复合三子镜稀疏孔径光瞳结构的研究

由于在截止频率区域内稀疏孔径系统的调制传递函数(MTF)比全孔径系统的调制传递函数下降,甚至调制传递函数可能出现零点而影响成像质量,通过稀疏孔径系统的结构优化可以获得调制传递函数分布比较理想的孔径结构。给出了基于实际空间截止频率ρR和子孔径直径的稀疏孔径结构优化准则,对复合三子镜稀疏孔径结构进行优化,分析了优化前后的调制传递函数变化,并对优化结构的复合三子镜稀疏孔径系统模拟成像和维纳滤波,比较优化前和优化后稀疏孔径结构的成像情况。结果表明结构优化是稀疏孔径光学系统设计的一个关键部分,应用的优化准则对稀疏孔径结构优化是合理的,通过结构优化可以使复合三子镜稀疏孔径系统的成像质量得到改善。

Research on Pupil Configuration of Dual Three Sub-Apertures Sparse-Aperture System

The modulation transfer function (MTF) of a sparse-aperture system is lower than that of a filled-aperture system within the cut-off frequency. The zero values of MTFs may be produced at some mid-spatial frequencies, which affects the image quality. Configuration optimization of sparse-aperture systems can achieve a sparse-aperture configuration with more uniform MTF. A criterion is given to optimize the sparse-aperture system, which is directly linked with the maximum spatial frequency ρR (or practical resolution) and the diameters of the sub-apertures. Optimal configuration of dual three sub-apertures and the image simulations are obtained. Wiener filter technique is applied. The image simulations and the MTFs comparison of optimized configuration and un-optimized configuration of dual three sub-apertures show that configuration optimization is a key aspect of the design for sparse-aperture systems. The optimization criterion of sparse-aperture systems is reasonable and the image quality can be improved by optimizing configuration.