二向异性鱼眼镜头理论分析与设计实现

Theoretical Analysis and Design of Bi-Directional Anisotropic Fisheye Lens

为了提高鱼眼镜头在单机位球幕放映系统中的像素利用率,提出了二向异性鱼眼镜头的设计思想。通过理论分析柱面透镜的特性,给出了柱像散对各向度焦距的函数关系,也给出了弧矢和子午二向度共面成像的焦距配置关系;对二向异性鱼眼镜头结构进行了分析与设计,通过在镜头结构中引入柱面透镜,使之具有各向度差异化的渐变式焦距,该镜头在相同工作视场条件下,实现了弧矢和子午两向度的像高差异,形成了各向异性的映射规律。所设计的镜头光学结构中含有4个弧矢柱面和一个子午柱面,弧矢和子午向度的最大像高比为1.52∶1,且具有较高的分辨能力。利用二向异性数字鱼眼镜头构建单机位球幕电影放映系统与使用传统鱼眼镜头相比至少可提高像素利用率52%。

In order to improve the pixel utilization rate of single projector dome movie system constructed by fisheye lens, the design concept of bi-directional anisotropic digital fisheye projection lens is proposed. By analyzing the characteristics of cylindrical lens, the function relationship of astigmatism and the focal length of cylindrical lens is given, and the focal length distribution relationship in sagittal direction and meridian direction is given. The structure of bi-directional digital fisheye projection lens is analyzed and designed, and gradual changing focal lengths along dimensions are produced by introducing cylindrical lens in lens structure. The lens have different image heights in sagittal direction and meridian direction at the same field of view, finally, the anisotropic mapping law is formed. The optical system of lens contains four sagittal cylindrical surfaces and one meridian cylindrical surface, the ratio of the sagittal image height to the meridian image height is 1.52： 1, with high resolution. Compared with the traditional fisheye lens, the pixel utilization rate of the single projector digital dome screen system constructed by the bi- directional anisotropic digital fisheye projection lens is increased by 52%.