Marker-less real-time intra-operative camera and hand-eye calibration procedure for surgical augmented reality
Marker-less real-time intra-operative camera and hand-eye calibration procedure for surgical augmented reality
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DOI：
10.1049/htl.2019.0094
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发表时间：
2019-12-01
影响因子：
2.1
通讯作者：
Salcudean, Septimiu E.
中科院分区：
文献类型：
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作者：
Kalia, Megha;Mathur, Prateek;Salcudean, Septimiu E.
准确的医疗增强现实 (AR) 渲染需要两次校准：相机固有矩阵估计和手眼变换。我们提出了一个统一的、实用的、无标记的实时系统来估计手术期间的这两种转变。对于相机校准，我们在术前在距内窥镜的多个距离处进行校准，以将相机固有矩阵参数化为距内窥镜距离的函数。然后，我们通过在不到 1 秒的时间内估计手术部位与内窥镜的距离来检索术中相机参数。与之前的工作不同，我们的方法不需要将内窥镜从患者体内取出；对于手眼校准，与需要识别标记的传统方法相反，我们使用 3D 渲染的工具提示。当外科医生移动器械并观察实际和渲染的工具提示之间的偏移时，他们可以选择视觉误差较大的点并手动使器械提示与虚拟渲染的工具提示相匹配。为了评估手眼校准，5 名受试者在达芬奇机器人上进行了手眼校准程序。仅使用三个数据点即可实现约 7 毫米的平均目标配准误差。
Accurate medical Augmented Reality (AR) rendering requires two calibrations, a camera intrinsic matrix estimation and a hand-eye transformation. We present a unified, practical, marker-less, real-time system to estimate both these transformations during surgery. For camera calibration we perform calibrations at multiple distances from the endoscope, pre-operatively, to parametrize the camera intrinsic matrix as a function of distance from the endoscope. Then, we retrieve the camera parameters intra-operatively by estimating the distance of the surgical site from the endoscope in less than 1 s. Unlike in prior work, our method does not require the endoscope to be taken out of the patient; for the hand-eye calibration, as opposed to conventional methods that require the identification of a marker, we make use of a rendered tool-tip in 3D. As the surgeon moves the instrument and observes the offset between the actual and the rendered tool-tip, they can select points of high visual error and manually bring the instrument tip to match the virtual rendered tool tip. To evaluate the hand-eye calibration, 5 subjects carried out the hand-eye calibration procedure on a da Vinci robot. Average Target Registration Error of approximately 7mm was achieved with just three data points.