Efficient 2D-3D Matching for Multi-Camera Visual Localization

Visual localization, i.e., determining the position and orientation of a vehicle with respect to a map, is a key problem in autonomous driving. We present a multicamera visual inertial localization algorithm for large scale environments. To efficiently and effectively match features against a pre-built global 3D map, we propose a prioritized feature matching scheme for multi-camera systems. In contrast to existing works, designed for monocular cameras, we (1) tailor the prioritization function to the multi-camera setup and (2) run feature matching and pose estimation in parallel. This significantly accelerates the matching and pose estimation stages and allows us to dynamically adapt the matching efforts based on the surrounding environment. In addition, we show how pose priors can be integrated into the localization system to increase efficiency and robustness. Finally, we extend our algorithm by fusing the absolute pose estimates with motion estimates from a multi-camera visual inertial odometry pipeline (VIO). This results in a system that provides reliable and drift-less pose estimation. Extensive experiments show that our localization runs fast and robust under varying conditions, and that our extended algorithm enables reliable real-time pose estimation.Comment: 7 pages, 5 figure

Copolymerization of Mesoporous Styrene-Bridged Organosilica Nanoparticles with Functional Monomers for the Stimuli-Responsive Remediation of Water

For every mass product, there are problems associated with the resulting waste. Residues of hormones in urine cannot be removed sufficiently from wastewater, and this has undesired consequences. An ideal adsorbent would take up the impurity, enable a simple separation and recyclability. Polymer colloids with high affinity towards the drug, accessible porosity, high surface area, and stimuli-responsive properties would be candidates, but such a complex system does not exist. Here, porous vinyl-functionalized organosilica nanoparticles prepared from a styrene bridged sol-gel precursor act as monomers. Initiation of the polymerization at the pore walls and addition of functional monomers result in a special copolymer, which is covalently linked to the surface and covers it. An orthogonal modification of external surface was done by click attachment of a thermoresponsive polymer. The final core-shell system is able to remove quantitatively hydrophobic molecules such as the hormone progesterone from water. A change of temperature closes the pores and induces the aggregation of the particles. After separation one can reopen the particles and recycle them. © 2020 The Authors. Published by Wiley-VCH Gmb

On Geometric Constraints for Practical Visual Localization

Visual localization, i.e., determining an image pose with respect to a map, is a key problem for many applications such as autonomous navigation as well as augmented and virtual reality (AR/VR). With more and more of these applications evolving from a pure research interest to commercial products, academic methods are enhanced with engineering solutions to circumvent particularly difficult problems and boost overall performance. However, these new solutions also raise new challenges that need to be addressed. In this thesis we consider two of them, namely efficiency in localization with multi-camera systems, and privacy preservation in cloud-based localization systems. In particular, we demonstrate that carefully designed geometric constraints can provide benefits beyond improvements in just localization accuracy and recall. We show that considering both appearance and geometry in prioritized feature matching helps to find the best trade-off between a high likelihood to find correct associations and obtaining good geometric constraints from them. Additionally, we demonstrate that deliberate relaxation of some geometric constraints can be used to reliably hide private information with only a small impact on localization accuracy. First, we apply this relaxation in the first privacy-preserving localization and mapping pipeline to protect private information in the scene. Second, we adopt the relaxation approach to enable cloud-based localization without leaking the user’s pose to the server

Meso-Architecture Block Copolymers with High Surface Area Styrene-Bridged Organosilica Particles as Constituent for the Stimuli-Responsive Remediation of Water

The development of drugs for birth-control has changed society, and they are used by billions of woman on an every day basis. As for every mass product, there are problems associated with the waste it causes. One has found that residues of hormones in the urine of woman cannot be removed sufficiently from waste-water and this, in-turn, has already observable and undesired consequences in the biosphere. Apart from the removal of drugs, one is in general seeking new methods for the removal of hydrophobic impurities from waste-water. An ideal system would quantitatively take up the impurity, entrap it followed by preferably simple separation. Finally, one wants to reuse the absorbent, which implies the possibility for regeneration and recycling. Such as complex set of tasks requires a relatively complex materials architecture. Functional organic polymers with high affinity towards the drug, with stable open porosity and high surface area, stimuli-responsive properties and in the form of colloidal dispersions could do the job. Unfortunately, such a system does not exist. We solved this problem by generating mesoporous organosilica nanoparticles, which are monomers at the same time. Initiation of the polymerization reaction by surface-bound pore-walls leads to the formation of a special type of block-copolymer. The pore-walls are covered by the polymer, which cannot leach. An orthogonal modification was achieved by modification of the external surfaces of the particles with a thermoresponsive polymer by click-chemistry. The final core-shell system was able to remove hydrophobic molecules such as the hormone progesterone from water. A change of temperature induces the collapse of the thermoresponsive polymer, which closes the pores and induces aggregation of the particles. After separation of the particles, and thus also the entrapped impurity, from the solvent, one can re-open the pores, which leads to a release of the adsorbed compound(s)

Copolymerization of Mesoporous Styrene-Bridged Organosilica Nanoparticles with Functional Monomers for the Stimuli-Responsive Remediation of Water

For every mass product, there are problems associated with the resulting waste. Residues of hormones in urine cannot be removed sufficiently from wastewater, and this has undesired consequences. An ideal adsorbent would take up the impurity, enable a simple separation and recyclability. Polymer colloids with high affinity towards the drug, accessible porosity, high surface area and stimuli-responsive properties would be candidates, but such a complex system does not exist. Here, porous vinyl-functionalized organosilica nanoparticles prepared from a styrene bridged sol-gel precursor act as monomers. Initiation of the polymerization at the pore-walls and addition of functional monomers result in a special copolymer, which is covalently linked to the surface and covers it. An orthogonal modification of external surface was done by click attachment of a thermoresponsive polymer. The final core-shell system is able to remove quantitatively hydrophobic molecules such as the hormone progesterone from water. A change of temperature closes the pores and induces the aggregation of the particles. After separation one can reopen the particles and recycle them.publishe

Efficient 2D-3D Matching for Multi-Camera Visual Localization

Visual localization, i.e., determining the position and orientation of a vehicle with respect to a map, is a key problem in autonomous driving. We present a multi-camera visual inertial localization algorithm for large scale environments. To efficiently and effectively match features against a pre-built global 3D map, we propose a prioritized feature matching scheme for multi-camera systems. In contrast to existing works, designed for monocular cameras, we (1) tailor the prioritization function to the multi-camera setup and (2) run feature matching and pose estimation in parallel. This significantly accelerates the matching and pose estimation stages and allows us to dynamically adapt the matching efforts based on the surrounding environment. In addition, we show how pose priors can be integrated into the localization system to increase efficiency and robustness. Finally, we extend our algorithm by fusing the absolute pose estimates with motion estimates from a multi-camera visual inertial odometry pipeline (VIO). This results in a system that provides reliable and drift-less pose estimation. Extensive experiments show that our localization runs fast and robust under varying conditions, and that our extended algorithm enables reliable real-time pose estimation

Copolymerization of Mesoporous Styrene‐Bridged Organosilica Nanoparticles with Functional Monomers for the Stimuli‐Responsive Remediation of Water

For every mass product, there are problems associated with the resulting waste. Residues of hormones in urine cannot be removed sufficiently from wastewater, and this has undesired consequences. An ideal adsorbent would take up the impurity, enable a simple separation and recyclability. Polymer colloids with high affinity towards the drug, accessible porosity, high surface area and stimuli-responsive properties would be candidates, but such a complex system does not exist. Here, porous vinyl-functionalized organosilica nanoparticles prepared from a styrene bridged sol-gel precursor act as monomers. Initiation of the polymerization at the pore-walls and addition of functional monomers result in a special copolymer, which is covalently linked to the surface and covers it. An orthogonal modification of external surface was done by click attachment of a thermoresponsive polymer. The final core-shell system is able to remove quantitatively hydrophobic molecules such as the hormone progesterone from water. A change of temperature closes the pores and induces the aggregation of the particles. After separation one can reopen the particles and recycle them.publishe