Egocentric augmented reality (AR) interfaces are quickly becoming a key asset for assisting high precision activities in the peripersonal space in several application fields. In these applications, accurate and robust registration of computer-generated information to the real scene is hard to achieve with traditional Optical See-Through (OST) displays given that it relies on the accurate calibration of the combined eye-display projection model. The calibration is required to efficiently estimate the projection parameters of the pinhole model that encapsulate the optical features of the display and whose values vary according to the position of the user’s eye. In this article, we describe an approach that prevents any parallax-related AR misregistration at a pre-defined working distance in OST displays with infinity focus; our strategy relies on the use of a magnifier placed in front of the OST display, and features a proper parameterization of the virtual rendering camera achieved through a dedicated calibration procedure that accounts for the contribution of the magnifier. We model the registration error due to the viewpoint parallax outside the ideal working distance. Finally, we validate our strategy on a OST display, and we show that sub-millimetric registration accuracy can be achieved for working distances of $\pm 100$ mm around the focal length of the magnifier.

中文翻译：

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个人空间中增强现实光学透视显示器的无视差注册

以自我为中心的增强现实 (AR) 界面正迅速成为在多个应用领域中辅助个人空间中高精度活动的关键资产。在这些应用中，传统的光学透视 (OST) 显示器很难将计算机生成的信息准确和稳健地配准到真实场景，因为它依赖于组合眼睛显示投影模型的精确校准。需要校准以有效地估计封装了显示器的光学特征并且其值根据用户眼睛的位置而变化的针孔模型的投影参数。在本文中，我们描述了一种方法，该方法可防止在具有无限远焦距的 OST 显示器中在预定义的工作距离内出现任何与视差相关的 AR 错位；我们的策略依赖于使用放置在 OST 显示器前面的放大镜，并通过专门的校准程序实现虚拟渲染相机的适当参数化，该程序考虑了放大镜的贡献。由于理想工作距离之外的视点视差，我们对配准误差进行建模。最后，我们在 OST 显示器上验证了我们的策略，并表明对于$\pm 100$mm 围绕放大镜的焦距。