Records |
Author |
Bogdan Raducanu; Fadi Dornaika |
Title |
Texture-independent recognition of facial expressions in image snapshots and videos |
Type |
Journal Article |
Year |
2013 |
Publication |
Machine Vision and Applications |
Abbreviated Journal |
MVA |
Volume |
24 |
Issue |
4 |
Pages |
811-820 |
Keywords |
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Abstract |
This paper addresses the static and dynamic recognition of basic facial expressions. It has two main contributions. First, we introduce a view- and texture-independent scheme that exploits facial action parameters estimated by an appearance-based 3D face tracker. We represent the learned facial actions associated with different facial expressions by time series. Second, we compare this dynamic scheme with a static one based on analyzing individual snapshots and show that the former performs better than the latter. We provide evaluations of performance using three subspace learning techniques: linear discriminant analysis, non-parametric discriminant analysis and support vector machines. |
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Corporate Author |
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Thesis |
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Publisher |
Springer-Verlag |
Place of Publication |
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Editor |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0932-8092 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
OR; 600.046; 605.203;MV |
Approved |
no |
Call Number |
Admin @ si @ RaD2013 |
Serial |
2230 |
Permanent link to this record |
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Author |
Ferran Diego; Joan Serrat; Antonio Lopez |
Title |
Joint spatio-temporal alignment of sequences |
Type |
Journal Article |
Year |
2013 |
Publication |
IEEE Transactions on Multimedia |
Abbreviated Journal |
TMM |
Volume |
15 |
Issue |
6 |
Pages |
1377-1387 |
Keywords |
video alignment |
Abstract |
Video alignment is important in different areas of computer vision such as wide baseline matching, action recognition, change detection, video copy detection and frame dropping prevention. Current video alignment methods usually deal with a relatively simple case of fixed or rigidly attached cameras or simultaneous acquisition. Therefore, in this paper we propose a joint video alignment for bringing two video sequences into a spatio-temporal alignment. Specifically, the novelty of the paper is to formulate the video alignment to fold the spatial and temporal alignment into a single alignment framework. This simultaneously satisfies a frame-correspondence and frame-alignment similarity; exploiting the knowledge among neighbor frames by a standard pairwise Markov random field (MRF). This new formulation is able to handle the alignment of sequences recorded at different times by independent moving cameras that follows a similar trajectory, and also generalizes the particular cases that of fixed geometric transformation and/or linear temporal mapping. We conduct experiments on different scenarios such as sequences recorded simultaneously or by moving cameras to validate the robustness of the proposed approach. The proposed method provides the highest video alignment accuracy compared to the state-of-the-art methods on sequences recorded from vehicles driving along the same track at different times. |
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Series Editor |
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Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1520-9210 |
ISBN |
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Medium |
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Area |
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Conference |
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Notes |
ADAS |
Approved |
no |
Call Number |
Admin @ si @ DSL2013; ADAS @ adas @ |
Serial |
2228 |
Permanent link to this record |
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Author |
German Ros; J. Guerrero; Angel Sappa; Antonio Lopez |
Title |
VSLAM pose initialization via Lie groups and Lie algebras optimization |
Type |
Conference Article |
Year |
2013 |
Publication |
Proceedings of IEEE International Conference on Robotics and Automation |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
5740 - 5747 |
Keywords |
SLAM |
Abstract |
We present a novel technique for estimating initial 3D poses in the context of localization and Visual SLAM problems. The presented approach can deal with noise, outliers and a large amount of input data and still performs in real time in a standard CPU. Our method produces solutions with an accuracy comparable to those produced by RANSAC but can be much faster when the percentage of outliers is high or for large amounts of input data. On the current work we propose to formulate the pose estimation as an optimization problem on Lie groups, considering their manifold structure as well as their associated Lie algebras. This allows us to perform a fast and simple optimization at the same time that conserve all the constraints imposed by the Lie group SE(3). Additionally, we present several key design concepts related with the cost function and its Jacobian; aspects that are critical for the good performance of the algorithm. |
Address |
Karlsruhe; Germany; May 2013 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1050-4729 |
ISBN |
978-1-4673-5641-1 |
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Expedition |
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Conference |
ICRA |
Notes |
ADAS; 600.054; 600.055; 600.057 |
Approved |
no |
Call Number |
Admin @ si @ RGS2013a; ADAS @ adas @ |
Serial |
2225 |
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Author |
David Aldavert; Marçal Rusiñol; Ricardo Toledo; Josep Llados |
Title |
Integrating Visual and Textual Cues for Query-by-String Word Spotting |
Type |
Conference Article |
Year |
2013 |
Publication |
12th International Conference on Document Analysis and Recognition |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
511 - 515 |
Keywords |
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Abstract |
In this paper, we present a word spotting framework that follows the query-by-string paradigm where word images are represented both by textual and visual representations. The textual representation is formulated in terms of character $n$-grams while the visual one is based on the bag-of-visual-words scheme. These two representations are merged together and projected to a sub-vector space. This transform allows to, given a textual query, retrieve word instances that were only represented by the visual modality. Moreover, this statistical representation can be used together with state-of-the-art indexation structures in order to deal with large-scale scenarios. The proposed method is evaluated using a collection of historical documents outperforming state-of-the-art performances. |
Address |
Washington; USA; August 2013 |
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Series Volume |
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Edition |
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ISSN |
1520-5363 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
ICDAR |
Notes |
DAG; ADAS; 600.045; 600.055; 600.061 |
Approved |
no |
Call Number |
Admin @ si @ ART2013 |
Serial |
2224 |
Permanent link to this record |
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Author |
Marc Castello; Jordi Gonzalez; Ariel Amato; Pau Baiget; Carles Fernandez; Josep M. Gonfaus; Ramon Mollineda; Marco Pedersoli; Nicolas Perez de la Blanca; Xavier Roca |
Title |
Exploiting Multimodal Interaction Techniques for Video-Surveillance |
Type |
Book Chapter |
Year |
2013 |
Publication |
Multimodal Interaction in Image and Video Applications Intelligent Systems Reference Library |
Abbreviated Journal |
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Volume |
48 |
Issue |
8 |
Pages |
135-151 |
Keywords |
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Abstract |
In this paper we present an example of a video surveillance application that exploits Multimodal Interactive (MI) technologies. The main objective of the so-called VID-Hum prototype was to develop a cognitive artificial system for both the detection and description of a particular set of human behaviours arising from real-world events. The main procedure of the prototype described in this chapter entails: (i) adaptation, since the system adapts itself to the most common behaviours (qualitative data) inferred from tracking (quantitative data) thus being able to recognize abnormal behaviors; (ii) feedback, since an advanced interface based on Natural Language understanding allows end-users the communicationwith the prototype by means of conceptual sentences; and (iii) multimodality, since a virtual avatar has been designed to describe what is happening in the scene, based on those textual interpretations generated by the prototype. Thus, the MI methodology has provided an adequate framework for all these cooperating processes. |
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Corporate Author |
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Thesis |
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Publisher |
Springer Berlin Heidelberg |
Place of Publication |
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Editor |
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Language |
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Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1868-4394 |
ISBN |
978-3-642-35931-6 |
Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISE; 605.203; 600.049 |
Approved |
no |
Call Number |
CGA2013 |
Serial |
2222 |
Permanent link to this record |
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Author |
Francisco Javier Orozco; Ognjen Rudovic; Jordi Gonzalez; Maja Pantic |
Title |
Hierarchical On-line Appearance-Based Tracking for 3D Head Pose, Eyebrows, Lips, Eyelids and Irises |
Type |
Journal Article |
Year |
2013 |
Publication |
Image and Vision Computing |
Abbreviated Journal |
IMAVIS |
Volume |
31 |
Issue |
4 |
Pages |
322-340 |
Keywords |
On-line appearance models; Levenberg–Marquardt algorithm; Line-search optimization; 3D face tracking; Facial action tracking; Eyelid tracking; Iris tracking |
Abstract |
In this paper, we propose an On-line Appearance-Based Tracker (OABT) for simultaneous tracking of 3D head pose, lips, eyebrows, eyelids and irises in monocular video sequences. In contrast to previously proposed tracking approaches, which deal with face and gaze tracking separately, our OABT can also be used for eyelid and iris tracking, as well as 3D head pose, lips and eyebrows facial actions tracking. Furthermore, our approach applies an on-line learning of changes in the appearance of the tracked target. Hence, the prior training of appearance models, which usually requires a large amount of labeled facial images, is avoided. Moreover, the proposed method is built upon a hierarchical combination of three OABTs, which are optimized using a Levenberg–Marquardt Algorithm (LMA) enhanced with line-search procedures. This, in turn, makes the proposed method robust to changes in lighting conditions, occlusions and translucent textures, as evidenced by our experiments. Finally, the proposed method achieves head and facial actions tracking in real-time. |
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Publisher |
Elsevier |
Place of Publication |
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Editor |
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Conference |
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Notes |
ISE; 605.203; 302.012; 302.018; 600.049 |
Approved |
no |
Call Number |
ORG2013 |
Serial |
2221 |
Permanent link to this record |
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Author |
Muhammad Muzzamil Luqman; Jean-Yves Ramel; Josep Llados; Thierry Brouard |
Title |
Fuzzy Multilevel Graph Embedding |
Type |
Journal Article |
Year |
2013 |
Publication |
Pattern Recognition |
Abbreviated Journal |
PR |
Volume |
46 |
Issue |
2 |
Pages |
551-565 |
Keywords |
Pattern recognition; Graphics recognition; Graph clustering; Graph classification; Explicit graph embedding; Fuzzy logic |
Abstract |
Structural pattern recognition approaches offer the most expressive, convenient, powerful but computational expensive representations of underlying relational information. To benefit from mature, less expensive and efficient state-of-the-art machine learning models of statistical pattern recognition they must be mapped to a low-dimensional vector space. Our method of explicit graph embedding bridges the gap between structural and statistical pattern recognition. We extract the topological, structural and attribute information from a graph and encode numeric details by fuzzy histograms and symbolic details by crisp histograms. The histograms are concatenated to achieve a simple and straightforward embedding of graph into a low-dimensional numeric feature vector. Experimentation on standard public graph datasets shows that our method outperforms the state-of-the-art methods of graph embedding for richly attributed graphs. |
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Publisher |
Elsevier |
Place of Publication |
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Editor |
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Edition |
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ISSN |
0031-3203 |
ISBN |
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Area |
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Conference |
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Notes |
DAG; 600.042; 600.045; 605.203 |
Approved |
no |
Call Number |
Admin @ si @ LRL2013a |
Serial |
2270 |
Permanent link to this record |
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Author |
Carles Sanchez; Debora Gil; Antoni Rosell; Albert Andaluz; F. Javier Sanchez |
Title |
Segmentation of Tracheal Rings in Videobronchoscopy combining Geometry and Appearance |
Type |
Conference Article |
Year |
2013 |
Publication |
Proceedings of the International Conference on Computer Vision Theory and Applications |
Abbreviated Journal |
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Volume |
1 |
Issue |
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Pages |
153--161 |
Keywords |
Video-bronchoscopy, tracheal ring segmentation, trachea geometric and appearance model |
Abstract |
Videobronchoscopy is a medical imaging technique that allows interactive navigation inside the respiratory pathways and minimal invasive interventions. Tracheal procedures are ordinary interventions that require measurement of the percentage of obstructed pathway for injury (stenosis) assessment. Visual assessment of stenosis in videobronchoscopic sequences requires high expertise of trachea anatomy and is prone to human error. Accurate detection of tracheal rings is the basis for automated estimation of the size of stenosed trachea. Processing of videobronchoscopic images acquired at the operating room is a challenging task due to the wide range of artifacts and acquisition conditions. We present a model of the geometric-appearance of tracheal rings for its detection in videobronchoscopic videos. Experiments on sequences acquired at the operating room, show a performance close to inter-observer variability |
Address |
Barcelona; February 2013 |
Corporate Author |
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Thesis |
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Publisher |
SciTePress |
Place of Publication |
Portugal |
Editor |
Sebastiano Battiato and José Braz |
Language |
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Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
LNCS |
Series Volume |
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Series Issue |
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Edition |
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ISSN |
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ISBN |
978-989-8565-47-1 |
Medium |
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Area |
800 |
Expedition |
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Conference |
VISAPP |
Notes |
IAM;MV; 600.044; 600.047; 600.060; 605.203 |
Approved |
no |
Call Number |
IAM @ iam @ SGR2013 |
Serial |
2123 |
Permanent link to this record |
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Author |
Anjan Dutta; Josep Llados; Umapada Pal |
Title |
A symbol spotting approach in graphical documents by hashing serialized graphs |
Type |
Journal Article |
Year |
2013 |
Publication |
Pattern Recognition |
Abbreviated Journal |
PR |
Volume |
46 |
Issue |
3 |
Pages |
752-768 |
Keywords |
Symbol spotting; Graphics recognition; Graph matching; Graph serialization; Graph factorization; Graph paths; Hashing |
Abstract |
In this paper we propose a symbol spotting technique in graphical documents. Graphs are used to represent the documents and a (sub)graph matching technique is used to detect the symbols in them. We propose a graph serialization to reduce the usual computational complexity of graph matching. Serialization of graphs is performed by computing acyclic graph paths between each pair of connected nodes. Graph paths are one-dimensional structures of graphs which are less expensive in terms of computation. At the same time they enable robust localization even in the presence of noise and distortion. Indexing in large graph databases involves a computational burden as well. We propose a graph factorization approach to tackle this problem. Factorization is intended to create a unified indexed structure over the database of graphical documents. Once graph paths are extracted, the entire database of graphical documents is indexed in hash tables by locality sensitive hashing (LSH) of shape descriptors of the paths. The hashing data structure aims to execute an approximate k-NN search in a sub-linear time. We have performed detailed experiments with various datasets of line drawings and compared our method with the state-of-the-art works. The results demonstrate the effectiveness and efficiency of our technique. |
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Elsevier |
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ISSN |
0031-3203 |
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Notes |
DAG; 600.042; 600.045; 605.203; 601.152 |
Approved |
no |
Call Number |
Admin @ si @ DLP2012 |
Serial |
2127 |
Permanent link to this record |
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Author |
Laura Igual; Agata Lapedriza; Ricard Borras |
Title |
Robust Gait-Based Gender Classification using Depth Cameras |
Type |
Journal Article |
Year |
2013 |
Publication |
EURASIP Journal on Advances in Signal Processing |
Abbreviated Journal |
EURASIPJ |
Volume |
37 |
Issue |
1 |
Pages |
72-80 |
Keywords |
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Abstract |
This article presents a new approach for gait-based gender recognition using depth cameras, that can run in real time. The main contribution of this study is a new fast feature extraction strategy that uses the 3D point cloud obtained from the frames in a gait cycle. For each frame, these points are aligned according to their centroid and grouped. After that, they are projected into their PCA plane, obtaining a representation of the cycle particularly robust against view changes. Then, final discriminative features are computed by first making a histogram of the projected points and then using linear discriminant analysis. To test the method we have used the DGait database, which is currently the only publicly available database for gait analysis that includes depth information. We have performed experiments on manually labeled cycles and over whole video sequences, and the results show that our method improves the accuracy significantly, compared with state-of-the-art systems which do not use depth information. Furthermore, our approach is insensitive to illumination changes, given that it discards the RGB information. That makes the method especially suitable for real applications, as illustrated in the last part of the experiments section. |
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Notes |
MILAB; OR;MV |
Approved |
no |
Call Number |
Admin @ si @ ILB2013 |
Serial |
2144 |
Permanent link to this record |
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Author |
Michal Drozdzal; Santiago Segui; Carolina Malagelada; Fernando Azpiroz; Petia Radeva |
Title |
Adaptable image cuts for motility inspection using WCE |
Type |
Journal Article |
Year |
2013 |
Publication |
Computerized Medical Imaging and Graphics |
Abbreviated Journal |
CMIG |
Volume |
37 |
Issue |
1 |
Pages |
72-80 |
Keywords |
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Abstract |
The Wireless Capsule Endoscopy (WCE) technology allows the visualization of the whole small intestine tract. Since the capsule is freely moving, mainly by the means of peristalsis, the data acquired during the study gives a lot of information about the intestinal motility. However, due to: (1) huge amount of frames, (2) complex intestinal scene appearance and (3) intestinal dynamics that make difficult the visualization of the small intestine physiological phenomena, the analysis of the WCE data requires computer-aided systems to speed up the analysis. In this paper, we propose an efficient algorithm for building a novel representation of the WCE video data, optimal for motility analysis and inspection. The algorithm transforms the 3D video data into 2D longitudinal view by choosing the most informative, from the intestinal motility point of view, part of each frame. This step maximizes the lumen visibility in its longitudinal extension. The task of finding “the best longitudinal view” has been defined as a cost function optimization problem which global minimum is obtained by using Dynamic Programming. Validation on both synthetic data and WCE data shows that the adaptive longitudinal view is a good alternative to the traditional motility analysis done by video analysis. The proposed novel data representation a new, holistic insight into the small intestine motility, allowing to easily define and analyze motility events that are difficult to spot by analyzing WCE video. Moreover, the visual inspection of small intestine motility is 4 times faster then by means of video skimming of the WCE. |
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Notes |
MILAB; OR; 600.046; 605.203 |
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no |
Call Number |
Admin @ si @ DSM2012 |
Serial |
2151 |
Permanent link to this record |
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Author |
David Geronimo; Joan Serrat; Antonio Lopez; Ramon Baldrich |
Title |
Traffic sign recognition for computer vision project-based learning |
Type |
Journal Article |
Year |
2013 |
Publication |
IEEE Transactions on Education |
Abbreviated Journal |
T-EDUC |
Volume |
56 |
Issue |
3 |
Pages |
364-371 |
Keywords |
traffic signs |
Abstract |
This paper presents a graduate course project on computer vision. The aim of the project is to detect and recognize traffic signs in video sequences recorded by an on-board vehicle camera. This is a demanding problem, given that traffic sign recognition is one of the most challenging problems for driving assistance systems. Equally, it is motivating for the students given that it is a real-life problem. Furthermore, it gives them the opportunity to appreciate the difficulty of real-world vision problems and to assess the extent to which this problem can be solved by modern computer vision and pattern classification techniques taught in the classroom. The learning objectives of the course are introduced, as are the constraints imposed on its design, such as the diversity of students' background and the amount of time they and their instructors dedicate to the course. The paper also describes the course contents, schedule, and how the project-based learning approach is applied. The outcomes of the course are discussed, including both the students' marks and their personal feedback. |
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ISSN |
0018-9359 |
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Notes |
ADAS; CIC |
Approved |
no |
Call Number |
Admin @ si @ GSL2013; ADAS @ adas @ |
Serial |
2160 |
Permanent link to this record |
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Author |
Joan Serrat; Felipe Lumbreras; Antonio Lopez |
Title |
Cost estimation of custom hoses from STL files and CAD drawings |
Type |
Journal Article |
Year |
2013 |
Publication |
Computers in Industry |
Abbreviated Journal |
COMPUTIND |
Volume |
64 |
Issue |
3 |
Pages |
299-309 |
Keywords |
On-line quotation; STL format; Regression; Gaussian process |
Abstract |
We present a method for the cost estimation of custom hoses from CAD models. They can come in two formats, which are easy to generate: a STL file or the image of a CAD drawing showing several orthogonal projections. The challenges in either cases are, first, to obtain from them a high level 3D description of the shape, and second, to learn a regression function for the prediction of the manufacturing time, based on geometric features of the reconstructed shape. The chosen description is the 3D line along the medial axis of the tube and the diameter of the circular sections along it. In order to extract it from STL files, we have adapted RANSAC, a robust parametric fitting algorithm. As for CAD drawing images, we propose a new technique for 3D reconstruction from data entered on any number of orthogonal projections. The regression function is a Gaussian process, which does not constrain the function to adopt any specific form and is governed by just two parameters. We assess the accuracy of the manufacturing time estimation by k-fold cross validation on 171 STL file models for which the time is provided by an expert. The results show the feasibility of the method, whereby the relative error for 80% of the testing samples is below 15%. |
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Elsevier |
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Notes |
ADAS; 600.057; 600.054; 605.203 |
Approved |
no |
Call Number |
Admin @ si @ SLL2013; ADAS @ adas @ |
Serial |
2161 |
Permanent link to this record |
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Author |
Fadi Dornaika; Abdelmalik Moujahid; Bogdan Raducanu |
Title |
Facial expression recognition using tracked facial actions: Classifier performance analysis |
Type |
Journal Article |
Year |
2013 |
Publication |
Engineering Applications of Artificial Intelligence |
Abbreviated Journal |
EAAI |
Volume |
26 |
Issue |
1 |
Pages |
467-477 |
Keywords |
Visual face tracking; 3D deformable models; Facial actions; Dynamic facial expression recognition; Human–computer interaction |
Abstract |
In this paper, we address the analysis and recognition of facial expressions in continuous videos. More precisely, we study classifiers performance that exploit head pose independent temporal facial action parameters. These are provided by an appearance-based 3D face tracker that simultaneously provides the 3D head pose and facial actions. The use of such tracker makes the recognition pose- and texture-independent. Two different schemes are studied. The first scheme adopts a dynamic time warping technique for recognizing expressions where training data are given by temporal signatures associated with different universal facial expressions. The second scheme models temporal signatures associated with facial actions with fixed length feature vectors (observations), and uses some machine learning algorithms in order to recognize the displayed expression. Experiments quantified the performance of different schemes. These were carried out on CMU video sequences and home-made video sequences. The results show that the use of dimension reduction techniques on the extracted time series can improve the classification performance. Moreover, these experiments show that the best recognition rate can be above 90%. |
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Elsevier |
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OR; 600.046;MV |
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Admin @ si @ DMR2013 |
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2185 |
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David Roche; Debora Gil; Jesus Giraldo |
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Multiple active receptor conformation, agonist efficacy and maximum effect of the system: the conformation-based operational model of agonism, |
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2013 |
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Drug Discovery Today |
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DDT |
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18 |
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7-8 |
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365-371 |
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The operational model of agonism assumes that the maximum effect a particular receptor system can achieve (the Em parameter) is fixed. Em estimates are above but close to the asymptotic maximum effects of endogenous agonists. The concept of Em is contradicted by superagonists and those positive allosteric modulators that significantly increase the maximum effect of endogenous agonists. An extension of the operational model is proposed that assumes that the Em parameter does not necessarily have a single value for a receptor system but has multiple values associated to multiple active receptor conformations. The model provides a mechanistic link between active receptor conformation and agonist efficacy, which can be useful for the analysis of agonist response under different receptor scenarios. |
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Elsevier |
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IAM; 600.057; 600.054 |
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IAM @ iam @ RGG2013a |
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2190 |
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