and experiment.