Research Of Wavefront Correction System For Application To Large-scale Measurement

The measurement of large-scale is very important to heavy industry. It is necessitated in the process of manufacturing and assembling large size workpiece, such as ship building, aerofoil assembling etc. With the development of technology, the high precision measurement of large-scale is needed by high-tech industry, especially in aerial and space industry. However the large-scale measurement is the weak point of measurement technology. Though the photoelectricity technology has improved the efficiency of large-scale measurement; the problem of low precision still puzzles the technologist. Nowadays how to improve the precision of large-scale measurement is a crucial task.Constant study indicates that atmosphere turbulence is one of the primary factors that affect the precision of measurement in photoelectricity large-scale measurement instrument. So how to eliminate the affect of atmosphere turbulence is the key to improve the large-scale measurement precision.In order to eliminate the atmosphere turbulence, Adaptive Optics technology is introduced to photoelectricity large-scale measurement, and a new Wavefront Correction System (Adaptive Optics system), which is applied to large-scale measurement instrument, is developed.This Adaptive Optics system is based on deconvolution Adaptive Optics theory, which has used the wavefront detecting and image deconvolution restoration technology. The Adaptive Optics system is constituted of three parts, which are an image device, a wavefront sensor and a digital image processing system. The imagedevice is used to capture the image, which is composed of a high-speed CCD and a camera lens. The wavefront sensor is used to detect the light wavefront aberrance, and a Hartmann-Shack wavefront sensor is adopted in this system. The digital image processing system is used to process the wavefront data and image, which is composed of computer software and hardware. The work principle of The Adaptive Optics system is as follows: first, The Hartmann-Shack wavefront sensor detects light wavefront, and if the light-wave is disturbed by atmosphere turbulence, the wavefront error will react on the wavefront data, which is detected by Hartmann-Shack wavefront sensor. After wavefront reconstruction and some other operation, the Optical Transfer Function can be obtained. At last, the aberration of the image will be corrected through processing of image deconvolution from wavefront detecting.The experiments with point sources and extended sources are performed respectively. The results show that the Adaptive Optics system can be used to restore the image that is disturbed by atmosphere efficientlyCompared with traditional Adaptive Optics system, the deconvolution Adaptive Optics system has the advantages of lower costs and simpler construction, because software is used to substitute the expensive optic components and controller. So the Adaptive Optics system is suitable for the large-scale measurement instrumentIn this paper, the mathematic model of light-wave transfers and image in atmosphere is analyzed firstly, and the theory of deconvolution Adaptive Optics is demonstrated then, whereafter the design of hardware and software of the system is introduced, the experiment and result are presented and analyzed at last.