Pancake optics (also known as polarization-based catadioptric system) has been widely used as the imaging lens for virtual reality (VR) and mixed reality (MR) headsets because of its compact formfactor and excellent image quality. However, such a folded pancake optics not only dramatically lowers the optical efficiency to 25% because of the utilization of a half mirror, but also suffers from ghost images due to the stray light from multiple surface reflections and imperfect polarization control inside the optical system. In this paper, the origins including the light paths of the ghost images are explored by experiment and then analyzed by simulation. The effect of different incident angles on the intensity of each ghost is also investigated.

中文翻译：

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煎饼虚拟现实系统的重影图像分析

薄饼光学器件（也称为基于偏振的折反射系统）因其紧凑的外形和出色的图像质量而被广泛用作虚拟现实（VR）和混合现实（MR）耳机的成像镜头。然而，这种折叠式薄饼光学器件不仅由于使用了半透半反镜而使光学效率大幅降低至25%，而且由于多次表面反射产生的杂散光以及光学系统内部不完善的偏振控制而导致出现重影。本文通过实验探究了鬼像的光路等根源，并通过仿真进行了分析。还研究了不同入射角对每个鬼影强度的影响。