Machine vision applications in UAVs for autonomous aerial refueling and runway detection

This research focuses on the application of Machine Vision (MV) techniques and algorithms to the problems of Autonomous Aerial Refueling (AAR) and Runway Detection. In particular, real laboratory based hardware was used in a simulated environment to emulate real-life conditions for AAR. It was shown that the K-Means Clustering Algorithm solution to the Marker Detection problem could be executed at a frame rate of 30 Hz and it averaged a tracking error of less than one pixel while utilizing only 0.16% of the image. It was also shown that the solution to the Runway Detection problem could be executed at a frame rate of 20 Hz which is acceptable for use in an UAV performing reconnaissance work. Data from these tests suggest that both software schemes are suitable for applications in moving vehicles and that the accuracy of the measurements produced by the schemes make them suitable for UAV applications

ИНТЕЛЛЕКТУАЛЬНЫЙ числовым программным ДЛЯ MIMD-компьютер

For most scientific and engineering problems simulated on computers the solving of problems of the computational mathematics with approximately given initial data constitutes an intermediate or a final stage. Basic problems of the computational mathematics include the investigating and solving of linear algebraic systems, evaluating of eigenvalues and eigenvectors of matrices, the solving of systems of non-linear equations, numerical integration of initial- value problems for systems of ordinary differential equations.Для більшості наукових та інженерних задач моделювання на ЕОМ рішення задач обчислювальної математики з наближено заданими вихідними даними складає проміжний або остаточний етап. Основні проблеми обчислювальної математики відносяться дослідження і рішення лінійних алгебраїчних систем оцінки власних значень і власних векторів матриць, рішення систем нелінійних рівнянь, чисельного інтегрування початково задач для систем звичайних диференціальних рівнянь.Для большинства научных и инженерных задач моделирования на ЭВМ решение задач вычислительной математики с приближенно заданным исходным данным составляет промежуточный или окончательный этап. Основные проблемы вычислительной математики относятся исследования и решения линейных алгебраических систем оценки собственных значений и собственных векторов матриц, решение систем нелинейных уравнений, численного интегрирования начально задач для систем обыкновенных дифференциальных уравнений

Doctor of Philosophy

dissertationConfocal microscopy has become a popular imaging technique in biology research in recent years. It is often used to study three-dimensional (3D) structures of biological samples. Confocal data are commonly multichannel, with each channel resulting from a different fluorescent staining. This technique also results in finely detailed structures in 3D, such as neuron fibers. Despite the plethora of volume rendering techniques that have been available for many years, there is a demand from biologists for a flexible tool that allows interactive visualization and analysis of multichannel confocal data. Together with biologists, we have designed and developed FluoRender. It incorporates volume rendering techniques such as a two-dimensional (2D) transfer function and multichannel intermixing. Rendering results can be enhanced through tone-mappings and overlays. To facilitate analyses of confocal data, FluoRender provides interactive operations for extracting complex structures. Furthermore, we developed the Synthetic Brainbow technique, which takes advantage of the asynchronous behavior in Graphics Processing Unit (GPU) framebuffer loops and generates random colorizations for different structures in single-channel confocal data. The results from our Synthetic Brainbows, when applied to a sequence of developing cells, can then be used for tracking the movements of these cells. Finally, we present an application of FluoRender in the workflow of constructing anatomical atlases

COBE's search for structure in the Big Bang

The launch of Cosmic Background Explorer (COBE) and the definition of Earth Observing System (EOS) are two of the major events at NASA-Goddard. The three experiments contained in COBE (Differential Microwave Radiometer (DMR), Far Infrared Absolute Spectrophotometer (FIRAS), and Diffuse Infrared Background Experiment (DIRBE)) are very important in measuring the big bang. DMR measures the isotropy of the cosmic background (direction of the radiation). FIRAS looks at the spectrum over the whole sky, searching for deviations, and DIRBE operates in the infrared part of the spectrum gathering evidence of the earliest galaxy formation. By special techniques, the radiation coming from the solar system will be distinguished from that of extragalactic origin. Unique graphics will be used to represent the temperature of the emitting material. A cosmic event will be modeled of such importance that it will affect cosmological theory for generations to come. EOS will monitor changes in the Earth's geophysics during a whole solar color cycle

Searching for High-energy Neutrinos from Supernovae with IceCube and an Optical Follow-up Program

In violent astrophysical processes high-energy neutrinos of TeV to PeV energies are expected to be produced along with the highest energy cosmic rays. The acceleration of nuclei to very high energies is assumed to takes place in astrophysical shocks and neutrinos are produced in the interaction of these cosmic rays with ambient baryons or photons. The neutrinos then escape the acceleration region and propagate through space without interaction, while the nuclei are deflected in magnetic fields and no longer carry information about their source position. Unlike gamma-rays, neutrinos are solely produced in hadronic processes and can therefore reveal the sources of charged cosmic rays. The IceCube neutrino detector, which is located at the geographical South Pole, has been build to detect these high-energy astrophysical neutrinos. The deep clear Antarctic ice is instrumented with light sensors on a grid, thus forming a Cherenkov particle detector, which is capable of detecting charged particles induced by neutrinos above 100 GeV. Transient neutrino sources such as Gamma-Ray Bursts (GRBs) and Supernovae (SNe) are hypothesized to emit bursts of high-energy neutrinos on a time-scale of ≤ 100 s. While GRB neutrinos would be produced in the high relativistic jets driven by the central engine, corecollapse SNe might host soft-relativistic jets which become stalled in the outer layers of the progenitor star and lead to an efficient production of high-energy neutrinos. This work aims for an increased sensitivity for these neutrinos and for a possible identification of their sources. Towards this goal, a low-threshold optical follow-up program for neutrino multiplets detected with IceCube has been implemented. If a neutrino multiplet – i.e. two or more neutrinos from the same direction within 100 s – is found by IceCube a trigger is sent to the Robotic Optical Transient Search Experiment (ROTSE). The 4 ROTSE telescopes immediately start an observation program of the corresponding region of the sky in order to detect a possible optical counterpart to the neutrino events. Complementary to previous transient neutrino searches, which have been performed offline on IceCube data on source regions and time windows provided by gamma-ray satellites, this neutrino search is applied – for the first time – in real time to neutrino data at the South Pole. It is sensitive to transient objects, including those which are gamma-ray dark or not detected by gamma-ray satellites. In addition to a gain in sensitivity, the optical observations may allow the identification of the transient neutrino source, be it a SN, a GRB or any other transient phenomenon producing an optical signal. Hence, it enables to test the hypothesis of soft relativistic jets in SNe and may shed light on the connection between GRBs, SNe and relativistic jets. The content of this work are the development and implementation of the optical follow-up program as well as the analysis of the data collected in the first year of operation. No statistically significant excess in the rate of neutrino multiplets has been observed and furthermore no coincidence with an optical counterpart was found. However, for the first time stringent limits can be set on current models predicting a high-energy neutrino flux from soft relativistic hadronic jets in core-collapse SNe. It can be concluded that a sub-population of SNe with jets with a typical Lorentz boost factor of 10 and a jet energy of 3 × 1051 erg does not exceed 4:2% at 90% confidence.Suche nach Hoch-energetischen Neutrinos von Supernovae mit IceCube und einem Optischen Nachbeobachtungsprogramm In energiereichen astrophysikalischen Prozessen erwartet man die Produktion von Neutrinos mit Energien im TeV bis PeV Bereich Seite an Seite mit der Produktion der hochenergetischen komischen Strahlung. Die Beschleunigung der Kerne zu den gemessenen hohen Energien findet vermutlich in astrophysikalischen Schocks statt. In Wechselwirkungen mit den umgebenden Baryonen und Photonen werden dann Neutrinos produziert. Diese Neutrinos können die Beschleunigungsregion verlassen und propagieren ungehindert durch den Raum, während die Kerne in intergalaktischen Magnetfeldern abgelenkt werden und sich ihre Quellen somit nicht mehr zurück verfolgen lassen. Im Gegensatz zu Photonen werden Neutrinos ausschließlich in hadronischen Prozessen erzeugt und erlauben es so, die Quellen der kosmischen Strahlung zu identifizieren. Zum Nachweis dieser astrophysikalischen Neutrinos wurde am geographischen Südpol der Neutrinodetektor IceCube gebaut. Das tiefe antarktische Eis wurde dafür mit Lichtsensoren ausgestattet und auf diese Weise in einen Tscherenkov Teilchendetektor verwandelt, welcher geladene Teilchen nachweisen kann, die durch Neutrinos mit Energies oberhalb von 100 GeV induziert werden. Theoretische Modelle sagen vorher, dass transiente Neutrinoquellen wie Gammastrahlungsausbrüche (GRBs) und Supernovae (SNe) kurze Ausbrüche – sogenannte “Bursts” – von hochenergetischen Neutrinos auf einer Zeitskala von ≤ 100 s emittieren. Während GRB Neutrinos in hoch relativistischen Jets produziert werden, könnten Kernkollaps-Supernovae (CCSNs) einen schwach relativistischen Jet beherbergen, dem es nicht gelingt, die äußere Hülle des Vorgängersternes zu durchdringen, sondern der darin zum Stillstand kommt und so für effiziente Neutrinoproduktion sorgt. Ziel diese Arbeit ist die Verbesserung der Sensitivität für die Messung diese Neutrinos und die Identifikation ihrer Quellen. Dafür wurde ein optisches Nachverfolgungsprogramm für Neutrinomultipletts entwickelt, welche mit dem IceCube Neutrinodetektor gemessen werden. Falls ein Neutrinomultiplett – d.h. mindestens zwei Neutrinos aus der gleichen Richtung innerhalb von 100 s – von IceCube gefunden wird, wird ein Trigger an das Robotic Optical Transient Search Experiment (ROTSE) gesendet. Die vier ROTSE Teleskope starten unmittelbar ein Beobachtungsprogramm für die entsprechende Richtung am Himmel, um ein optisches Gegenstück zu den Neutrinoereignisse detektieren zu können. Im Gegensatz zu den bisher durchgeführten Suchen nach transienten Neutrinoquellen, welche offline durchgeführt und durch die von Gammastrahlensatelliten bereitgestellte Informationen getriggert werden, wird diese Analyse als bislang erste Analyse in Echtzeit auf Neutrinodaten am Südpol angewendet. Sie ermöglicht die Detektion von transienten Objekten, einschließlich solcher, die keine Gammastrahlen emittieren oder die nicht von Satelliten beobachtet werden können. Zusätzlich zu einer Verbesserung der Sensitivität können die optischen Beobachtungen eine Identifikation der Quelle erlauben, unabhängig davon, ob es sich um eine SN, einen GRB oder eine anderes transientes Phänomen handelt, das ein optisches Signal erzeugt. Folglich kann mit dieser Methode das Modell für schwach relativistische Jets in SNe getestet, sowie Aufschluß über die Verbindung zwischen GRBs, SNe und relativistischen Jets gegeben werden. Der Inhalt dieser Arbeit ist die Entwicklung und Durchführung des optischen Nachverfolgungsprogramms sowie die Analyse der Daten, welche während des ersten Jahres des Betriebs aufgenommen wurden. In den Daten wurde weder ein statistisch signifikanter Exzess der Neutrinomultiplettrate noch ein optisches Gegenstück zu einem der Neutrinomultipletts gefunden. Diese Analyse erlaubt daher zum ersten mal ein strenges Limit auf aktuelle Modelle zu setzen, welche einen Fluss hochenergetischer Neutrinos aus schwach relativistischen hadronischen Jets in Kernkollaps-Supernovae vorhersagen. Es kann mit einem Vertrauensintervall von 90% ausgeschlossen werden, dass die Subpopulation von SNe mit Jets mit typischen Lorentz Boost Faktoren von 10 und Jetenergien von 3 × 1051 erg 4:2% überschreitet. Komplette Version ist aus urheberrechtlichen Gründen vorübergehend gesperrt

Assistive Technology and Biomechatronics Engineering

This Special Issue will focus on assistive technology (AT) to address biomechanical and control of movement issues in individuals with impaired health, whether as a result of disability, disease, or injury. All over the world, technologies are developed that make human life richer and more comfortable. However, there are people who are not able to benefit from these technologies. Research can include development of new assistive technology to promote more effective movement, the use of existing technology to assess and treat movement disorders, the use and effectiveness of virtual rehabilitation, or theoretical issues, such as modeling, which underlie the biomechanics or motor control of movement disorders. This Special Issue will also cover Internet of Things (IoT) sensing technology and nursing care robot applications that can be applied to new assistive technologies. IoT includes data, more specifically gathering them efficiently and using them to enable intelligence, control, and new applications

Change blindness: eradication of gestalt strategies

Arrays of eight, texture-defined rectangles were used as stimuli in a one-shot change blindness (CB) task where there was a 50% chance that one rectangle would change orientation between two successive presentations separated by an interval. CB was eliminated by cueing the target rectangle in the first stimulus, reduced by cueing in the interval and unaffected by cueing in the second presentation. This supports the idea that a representation was formed that persisted through the interval before being 'overwritten' by the second presentation (Landman et al, 2003 Vision Research 43149–164]. Another possibility is that participants used some kind of grouping or Gestalt strategy. To test this we changed the spatial position of the rectangles in the second presentation by shifting them along imaginary spokes (by ±1 degree) emanating from the central fixation point. There was no significant difference seen in performance between this and the standard task [F(1,4)=2.565, p=0.185]. This may suggest two things: (i) Gestalt grouping is not used as a strategy in these tasks, and (ii) it gives further weight to the argument that objects may be stored and retrieved from a pre-attentional store during this task

Characteristics of flight simulator visual systems

The physical parameters of the flight simulator visual system that characterize the system and determine its fidelity are identified and defined. The characteristics of visual simulation systems are discussed in terms of the basic categories of spatial, energy, and temporal properties corresponding to the three fundamental quantities of length, mass, and time. Each of these parameters are further addressed in relation to its effect, its appropriate units or descriptors, methods of measurement, and its use or importance to image quality

An interplay of feedforward and feedback signals supporting visual cognition

Vast majority of visual cognitive functions from low to high level rely not only on feedforward signals carrying sensory input to downstream brain areas but also on internally-generated feedback signals traversing the brain in the opposite direction. The feedback signals underlie our ability to conjure up internal representations regardless of sensory input – when imagining an object or directly perceiving it. Despite ubiquitous implications of feedback signals in visual cognition, little is known about their functional organization in the brain. Multiple studies have shown that within the visual system the same brain region can concurrently represent feedforward and feedback contents. Given this spatial overlap, (1) how does the visual brain separate feedforward and feedback signals thus avoiding a mixture of the perceived and the imagined? Confusing the two information streams could lead to potentially detrimental consequences. Another body of research demonstrated that feedback connections between two different sensory systems participate in a rapid and effortless signal transmission across them. (2) How do nonvisual signals elicit visual representations? In this work, we aimed to scrutinize the functional organization of directed signal transmission in the visual brain by interrogating these two critical questions. In Studies I and II, we explored the functional segregation of feedforward and feedback signals in grey matter depth of early visual area V1 using 7T fMRI. In Study III we investigated the mechanism of cross-modal generalization using EEG. In Study I, we hypothesized that functional segregation of external and internally-generated visual contents follows the organization of feedforward and feedback anatomical projections revealed in primate tracing anatomy studies: feedforward projections were found to terminate in the middle cortical layer of primate area V1, whereas feedback connections project to the superficial and deep layers. We used high-resolution layer-specific fMRI and multivariate pattern analysis to test this hypothesis in a mental rotation task. We found that rotated contents were predominant at outer cortical depth compartments (i.e. superficial and deep). At the same time perceived contents were more strongly represented at the middle cortical compartment. These results correspond to the previous neuroanatomical findings and identify how through cortical depth compartmentalization V1 functionally segregates rather than confuses external from internally-generated visual contents. For the more precise estimation of signal-by-depth separation revealed in Study I, next we benchmarked three MR-sequences at 7T - gradient-echo, spin-echo, and vascular space occupancy - in their ability to differentiate feedforward and feedback signals in V1. The experiment in Study II consisted of two complementary tasks: a perception task that predominantly evokes feedforward signals and a working memory task that relies on feedback signals. We used multivariate pattern analysis to read out the perceived (feedforward) and memorized (feedback) grating orientation from neural signals across cortical depth. Analyses across all the MR-sequences revealed perception signals predominantly in the middle cortical compartment of area V1 and working memory signals in the deep compartment. Despite an overall consistency across sequences, spin-echo was the only sequence where both feedforward and feedback information were differently pronounced across cortical depth in a statistically robust way. We therefore suggest that in the context of a typical cognitive neuroscience experiment manipulating feedforward and feedback signals at 7T fMRI, spin-echo method may provide a favorable trade-off between spatial specificity and signal sensitivity. In Study III we focused on the second critical question - how are visual representations activated by signals belonging to another sensory modality? Here we built our hypothesis following the studies in the field of object recognition, which demonstrate that abstract category-level representations emerge in the brain after a brief stimuli presentation in the absence of any explicit categorization task. Based on these findings we assumed that two sensory systems can reach a modality-independent representational state providing a universal feature space which can be read out by both sensory systems. We used EEG and a paradigm in which participants were presented with images and spoken words while they were conducting an unrelated task. We aimed to explore whether categorical object representations in both modalities reflect a convergence towards modality-independent representations. We obtained robust representations of objects and object categories in visual and auditory modalities; however, we did not find a conceptual representation shared across modalities at the level of patterns extracted from EEG scalp electrodes in our study. Overall, our results show that feedforward and feedback signals are spatially segregated in the grey matter depth, possibly reflecting a general strategy for implementation of multiple cognitive functions within the same brain region. This differentiation can be revealed with diverse MR-sequences at 7T fMRI, where spin-echo sequence could be particularly suitable for establishing cortical depth-specific effects in humans. We did not find modality-independent representations which, according to our hypothesis, may subserve the activation of visual representations by the signals from another sensory system. This pattern of results indicates that identifying the mechanisms bridging different sensory systems is more challenging than exploring within-modality signal circuitry and this challenge requires further studies. With this, our results contribute to a large body of research interrogating how feedforward and feedback signals give rise to complex visual cognition