Welcome



Welcome to the Computer Graphics Group at RWTH Aachen University!

The research and teaching activities at our institute focus on geometry acquisition and processing, on interactive visualization, and on related areas such as computer vision, photo-realistic image synthesis, and ultra high speed multimedia data transmission.

In our projects we are cooperating with various industry companies as well as with academic research groups around the world. Results are published and presented at high-profile conferences and symposia. Additional funding sources, among others, are the Deutsche Forschungsgemeinschaft and the European Union.

News

We have two papers on Quad Meshes and Quad Layouts at SIGGRAPH Asia 2014

Sept. 15, 2014

gamescom 2014

Our group will be presenting at the "gamescom" fair in Cologne again this year from 8/13/2014 till 8/17/2014. We will give an insight into our activities and inform about possibilities of studying graphics-centered computer science at RWTH Aachen University and how this will prepare (not only) for work in the games industry. Of course, we will also have something to play at our booth. More information

July 24, 2014

We have a paper on Mobile Localization at ECCV 2014.

July 7, 2014

We have a paper on Quad Layout Optimization in Computer Graphics Forum.

June 20, 2014

Zometool Shape Approximation

We have two new publications (TVCG 2014 and GMOD/GMP 2014) on freeform shape approximation using the Zometool system. Please see the project page for more information. UPDATE: Now with Windows binaries (and source code) for a 3D Viewer to interactively view the resulting Zome meshes.

April 25, 2014

3D Model of Aachens Cathedral

In cooperation with the Domkapitel Aachen we constructed an information kiosk, placed in the "Dom-Information". Visitors can interactively explore a 3D Model of Aachens cathedral, which is made from laser scans and photos. A Video showing a flight through the cathedral can be downloaded from here.

April 24, 2014

Recent Publications

Scalable 6-DOF Localization on Mobile Devices

13th European Conference on Computer Vision (ECCV'14)

Recent improvements in image-based localization have produced powerful methods that scale up to the massive 3D models emerging from modern Structure-from-Motion techniques. However, these approaches are too resource intensive to run in real-time, let alone to be implemented on mobile devices. In this paper, we propose to combine the scalability of such a global localization system running on a server with the speed and precision of a local pose tracker on a mobile device. Our approach is both scalable and drift-free by design and eliminates the need for loop closure. We propose two strategies to combine the information provided by local tracking and global localization. We evaluate our system on a large-scale dataset of the historic inner city of Aachen where it achieves interactive framerates at a localization error of less than 50cm while using less than 5MB of memory on the mobile device.

 

Efficient Enforcement of Hard Articulation Constraints in the Presence of Closed Loops and Contacts

Eurographics 2014

In rigid body simulation, one must distinguish between contacts (so-called unilateral constraints) and articulations (bilateral constraints). For contacts and friction, iterative solution methods have proven most useful for interactive applications, often in combination with Shock-Propagation in cases with strong interactions between contacts (such as stacks), prioritizing performance and plausibility over accuracy. For articulation constraints, direct solution methods are preferred, because one can rely on a factorization with linear time complexity for tree-like systems, even in ill-conditioned cases caused by large mass-ratios or high complexity. Despite recent advances, combining the advantages of direct and iterative solution methods wrt. performance has proven difficult and the intricacy of articulations in interactive applications is often limited by the convergence speed of the iterative solution method in the presence of closed kinematic loops (i.e. auxiliary constraints) and contacts. We identify common performance bottlenecks in the dynamic simulation of unilateral and bilateral constraints and are able to present a simulation method, that scales well in the number of constraints even in ill-conditioned cases with frictional contacts, collisions and closed loops in the kinematic graph. For cases where many joints are connected to a single body, we propose a technique to increase the sparsity of the positive definite linear system. A solution to these bottlenecks is presented in this paper to make the simulation of a wider range of mechanisms possible in real-time without extensive parameter tuning.

 

Dense 3D Semantic Mapping of Indoor Scenes from RGB-D Images

IEEE International Conference on Robotics and Automation (ICRA'14)

Dense semantic segmentation of 3D point clouds is a challenging task. Many approaches deal with 2D semantic segmentation and can obtain impressive results. With the availability of cheap RGB-D sensors the field of indoor semantic segmentation has seen a lot of progress. Still it remains unclear how to deal with 3D semantic segmentation in the best way. We propose a novel 2D-3D label transfer based on Bayesian updates and dense pairwise 3D Conditional Random Fields. This approach allows us to use 2D semantic segmentations to create a consistent 3D semantic reconstruction of indoor scenes. To this end, we also propose a fast 2D semantic segmentation approach based on Randomized Decision Forests. Furthermore, we show that it is not needed to obtain a semantic segmentation for every frame in a sequence in order to create accurate semantic 3D reconstructions. We evaluate our approach on both NYU Depth datasets and show that we can obtain a significant speed-up compared to other methods.

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