1,720,956 research outputs found
Active vision for efficient 3D reconstruction and rendering
No full textUniversity of Minnesota Ph.D. dissertation. June 2025. Major: Computer Science. Advisor: Nikolaos Papanikolopoulos. 1 computer file (PDF); ix, 95 pages.Active vision (AV) has been in the spotlight of robotics research due to its emergence in numerous applications, including urban surveillance, agriculture, and biomedicine just to list a few. Two major AV problems that gained popularity are the 3D reconstruction and scene rendering of targeted environments using different views of 2D images. While collecting and processing a large number of arbitrarily taken 2D images may become an arduous process in several practical settings, an efficient solution is to seek the optimal placement of available cameras in the 3D space so as to obtain the necessary visual information from fewer yet more informative images to effectively reconstruct or render environments of interest. In the first chapter, we introduce the problems of view planning (VP) and scene rendering, and the open challenges that this thesis addresses. The second chapter aims to alleviate the reliance on a pre-defined mesh model of the environment, which is a common assumption in existing model-based VP approaches. To that end, this chapter presents an efficient and realistic VP pipeline, which aims to optimize the viewpoints of cameras and hence the quality of the 3D reconstruction of a field of row crops without need for a given mesh model. The goal of the third chapter is to cope with the challenge of existing environmental noise that is not explicitly accounted for in existing VP approaches. To that end, a novel geometric-based reconstruction quality function is introduced for VP, that accounts for the existing noise of the environment, without requiring its closed-form expression. With no analytic expression of the objective function, this chapter presents an adaptive Bayesian optimization framework for accurate 3D reconstruction in the presence of environmental noise. The fourth chapter aims (i) to overcome the errors induced by certain geometric proxies in geometric-based VP approaches arising from e.g. non-informative and insufficient geometric cues, and (ii) to identify optimal VP solutions with adaptivity to similar yet unknown environments without need for re-training/re-optimization. This chapter presents an alternative VP framework that considers a reconstruction quality-based optimization formulation. The fifth chapter focuses on the 3D scene rendering task, relying on the so-termed Gaussian splatting (GS) models that provide outstanding visual quality along with computational efficiency. It proposes an active image selection framework to assist GS models aiming to address the limitations of existing passive GS approaches. Specifically, these approaches rely on either (i) densely collected views that introduce redundancy and increase processing and computational costs, or (ii) sparse-view settings that may result in reduced scene coverage and limited expressiveness of the 3D scene representation.Bacharis, Athanasios. (2025). Active vision for efficient 3D reconstruction and rendering. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/278059
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
Active vision for efficient 3D reconstruction and rendering
Get PDFUniversity of Minnesota Ph.D. dissertation.July 2025. Major: Computer Science. Advisor: Nikolaos Papanikolopoulos. 1 computer file (PDF); vi, 95 pages.Active vision (AV) has been in the spotlight of robotics research due to its emergence in numerous applications, including urban surveillance, agriculture, and biomedicine just to list a few. Two major AV problems that gained popularity are the 3D reconstruction and scene rendering of targeted environments using different views of 2D images. While collecting and processing a large number of arbitrarily taken 2D images may become an arduous process in several practical settings, an efficient solution is to seek the optimal placement of available cameras in the 3D space so as to obtain the necessary visual information from fewer yet more informative images to effectively reconstruct or render environments of interest. In the first chapter, we introduce the problems of view planning (VP) and scene rendering, and the open challenges that this thesis addresses. The second chapter aims to alleviate the reliance on a pre-defined mesh model of the environment, which is a common assumption in existing model-based VP approaches. To that end, this chapter presents an efficient and realistic VP pipeline, which aims to optimize the viewpoints of cameras and hence the quality of the 3D reconstruction of a field of row crops without need for a given mesh model. The goal of the third chapter is to cope with the challenge of existing environmental noise that is not explicitly accounted for in existing VP approaches. To that end, a novel geometric-based reconstruction quality function is introduced for VP, that accounts for the existing noise of the environment, without requiring its closed-form expression. With no analytic expression of the objective function, this chapter presents an adaptive Bayesian optimization framework for accurate 3D reconstruction in the presence of environmental noise. The fourth chapter aims (i) to overcome the errors induced by certain geometric proxies in geometric-based VP approaches arising from e.g. non-informative and insufficient geometric cues, and (ii) to identify optimal VP solutions with adaptivity to similar yet unknown environments without need for re-training/re-optimization. This chapter presents an alternative VP framework that considers a reconstruction quality-based optimization formulation. The fifth chapter focuses on the 3D scene rendering task, relying on the so-termed Gaussian splatting (GS) models that provide outstanding visual quality along with computational efficiency. It proposes an active image selection framework to assist GS models aiming to address the limitations of existing passive GS approaches. Specifically, these approaches rely on either (i) densely collected views that introduce redundancy and increase processing and computational costs, or (ii) sparse-view settings that may result in reduced scene coverage and limited expressiveness of the 3D scene representation.Bacharis, Athanasios. (2025). Active vision for efficient 3D reconstruction and rendering. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/277408
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
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