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Records |
Links |
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Author |
Miquel Ferrer; Ernest Valveny; F. Serratosa |
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Title |
Median graph: A new exact algorithm using a distance based on the maximum common subgraph |
Type |
Journal Article |
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Year |
2009 |
Publication |
Pattern Recognition Letters |
Abbreviated Journal |
PRL |
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Volume |
30 |
Issue |
5 |
Pages |
579–588 |
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Keywords |
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Abstract |
Median graphs have been presented as a useful tool for capturing the essential information of a set of graphs. Nevertheless, computation of optimal solutions is a very hard problem. In this work we present a new and more efficient optimal algorithm for the median graph computation. With the use of a particular cost function that permits the definition of the graph edit distance in terms of the maximum common subgraph, and a prediction function in the backtracking algorithm, we reduce the size of the search space, avoiding the evaluation of a great amount of states and still obtaining the exact median. We present a set of experiments comparing our new algorithm against the previous existing exact algorithm using synthetic data. In addition, we present the first application of the exact median graph computation to real data and we compare the results against an approximate algorithm based on genetic search. These experimental results show that our algorithm outperforms the previous existing exact algorithm and in addition show the potential applicability of the exact solutions to real problems. |
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Publisher |
Elsevier Science Inc. |
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Edition |
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ISSN |
0167-8655 |
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Notes |
DAG |
Approved |
no |
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Call Number |
DAG @ dag @ FVS2009a |
Serial |
1114 |
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Permanent link to this record |
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Author |
Fadi Dornaika; Angel Sappa |
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Title |
Instantaneous 3D motion from image derivatives using the Least Trimmed Square Regression |
Type |
Journal Article |
|
Year |
2009 |
Publication |
Pattern Recognition Letters |
Abbreviated Journal |
PRL |
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Volume |
30 |
Issue |
5 |
Pages |
535–543 |
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Keywords |
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Abstract |
This paper presents a new technique to the instantaneous 3D motion estimation. The main contributions are as follows. First, we show that the 3D camera or scene velocity can be retrieved from image derivatives only assuming that the scene contains a dominant plane. Second, we propose a new robust algorithm that simultaneously provides the Least Trimmed Square solution and the percentage of inliers-the non-contaminated data. Experiments on both synthetic and real image sequences demonstrated the effectiveness of the developed method. Those experiments show that the new robust approach can outperform classical robust schemes. |
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Elsevier Science Inc. |
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ISSN |
0167-8655 |
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Notes |
ADAS |
Approved |
no |
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Call Number |
ADAS @ adas @ DoS2009a |
Serial |
1115 |
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Permanent link to this record |
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Author |
Xavier Baro; Sergio Escalera; Jordi Vitria; Oriol Pujol; Petia Radeva |
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Title |
Traffic Sign Recognition Using Evolutionary Adaboost Detection and Forest-ECOC Classification |
Type |
Journal Article |
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Year |
2009 |
Publication |
IEEE Transactions on Intelligent Transportation Systems |
Abbreviated Journal |
TITS |
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Volume |
10 |
Issue |
1 |
Pages |
113–126 |
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Keywords |
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Abstract |
The high variability of sign appearance in uncontrolled environments has made the detection and classification of road signs a challenging problem in computer vision. In this paper, we introduce a novel approach for the detection and classification of traffic signs. Detection is based on a boosted detectors cascade, trained with a novel evolutionary version of Adaboost, which allows the use of large feature spaces. Classification is defined as a multiclass categorization problem. A battery of classifiers is trained to split classes in an Error-Correcting Output Code (ECOC) framework. We propose an ECOC design through a forest of optimal tree structures that are embedded in the ECOC matrix. The novel system offers high performance and better accuracy than the state-of-the-art strategies and is potentially better in terms of noise, affine deformation, partial occlusions, and reduced illumination. |
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Edition |
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ISSN |
1524-9050 |
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Notes |
OR;MILAB;HuPBA;MV |
Approved |
no |
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Call Number |
BCNPCL @ bcnpcl @ BEV2008 |
Serial |
1116 |
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Permanent link to this record |
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Author |
Niki Aifanti; Angel Sappa; N. Grammalidis; Sotiris Malassiotis |
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Title |
Advances in Tracking and Recognition of Human Motion |
Type |
Book Chapter |
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Year |
2009 |
Publication |
Encyclopedia of Information Science and Technology |
Abbreviated Journal |
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Volume |
I |
Issue |
2nd edition |
Pages |
65–71 |
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Notes |
ADAS |
Approved |
no |
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Call Number |
ADAS @ adas @ ASG2009 |
Serial |
1143 |
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Permanent link to this record |
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Author |
Mohammad Rouhani |
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Title |
3D Data Fitting and Tracking for Real Time Applications |
Type |
Report |
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Year |
2009 |
Publication |
CVC Technical Report |
Abbreviated Journal |
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Volume |
138 |
Issue |
138 |
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Address |
Barcelona, Spain |
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Thesis |
Master's thesis |
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Notes |
invisible;ADAS |
Approved |
no |
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Call Number |
Admin @ si @ Rou2009 |
Serial |
1150 |
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Permanent link to this record |
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Author |
Sergio Escalera; Oriol Pujol; Petia Radeva |
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Title |
Separability of Ternary Codes for Sparse Designs of Error-Correcting Output Codes |
Type |
Journal Article |
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Year |
2009 |
Publication |
Pattern Recognition Letters |
Abbreviated Journal |
PRL |
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Volume |
30 |
Issue |
3 |
Pages |
285–297 |
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Keywords |
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Abstract |
Error Correcting Output Codes (ECOC) represent a successful framework to deal with multi-class categorization problems based on combining binary classifiers. In this paper, we present a new formulation of the ternary ECOC distance and the error-correcting capabilities in the ternary ECOC framework. Based on the new measure, we stress on how to design coding matrices preventing codification ambiguity and propose a new Sparse Random coding matrix with ternary distance maximization. The results on the UCI Repository and in a real speed traffic categorization problem show that when the coding design satisfies the new ternary measures, significant performance improvement is obtained independently of the decoding strategy applied. |
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Notes |
MILAB;HuPBA |
Approved |
no |
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Call Number |
BCNPCL @ bcnpcl @ EPR2009a |
Serial |
1153 |
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Permanent link to this record |
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Author |
Bogdan Raducanu; Jordi Vitria; D. Gatica-Perez |
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Title |
You are Fired! Nonverbal Role Analysis in Competitive Meetings |
Type |
Conference Article |
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Year |
2009 |
Publication |
IEEE International Conference on Audio, Speech and Signal Processing |
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Pages |
1949–1952 |
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Abstract |
This paper addresses the problem of social interaction analysis in competitive meetings, using nonverbal cues. For our study, we made use of ldquoThe Apprenticerdquo reality TV show, which features a competition for a real, highly paid corporate job. Our analysis is centered around two tasks regarding a person's role in a meeting: predicting the person with the highest status and predicting the fired candidates. The current study was carried out using nonverbal audio cues. Results obtained from the analysis of a full season of the show, representing around 90 minutes of audio data, are very promising (up to 85.7% of accuracy in the first case and up to 92.8% in the second case). Our approach is based only on the nonverbal interaction dynamics during the meeting without relying on the spoken words. |
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Address |
Taipei, Taiwan |
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Series Editor |
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ISSN |
1520-6149 |
ISBN |
978-1-4244-2353-8 |
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Conference |
ICASSP |
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Notes |
OR;MV |
Approved |
no |
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Call Number |
BCNPCL @ bcnpcl @ RVG2009 |
Serial |
1154 |
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Permanent link to this record |
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Author |
David Masip; Agata Lapedriza; Jordi Vitria |
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Title |
Boosted Online Learning for Face Recognition |
Type |
Journal Article |
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Year |
2009 |
Publication |
IEEE Transactions on Systems, Man and Cybernetics part B |
Abbreviated Journal |
TSMCB |
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Volume |
39 |
Issue |
2 |
Pages |
530–538 |
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Keywords |
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Abstract |
Face recognition applications commonly suffer from three main drawbacks: a reduced training set, information lying in high-dimensional subspaces, and the need to incorporate new people to recognize. In the recent literature, the extension of a face classifier in order to include new people in the model has been solved using online feature extraction techniques. The most successful approaches of those are the extensions of the principal component analysis or the linear discriminant analysis. In the current paper, a new online boosting algorithm is introduced: a face recognition method that extends a boosting-based classifier by adding new classes while avoiding the need of retraining the classifier each time a new person joins the system. The classifier is learned using the multitask learning principle where multiple verification tasks are trained together sharing the same feature space. The new classes are added taking advantage of the structure learned previously, being the addition of new classes not computationally demanding. The present proposal has been (experimentally) validated with two different facial data sets by comparing our approach with the current state-of-the-art techniques. The results show that the proposed online boosting algorithm fares better in terms of final accuracy. In addition, the global performance does not decrease drastically even when the number of classes of the base problem is multiplied by eight. |
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Original Title |
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Series Editor |
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Series Title |
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Edition |
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ISSN |
1083–4419 |
ISBN |
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Expedition |
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Notes |
OR;MV |
Approved |
no |
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Call Number |
BCNPCL @ bcnpcl @ MLV2009 |
Serial |
1155 |
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Permanent link to this record |
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Author |
Ignasi Rius; Jordi Gonzalez; Javier Varona; Xavier Roca |
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Title |
Action-specific motion prior for efficient bayesian 3D human body tracking |
Type |
Journal Article |
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Year |
2009 |
Publication |
Pattern Recognition |
Abbreviated Journal |
PR |
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Volume |
42 |
Issue |
11 |
Pages |
2907–2921 |
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Keywords |
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Abstract |
In this paper, we aim to reconstruct the 3D motion parameters of a human body
model from the known 2D positions of a reduced set of joints in the image plane.
Towards this end, an action-specific motion model is trained from a database of real
motion-captured performances. The learnt motion model is used within a particle
filtering framework as a priori knowledge on human motion. First, our dynamic
model guides the particles according to similar situations previously learnt. Then, the solution space is constrained so only feasible human postures are accepted as valid solutions at each time step. As a result, we are able to track the 3D configuration of the full human body from several cycles of walking motion sequences using only the 2D positions of a very reduced set of joints from lateral or frontal viewpoints. |
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Series Editor |
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Series Issue |
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Edition |
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ISSN |
0031-3203 |
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 |
ISE |
Approved |
no |
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Call Number |
ISE @ ise @ RGV2009 |
Serial |
1159 |
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Permanent link to this record |
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Author |
Mikhail Mozerov; Ariel Amato; Xavier Roca; Jordi Gonzalez |
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Title |
Solving the Multi Object Occlusion Problem in a Multiple Camera Tracking System |
Type |
Journal |
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Year |
2009 |
Publication |
Pattern Recognition and Image Analysis |
Abbreviated Journal |
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Volume |
19 |
Issue |
1 |
Pages |
165-171 |
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Keywords |
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Abstract |
An efficient method to overcome adverse effects of occlusion upon object tracking is presented. The method is based on matching paths of objects in time and solves a complex occlusion-caused problem of merging separate segments of the same path. |
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Series Editor |
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Edition |
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ISSN |
1054-6618 |
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Notes |
ISE |
Approved |
no |
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Call Number |
ISE @ ise @ MAR2009a |
Serial |
1160 |
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Permanent link to this record |
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Author |
Carlo Gatta; Juan Diego Gomez; Francesco Ciompi; Oriol Rodriguez-Leor; Petia Radeva |
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Title |
Toward robust myocardial blush grade estimation in contrast angiography |
Type |
Conference Article |
|
Year |
2009 |
Publication |
4th Iberian Conference on Pattern Recognition and Image Analysis |
Abbreviated Journal |
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Volume |
5524 |
Issue |
|
Pages |
249–256 |
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Keywords |
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Abstract |
The assessment of Myocardial Blush Grade after primary angioplasty is a precious diagnostic tool to understand if the patient needs further medication or the use of specifics drugs. Unfortunately, the assessment of MBG is difficult for non highly specialized staff. Experimental data show that there is poor correlation between MBG assessment of low and high specialized staff, thus reducing its applicability. This paper proposes a method able to achieve an objective measure of MBG, or a set of parameters that correlates with the MBG. The method tracks the blush area starting from just one single frame tagged by the physician. As a consequence, the blush area is kept isolated from contaminating phenomena such as diaphragm and arteries movements. We also present a method to extract four parameters that are expected to correlate with the MBG. Preliminary results show that the method is capable of extracting interesting information regarding the behavior of the myocardial perfusion. |
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Address |
Póvoa de Varzim, Portugal |
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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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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
LNCS |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0302-9743 |
ISBN |
978-3-642-02171-8 |
Medium |
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Area |
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Expedition |
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Conference |
IbPRIA |
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Notes |
MILAB |
Approved |
no |
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Call Number |
BCNPCL @ bcnpcl @ GGC2009 |
Serial |
1161 |
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Permanent link to this record |
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Author |
Francesco Ciompi; Oriol Pujol; Oriol Rodriguez-Leor; Carlo Gatta; Angel Serrano; Petia Radeva |
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Title |
Enhancing In-Vitro IVUS Data for Tissue Characterization |
Type |
Conference Article |
|
Year |
2009 |
Publication |
4th Iberian Conference on Pattern Recognition and Image Analysis |
Abbreviated Journal |
|
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|
Volume |
5524 |
Issue |
|
Pages |
241–248 |
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Keywords |
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Abstract |
Intravascular Ultrasound (IVUS) data validation is usually performed by comparing post-mortem (in-vitro) IVUS data and corresponding histological analysis of the tissue, obtaining a reliable ground truth. The main drawback of this method is the few number of available study cases due to the complex procedure of histological analysis. In this work we propose a novel semi-supervised approach to enhance the in-vitro training set by including examples from in-vivo coronary plaques data set. For this purpose, a Sequential Floating Forward Selection method is applied on in-vivo data and plaque characterization performances are evaluated by Leave-One-Patient-Out cross-validation technique. Supervised data inclusion improves global classification accuracy from 89.39% to 91.82%. |
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Address |
Póvoa de Varzim, Portugal |
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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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Series Editor |
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Series Title |
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Abbreviated Series Title |
LNCS |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0302-9743 |
ISBN |
978-3-642-02171-8 |
Medium |
|
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Area |
|
Expedition |
|
Conference |
IbPRIA |
|
|
Notes |
MILAB;HuPBA |
Approved |
no |
|
|
Call Number |
BCNPCL @ bcnpcl @ CPR2009a |
Serial |
1162 |
|
Permanent link to this record |
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Author |
Carme Julia; Angel Sappa; Felipe Lumbreras; Joan Serrat; Antonio Lopez |
|
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Title |
An iterative multiresolution scheme for SFM with missing data |
Type |
Journal Article |
|
Year |
2009 |
Publication |
Journal of Mathematical Imaging and Vision |
Abbreviated Journal |
JMIV |
|
|
Volume |
34 |
Issue |
3 |
Pages |
240–258 |
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Keywords |
|
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|
Abstract |
Several techniques have been proposed for tackling the Structure from Motion problem through factorization in the case of missing data. However, when the percentage of unknown data is high, most of them may not perform as well as expected. Focussing on this problem, an iterative multiresolution scheme, which aims at recovering missing entries in the originally given input matrix, is proposed. Information recovered following a coarse-to-fine strategy is used for filling in the missing entries. The objective is to recover, as much as possible, missing data in the given matrix.
Thus, when a factorization technique is applied to the partially or totally filled in matrix, instead of to the originally given input one, better results will be obtained. An evaluation study about the robustness to missing and noisy data is reported.
Experimental results obtained with synthetic and real video sequences are presented to show the viability of the proposed approach. |
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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 |
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ISBN |
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Medium |
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Area |
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Expedition |
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Notes |
ADAS |
Approved |
no |
|
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Call Number |
ADAS @ adas @ JSL2009a |
Serial |
1163 |
|
Permanent link to this record |
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Author |
Pau Baiget; Carles Fernandez; Xavier Roca; Jordi Gonzalez |
|
|
Title |
Generation of Augmented Video Sequences Combining Behavioral Animation and Multi Object Tracking |
Type |
Journal Article |
|
Year |
2009 |
Publication |
Computer Animation and Virtual Worlds |
Abbreviated Journal |
|
|
|
Volume |
20 |
Issue |
4 |
Pages |
473–489 |
|
|
Keywords |
|
|
|
Abstract |
In this paper we present a novel approach to generate augmented video sequences in real-time, involving interactions between virtual and real agents in real scenarios. On the one hand, real agent motion is estimated by means of a multi-object tracking algorithm, which determines real objects' position over the scenario for each time step. On the other hand, virtual agents are provided with behavior models considering their interaction with the environment and with other agents. The resulting framework allows to generate video sequences involving behavior-based virtual agents that react to real agent behavior and has applications in education, simulation, and in the game and movie industries. We show the performance of the proposed approach in an indoor and outdoor scenario simulating human and vehicle agents. Copyright © 2009 John Wiley & Sons, Ltd.
We present a novel approach to generate augmented video sequences in real-time, involving interactions between virtual and real agents in real scenarios. On the one hand, real agent motion is estimated by means of a multi-object tracking algorithm, which determines real objects' position over the scenario for each time step. On the other hand, virtual agents are provided with behavior models considering their interaction with the environment and with other agents. © 2009 Wiley Periodicals, Inc. |
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ISE @ ise @ BFR2009 |
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1170 |
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Author |
Javier Vazquez; C. Alejandro Parraga; Maria Vanrell; Ramon Baldrich |
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Title |
Color Constancy Algorithms: Psychophysical Evaluation on a New Dataset |
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Journal Article |
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2009 |
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Journal of Imaging Science and Technology |
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53 |
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3 |
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031105–9 |
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The estimation of the illuminant of a scene from a digital image has been the goal of a large amount of research in computer vision. Color constancy algorithms have dealt with this problem by defining different heuristics to select a unique solution from within the feasible set. The performance of these algorithms has shown that there is still a long way to go to globally solve this problem as a preliminary step in computer vision. In general, performance evaluation has been done by comparing the angular error between the estimated chromaticity and the chromaticity of a canonical illuminant, which is highly dependent on the image dataset. Recently, some workers have used high-level constraints to estimate illuminants; in this case selection is based on increasing the performance on the subsequent steps of the systems. In this paper we propose a new performance measure, the perceptual angular error. It evaluates the performance of a color constancy algorithm according to the perceptual preferences of humans, or naturalness (instead of the actual optimal solution) and is independent of the visual task. We show the results of a new psychophysical experiment comparing solutions from three different color constancy algorithms. Our results show that in more than a half of the judgments the preferred solution is not the one closest to the optimal solution. Our experiments were performed on a new dataset of images acquired with a calibrated camera with an attached neutral grey sphere, which better copes with the illuminant variations of the scene. |
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CAT @ cat @ VPV2009a |
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1171 |
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