UBC Theses and Dissertations
A stereoscopic "pickup" camera for the da Vinci surgical system Avinash, Apeksha
Visualization in robot-assisted minimally invasive surgery, performed with the da Vinci surgical system, is through a single stereo endoscope. The endoscope’s stereoscopic vision provides the surgeon with a sense of depth which is critical for surgery. Stereoscopic camera separation, or baseline, contributes to this perception and research in related fields has shown the benefits of an increased camera baseline. Minute surgical incisions, however, restrict current endoscopic baselines to small values. Furthermore, current clinical endoscopes have only four degrees of freedom within the surgical cavity, limiting the viewing angles provided. Restricted endoscopic movement, along with complex tumours, can make surgeries like partial nephrectomy (removal of kidney tumours) challenging. To overcome these limitations, alternate cameras have been proposed in the literature. One consistent drawback across the proposed research, however, is the lack of visual-motor alignment when working with these alternate camera views, bringing unnecessary mental strain to the surgeon. In this thesis, we present a stereoscopic "pickup" camera that has been designed to specifically address the endoscopic limitations outlined above. The camera has a special grasping interface that mates securely with a surgical instrument, and offers six degrees of freedom to provide a wider range of positions and angles to view the surgical site from. We also present a method to establish visual-motor aligned control of surgical instruments when viewing the surgical cavity through the "pickup" camera. Additionally, the placement of stereo cameras on the lateral side of the "pickup" camera's cylindrical body provides an opportunity to employ a larger camera baseline to improve the perception of depth. Two experimental user studies were conducted to validate the proposed system. First, the performance gained when visual-motor alignment is established with respect to the "pickup" camera is clearly exhibited with a 72.9% improvement in completion time and 80% improvement in accuracy. Secondly, the effect of an increased camera baseline on depth perception is studied. The results show that, over 28 subjects, depth perception was the strongest with a 20 mm baseline, which cannot be achieved with current endoscopic technology. The study also demonstrated that such large baselines, however, can be achieved with our "pickup" camera.
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