1,720,963 research outputs found
Image enhancement techniques for bioelectronic visual aids
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Verbesserung der Bildwahrnehmung beim prothetischen Sehen
No full textVision is the most crucial sense that a human being cannot live independently without. Visual prosthesis has been proposed as a promising solution to restore partial vision to people who lost their vision. Visual prostheses exploit the functional parts in the eye and the brain to enable partial restoration of vision. Despite its initial success, some challenges arise that hinder the ability of the patients implanted with visual prostheses to correctly recognize and localize objects. In this thesis, we introduce a variety of solutions to enhance the ability of visual prostheses users to correctly recognize and localize objects. Image processing and deep learning techniques are proposed in this thesis to simplify and better represent objects for visual prostheses users. One crucial challenge that arises in a typical visual prosthetic device is electrodes dropout, where some electrodes malfunction throughout time. To address this challenge, an optimal solution is proposed by translating the object of interest to a location in the visual field of the user such that the minimum amount of dropout exists. Another challenge that visual prostheses users face is the complexity of the viewed scene that is barely recognizable due to the low spatial and radiometric resolutions available through visual prostheses. Accordingly, we propose the utilization of clip art representation of images instead of the actual real photo to ease the recognition of any arbitrary object. We propose the use of You Only Look Once (YOLO), a deep learning model to retrieve the clip art that corresponds to an object detected by YOLO in a high-resolution photo. In addition, a deep learning-based approach using Generative Adversarial Networks (GANs), named PVGAN, is proposed to generate clip art images from given high-resolution photos to allow better and easier perception of the images in a visual prosthetic device. Finally, we combine three enhancement techniques with the GAN-generated clip art which are edge sharpening, corners sharpening and dropout handling to enhance object recognition and localization. The combined approach is tested in a mixed reality environment to simulate the visual representation perceived by visual prostheses users. A number of prosthetic vision simulation experiments were conducted on normally/correctly sighted participants to measure the efficacy of the proposed approaches using both computer screen and mixed reality. The results demonstrate that the usage of the proposed techniques enhances the ability of people to correctly recognize and localize objects. This could allow visual prostheses users to regain back their confidence and independence.Das Sehen ist der wichtigste Sinn, ohne den ein Mensch nicht unabhängig leben kann. Sehprothesen wurden als viel versprechende Lösung vorgeschlagen, um Menschen, die ihre Sehkraft verloren haben, zu helfen und ihnen ein teilweises Sehvermögen zu geben. Sie nutzen die funktionellen Teile des Auges und des Gehirns, um eine teilweise Wiederherstellung des Sehvermögens zu erzielen. Trotz anfänglicher Erfolge gibt es einige Probleme hinsichtlich der Fähigkeit der mit Sehprothesen ausgestatteten Patienten, Objekte richtig zu erkennen und zu lokalisieren. In dieser Arbeit stellen wir eine Reihe von Lösungen vor, um die Fähigkeiten von Sehprothesenträgern zu verbessern, Objekte richtig zu erkennen und zu lokalisieren. Techniken der Bildverarbeitung und des Deep Learning zur vereinfachten Nutzung von Sehprothesen werden entwickelt. Eine entscheidende Herausforderung, die bei einer typischen Sehprothese auftritt, ist der Ausfall von einzelnen Elektroden im Laufe der Zeit der Benutzung. Zur Bewältigung dieser Herausforderung wird eine optimale Lösung vorgeschlagen, indem das Objekt des Interesses an eine Position des Implantats im Gesichtsfeld des Benutzers verschoben wird, so dass das die Fläche des Objektsegments von möglichst wenigen ausfallenden Elektroden betroffenist. Eine weitere Herausforderung für die Nutzer von Sehprothesen ist die Komplexität der betrachteten Szene, die aufgrund der geringen räumlichen und radiometrischen Auflösung, die mit Sehprothesen möglich ist, kaum erkennbar ist. Dementsprechend schlagen wir die Verwendung von clip art-Darstellungen der abgebildeten Objekte anstelle der realen Fotos vor, um die Erkennung beliebiger Objekte zu erleichtern. Wir schlagen die Verwendung von You Only Look Once (YOLO) vor, einem Modell für tiefes Lernen, um die clip art Darstellung abzurufen, die einem Objekt entspricht, das, auch mittles YOLO, in einem hochauflösenden Foto erkannt wurde. Darüber hinaus wird ein auf Deep Learning basierender Ansatz mit generativen adversarialen Netzwerken (GANs), genannt PVGAN, vorgeschlagen, um clip art-Bilder aus gegebenen hochauflösenden Fotos zu generieren, um eine bessere und einfachere Wahrnehmung der Bilder in einer Sehprothese zu ermöglichen. Schließlich kombinieren wir drei Methoden zur Verbesserung der Objekterkennung und lokalisierung mit den GAN-generierten Cliparts, nämlich Kantenschärfung, Eckenschärfung und Dropout. Der kombinierte Ansatz wird in einer Gemischte-Realität-Umgebung getestet, um die visuelle Darstellung zu simulieren, die von Prothesenbenutzern wahrgenommen wird. Eine Reihe von Experimenten zur Simulation des Sehvermögens von Prothesenträgern wurde an normalsichtigen Teilnehmern durchgeführt, um die Wirksamkeit der vorgeschlagenen Ansätze sowohl auf dem Computerbildschirm als auch in der gemischte Realität zu ermitteln. Die Ergebnisse zeigen, dass die Anwendung der vorgeschlagenen Techniken die Fähigkeit von Menschen verbessert, Objekte korrekt zu erkennen und zu lokalisieren. Dies könnte Nutzern von Sehprothesen ermöglichen, ihr Selbstvertrauen und ihre Unabhängigkeit wiederzuerlangen
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
