SurgPose: Generalisable Surgical Instrument Pose Estimation using Zero-Shot Learning and Stereo Vision
Utsav Rai, Haozheng Xu, Stamatia Giannarou
TL;DR
This work tackles the lack of generalisable 6DoF pose estimation for unseen surgical instruments in RMIS by introducing a zero-shot RGB-D pipeline that combines stereo depth from RAFT-Stereo with an enhanced Mask R-CNN segmentation for improved mask quality. The method replaces SAM in SAM-6D with a fine-tuned Mask R-CNN and leverages pseudo-labels from CAD projections refined by depth disparity, enabling effective zero-shot pose estimation without instrument-specific retraining. Extensive experiments on a new surgical instrument dataset show the proposed approach outperforms state-of-the-art zero-shot models in occluded scenarios and achieves competitive, sometimes superior, 2D projection accuracy, validating practical applicability in reflective, cluttered RMIS environments. The results demonstrate the viability of RGB-D zero-shot methods for RMIS, highlighting the importance of accurate segmentation, stereo depth, and synthetic data augmentation for generalisability and reliability.
Abstract
Accurate pose estimation of surgical tools in Robot-assisted Minimally Invasive Surgery (RMIS) is essential for surgical navigation and robot control. While traditional marker-based methods offer accuracy, they face challenges with occlusions, reflections, and tool-specific designs. Similarly, supervised learning methods require extensive training on annotated datasets, limiting their adaptability to new tools. Despite their success in other domains, zero-shot pose estimation models remain unexplored in RMIS for pose estimation of surgical instruments, creating a gap in generalising to unseen surgical tools. This paper presents a novel 6 Degrees of Freedom (DoF) pose estimation pipeline for surgical instruments, leveraging state-of-the-art zero-shot RGB-D models like the FoundationPose and SAM-6D. We advanced these models by incorporating vision-based depth estimation using the RAFT-Stereo method, for robust depth estimation in reflective and textureless environments. Additionally, we enhanced SAM-6D by replacing its instance segmentation module, Segment Anything Model (SAM), with a fine-tuned Mask R-CNN, significantly boosting segmentation accuracy in occluded and complex conditions. Extensive validation reveals that our enhanced SAM-6D surpasses FoundationPose in zero-shot pose estimation of unseen surgical instruments, setting a new benchmark for zero-shot RGB-D pose estimation in RMIS. This work enhances the generalisability of pose estimation for unseen objects and pioneers the application of RGB-D zero-shot methods in RMIS.
