Map Memory Management for Real-Time Displaying in Virtual Experience

In this paper, an application of simultaneous localization and mapping (SLAM) combined with visual reality (VR) is proposed to let the user experience and interact with an real environment through the headset with a mobile phone such that the user can easily visit the environment with cheaper equipment at any time. Compared with exploring an environment with general 2D map, the user can view the environment more realistically in an immersive manner. Here, an intensive map of environment with huge amount of point clouds, which is generated by employing the RTAB-Map SLAM with RGB-D cameras, is utilized to provide a more complete observation to the user than that of the sparse map. Since the memory of a mobile phone is limited and smaller than a personal computer, the data of whole map cannot be transmitted to the mobile phone once for VR displaying. Based on the architecture of memory management for detecting loop closure in the RTAB-Map SLAM, an efficient memory management for extracting the point cloud data to achieve the real-time VR displaying performance is designed by utilizing the Bayesian filtering and data clustering. The proposed approaches have been validated and analyzed in the experiments to present that our method can effectively reduce the memory usage for continuously and smoothly displaying the virtual scene.