1,720,964 research outputs found
MUBIDUS-I: A multibiometric and multipurpose dataset
No full textIndividual biometric traits can seldom fulfill the requirements of security systems in the wild, so researchers were led to investigate multi-biometric/multi-modal systems. This has produced increasing demand for datasets suitable for validating multi-trait and multi-modal biometric systems. Recent devices available for image acquisition and processing can provide a wide range of data sources for biometric applications. The purpose of this work is to present a new multi-biometric dataset that includes a number of traits and acquisition devices wider than most existing datasets. It includes images and videos acquired from 80 subjects in an indoor and outdoor environment, in controlled and non-controlled conditions. Traits such as face, periocular regions, ear, iris, and others are acquired by cameras, mobile devices, and a drone. The data are structured to support experiments adhering to the most common protocols in the literature
Remote 3D face reconstruction by means of autonomous unmanned aerial vehicles
No full textThe 3D face model of an individual includes a rich amount of information useful in many application scenarios. Currently, the 3D reconstruction from images is obtained through multiple acquisitions at different distances and angles in a controlled environment. “In the wild’ conditions, or inadequate acquisition systems, can make 3D reconstruction a strongly error-prone problem. This paper illustrates a system that creates 3D face models from images taken by unmanned aerial vehicles in a completely automatic way. The proposed method is adaptive, dynamic, and contactless. No human intervention is required for image acquisition. Experimental results are described—in particular, the comparison between the ideal 3D reconstructions, obtained in controlled and cooperative conditions, and the reconstructions obtained by the drone during flight at different resolutions. The results show good overlap of the models and a low co-registration error. Given the free mobility of the UAVs, the system is suitable, among other applications, for biometrics and open-air access control over large areas
Ollivier-Ricci Curvature For Head Pose Estimation From a Single Image
No full textHead pose estimation is not only a crucial challenge for many real-world applications, such as driver attention detection analysis, but it represents an interesting strategy to support biometric frameworks as well. This paper aims to estimate head pose from a single image by applying notions of network curvature. In the real world, many complex networks have groups of nodes that are well connected to each other with significant functional roles. Similarly, the interactions of facial landmarks can be represented as complex dynamic systems modeled by weighted graphs. The functionality of such a system is therefore intrinsically linked to the topology and geometry of the underlying graph. In this work, using the geometric notion of Ollivier-Ricci curvature (ORC) on weighted graphs as input to the XGBoost regression model, we show that the intrinsic geometric basis of ORC offers a natural approach to discovering underlying common structure within a pool of poses. Experiments on the BIWI, AFLW2000 and Pointing`04 datasets show that the ORC XGB method performs well compared to state-ofthe-art methods, both landmark-based and image-only
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
A Range/Domain Approximation Error Based Approach for Fractal Image Compression
Full text linkFractals can be an effective approach for several applications
other than image coding and transmission: database indexing,
texture mapping, and even pattern recognition problems
such as writer authentication. However, fractal-based algorithms
are strongly asymmetric because, in spite of the linearity of the decoding
phase, the coding process is much more time consuming.
Many different solutions have been proposed for this problem, but
there is not yet a standard for fractal coding. This paper proposes
a method to reduce the complexity of the image coding phase by
classifying the blocks according to an approximation error measure.
It is formally shown that postponing range\slash domain comparisons
with respect to a preset block, it is possible to reduce
drastically the amount of operations needed to encode each range.
The proposed method has been compared with three other fractal
coding methods, showing under which circumstances it performs
better in terms of both bit rate and/or computing time
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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