超大幅宽低畸变成像系统设计与分析

Design and analysis of super large width and low distortion imaging system

针对光机扫描式超大幅宽对地观测面临的地面成像畸变导致的分辨率随扫描视场增大而急剧降低的问题,提出了一种变焦距摆扫配合可调狭缝光阑成像的方法,推导了其在超大幅宽成像过程中需满足的变焦扫描与光阑控制关系式.理论分析表明:当系统光轴倾斜角度和狭缝大小与瞬时焦距满足对应关系时,可有效消除地面成像畸变,解决边缘分辨率急剧降低的问题,实现大幅宽扫描成像过程中地面分辨率始终与星下点分辨率保持一致.此外,设计了一套变焦摆扫成像系统,分析证明了该方法具有较大可行性,这对未来超大幅宽、高分辨率对地成像观测具有重要指导意义.

In the way of pursing large width and high resolution imaging,ground imaging distortion is an important factor that needs to be eliminated,therefore,a zoom scanning combine with adjustable slit diaphragm imaging method was proposed in this paper. The corresponding control formula of zoom scanning and slit were deduced. Results show that,under appropriate controlling,this method could effectively reduce the ground distortion brought by the increase of the scanning angle and can maintain the ground resolution to be unchanged（ same as the resolution under sub-satellite point） during a wide scan imaging process. Besides,a zoom swing scanning imaging system was designed to verify the feasibility of our method in large width and high resolution imaging applications. This is of great significance for the development of large width and high resolution imaging observation.