消畸变成像折反射全景成像系统设计

摘要

A catadioptric system uses a combination of lenses and mirrors placed in a carefully arranged configuration to capture a much wider field of view. However, images obtained by u-sing a single-viewpoint catadioptric omnidirectional system have a large amount of visual distortion. To design a catadioptric omnidirectional system with undistorted imaging, appropriate surfaces were presented. The surfaces preserved a linear relationship between the angle of incidence of light onto the surface and the angle of reflection onto the imaging device, as does a normal mirror. The reflective mirror and the lens were designed for a catadioptric omnidirectional camera with the F number 3. 3 and the field of view 138°. The modulation transfer function is better than 0. 6 at 66. 7 lp/mm and the distortion is less than 4% over the whole active area of the image sensor. The deduction of the reflective surfaces offers an essential model and a computing method to design a catadioptric omnidirectional system with undistorted imaging.%单视点折反射全景成像系统畸变较大,通过计算反射镜面型可有效地实现折反射全景成像系统消畸变成像.在反射镜入射角与反射角呈线性关系的基础上,推导适用于消畸变折反射全景成像的反射镜面型公式.为说明反射镜面型的准确性,设计了F＃为3.3,视场为138°的消畸变成像折反射全景成像系统,并利用实际像平面和虚拟像平面间的坐标映射关系,实现了系统的消畸变设计.各视场MTF在奈奎斯特频率下均达到0.6,边缘视场相对畸变小于4％.结果表明:该面型可实现消畸变折反射全景成像,反射角光线追迹法适用于折反射全景成像系统畸变评价,为折反射全景成像系统消畸变设计提供了必要的模型和计算方法.