Towards Noise Resilient SLAM

Sparse-indirect SLAM systems have been dominantly popular due to their computational efficiency and photometric invariance properties. Depth sensors are critical to SLAM frameworks for providing scale information to the 3D world, yet known to be plagued by a wide variety of noise sources, possessing lateral and axial components. In this work, we demonstrate the detrimental impact of these depth noise components on the performance of the state-of-the-art sparse-indirect SLAM system (ORB-SLAM2). We propose (i) Map-Point Consensus based Outlier Rejection (MC-OR) to counter lateral noise, and (ii) Adaptive Virtual Camera (AVC) to combat axial noise accurately. MC-OR utilizes consensus information between multiple sightings of the same landmark to disambiguate noisy depth and filter it out before pose optimization. In AVC, we introduce an error vector as an accurate representation of the axial depth error. We additionally propose an adaptive algorithm to find the virtual camera location for projecting the error used in the objective function of the pose optimization. Our techniques work equally well for stereo image pairs and RGB-D input directly used by sparse-indirect SLAM systems. Our methods were tested on the TUM (RGB-D) and EuRoC (stereo) datasets and we show that they outperform existing state-of-the-art ORB-SLAM2 by 2-3x, especially in sequences critically affected by depth noise.