Paper accepted at ICIP 2021

We are happy to announce that our paper “SEMANTIC SEGMENTATION IN DEPTH DATA : A COMPARATIVE EVALUATION OF IMAGE AND POINT CLOUD BASED METHODS” has been accepted for publication at the ICIP 2021 IEEE International Conference on Image Processing which will take place from September 19th to 22nd, 2021 at Anchorage, Alaska, USA.

Abstract: The problem of semantic segmentation from depth images can be addressed by segmenting directly in the image domain or at 3D point cloud level. In this paper, we attempt for the first time to provide a study and experimental comparison of the two approaches. Through experiments on three datasets, namely SUN RGB-D, NYUdV2 and TICaM, we extensively compare various semantic segmentation algorithms, the input to which includes images and point clouds derived from them. Based on this, we offer analysis of the performance and computational cost of these algorithms that can provide guidelines on when each method should be preferred.

Authors: Jigyasa Katrolia, Lars Krämer, Jason Rambach, Bruno Mirbach, Didier Stricker



Paper Accepted at CVPR 2021 Conference!

We are proud that our paper “RPSRNet: End-to-End Trainable Rigid Point Set Registration Network using Barnes-Hut 2^D-Tree Representation” has been accepted for publication at the Computer Vision Pattern Recognition (CVPR) 2021 Conference, which will take place virtually online from June 19th to 25th. CVPR is the premier annual computer vision conference. Our paper was accepted from ~12000 submissions as one of 23.4% (acceptance rate: 23.4%).

Abstract: We propose RPSRNet – a novel end-to-end trainable deep neural network for rigid point set registration. For this task, we use a novel 2^D-tree representation for the input point sets and a hierarchical deep feature embedding in the neural network. An iterative transformation refinement module of our network boosts the feature matching accuracy in the intermediate stages. We achieve an inference speed of ~12-15$\,$ms to register a pair of input point clouds as large as ~250K. Extensive evaluations on (i) KITTI LiDAR-odometry and (ii) ModelNet-40 datasets show that our method outperforms prior state-of-the-art methods – e.g., on the KITTI dataset, DCP-v2 by 1.3 and 1.5 times, and PointNetLK by 1.8 and 1.9 times better rotational and translational accuracy respectively. Evaluation on ModelNet40 shows that RPSRNet is more robust than other benchmark methods when the samples contain a significant amount of noise and disturbance. RPSRNet accurately registers point clouds with non-uniform sampling densities, e.g., LiDAR data, which cannot be processed by many existing deep-learning-based registration methods.

“Rigid Point Set Registration using Barnes-Hut (BH) 2^D-tree
Representation — The center-of-masses (CoMs) and point-densities of
non-empty tree-nodes are computed for the respective BH-trees of the
source and target. These two attributes are input to our RPSRNet which
predicts rigid transformation from the global feature-embedding of the

Authors: Sk Aziz Ali, Kerem Kahraman, Gerd ReisDidier Stricker

To view the paper, please click here.

Paper Accepted in IEEE Access Journal!

We are happy to announce that our paper “Fast Gravitational Approach for Rigid Point Set Registration With Ordinary Differential Equations” has been accepted for publication in the IEEE Access Journal (Impact Factor: 3.745).

Abstract: This article introduces a new physics-based method for rigid point set alignment called Fast Gravitational Approach (FGA). In FGA, the source and target point sets are interpreted as rigid particle swarms with masses interacting in a globally multiply-linked manner while moving in a simulated gravitational force field. The optimal alignment is obtained by explicit modeling of forces acting on the particles as well as their velocities and displacements with second-order ordinary differential equations of n-body motion. Additional alignment cues can be integrated into FGA through particle masses. We propose a smooth-particle mass function for point mass initialization, which improves robustness to noise and structural discontinuities. To avoid the quadratic complexity of all-to-all point interactions, we adapt a Barnes-Hut tree for accelerated force computation and achieve quasilinear complexity. We show that the new method class has characteristics not found in previous alignment methods such as efficient handling of partial overlaps, inhomogeneous sampling densities, and coping with large point clouds with reduced runtime compared to the state of the art. Experiments show that our method performs on par with or outperforms all compared competing deep-learning-based and general-purpose techniques (which do not take training data) in resolving transformations for LiDAR data and gains state-of-the-art accuracy and speed when coping with different data.

Authors: Sk Aziz Ali, Kerem Kahraman, Christian Theobalt, Didier StrickerVladislav Golyanik

Link to the paper: