Deblurring Shaken and Partially Saturated Images

We address the problem of deblurring images degraded by camera shake blur and saturated (over-exposed) pixels. Saturated pixels violate the common assumption that the image-formation process is linear, and often cause ringing in deblurred outputs. We provide an analysis of ringing in general, and show that in order to prevent ringing, it is insufficient to simply discard saturated pixels. We show that even when saturated pixels are removed, ringing is caused by attempting to estimate the values of latent pixels that are brighter than the sensor’s maximum output. Estimating these latent pixels is likely to cause large errors, and these errors propagate across the rest of the image in the form of ringing. We propose a new deblurring algorithm that locates these error-prone bright pixels in the latent sharp image, and by decoupling them from the remainder of the latent image, greatly reduces ringing. In addition, we propose an approximate forward model for saturated images, which allows us to estimate these error-prone pixels separately without causing artefacts. Results are shown for non-blind deblurring of real photographs containing saturated regions, demonstrating improved deblurred image quality compared to previous work.     

New aspects in cationization of lignocellulose materials. IX. Flame retardancy effect of modification with nitrogen and sulfur containing groups

Lignocellulose materials were modified with 3-chlor-2-hydroxypropyltrimethylammoniumchloride, 1,3-bis(3-chlor-2-hydroxypropyl)imidazoliumhydrogensulphate, and 2-chlorethyl-sodiumsulphonate and the flame-retardant properties of materials obtained were studied. The flame-retardant effect was proved using the limited oxygen index (LOI) method and values up to 32.8 vol % of oxygen were determined. The LOI values were higher when the modification was done without using NaOH for activation, but in that case the alkylating groups were not chemically bonded to the material. The NaOH activation was necessary to obtain material with flame-retardant properties stable against washing. No synergistic effects were observed when the material was modified with both nitrogen- and sulfur-containing groups.     

Automatic annotation of tennis games: An integration of audio,vision, and learning

Fully automatic annotation of tennis game using broadcast video is a task with a great potential but with enormous challenges. In this paper we describe our approach to this task, which integrates computer vision, machine listening, and machine learning. At the low level processing, we improve upon our previously proposed state-of-the-art tennis ball tracking algorithm and employ audio signal processing techniques to detect key events and construct features for classifying the events. At high level analysis, we model event classification as a sequence labelling problem, and investigate four machine learning techniques using simulated event sequences. Finally, we evaluate our proposed approach on three real world tennis games, and discuss the interplay between audio, vision and learning. To the best of our knowledge, our system is the only one that can annotate tennis game at such a detailed level.     

Towards a Trajectory Planning Concept: Augmenting Path Planning Methods by Considering Speed Limit Constraints

Trajectory planning is an essential part of systems controlling autonomous entities such as vehicles or robots. It requires not only finding spatial curves but also that dynamic properties of the vehicles (such as speed limits for certain maneuvers) must be followed. In this paper, we present an approach for augmenting existing path planning methods to support basic dynamic constraints, concretely speed limit constraints. We apply this approach to the well known A* and state-of-the-art Theta* and Lazy Theta* path planning algorithms. We use a concept of trajectory planning based on a modular architecture in which spatial and dynamic parts can be easily implemented. This concept allows dynamic aspects to be processed during planning. Existing systems based on a similar concept usually add dynamics (velocity) into spatial curves in a post-processing step which might be inappropriate when the curves do not follow the dynamics. Many existing trajectory planning approaches, especially in mobile robotics, encode dynamic aspects directly in the representation (e.g. in the form of regular lattices) which requires a precise knowledge of the environmental and dynamic properties of particular autonomous entities making designing and implementing such trajectory planning approaches quite difficult. The concept of trajectory planning we implemented might not be as precise but the modular architecture makes the design and implementation easier because we can use (modified) well known path planning methods and define models of dynamics of autonomous entities separately. This seems to be appropriate for simulations used in feasibility studies for some complex autonomous systems or in computer games etc. Our basic implementation of the augmented A*, Theta* and Lazy Theta* algorithms is also experimentally evaluated. We compare (i) the augmented and basic A*, Theta* and Lazy Theta* algorithms and (ii) optimizing of augmented Theta* and Lazy Theta* for distance (the trajectory length) and duration (time needed to move through the trajectory).     

Fault-Tolerant Formation Driving Mechanism Designed for Heterogeneous MAVs-UGVs Groups

A fault-tolerant method for stabilization and navigation of 3D heterogeneous formations is proposed in this paper. The presented Model Predictive Control (MPC) based approach enables to deploy compact formations of closely cooperating autonomous aerial and ground robots in surveillance scenarios without the necessity of a precise external localization. Instead, the proposed method relies on a top-view visual relative localization provided by the micro aerial vehicles flying above the ground robots and on a simple yet stable visual based navigation using images from an onboard monocular camera. The MPC based schema together with a fault detection and recovery mechanism provide a robust solution applicable in complex environments with static and dynamic obstacles. The core of the proposed leader-follower based formation driving method consists in a representation of the entire 3D formation as a convex hull projected along a desired path that has to be followed by the group. Such an approach provides non-collision solution and respects requirements of the direct visibility between the team members. The uninterrupted visibility is crucial for the employed top-view localization and therefore for the stabilization of the group. The proposed formation driving method and the fault recovery mechanisms are verified by simulations and hardware experiments presented in the paper.     

Rückgewinnung von Metallen aus niedrigkonzentrierten Lösungen

Recycling of metals from low concentrated solutions. A review is given of processes used for the separation of metals from aqueous solutions, especially low concentration waste waters. Purification processes for waste water used only to reach values set by law are compared with processes that allow recovery of metals. Precipitation with and without additives, adsorption, processes with ion exchange resins, solvent extraction and membrane processes, especially liquid membrane permeation, are described. As a result of these considerations, a qualitative comparison of all the described processes becomes possible. For the separation of zinc from a waste water stream, a special economic comparison is also shown between precipitation processes and the liquid membrane permeation process. Finally, the latest developments in the fields of solvent extraction and liquid membrane permeation are discussed.     

Experimental observation of temperature gradients occurring in a single zeolite pellet

An experimental study has been made of temperature profiles incident within a zeolite adsorbent particle in the course of adsorption of n-heptan. Using thermocouple wires 0.1 mm in diameter it has been possible to measure simultaneously the temperatures of the surface and in the centre. It was observed that temperature differences between center of the pellet and ambient stagnant gas may be more than 20°C. The results of this work indicate that the overheating of an adsorbent particle is a very rapid process which is followed by a slow cooling of the hot particle. Experimental data are compared with predictions calculated from the theoretical model.     

Structure Development of NiO–YSZ Oxide Mixtures in Simulated Citrate–Nitrate Combustion Synthesis

Yttria-stabilized zirconia (NiO/YSZ) composites were prepared by the modified citrate–nitrate combustion synthesis. The citrate–nitrate combustion proceeded through several consecutive steps. Evolution of structure in the system and its changes were followed up by thermogravimetry-differential scanning calorimetry, X-ray powder diffraction, extended X-ray absorption fine structure, and high resolution transmission electron microscopy analyses of intermediate products prepared at distinct temperatures that correspond to different stages of the combustion process. It was shown that the crystalline structure developed gradually, first with crystallization of nano-sized NiO particles (400°–700°C), which was followed by crystallization of YSZ (800°–900°C). The final composite material after heat treatment at 1100°C comprised of nano-crystals with an average size of 6.5±2 nm.     

Synthesis, structure and magnetic properties of β-MnO 2 nanorods

We present synthesis, structure and magnetic properties of structurally well-ordered single-crystalline β-MnO₂ nanorods of 50–100 nm diameter and several μm length. Thorough structural characterization shows that the basic β-MnO₂ material is covered by a thin surface layer (∼2.5 nm) of α-Mn₂O₃ phase with a reduced Mn valence that adds its own magnetic signal to the total magnetization of the β-MnO₂ nanorods. The relatively complicated temperature-dependent magnetism of the nanorods can be explained in terms of a superposition of bulk magnetic properties of spatially segregated β-MnO₂ and α-Mn₂O₃ constituent phases and the soft ferromagnetism of the thin interface layer between these two phases.     

Physical crosslinking effects in α,ω-dihydroxy terminated polybutadienes

Structure and molecular dynamics of α,ω-dihydroxy terminated polybutadienes of varying number averaged molecular weight (1320-10?500 g/mol) have been investigated by Fourier-transformed infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, dielectric relaxation spectroscopy (DRS), differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS). DSC and DRS revealed an increase in the glass transition temperature upon decrease of the molecular weight, accompanied by an increasing dynamic fragility m (or steepness index) of the dielectric α-process. This correlation between T_g and m for different molecular weights indicates the presence of a physical network, where H-bonded end-group clusters act as temporary crosslinks. From the dielectric relaxation strength Δ?_α(M_n), the fraction of associated hydroxy groups (f_bond) was estimated showing a peak value for the two but shortest polymers, a behaviour that strongly resembles the molecular weight dependence of the fragility. By considering the quantity f_bond(M_n) in a modified Fox-Flory approach, the measured T_g(M_n) behaviour could be reproduced in a satisfying way. FTIR results support this general picture and show a considerable dependence of the extent of hydrogen bonding and formation of hydroxy groups associates on the molecular weight. Further, WAXS and DSC results disprove the idea of formation of pseudo-crystalline hydrophobic microdomains in these compounds as suggested by other authors.