An Improved Loop Closure Detection Algorithm Based on Scene Salient Regions

An improved loop closure detection algorithm based on scene salient regions is proposed for VSLAM (visual simultaneous localization and mapping) loop closures without consistent path and similar camera view. Firstly, a scene salient region based loop closure detection architecture is structured together with its probabilistic model. Then a key frame selecting method which combines feature tracking rate and RGB histogram matching is proposed to reduce the detection information redundancy. Next, a pre-matched scene selecting method based on inverted index is presented, which greatly improves the real-time performance of loop closure detection. Finally, according to the geometric property of the salient region in this paper, a geometric matching probability in observation is introduced to improve the algorithm's ability of distinguishing perceptual aliasing scenes. The comparative experiments show that the proposed algorithm gets a better recall ratio compared with FAB-MAP 2.0 in a condition of high precision and good real-time performance, when facing loop closures without consistent path and similar camera view.