Construction of hybrid visual map for indoor SLAM

Our previous work, SLAM with visual plane, allowed correct data association and computationally feasible solution for vision-based SLAM. In this paper, we propose a scheme of generating a hybrid visual map based on the visual plane framework. The hybrid visual map has two levels of map representations: 1) absolute map representation of distinctive visual planes via EKF-SLAM and 2) relative map representation of dense visual features for each visual plane via sparse information filter update. It can inherit the advantages of the visual plane by maintaining the absolute map. Moreover, the relative map can reconstruct a 3-D map of visual features efficiently without loosing dense visual information. The performance of the proposed method was verified by the experimental results of consistent hybrid visual maps in two real indoor environments.