Autonomous In-Plane Normal Positioning in Robotic Ultrasound Scanning

Ultrasound examination is pivotal in the preoperative assessment of Proximal Humerus Fractures (PHF). To construct a 3D representation of the entire upper arm, it is critical to minimize the relative error between the probe's axis and the skin's normal to secure high-fidelity images. In this research, we introduce an autonomous robotic ultrasound scanning system that facilitates both scanning and 3D reconstruction. To achieve precise control and diminish in-plane motion errors between the probe and skin, we introduce a method for in-plane normal vector search predicated on column similarity. This technique affords high-precision and high-frequency in-plane ultrasound scanning. Experimental findings confirm that our automated system consistently aligns the probe with the skin's normal direction on human arms, thighs, and abdomens. The findings reveal that, relative to traditional algorithms, our method realizes an 84% increase in speed, with an average error below 4.12°. To corroborate the algorithm's efficacy in real-time scanning, we reconstructed the 3D volume of volunteers' upper arms.