A Tip-Flexible Endoscope With Reconfigurable Baseline for Enhanced 3D Perception

Abstract

Stereoscopic endoscopes are widely used in minimally invasive cardiac surgery, providing 3D information of the thoracic cavity through small incisions. However, current high-precision 3D perception methods often reduce the flexibility of the endoscope, limiting its field of view. This study proposes a reconfigurable-baseline tip-flexible endoscope specifically designed for cardiac surgery, offering enhanced 3D perception capability. An anti-symmetric constraint architecture and a depth-driven baseline control method are adopted for high-precision 3D perception. Notably, it can adapt to multi-degree-of-freedom tip-flexible structures and constrained surgical environments without increasing the complexity of algorithms or sensors, thereby providing surgeons with greater operational space. In phantom-based experiments, the experimental group achieved a lower RMSE of 0.41 mm at 60–110 mm, compared to 0.58 mm in the control group. Similar results were observed in ex vivo tests, with RMSEs of 0.40 mm and 0.57 mm, respectively, reinforcing its clinical potential. External parameters remained within acceptable ranges, with the dominant error factor, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Delta \theta$</tex-math></inline-formula>, controlled to a RMSE of 0.01428<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula>. These results validate the proposed method and offer a new approach for high-precision 3D perception in minimally invasive surgery.