Online occlusion-free optimization scheme for active optical navigation system in robotic orthopedic surgeries

In robotic orthopedic surgeries, the intraoperative optical tracking system (OTS) is widely used to obtain the spatial relationship between the patient's lesion and surgical instrument via the use of positioning tools. Usually, the OTS remains stationary during surgery. If the line of sight (LoS) occlusion occurs, the surgery will be interrupted. To address this issue, this paper proposes a novel optimization scheme to proactively adjust the OTS viewpoint before occlusion occurs, guaranteeing that the LoS remains unobstructed by the occluder. To simplify the analysis process, the excessive number of LoSs from the OTS to the positioning tools are replaced by visual cone (VC) models. Subsequently, an optimization scheme is formulated to generate a desired viewpoint for the OTS and an occlusion-free adjusting trajectory for the navigation robot. Ultimately, the effectiveness of the proposed method is validated via simulations and experiments. Experimental results show that the proposed method is capable of maintaining the occlusion-free between VCs and the occluder as the occluder approaches the VCs. This active navigation technique is promising for the safe operations of robotic orthopedic surgeries.