Institute of Medical Technology, Hamburg University of Technology, 21073 Hamburg, Germany.
Sensors (Basel). 2020 May 8;20(9):2678. doi: 10.3390/s20092678.
Optical tracking systems are widely used, for example, to navigate medical interventions. Typically, they require the presence of known geometrical structures, the placement of artificial markers, or a prominent texture on the target's surface. In this work, we propose a 6D tracking approach employing volumetric optical coherence tomography (OCT) images. OCT has a micrometer-scale resolution and employs near-infrared light to penetrate few millimeters into, for example, tissue. Thereby, it provides sub-surface information which we use to track arbitrary targets, even with poorly structured surfaces, without requiring markers. Our proposed system can shift the OCT's field-of-view in space and uses an adaptive correlation filter to estimate the motion at multiple locations on the target. This allows one to estimate the target's position and orientation. We show that our approach is able to track translational motion with root-mean-squared errors below 0 . 25 m m and in-plane rotations with errors below 0 . 3 ∘ . For out-of-plane rotations, our prototypical system can achieve errors around 0 . 6 ∘ .
光学跟踪系统被广泛应用于医学干预导航。通常，这些系统需要已知的几何结构、人工标记的放置，或目标表面的明显纹理。在这项工作中，我们提出了一种基于体积光学相干断层扫描（OCT）图像的 6D 跟踪方法。OCT 具有亚微米级的分辨率，采用近红外光穿透几毫米的深度，例如组织。因此，它提供了亚表面信息，我们可以利用这些信息来跟踪任意目标，即使是表面结构较差的目标，也无需标记。我们提出的系统可以在空间中移动 OCT 的视场，并使用自适应相关滤波器来估计目标上多个位置的运动。这允许我们估计目标的位置和方向。我们表明，我们的方法能够以低于 0.25 毫米的均方根误差跟踪平移运动，并且能够以低于 0.3 ∘ 的误差跟踪平面内旋转。对于离面旋转，我们的原型系统可以实现约 0.6 ∘ 的误差。
