Feldstein Ilja T, Ellis Stephen R
IEEE Trans Vis Comput Graph. 2021 Sep;27(9):3611-3625. doi: 10.1109/TVCG.2020.2980527. Epub 2021 Jul 29.
Designers of virtual reality (VR) systems are aware of the need to minimize delays between the user's tracked physical actions and the consequent displayed actions in the virtual environment. Such delays, also referred to as end-to-end latency, are known to degrade user performance and even cause simulator sickness. Though a wide variety of hardware and software design strategies have been used to reduce delays, techniques for measuring and minimizing latency continue to be needed since transmission and switching delays are likely to continue to introduce new sources of latency, especially in wireless mobile environments. This article describes a convenient low-cost technique for measuring end-to-end latencies using a human evaluator and an ordinary consumer camera (e.g., cell phone camera). Since the technique does not depend upon the use of specialized hardware and software, it differs from other methods in that it can easily be used to measure latencies of systems in the specific hardware and software configuration and the relevant performance environments. The achievable measurement accuracy was assessed in an experimental trial. Results indicate a measurement uncertainty below 10 ms. Some refinements to the technique are discussed, which may further reduce the measurement uncertainty to approximately 1 ms.
虚拟现实（VR）系统的设计者们意识到，有必要将用户所追踪的身体动作与虚拟环境中随之显示的动作之间的延迟降至最低。这种延迟，也被称为端到端延迟，已知会降低用户表现，甚至导致模拟器不适。尽管已经采用了各种各样的硬件和软件设计策略来减少延迟，但由于传输和切换延迟可能会继续引入新的延迟源，特别是在无线移动环境中，所以仍然需要测量和最小化延迟的技术。本文介绍了一种使用人工评估者和普通消费级相机（如手机相机）来测量端到端延迟的便捷低成本技术。由于该技术不依赖于专用硬件和软件的使用，它与其他方法的不同之处在于，它可以轻松地用于测量特定硬件和软件配置以及相关性能环境下系统的延迟。在一项实验试验中评估了可达到的测量精度。结果表明测量不确定度低于10毫秒。文中还讨论了对该技术的一些改进，这些改进可能会将测量不确定度进一步降低至约1毫秒。
