Stereoscopic, head-tracked display systems can show users realistic, world-locked virtual objects and environments. However, discrepancies between the rendering pipeline and physical viewing conditions can lead to perceived instability in the rendered content resulting in reduced realism, immersion, and, potentially, visually-induced motion sickness. The requirements to achieve perceptually stable world-locked rendering are unknown due to the challenge of constructing a wide field of view, distortion-free display with highly accurate head- and eye-tracking. In this work we introduce new hardware and software built upon recently introduced hardware and present a system capable of rendering virtual objects over real-world references without perceivable drift under such constraints. The platform is used to study acceptable errors in render camera position for world-locked rendering in augmented and virtual reality scenarios, where we find an order of magnitude difference in perceptual sensitivity between them. We conclude by comparing study results with an analytic model which examines changes to apparent depth and visual heading in response to camera displacement errors. We identify visual heading as an important consideration for world-locked rendering alongside depth errors from incorrect disparity.

翻译：立体、头部追踪显示系统能够向用户展示逼真的、世界锁定的虚拟物体与环境。然而，渲染管线与实际物理观视条件之间的偏差可能导致渲染内容出现可感知的不稳定性，从而降低真实感和沉浸感，甚至可能引发视觉诱导的晕动症。由于构建具有高精度头部和眼球追踪功能、且无失真的宽视场显示器面临挑战，实现感知稳定的世界锁定渲染所需的条件尚不明确。本研究基于近期推出的硬件，构建了新型软硬件系统，能够在满足前述约束条件下，将虚拟物体叠加于真实世界参考物之上且无感知漂移。该平台被用于研究增强现实与虚拟现实场景中世界锁定渲染对渲染相机位置的可接受误差阈值，发现两者在感知灵敏度上存在一个数量级的差异。最后，我们通过分析模型（该模型考察了相机位姿误差对表观深度与视觉朝向的影响）对实验结果进行对比，指出视觉朝向（visual heading）与视差错误导致的深度误差均是世界锁定渲染中需重点考虑的因素。