Indirect Imaging Method of Ritchey-Chretien Optical System with Large Field of View

Ritchey-Chretien (RC) optical system is widely used in long-distance detection fields such as aviation and aerospace. Due to its small field of view, additional optical elements arc usually used to achieve large field of view imaging, but this will lead to a complex structure, which is not good for miniaturization and lightweight of the system. In view of this, a R-C system indirect imaging method is proposed. First, the aberration characteristics of the system arc analyzed. Then, the wavefront model is constructed based on the wavefront aberration theory and Zernike polynomial. Second, the PSF model is established by Fourier transform. Finally, the image is processed by combining the deconvolution algorithm. In the case that only primary and secondary mirrors arc used, the R-C system can achieve large field of view imaging. The R-C optical system with a focal length of 1300 mm, a full field of view of 0.9 degrees and an F number of 1 is simulated. The simulation results show that the MIT of the proposed method increases by about 0.25 on average at a frequency of 10 cycle/mm, and the imaging quality is significantly improved.