从自正常定位到全向跟踪：用于机器人超声成像的实时表面建模支持的探头倾斜控制
From Self-Normal-Positioning to Omni-Directional Tracking: Real-Time Surface Modeling Enabled Probe Tilt Control for Robotic Ultrasound Imaging
AI总结：
该研究针对机器人超声成像中现有系统仅支持探头法向定位的局限，提出整合RGB-D感知等的全向探头朝向控制框架，实现了高精度的任意角度跟踪，可获取临床所需非法向诊断视图。
AI中文摘要：
超声（US）可提供实时、无辐射的成像，但其图像质量高度依赖探头相对于患者身体的朝向。机器人超声可减少操作员工作量并提高采集一致性；然而，大多数现有系统聚焦于正常定位，即探头保持垂直于局部表面。该约束对于超声心动图等检查而言并不适用，这类检查中获取诊断视图需要探头处于非法向角度。因此，具有临床实用性的机器人系统必须实时感知局部表面并维持所需的探头朝向。本文提出一种全向探头朝向控制框架，整合RGB-D感知、局部表面建模与任务空间朝向控制。表面模型融合多视点云并提供局部表面的二次估计，随后相对于法向编码所需成像方向，使探头能跟踪任意角度。该框架通过平面跟踪、体模目标角度恢复及专家选定视图的体内跟踪进行评估。结果显示，平均角度跟踪误差为1.06±0.66度；系统相对于表面法向恢复的非法向倾斜角最高达44.39±2.59度，且在体模与体内实验中均成功获取所需心腔视图。
英文摘要：
Ultrasound (US) provides real-time, radiation-free imaging, but the image quality depends strongly on how the probe is oriented against the patient body. Robotic US can reduce operator workload and improve acquisition consistency; however, most existing systems focus on normal positioning, where the probe is maintained perpendicular to the local surface. This constraint is inadequate for examinations like echocardiography, where obtaining a diagnostic view requires a non-normal probe angle. Consequently, a clinically useful robotic system must sense the local surface in real-time and preserve the desired probe orientation. Here, we propose an omni-directional probe-orientation control framework that integrates RGB-D perception, local-surface modeling, and task-space orientation control. The surface model fuses multi-view point clouds and provides a quadratic estimate of the local surface. A desired imaging direction is then encoded relative to the normal, enabling the probe to track arbitrary angles. The framework was evaluated through flat-surface tracking, phantom target-angle recovery, and in-vivo tracking of an expert selected view. Results show that the mean angular tracking error was 1.06 +- 0.66 deg. The system recovered a non-normal tilt angle of up to 44.39 +- 2.59 deg relative to the surface normal, and acquired the desired heart chamber view in the phantom and in-vivo experiments.
