Optical System Design of Space Camera with Long Focal Length and Correction of Image Distortion
Li Xuyang1,2 Li Yingcai1 Ma Zhen1,2 Yi Hongwei1 He Tianbing1 (1Xi′an Institute of Optics and Precision Machanicas,Chinese Acadamy of Sciences,Xi′an,Shaanxi 710119,China 2Graduate University of Chinese Acadamy of Sciences,Beijing 100049,China)
With the development of space optical technology,time delay and integration charge coupled device (TDI-CCD) space camera has been widely applied. TDI-CCD image sensor not only improves signal-noise-ratio(SNR) of the optical system but also makes the opto-mechanical structure of the camera more compact,but the optical system distortion will affecte image quality,so the optical system design must satisfy the new demand. The optical system distortion which affects TDI-CCD integral is analyzed. The method of image distortion elimination of space camera optical system is researched. An optical system is designed with distortion correction lens which is characterized by the spectral band of 450~900 nm,focal length of 6000 mm;%98%94,and F number of 10. The result indicates that the view field angle reaches 1.6°,optical system distortion is less than 0.01%. modulation transfer function reaches 0.50 at 50 lp/mm Nyquist frequency with 0.06 central obscure,and the quality of image reaches the diffraction limit. The designzd optical system can meet the demand for the use of high resolution space cameras,and is suitable for multi-spectrum,stereo imaging,and stereo mapping camera system which has little distortion.