Analysis And Simulation Of Dynamic Image Captured By Satellite-based TDICCD Camerar

As the progress of optical remote reconnaissance technology, optical axisvibration caused by satellite platform along with the atmosphere have become theprimary two factors which affect imaging quality of dynamic high resolutioncamera. Due to the resonance oscillation of worm wheel or engine can result inabnormal image motion when the optical systems are fixed on spacecraft or satelliteplatform, and that will lead to image blurring. Through appropriate design, thevibration could be minimized. Regardless how to stabilize its mechanic viatechnique, the vibration still will lead the transfer function decline and hence resultin image distortion. When optical remote reconnaissance system imaging over theground, it is inevitable to pass through the atmosphere. On one hand, since theluminous energy absorption and scattering by particles in atmosphere will lead theatmospheric transfer function decline, and hence luminous energy damping,objective contrast decrease and image blurring. On the other hand, since the effectof atmospheric turbulence could give rise to the variation of light intensit y andphase, as well as the deflection of light beam, and hence lead to image deformation.Analysing dynamic imaging process of Satellite-bone TDI CCD camera andcarrying through dynamic imaging simulation play vital roles in improving thequality of camera imaging and the subsequence image processing. This not onlycould provide arithmetic support for image processing and provide basis for comingup with the satellite control index, but also complete the full-link simulation ofsystem. The concrete works of this article as followed:Firstly, this article carried out the analysis of vibrations of satellite platform,derived the formulas which compute the dynamic transfer function throughvibratory power spectral density function, and established TDI CCD camera systemimage quality degrade mathematical model in the influence of optical axis vibrationthrough the basic principle of TDI CCD imaging. Results demonstrate that theeffects of satellite platform optical axis vibration are spatial, not only the existe nceof image blurring but also geometric deformation, and along with the difference of deformation and image blurring in different direction.Secondly, through the analysis of atmospheric scatter and absorption as well asatmospheric turbulence, this article obtained the conclusion which atmosphericscatter and absorption transfer function are correlated with atmospherictransmittivity, atmospheric eikonal function and ground object radical luminance.Then, this article calculated and analysed the effect that different visibilities incountry and in city affect the atmospheric transmissivity, and that different solarattitude angles influence the atmospheric eikonal radiance. Latter, based on the factthat atmospheric transfer function mainly related to refractive index constants, andthrough the analysis of refractive index constants on different attitude and differenttime in the same location, this article reached to the roles which those factors playedin the atmospheric transfer function.Finally, several TDI CCD dynamic imaging simulations were carried out basedon mathematical model mentioned above and also according to the principle ofsampled imaging system. Results demonstrate that optical axis vibration of satelliteplatform and atmosphere are the primary factors which affect optical remotereconnaissance imaging in the TDI CCD dynamic imaging process.