The Imaging Quality Research On Large Aperture And Long Focal Length Scanning Optical Syetem

In order to achieve high-resolution and large-range observation in the remotesensing, this paper presented an outside scanning observing optical mode. based onthe scanning mirror imaging system, this paper focused on the analysis of imagingMTF that affected by image-shift which caused by the mirror swing; studied theeffect of satellite vibration on scanning optical system, on this basis, analyze thelaw of the scanning imaging system under the satellite vibration.The main content of this paper includes the following aspects:Firstly, the large diameter optical system and selection of CCD elements ha vebeen completed, according to the demand of detection; the radiant luminance of thescanning optical system at the image plane has been calculated by usingatmospheric transmission software of Modtran and thus the CCD exposure time atdifferent time have been calculated.Secondly, the theory of moving image modulation transfer function (MTF) andits numerical calculation methods have been presented, the principle of scanningmirror that affects the image quality has been analyzed. The relation between thespeed of scanning mirror and the MTF has been established. The speed of scanningmirror at different exposure time is0.005°/s has been given, and at this speed, theimaging quality of the scanning optical system at different exposure time can meetour demand.Finally, this paper presents a classification of the satellite vibration. On thisbasis, the impact of vibration on the optical imaging system MTF has beencalculated. The interaction law of the motion of scanning mirror and the vibration ofsatellite has been studied. MTF of scanning mirror system under satellite vibrationhas been calculated. The results showed that: in the low-frequency region,increasing the frequency and vibration amplitude will result in the rapid decline ofthe system transfer function, and seriously affecting the imaging quality. As thefrequency increases in the high-frequency vibration region, the impact ofhigh-frequency vibration to the system transfer function decreases, because of the vibration amplitude decreases, Low-frequency vibration is the main factor thataffects the decline of scanning mirror imaging system transfer function.The imaging law of larger aperture and long focus scanning optical system hasbeen researched in detail, the result of this paper presented theoretical foundation ofthe deep research of scanning optical system and the engineering research.