External localization system for mobile robotics

We present a fast and precise vision-based software intended for multiple robot localization. The core component of the proposed localization system is an efficient method for black and white circular pattern detection. The method is robust to variable lighting conditions, achieves sub-pixel precision, and its computational complexity is independent of the processed image size. With off-the-shelf computational equipment and low-cost camera, its core algorithm is able to process hundreds of images per second while tracking hundreds of objects with millimeter precision. We propose a mathematical model of the method that allows to calculate its precision, area of coverage, and processing speed from the camera’s intrinsic parameters and hardware’s processing capacity. The correctness of the presented model and performance of the algorithm in real-world conditions are verified in several experiments. Apart from the method description, we also publish its source code; so, it can be used as an enabling technology for various mobile robotics problems

Survey and Evaluation of Advanced Mobility Management Schemes in the Host Identity Layer

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Low-cost embedded system for relative localization in robotic swarms

In this paper, we present a small, light-weight, low-cost, fast and reliable system designed to satisfy requirements of relative localization within a swarm of micro aerial vehicles. The core of the proposed solution is based on off-the-shelf components consisting of the Caspa camera module and Gumstix Overo board accompanied by a developed efficient image processing method for detecting black and white circular patterns. Although the idea of the roundel recognition is simple, the developed system exhibits reliable and fast estimation of the relative position of the pattern up to 30 fps using the full resolution of the Caspa camera. Thus, the system is suited to meet requirements for a vision based stabilization of the robotic swarm. The intent of this paper is to present the developed system as an enabling technology for various robotic tasks

Simple yet stable bearing-only navigation

This article describes a simple monocular navigation system for a mobile robot based on the map-and-replay technique. The presented method is robust and easy to implement and does not require sensor calibration or structured environment, and its computational complexity is independent of the environment size. The method can navigate a robot while sensing only one landmark at a time, making it more robust than other monocular approaches. The aforementioned properties of the method allow even low-cost robots to effectively act in large outdoor and indoor environments with natural landmarks only. The basic idea is to utilize a monocular vision to correct only the robot's heading, leaving distance measurements to the odometry. The heading correction itself can suppress the odometric error and prevent the overall position error from diverging. The influence of a map-based heading estimation and odometric errors on the overall position uncertainty is examined. A claim is stated that for closed polygonal trajectories, the position error of this type of navigation does not diverge. The claim is defended mathematically and experimentally. The method has been experimentally tested in a set of indoor and outdoor experiments, during which the average position errors have been lower than 0.3 m for paths more than 1 km long

FPGA based speeded up robust features

We present an implementation of the Speeded Up Robust Features (SURF) on a Field Programmable Gate Array (FPGA). The SURF algorithm extracts salient points from image and computes descriptors of their surroundings that are invariant to scale, rotation and illumination changes. The interest point detection and feature descriptor extraction algorithm is often used as the first stage in autonomous robot navigation, object recognition and tracking etc. However, detection and extraction are computationally demanding and therefore can't be used in systems with limited computational power. We took advantage of algorithm's natural parallelism and implemented it's most demanding parts in FPGA logic. Several modifications of the original algorithm have been made to increase it's suitability for FPGA implementation. Experiments show, that the FPGA implementation is comparable in terms of precision, speed and repeatability, but outperforms the CPU and GPU implementation in terms of power consumption. Our implementation is intended to be used in embedded systems which are limited in computational power or as the first stage preprocessing block, which allows the computational resources to focus on higher level algorithms

Királis vegyületek szintézise poláris fémorganikus vegyületek regio- és sztereoszelektív reakcióival = Synthesis of Chiral Compounds via Regio- and Stereoselective Reactions of Polar Organometallics

A kutatómunka során hatékony szintetikus módszereket dolgoztunk ki atropizomériát mutató új 1-arilpirrol-származékok előállítására poláris fémorganikus reagensekkel. Három kulcsintermedier optikai izomerjeinek rezolválását oldottuk meg és az enantiomerek abszolút konfigurációit röntgendiffrakció és CD-spektroszkópia segítségével meghatároztuk. Szintetikus módszereket dolgoztunk ki az optikailag aktív 1-arilpirrol-származékok további kémiai átalakításaira, és több új, az irodalomban eddig nem ismert bifunkciós vegyületet állítottunk elő. Az atropizomerek sztereokémiai stabilitását moklekulamodellezéssel becsültük meg az eredményeket néhány esetben összevetettük az NMR-mérésekkel kapott kísérleti adatokkal. Új kinetikus rezolválási módszereket dolgoztunk ki optikailag aktív 2-benziloximetil-3-helyettesített-oxiránok előállítására, majd fémorganikus bázisok jelenlétében megvalósítottuk enantioszelektív átrendeződési reakcióikat. A kapott optikailag aktív oxetánokból és cisz-but-2-én-1,4-diol-származékokból optikailag aktív heterociklusokat (pirrolidin, pirrolin, stb) állítottunk elő. A kutatási eredményeket új, biológiai tesztelésre átadott vegyületek szintézisében hasznosítottuk és tesztreakciókat végeztünk a bifunkciós vegyületek királis ligandként, szintetikus építőelemként történő hasznosítására. | In the framework of the research project efficient methods were developed for the preparation of new 1-arypyrrole derivatives using polar organometallics. Three atropisomeric key compounds were resolved and the absolute configurations of the enantiomers were determined by X-ray and CD-spctroscopy. Synthetic methods have been elaborated for further chemical transformations of the optically active 1-arylpyrroles. Thus, series of new bifunctional chiral compounds were prepared. Rotational barriers were estimated by molecular modelling and the results were compared (in several cases) with the experimental NMR data. New kinetic resolution methods were also developed for the preparation of optically active 2-benzyloxymethyl-3-substituted-oxiranes then base promoted enantioselective rearrangement reactions were carried out. The produced optically active oxetane- and cis-but-2-ene-1,4-diol derivatives were transformed into optically active heterocycles (pyrrolidines, pyrrolines, etc). Our results were applied in the synthesis of new pyrrolobenzoxazepines which were sent for biological screening. On the other hand test reactions were carried out with the new compounds to check their properties as chiral ligands or synthetic building blocks

A new xantphos-type ligand and its gold(I) complexes: Synthesis, structure, luminescence

A novel xantphos analog diphosphine ligand, 9,9-dimethyl-4,5-bis(diphenylphosphinomethyl)-9H-xanthene (X(CP)2), with methylene groups inserted between the xanthene skeleton and the two diphenylphosphine units, has been synthesized. A two-coordinate and a three-coordinate gold(I) complex of the ligand, [Au2Cl2(X(CP)2)] and [AuCl(X(CP)2)], have been prepared and studied by X-ray diffraction, NMR and optical spectroscopy. In the solid state, [AuCl(X(CP)2)] adopts a highly ordered structure with a planar xanthene skeleton that faces another plane composed of two phenyl rings and the AuCl moiety. The structure of [Au2Cl2(X(CP)2)] is much less regular, the two P–Au–Cl vectors point to the opposite sides of the folded xanthene backbone. The exchange-broadened resonances in the NMR spectra of [AuCl(X(CP)2))] indicate that this complex exists as a mixture of various chemical species and/or conformers in solution. In contrast, the NMR spectra of [Au2Cl2(X(CP)2)] exclude any medium-range exchange processes. Aurophilic interactions are absent in both X(CP)2 complexes. X(CP)2, as well as its two gold complexes, is phosphorescent in the solid state; the complexes emit at higher wavelengths and with longer lifetimes than the free ligand

Prediction of the efficiency of diastereoisomer separation on the basis of the behaviour of enantiomeric mixtures

The composition of a crystalline diastereoisomer (eeDIA) is determined either by the eutectic composition of the racemic compound (eeEuRac) or that of resolving agent (eeEuRes) and the higher ee value has the more dominant effect.</p

A practical multirobot localization system

We present a fast and precise vision-based software intended for multiple robot localization. The core component of the software is a novel and efficient algorithm for black and white pattern detection. The method is robust to variable lighting conditions, achieves sub-pixel precision and its computational complexity is independent of the processed image size. With off-the-shelf computational equipment and low-cost cameras, the core algorithm is able to process hundreds of images per second while tracking hundreds of objects with a millimeter precision. In addition, we present the method's mathematical model, which allows to estimate the expected localization precision, area of coverage, and processing speed from the camera's intrinsic parameters and hardware's processing capacity. The correctness of the presented model and performance of the algorithm in real-world conditions is verified in several experiments. Apart from the method description, we also make its source code public at \emph{http://purl.org/robotics/whycon}; so, it can be used as an enabling technology for various mobile robotic problems