望远超分辨成像中的视场光阑影响及补偿机理

根据衍射光学理论,分析了基于瞳函数调制的望远超分辨成像系统中,用于视场选择和过滤旁瓣影响的视场光阑的衍射效应对于成像效果的影响机理,并给出了补偿原理和方案。微孔视场光阑和四环带阶跃型位相滤波器分别放置在系统一次像面和出瞳位置。理论分析和仿真表明:视场光阑口径越小,最终像面光斑主瓣越宽甚至失去超分辨效果,旁瓣光强峰值与主瓣光强峰值之比也越高。对此时出瞳处的光场振幅、位相场分别进行多项式拟合,求解进行修正的复振幅型光瞳滤波器设计参数,可以有效抑制视场光阑的衍射效应,获得良好的超分辨成像效果,且超分辨成像与光阑效应补偿合二为一,不会增加系统光路的复杂度。并进行了实际实验,验证了以上设计方法的有效性。以上研究结果可为应用在天文观测、空间探测等方面的超分辨成像系统设计提供依据。

Effect and compensation mechanism of field stop in telescopic super-resolution imaging

According to the theory of diffractive optics, the imaging quality influence mechanism of the diffraction effect of the field stop for the field of view selection and side lobes filtering in the pupil function modulated modulation telescope telescopic super-resolution imaging was analyzed, and the compensating principle and method were given. The tiny hole field stop and the four-ring step phase filter were placed in the first image plane and the exit pupil respectively. Theoretical analysis and simulation show that the smaller the field stop aperture, the wider the main lobe of the spot on the final image surface, (even the super-resolution effect will disappear), and the higher the ratio of the peak intensity of the side lobe to the peak intensity of the main lobe. The polynomial fitting of the amplitude and phase fields at the exit pupil and the solving of the modified complex-amplitude pupil filter design parameters can effectively suppress the diffraction effect of the field stop, which leads to a good super-resolution imaging. Moreover, the super-resolution imaging and the pupil effect compensation were combined into one, which did not increase the complexity of the system optical path. The actual experiment was carried out to verify the availability of the above design method. The above research results can be used as a basis for the design of super-resolution imaging system applied in the astronomical observation and space exploration.