Purpose:

The use of an optical see-through head-mounted display (OST-HMD) in augmented reality (AR) has significantly increased in recent years, but the alignment between the virtual scene and physical reality is still a challenge. A fast and accurate calibration method of OST-HMD is important for augmented reality in the medical field.

Methods:

We proposed a fast online calibration procedure for OST-HMD with the aid of an optical tracking system. Two 3D datasets are collected in this procedure: the virtual points rendered in front of the observer’s eyes and the corresponding points in optical tracking space. The transformation between these two 3D coordinates is solved to build the connection between virtual and real space. An AR-based surgical navigation system is developed with the help of this procedure, which is used for experiment verification and clinical trial.

Results:

Phantom experiment based on the 3D-printed skull is performed, and the average root-mean-square error of control points between rendered object and skull model is \(1.30 \pm 0.39\) mm, and the time consumption of the calibration procedure can be less than 30 s. A clinical trial is also conducted to show the feasibility in real surgery theatre.

Conclusions:

The proposed calibration method does not rely on the camera of the OST-HMD and is very easy to operate. Phantom experiment and clinical case demonstrated the feasibility of our AR-based surgical navigation system and indicated it has the potential in clinical application.

中文翻译：

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使用 Microsoft HoloLens 快速准确地在线校准光学透视头戴式显示器，用于基于 AR 的手术导航。

目的：

近年来，光学透视头戴式显示器 (OST-HMD) 在增强现实 (AR) 中的使用显着增加，但虚拟场景与物理现实之间的对齐仍然是一个挑战。OST-HMD 的快速准确校准方法对于医疗领域的增强现实非常重要。

方法：

我们在光学跟踪系统的帮助下提出了 OST-HMD 的快速在线校准程序。在此过程中收集了两个 3D 数据集：呈现在观察者眼前的虚拟点和光学跟踪空间中的相应点。解决这两个 3D 坐标之间的转换，以建立虚拟和现实空间之间的连接。在此过程的帮助下开发了基于 AR 的手术导航系统，用于实验验证和临床试验。

结果：

进行基于3D打印头骨的幻影实验，渲染对象与头骨模型控制点的平均均方根误差为\(1.30 \pm 0.39\)  mm，校准程序的时间消耗可以小于 30 s。还进行了一项临床试验，以证明在真实手术室中的可行性。

结论：

所提出的校准方法不依赖于 OST-HMD 的摄像头，并且非常易于操作。体模实验和临床案例证明了我们基于 AR 的手术导航系统的可行性，并表明它具有临床应用的潜力。