1,720,977 research outputs found
From scans to models: Registration of 3D human shapes exploiting texture information
Full text linkNew scanning technologies are increasing the importance of 3D mesh data, and of algorithms that can reliably register meshes obtained from multiple scans. Surface registration is important e.g. for building full 3D models from partial scans, identifying and tracking objects in a 3D scene, creating statistical shape models.
Human body registration is particularly important for many applications, ranging from biomedicine and robotics to the production of movies and video games; but obtaining accurate and reliable registrations is challenging, given the articulated, non-rigidly deformable structure of the human body.
In this thesis, we tackle the problem of 3D human body registration. We start by analyzing the current state of the art, and find that: a) most registration techniques rely only on geometric information, which is ambiguous on flat surface areas; b) there is a lack of adequate datasets and benchmarks in the field. We address both issues.
Our contribution is threefold. First, we present a model-based registration technique for human meshes that combines geometry and surface texture information to provide highly accurate mesh-to-mesh correspondences. Our approach estimates scene lighting and surface albedo, and uses the albedo to construct a high-resolution textured 3D body model that is brought into registration with multi-camera image data using a robust matching term.
Second, by leveraging our technique, we present FAUST (Fine Alignment Using Scan Texture), a novel dataset collecting 300 high-resolution scans of 10 people in a wide range of poses. FAUST is the first dataset providing both real scans and automatically computed, reliable ground-truth correspondences between them.
Third, we explore possible uses of our approach in dermatology. By combining our registration technique with a melanocytic lesion segmentation algorithm, we propose a system that automatically detects new or evolving lesions over almost the entire body surface, thus helping dermatologists identify potential melanomas.
We conclude this thesis investigating the benefits of using texture information to establish frame-to-frame correspondences in dynamic monocular sequences captured with consumer depth cameras. We outline a novel approach to reconstruct realistic body shape and appearance models from dynamic human performances, and show preliminary results on challenging sequences captured with a Kinect
Optimal throughput and delay in delay-tolerant networks with ballistic mobility
No full textThis work studies delay and throughput achievable in delay-tolerant networks with ballistic mobility -- informally, when the average distance a node travels before changing direction does not become vanishingly small as the number of nodes in the deployment area grows. Ballistic mobility is a simple condition satisfied by a large number of well-studied mobility models, including the i.i.d. model, the random waypoint model, the uniform mobility model and Levy walks with exponent less than 1. Our contribution is twofold. First, we show that, under some very mild and natural hypotheses satisfied by all models in the literature, ballistic mobility is strictly necessary to achieve simultaneously, as the number of nodes grows, a) per-node throughput that does not become vanishingly small and b) communication delay that does not become infinitely large. Any network whose nodes exhibit a more "local" mobility pattern (e.g. Levy walks with exponent greater than 1, or Brownian motion) must sacrifice either a) or b), regardless of the communication scheme adopted -- even with network coding.
Second, we present a novel packet routing scheme. Our scheme is relatively simple and does not rely on centralized control, replication, or static base stations. At the same time it achieves both non-vanishing throughput and bounded delay as the number of nodes grows, on any network with ballistic mobility (i.e. whenever they can be simultaneously achieved), asymptotically outperforming any existing communication scheme that exploits node mobility to boost throughput
psort
Full text linkpsort è stato il più veloce software di ordinamento per macchine di classe PC dal 2008 al 2011 (benchmark Pennysort, http://sortbenchmark.org) e un suo adattamento per cluster ha migliorato il record per il benchmark datamation di quasi un ordine di grandezza nel 2011. Il rapporto tecnico ufficiale si trova sul sito sortbenchmark.org (che cataloga i più efficienti software di ordinamento per varie categorie di task/hardware - originariamente mantenuto dal premio Turing Jim Gray) all'URL http://sortbenchmark.org/psort_2011.pdf -- Ulteriori dettagli si possono trovare nelle pubblicazioni:
P. Bertasi, M. Bressan, E. Peserico. psort, yet another fast stable sorting software, ACM Journal of Experimental Algorithmics, vol. 16, 2011 --
P. Bertasi, M. Bonazza, M. Bressan, E. Peserico. Datamation: a quarter of a century and four orders of magnitude later. Proc. of IEEE CLUSTER 201
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Psoriasis segmentation through chromatic regions and Geometric Active Contours
No full textWe present a novel approach to the segmentation of psoriasis lesions in "full body" digital photographs potentially involving dozens or even hundreds of separate lesions. Our algorithm first isolates a set of zones that certainly correspond to lesional plaques based on chromatic information, and then expands these zones to achieve an accurate segmentation of plaques through a Geometric Active Contours method. The variability in segmentation between our algorithm and different human operators appears comparable to the variability between human operators
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Variability in human and automated segmentation of dermoscopy images of melanocytic skin lesions
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