Abstract In this paper, we introduce an innovative method to improve the convergence speed and accuracy of object detection neural networks. Our approach, Converge-Fast-Auxnet, is based on employing multiple, dependent loss metrics and weighting them optimally using an on-line trained auxiliary network. Experiments are performed in the well-known RoboCup@Work challenge environment. A fully convolutional segmentation network is trained on detecting objects' pickup points. We empirically obtain an approximate measure for the rate of success of a robotic pickup operation based on the accuracy of the object detection network. Our experiments show that adding an optimally weighted Euclidean distance loss to a network trained on the commonly used Intersection over Union (IoU) metric reduces the convergence time by 42.48%. The estimated pickup rate is improved by 39.90%. Compared to state-of-the-art task weighting methods, the improvement is 24.5% in convergence, and 15.8% on the estimated pickup rate. Continue reading...

Abstract In this paper, we introduce a SLAM front end called NOctoSLAM. The approach adopts an octree-based map representation that implicitly enables source and reference data association for point to plane ICP registration. Additionally, the data structure is used to group map points to approximate surface normals. The multi-resolution capability of octrees, achieved by aggregating information in parent nodes, enables us to compensate for spatially unbalanced sensor data typically provided by multi-line lidar sensors. The octree-based data association is only approximate, but our empirical evaluation shows that NOctoSLAM achieves the same pose estimation accuracy as a comparable, point cloud based approach. However, NOctoSLAM can perform twice as many registration iterations per time unit. In contrast to point cloud based surface normal maps, where the map update duration depends on the current map size, we achieve a constant map update duration including surface normal recalculation. Therefore, NOctoSLAM does not require elaborate and environment dependent data filters. The results of our experiments show a mean positional error of 0.029 m and 0.019 rad, with a low standard deviation of 0.005 m and 0.006 rad, outperforming the state-of-the-art by remaining accurate while running online. Continue reading...