Real-Time Camera Localization during Robot-Assisted Telecystoscopy for Bladder Cancer Surveillance

作     者：Gong, Chen Zhou, Yaxuan Lewis, Andrew Chen, Pengcheng Speich, Jason R. Porter, Michael P. Hannaford, Blake Seibel, Eric J. 

作者机构：Mechanical Engineering University of Washington 3900 E Stevens Way NE Seattle 98195 WA United States Electrical and Computer Engineering University of Washington 185 W Stevens Way NE Seattle 98195 WA United States Center for Research and Education in Simulation Technologies (CREST) University of Washington 1959 NE Pacific St. Seattle 98195 WA United States Department of Urology University of Washington 1959 NE Pacific St. Seattle 98195 WA United States 

出 版 物：《Journal of Medical Robotics Research》 (J. Med. Robotics Res.)

年 卷 期：2022年第7卷第2-3期

主　　题：3D reconstruction camera re-localization image retrieval Telecystoscopy telemedicine 

摘      要：Telecystoscopy can lower the barrier to access critical urologic diagnostics for patients around the world. A major challenge for robotic control of flexible cystoscopes and intuitive teleoperation is the pose estimation of the scope tip. We propose a novel real-time camera localization method using video recordings from a prior cystoscopy and 3D bladder reconstruction to estimate cystoscope pose within the bladder during follow-up telecystoscopy. We map prior video frames into a low-dimensional space as a dictionary so that a new image can be likewise mapped to efficiently retrieve its nearest neighbor among the dictionary images. The cystoscope pose is then estimated by the correspondence among the new image, its nearest dictionary image, and the prior model from 3D reconstruction. We demonstrate performance of our methods using bladder phantoms with varying fidelity and a servo-controlled cystoscope to simulate the use case of bladder surveillance through telecystoscopy. The servo-controlled cystoscope with 3 degrees of freedom (angulation, roll, and insertion axes) was developed for collecting cystoscope videos from bladder phantoms. Cystoscope videos were acquired in a 2.5D bladder phantom (bladder-shape cross-section plus height) with a panorama of a urothelium attached to the inner surface. Scans of the 2.5D phantom were performed in separate arc trajectories each of which is generated by actuation on the angulation with a fixed roll and insertion length. We further included variance in moving speed, imaging distance and existence of bladder tumors. Cystoscope videos were also acquired in a water-filled 3D silicone bladder phantom with hand-painted vasculature. Scans of the 3D phantom were performed in separate circle trajectories each of which is generated by actuation on the roll axis under a fixed angulation and insertion length. These videos were used to create 3D reconstructions, dictionary sets, and test data sets for evaluating the computational effici