Academic literature on the topic 'Stereo kamera'

Zusammenfassung Die optische dreidimensionale Formerfassung spiegelnd reflektierender Objekte ist in der Messtechnik immer noch eine schwierige Aufgabe. Die Deflektometrie rekonstruiert die Oberfläche durch Beobachtung verzerrter Bilder einer reflektierten Referenzszene. In diesem Beitrag wird erstmalig ein neuer Ansatz präsentiert, bei dem das deflektometrische Messverfahren effizient mit einer Lichtfeldkamera kombiniert wird. Eine Interpretation der Kamera als hochgradig multiples Kamera-Array erlaubt es, das deflektometrische Messproblem mit einem Multi-Stereo-Ansatz zu lösen. Die Leistungsfähigkeit der Oberflächenrekonstruktion wird in experimentellen Messungen bestätigt und es zeigt sich, dass durch die Kombination von Deflektometrie mit Lichtfeldkameras hohe Genauigkeiten erreicht werden können.

Pada pengendalian robot jarak jauh, dibutuhkan informasi mengenai sekitar dari robot. Informasi ini mambuat operator dapat mengendalikan robotnya dengan lebih baik. Informasi visual adalah informasi yang paling banyak digunakan oleh sistem pengoperasian robot jarak jauh. Informasi visual yang digunakan sebagian besar masih menggunakan informasi dua dimensi. Robot menggunakan sebuah kamera dan operator melihat informasi dari sebuah layar monitor. Hal ini memiliki kekurangan antara lain operator tidak mendapatkan efek kedalaman sehingga operator memiliki kesulitn untuk mengira jarak antara robot dan objek didepannya. Kekurangan ini dapat diselesaikan dengan menggunakan sistem visual tiga dimensi. Namun sistem ini membutuhkan kamera stereo yang tidak murah. Penelitian ini meneliti sebuah sistem yang mengunakan dua buah webcam yang terhubung dengan sebuah komputer, dan operator dapat merasakan sensasi 3 dimensi dengan menggunakan sebuah Virtual reality headset Kamera-kamera ini diletakan pada dua motor steper sehingga digerakan keatas-kebawah serta samping kiri dan kanan. Kemampuan gerak ini membuat operator mendapat informasi mengenai keadaan sekeliling dari robot. Motor-motor ini dikendalikan dari headset sehingga memudahkan operator. Sistem ini diharapkan dapat digunakan pada robot yang dikendalikan jarak jauh sehingga operator dapat mengoperasikan robot lebih baik lagi.

Banyak tantangan yang harus dihadapi ketika melaksanakan survei <br />Ground Control Point (GCP). Salah satu upaya meminimalisir jumlah titik kontrol adalah melakukan pengukuran posisi dan orientasi foto udara tanpa GCP, atau disebut direct georeferencing . Penelitian ini menguji metode direct georeferenci ng terhadap data yang ada di Indonesia, sehingga nantinya dapat mengurangi jumlah penggunaan GCP. Data yang digunakan dalam penelitian ini adalah foto udara Palu yang diakuisisi dengan kamera RCD30, parameter Exterior Orientation (EO), dan titik Independen t Check Point (ICP). Jumlah ICP yang digunakan sebanyak 8 titik. Pengukuran langsung posisi dan orientasi sensor kamera kemudian dilakukan dengan data-data tersebut tanpa menggunakan GCP. Analisis dilakukan dari dua aspek, yaitu ketelitian hasil foto udara dan perbandingan nilai X, Y, Z antar model. Hasil statistik perataan menunjukkan nilai sigma naught = 2,7 mikron, sehingga masih masuk dalam toleransi 1 piksel. Hasil uji akurasi menunjukkan nilai 1,9 m untuk ketelitian horizontal (CE90) dan 3,6 m untuk ketelitian vertikal (LE90), sehingga ketelitian horizontal masuk pada skala 1:5.000 kelas 3 atau skala 1:10.000 kelas 1, dan ketelitian vertikal masuk pada skala 1:10.000 kelas 3 atau skala 1:25.000 kelas 1. Dilihat dari sisi konsistensi antar model stereo, rata-rata perbedaan koordinat dan elevasi pada setiap model stereo berada di bawah 0,5 m, di mana rata-rata ΔX = 0,1173 m, ΔY = 0,2167 m, dan ΔZ = 0,2793 m. Artinya, meski penggunaan metode direct georeferencing dapat mengurangi akurasi absolut, namun hal tersebut tidak berpengaruh terhadap konsistensi antar model stereonya.

Pengukuran estimasi jarak sebuah objek dapat dilakukan dengan berbagai cara, antara lain dengan memanfaatkan sensor pengukur jarak seperti sensor ultrasonik, sensor infra merah dan laser. Tetapi cara tersebut memiliki kekurangan seperti memiliki batasan-batasan karakteristik bahan yang digunakan dan memiliki kesulitan tersendiri jika dikaitkan dengan orientasi dimana objek tersebut berada. Berdasarkan kelebihan tersebut maka pada penelitian ini akan dirancang suatu sistem pengukuran orientasi objek menggunakan metode Stereo vision yang berbasis Raspberry pi. Sistem orientasi objek ini mengacu pada estimasi jarak dan dimensi objek. Metode Stereo vision melakukan pengukuran jarak dan dimensi secara visual dengan menggunakan dua buah kamera webcam. Akusisi citra dilakukan dalam interval waktu yang bersamaan, sehingga akan terdapat dua citra yang memiliki objek yang sama tetapi dari sudut pandang yang berbeda. Kedua citra akan digunakan untuk menghitung nilai disparitas yang akan digunakan sebagai salah satu parameter dalam melakukan pengukuran jarak. Menghitung nilai disparitas citra dilakukan menggunakan beberapa metode image processing yaitu menggunakan deteksi tepi Canny edge, deteksi garis Hough line transform dan deteksi sudut Harris corner. Penelitian ini dapat digunakan sebagai alat pengukuran jarak dan dimensi objek yang bergerak secara real time dengan tingkat akurasi diatas 95% dengan tingkat presisi 100%.

Sistem multi-robot telah diterapkan pada tugas-tugas kompleks yang biasanya dilakukan oleh manusia. Untuk dapat menjalankan tugasnya, robot perlu bernavigasi ke dari suatu posisi ke posisi lain. Agar dapat bernavigasi dengan baik, robot memerlukan peta sebagai acuannya dalam bernavigasi. Simultaneous Localization and Mapping (SLAM) merupakan sebuah metode bagi robot untuk dapat membuat peta dan melakukan lokalisasi. ORB SLAM-2 merupakan sebuah metode SLAM berbasis sensor visual yang kompatibel terhadap kamera monokular, stereo, maupun RGBD. Dengan menggunakan kamera monokular, penelitian ini bertujuan untuk membuat rancangan sistem pemetaan lingkungan multi-robot dengan menggunakan algoritma ORB SLAM-2. Tugas akhir ini merancang sistem desentralisasi sehingga algoritma dijalankan pada kedua robot. Kemudian setiap robot melakukan pemetaan lingkungannya dan mengirimkannya ke komputer agar dapat divisualisasi. Pada percobaannya, rancangan ini berhasil membuat sistem melaksanakan tugasnya dengan baik. Peta yang dihasilkan oleh sistem ini memiliki skala sekitar 1 : 5,81. Sistem juga dapat memvisualisasikan peta yang dihasilkan oleh masing-masing robot pada sebuah komputer server. Berdasarkan hasil percobaan, dapat disimpulkan bahwa sistem pemetaan lingkungan multi-robot menggunakan ORB SLAM-2 dapat dilakukan dengan mendesentralisasi sistem. Dengan ini, beban kerja sistem terbagi menjadi dua, pertama pemrosesan gambar dilakukan oleh masing-masing robot hingga menghasilkan titik-titik peta dan kedua komputer server bertugas untuk memvisualisasikan titik-titik peta yang dihasilkan robot pada antarmuka pengguna.

This study aimed to describe the morphological characters and morphometric measurements of worker level from the genus and species of stingless bee colonies in coastal areas. Observation of morphological characters and morphometric measurements used a microscope (stereo model Nikon C-LEEDS equipped with obtilab viewers software camera and image raster). The stingless bee species found in coastal areas belonged to the genus Tetragonula which consisted of Tetragonula sapiens and T. clypearis. T. sapiens was found in two locations, namely the coast of Airlow Hamlet and Negeri Rutong. T. clypearis was found in four locations, i.e., on the coast of Dusun Airlow, Negeri Rutong, Negeri Hukurila and Dusun Seri. Morphological identification was done by identifying ten morphological characters, and morphometric identification was done by measuring fourteen body parts. The results of this study indicated that the morphological and morphometric characters of T. sapiens workers were dominantly black in color with a body size of 3.74-4.25 mm. The first through the sixth abdomen tergites were black. The morphological and morphometric characters T. clypearis had a brownish black body color with a body size of 2.81-3.38 mm, a black thorax covered by six longitudinal hair bands and each separated by five conspicuous glabrous, the first and second abdomen tergites were brownish whereas the third through the sixth were black. Keywords: Ambon Island, morphology, morphometric, stingless bees. ABSTRAK Penelitian ini bertujuan untuk mendeskripsikan karakter morfologi dan pengukuran morfometrik strata pekerja dari genus dan spesies lebah tak bersengat koloni daerah pesisir. Pengamatan karakter morfologi dan pengukuran morfometrik menggunakan mikroskop (stereo model Nikon C-LEEDS yang dilengkapi kamera software obtilab viewers dan image raster). Spesies lebah tak bersengat yang ditemukan di daerah pesisir pantai tergolong dalam genus Tetragonula yang terdiri dari Tetragonula sapiens dan T. clypearis. T. sapiens ditemukan di dua lokasi yaitu pesisir pantai Dusun Airlow dan Negeri Rutong. T. clypearis ditemukan di empat lokasi, yaitu di pesisir pantai Dusun Airlow, Negeri Rutong, Negeri Hukurila dan Dusun Seri. Identifikasi morfologi dilakukan dengan mengidentifikasi sepuluh karakter morfologi dan identifikasi morfometrik dilakukan dengan cara mengukur empat belas bagian tubuh. Hasil penelitian ini menunjukan karakter morfologi dan morfometrik tubuh pekerja T. sapiens dominan berwarna hitam dengan ukuran tubuh 3.74-4.25 mm. Abdomen dan tergite satu sampai enam berwarna hitam. Karakter morfologi dan morfometrik T. clypearis memiliki warna tubuh hitam kecoklatan dengan ukuran tubuh 2.81-3.38 mm, thorax berwarna hitam yang ditutupi oleh enam hair bands longitudinal dan masing-masing dipisahkan oleh lima glabrous yang mencolok, abdomen dan tergite pertama sampai kedua berwarna kecoklatan sedangkan tergite ketiga sampai enam berwarna hitam. Kata kunci: Lebah tak bersengat, morfologi, morfometrik, Pulau Ambon.

Tujuan penelitian mengenai struktur morfologi dan anatomi perkembangan Cypraea moneta adalah mempelajari perkembangan morfologi dan anatomi C. moneta jantan dan betina. Spesimen diukur panjang cangkang dan berat, kemudian dikelompokkan menurut panjang cangkang. Cangkang spesimen dicerna dengan menggunakan HCl 5%, kemudian dibedah dengan menggunakan micro dissection kit di bawah mikroskop stereo yang telah terhubung dengan monitor PC dan kamera digital. Organ yang diamati meliputi mantel dan papila, tentakel, mata, kakiperut, dan organ reproduksi. Hasilnya memperlihatkan bahwa tidak ada perbedaan antara warna mantel, tipe papila, kakiperut, mata, tentakel jantan dan tentakel betina. Perkembangan morfologi ditandai dengan pertambahan ukuran cangkang, berat, jumlah geligi pada cangkang, dan bentuk cangkang. Jantan berkembang testis dan kelenjar testis, betina dengan ovarium dan lubang genital. Warna testis dan ovarium berubah sesuai dengan perkembangan kematangannya. Kata kunci: Cypraea moneta, Pantai Krakal, perkembangan morfologi dan anatomi

ZusammenfassungIn diesem Beitrag wird die dreidimensionale Rekonstruktion einer gewölbten, texturierten Flügeloberfläche eines im Windkanal frei fliegenden Lannerfalken mit Hilfe eines Stereo Kamerasystems vorgestellt. Die Verwendung zweier Kameras ermöglicht die Ermittlung der Korrespondenz gesuchter Oberflächenpunkte in beiden Kamerabildern und die anschließende Triangulation der Korrespondenzpaare in räumliche Koordinaten. Die Bestimmung der zusammengehörenden Bildpunktpaare erfolgt durch Ermittlung des Verschiebungsfeldes zwischen den Kameras mit Hilfe eines Semi-Global Block Matching Algorithmus. Zur Reduktion der Komplexität werden die Bilder anhand der Epipolar Geometrie entzerrt. Die Analyse zeigt, dass sich mit diesen Methoden die Struktur der Oberfläche eines Lannerfalken im Schlagflug und die Bewegung innerhalb einer Zeitsequenz mit hinreichender Genauigkeit für aerodynamische Analysen rekonstruieren lassen.

Stereo vision is one of the most popular elements in the field of mobile robots and significantly contributes to their autonomous behaviour. The aim of the diploma thesis was to design and implement a camera module as a hardware sensor input, which is independent, with the possibility of supplementing the system with other cameras, and to create a depth map from a pair of cameras. The diploma thesis consists of theoretical and practical part, including the conclusion of results. The theoretical part introduces the ROS framework, discusses methods of creating depth maps, and provides an overview of the most popular stereo cameras in robotics. The practical part describes in detail the preparation of the experiment and its implementation. It also describes the camera calibration and the depth map creating. The last chapter contains an evaluation of the experiment.

This document focuses on stereoscopic vision, machine vision and 3D scene reconstruction. First we create mathematic framework which is later used to determine solution for problems appearing during creation of scene reconstruction application.

The focus of this thesis is to theoretically design, describe, implement and verify thefunctionality of the selected concept for race track mapping. The theoretical part ofthe thesis describes the ORB-SLAM2 algorithm for vehicle localization. It then furtherdescribes the format of the map - occupancy grid and the method of its creation. Suchmap should be in a suitable format for use by other trajectory planning systems. Severalcameras, as well as computer units, are described in this part, and based on parametersand tests, the most suitable ones are selected. The thesis also proposes the architectureof the mapping system, it describes the individual units that make up the system, aswell as what is exchanged between the units, and in what format the system output issent. The individual parts of the system are first tested separately and subsequently thesystem is tested as a whole. Finally, the achieved results are evaluated as well as thepossibilities for further expansion.

The Professorship of Digital Signal Processing and Circuit Technology of Chemnitz University of Technology conducts research in the field of three-dimensional space measurement with optical sensors. In recent years this field has made major progress. For example innovative, active techniques such as the “structured light“-principle are able to measure even homogeneous surfaces and find its way into the consumer electronic market in terms of Microsoft’s Kinect® at the present time. Furthermore, high-resolution optical sensors establish powerful, passive stereo vision systems in the field of indoor surveillance. Thereby they induce new application domains such as security and assistance systems for domestic environments. However, the constraint field of view can be still considered as an essential characteristic of all these technologies. For instance, in order to measure a volume in size of a living space, two to three deployed 3D sensors have to be applied nowadays. This is due to the fact that the commonly utilized perspective projection principle constrains the visible area to a field of view of approximately 120°. On the contrary, novel fish-eye lenses allow the realization of omnidirectional projection models. Therewith, the visible field of view can be enlarged up to more than 180°. In combination with a 3D measurement approach, thus, the number of required sensors for entire room coverage can be reduced considerably. Motivated by the requirements of the field of indoor surveillance, the present work focuses on the combination of the established stereo vision principle and omnidirectional projection methods. The entire 3D measurement of a living space by means of one single sensor can be considered as major objective. As a starting point for this thesis chapter 1 discusses the underlying requirement, referring to various relevant fields of application. Based on this, the distinct purpose for the present work is stated. The necessary mathematical foundations of computer vision are reflected in Chapter 2 subsequently. Based on the geometry of the optical imaging process, the projection characteristics of relevant principles are discussed and a generic method for modeling fish-eye cameras is selected. Chapter 3 deals with the extraction of depth information using classical (perceptively imaging) binocular stereo vision configurations. In addition to a complete recap of the processing chain, especially occurring measurement uncertainties are investigated. In the following, Chapter 4 addresses special methods to convert different projection models. The example of mapping an omnidirectional to a perspective projection is employed, in order to develop a method for accelerating this process and, hereby, for reducing the computational load associated therewith. Any errors that occur, as well as the necessary adjustment of image resolution, are an integral part of the investigation. As a practical example, an application for person tracking is utilized in order to demonstrate to which extend the usage of “virtual views“ can increase the recognition rate for people detectors in the context of omnidirectional monitoring. Subsequently, an extensive search with respect to omnidirectional imaging stereo vision techniques is conducted in chapter 5. It turns out that the complete 3D capture of a room is achievable by the generation of a hemispherical depth map. Therefore, three cameras have to be combined in order to form a trinocular stereo vision system. As a basis for further research, a known trinocular stereo vision method is selected. Furthermore, it is hypothesized that, applying a modified geometric constellation of cameras, more precisely in the form of an equilateral triangle, and using an alternative method to determine the depth map, the performance can be increased considerably. A novel method is presented, which shall require fewer operations to calculate the distance information and which is to avoid a computational costly step for depth map fusion as necessary in the comparative method. In order to evaluate the presented approach as well as the hypotheses, a hemispherical depth map is generated in Chapter 6 by means of the new method. Simulation results, based on artificially generated 3D space information and realistic system parameters, are presented and subjected to a subsequent error estimate. A demonstrator for generating real measurement information is introduced in Chapter 7. In addition, the methods that are applied for calibrating the system intrinsically as well as extrinsically are explained. It turns out that the calibration procedure utilized cannot estimate the extrinsic parameters sufficiently. Initial measurements present a hemispherical depth map and thus con.rm the operativeness of the concept, but also identify the drawbacks of the calibration used. The current implementation of the algorithm shows almost real-time behaviour. Finally, Chapter 8 summarizes the results obtained along the studies and discusses them in the context of comparable binocular and trinocular stereo vision approaches. For example the results of the simulations carried out produced a saving of up to 30% in terms of stereo correspondence operations in comparison with a referred trinocular method. Furthermore, the concept introduced allows the avoidance of a weighted averaging step for depth map fusion based on precision values that have to be calculated costly. The achievable accuracy is still comparable for both trinocular approaches. In summary, it can be stated that, in the context of the present thesis, a measurement system has been developed, which has great potential for future application fields in industry, security in public spaces as well as home environments.

In den letzten Jahren kommen immer mehr nicht perspektivische Kamerasysteme beim maschinellen Sehen zur Anwendung, die vor allem ein deutlich erweitertes Blickfeld bieten. Das klassische perspektivische Abbildungsmodell lässt sich hier häufig nicht mehr erfolgreich anwenden. In dieser Arbeit wird ein generisches Abbildungsmodell vorgestellt, welches übliche Kamerasysteme akkurat modellieren kann. Solche Kamerasysteme schließen insbesondere klassische perspektivische Systeme, aber auch Fischaugen- und Spiegellinsen-Kamerasysteme ein. Die Nutzung eines einheitlichen Abbildungsmodells ermöglicht schließlich eine einfache Verwendung und Kalibrierung von heterogenen Stereokamerasystemen, also einer Kombination von unterschiedlichen Kameratypen, die vorteilhafte Eigenschaften gegenüber klassischen Stereosystemen bieten. Nicht zuletzt trägt die in dieser Arbeit vorgestellte einheitliche Modellierung und Kalibrierung von Mono- und Stereokamerasystemen dazu bei, Fehler durch falschen Umgang oder falsche Wahl von Methoden der Modellierung oder Kalibrierung zu vermeiden und den Kamerakalibrierprozess insgesamt zu vereinfachen. In dieser Arbeit wurden verschiedene Ansätze der Modellierung untersucht und evaluiert. Es wurde eine generische Modellierung vorgeschlagen, die die untersuchten spezifischen Abbildungsmodelle vollständig ersetzen kann. Für die Kalibrierung nicht linearer Abbildungsmodelle wurde eine einheitliche Methode zur Startwertbestimmung vorgeschlagen und evaluiert. Die Genauigkeit der Kalibrierung mittels einheitlicher Methoden wurde anhand diverser realer Kamerasysteme untersucht und bewertet. Es konnte gezeigt werden, dass die dabei auftretenden Fehler deutlich im Subpixelbereich liegen. Durch Erweiterung des klassischen Konzepts der Epipolargeometrie um die generische Abbildungsmodellierung konnten schließlich heterogene Stereokamerasysteme kalibriert und genaue Stereomodelle abgeleitet werden.
The application of perspective camera systems in photogrammetry and computer vision is state of the art. In recent years non-perspective and especially omnidirectional camera systems have increasingly been used in close-range photogrammetry tasks. In general, the perspective camera model, i.e. pinhole model, cannot be applied when using non-perspective camera systems. However, several camera models for different omnidirectional camera systems are proposed in literature. Using different types of cameras in a heterogeneous camera system may lead to an advantageous combination. The advantages of different camera systems, e.g. field of view and resolution, result in a new enhanced camera system. If these different kinds of cameras can be modeled, using a unified camera model, the total calibration process can be simplified. Sometimes it is not possible to give the specific camera model in advance. In these cases a generic approach is helpful too. Furthermore, a simple stereo reconstruction becomes possible when using a fisheye and a perspective camera for example. In this work camera models for perspective, wide-angle and omnidirectional camera systems were evaluated. A generic camera model were introduced that fully substitutes specific camera models. The crucial initialization of the model''s parameters is conducted using a new generic method that is independent of the particular camera system. The accuracy of this generic camera calibration approach is validated by the calibration of a dozen of real camera systems up to subpixel accuracy. Finally, it has been shown that a unified method of modeling, parameter approximation and calibration of interior and exterior orientation can be applied to a generic stereo system to derive precise 3D object data.

Tato práce se snaží najít odpověď na otázku, zda je v současnosti možné autonomně měřit rychlost vozidel pomocí stereoskopické měřící metody s průměrnou chybou v rozmezí 1 km/h, maximální chybou v rozmezí 3 km/h a směrodatnou odchylkou v rozmezí 1 km/h. Tyto rozsahy chyb jsou založené na požadavcích organizace OIML, jejichž doporučení jsou základem metrologických legislativ mnoha zemí. Pro zodpovězení této otázky je zformulována hypotéza, která je následně testována. Metoda, která využívá stereo kameru pro měření rychlosti vozidel je navržena a experimentálně vyhodnocena. Výsledky pokusů ukazují, že navržená metoda překonává výsledky dosavadních metod. Průměrná chyba měření je přibližně 0.05 km/h, směrodatná odchylka chyby je menší než 0.20 km/h a maximální absolutní hodnota chyby je menší než 0.75 km/h. Tyto výsledky jsou v požadovaném rozmezí a potvrzují tedy testovanou hypotézu.

LIDAR (2D) has been widely used for mapping, localization and navigation in mobile robotics. However, its usage is limited to simple environments. This problem can be solved by adding more sensors and processing these data together. This paper explores a method how measurements from a stereo camera and LIDAR are fused to dynamical mapping. An occupancy grid map from LIDAR data is used as prerequisite and extended by a 2D grid map from stereo camera. This approach is based on the ground plane estimation in disparity map acquired from the stereo vision. For the ground plane detection, RANSAC and Least Squares methods are used. After obstacles determination, 2D occupancy map is generated. The output of this method is 2D map as a fusion of complementary maps from LIDAR and camera. Experimental results obtained from RUDA robot and MIT Stata Center Data Set are good enough to determine that this method is a benefit, although my implementation is still a prototype. In this paper, we present the applied methods, analyze the results and discuss the modifications and possible extensions to get better results.

This thesis deals with the task of three-dimensional scene reconstruction using image data obtained from multiple views. It is assumed that intrinsic parameters of the utilized cameras are known. The theoretical chapters describe the basic priciples of individual reconstruction steps. Variuous possible implementaions of data model suitable for this task are also described. The practical part also includes a comparison of false keypoint correspondence filtering, implementation of polar stereo rectification and comparison of disparity map calculation methods that are bundled with the OpenCV library. In the final portion of the thesis, examples of reconstructed 3D models are presented and discussed.

Tato práce popisuje problematiku návrhu a vývoje aplikace pro rekonstrukci 3D modelů z 2D obrazových dat, označované jako bundle adjustment. Práce analyzuje proces 3D rekonstrukce a důkladně popisuje jednotlivé kroky. Prvním z kroků je automatizované získání obrazové sady z internetu. Je představena sada skriptů pro hromadné stahování obrázků ze služeb Flickr a Google Images a shrnuty požadavky na tyto obrázky pro co nejlepší 3D rekonstrukci. Práce dále popisuje různé detektory, extraktory a párovací algoritmy klíčových bodů v obraze s cílem najít nejvhodnější kombinaci pro rekonstrukci budov. Poté je vysvětlen proces rekonstrukce 3D struktury, její optimalizace a jak je tato problematika realizovaná v našem programu. Závěr práce testuje výsledky získané z implementovaného programu pro několik různých datových sad a porovnává je s výsledky ostatních podobných programů, představených v úvodu práce.

Im Jahr 2017 gründeten die vier Herausgeber dieser Publikation, alle Mitglieder der Jungen Akademie, die Arbeitsgruppe "Lost in Translation". Sie verbindet die Frage, welche Prozesse hinter einer erfolgreichen Translation wissenschaftlicher Grundlagenforschung in anwendungsbezogene Kontexte stehen. Denn trotz intensivierter Bemühungen, gewonnene Erkenntnisse aus der Grundlagenforschung zur Anwendung zu bringen, besteht häufig eine Lücke zwischen dem theoretisch verfügbaren und dem tatsächlich genutzten Wissen. Eine Folge ist die Verzögerung wissenschaftlicher und gesellschaftlicher Entwicklungen, was angesichts der drängenden Herausforderungen unserer Zeit zu einem immanenten Problem wird. Auf dem am 1. Februar 2018 in der Mainzer Akademie abgehaltenen Symposium zu der Thematik kamen namhafte Experten aus der Krebs-, Versorgungs- und Neuroforschung sowie der Wirtschaft und Philosophie zusammen. Die Ergebnisse dieses fächerübergreifenden Austausches über Probleme, aber auch Potentiale der Translationsforschung werden in diesem Band vorgestellt.

Before I went to Bihar I knew little about embankments. I had seen levees in California, in the Sacramento–San Joaquin Delta and in the Central Valley. There, if you stand on an embankment on one side of the river, you can look across and see a matching embankment. Some have been set back from the river a half of a mile or so; but even then it is easy to grasp in a glance the relatively linear triad of a river and its pair of embankments. The first embankment I saw in Bihar after miles of bumping along in the back seat of a gray Tata Sumo SUV in the April heat was a steep-sided loaf of sand, maybe twelve feet above the adjacent land. I scrambled to the top and looked around. The Kamla River glared below, reflecting a hazy but intense sun. It flowed lazily between the embankment and a wide stretch of sand a few inches above the water. Together the water and the sandbank narrowed as they receded into the distance. I didn’t see another embankment. I was disoriented by the incessantly jarring ride and the heat, but I recall asking where the other embankment was. A gesture directed my eyes toward the horizon of low trees and brush and sandy soil. Nothing was very distinguishable in the monochromatic haze of dust and heat. Over the next two days my eyes and brain continued to struggle in vain to make sense of what I was seeing by comparing the north Indian state of Bihar to California. California rivers are powerful and can flood portions of the flat Central Valley, but they are in no way comparable to the rivers that rush out of the towering Himalaya. The Sierra Nevada ranges from five to twelve thousand feet. At twelve thousand feet in the Himalaya, one is still in the “middle hills,” where in spring there are forests of rhododendron trees blooming.

In the present work, Stress corrosion cracking (SCC) and its mechanical behavior are presented. SCC represents complex behavior due to electrochemical and mechanical interaction. Damage models are proposed to predict crack initiation time for stainless steel under constant load using the concept of continuum damage mechanics to show incremental damage accumulation which finally leads to failure of the material. Two damage models applicable to prediction of damage in SCC, Lemaitre damage model and damage driving force model proposed by Kamaya are compared. The comparative study of the results obtained by these damage models shows that in Lemaitre damage law cracks initiate randomly while in damage driving force model the stress concentration occurs around the periphery of damaged element results in increased damage force. The study can be used to estimate the crack initiation time in SCC under corrosive atmosphere.

To support the feasibility and the deployment of LFRs one of the main issues to be solved is the reliability of structural materials to be exposed to liquid metal coolant. Particularly the Liquid Metal Embrittlement (LME) of steels is of interest for nuclear reactors and spallation sources projects because structural materials for these systems are selected according to their corrosion resistance, irradiation embrittlement and compatibility with the coolant. This study was performed in the framework of MYRRHA project, a new-generation sub-critical reactor (based on the Accelerator Driving System concept) that uses Lead-Bismuth Eutectic (LBE) as coolant. LME phenomenon has been investigated by performing theoretical and experimental activity profiting and basing on the results obtained for the T91 m/f steel in contact with LBE. This paper first reviews the model of Kamdar: weak points and contradictions are highlighted. From an experimental point of view to verify the occurrence of LME, Slow Strain Rate Tensile tests were performed on the AISI 316L in LBE environment at SCK-CEN laboratories. Besides, a fracture surface analysis was carried out together with a microstructural analysis by using that Scanning Electron Microscopy. This was done in order to confirm the results obtained by the mechanical tests and to look for impurities in the metallic matrix. These impurities are an interesting feature in case of high scatter in the results. Indeed one of the difficulties was the opacity and conductivity of the medium. The methodological approach and the procedure are also duly described along with preliminary results.