In teleoperation systems, operator performance is negatively affected by time-delayed visual feedback. Predictive display (PD) compensates for delays by providing synthesized visual feedback. While most existing PD methods rely on a priori models (e.g., from laser range finding or stereo vision), recent work on monocular SLAM and SFM makes it possible to acquire PD models in single camera applications. In this work, we evaluate operator performance of PD visual feedback based on a coarse 3D model. We report the experimental results of 12 human tele-operators each performing 96 visual alignment tasks with a 300ms delay. Four operating modes are considered: delayed video (no PD), video-based PD using a stabilizing plane (homography), 3D model-based PD, and no delay (ground truth). The results indicate that vision-based PD (both plane and 3D model-based) is significantly better than delayed video. It reduced task completion time 40% and is nearly as good as the no delay condition. PD based on a sparse a 3D model was somewhat better than the simpler plane based method.

To tele-operate a robot, visual feedback is critical. However, communication channel latency can delay feedback to the point where the operator is impeded in performing his task. This work presents a vision-based “predictive display” system that compensates for visual delay. The approach is online and relatively uncalibrated, thus it has the advantage of being useful in unknown environments and many applications. From monocular eye-in-hand video, we incrementally compute a 3D graphics model of the robot site in real time using our new technique. The method exploits free-space/occlusion constraints on the scene to produce a physically consistent mesh. Novel vantage points are immediately rendered in response to the operator's control commands, without waiting for delayed video. We implement a full prototype tele-operation system where the operator controls, via a PHANTOM Omni device, a Barrett WAM robot mounted on a mobile Segway. Experiments with this setup validate the efficacy of the proposed approach. We demonstrate significant improvement in task completion time with predictive display on a real robot, while our previous related results were established only in simulation.