Imperial College London

STEFANOS ZAFEIRIOU, PhD

Faculty of EngineeringDepartment of Computing

Reader in Machine Learning and Computer Vision
 
 
 
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Contact

 

+44 (0)20 7594 8461s.zafeiriou Website CV

 
 
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Location

 

375Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

167 results found

Booth J, Roussos A, Ponniah A, Dunaway D, Zafeiriou Set al., 2018, Large Scale 3D Morphable Models, INTERNATIONAL JOURNAL OF COMPUTER VISION, Vol: 126, Pages: 233-254, ISSN: 0920-5691

JOURNAL ARTICLE

Chrysos GG, Antonakos E, Snape P, Asthana A, Zafeiriou Set al., 2018, A Comprehensive Performance Evaluation of Deformable Face Tracking "In-the-Wild", INTERNATIONAL JOURNAL OF COMPUTER VISION, Vol: 126, Pages: 198-232, ISSN: 0920-5691

JOURNAL ARTICLE

Trigeorgis G, Nicolaou MA, Schuller BW, Zafeiriou Set al., 2018, Deep Canonical Time Warping for Simultaneous Alignment and Representation Learning of Sequences., IEEE Trans Pattern Anal Mach Intell, Vol: 40, Pages: 1128-1138

Machine learning algorithms for the analysis of time-series often depend on the assumption that utilised data are temporally aligned. Any temporal discrepancies arising in the data is certain to lead to ill-generalisable models, which in turn fail to correctly capture properties of the task at hand. The temporal alignment of time-series is thus a crucial challenge manifesting in a multitude of applications. Nevertheless, the vast majority of algorithms oriented towards temporal alignment are either applied directly on the observation space or simply utilise linear projections-thus failing to capture complex, hierarchical non-linear representations that may prove beneficial, especially when dealing with multi-modal data (e.g., visual and acoustic information). To this end, we present Deep Canonical Time Warping (DCTW), a method that automatically learns non-linear representations of multiple time-series that are (i) maximally correlated in a shared subspace, and (ii) temporally aligned. Furthermore, we extend DCTW to a supervised setting, where during training, available labels can be utilised towards enhancing the alignment process. By means of experiments on four datasets, we show that the representations learnt significantly outperform state-of-the-art methods in temporal alignment, elegantly handling scenarios with heterogeneous feature sets, such as the temporal alignment of acoustic and visual information.

JOURNAL ARTICLE

Alabort-i-Medina J, Zafeiriou S, 2017, A Unified Framework for Compositional Fitting of Active Appearance Models, INTERNATIONAL JOURNAL OF COMPUTER VISION, Vol: 121, Pages: 26-64, ISSN: 0920-5691

JOURNAL ARTICLE

Cheng S, Marras I, Zafeiriou S, Pantic Met al., 2017, Statistical non-rigid ICP algorithm and its application to 3D face alignment, IMAGE AND VISION COMPUTING, Vol: 58, Pages: 3-12, ISSN: 0262-8856

JOURNAL ARTICLE

Chrysos GG, Zafeiriou S, 2017, Deep Face Deblurring, 30th IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW), Publisher: IEEE, Pages: 2015-2024, ISSN: 2160-7508

CONFERENCE PAPER

Georgakis C, Panagakis Y, Zafeiriou S, Pantic Met al., 2017, The Conflict Escalation Resolution (CONFER) Database, IMAGE AND VISION COMPUTING, Vol: 65, Pages: 37-48, ISSN: 0262-8856

JOURNAL ARTICLE

Sagonas C, Panagakis Y, Leidinger A, Zafeiriou Set al., 2017, Robust Joint and Individual Variance Explained, 30th IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), Publisher: IEEE, Pages: 5739-5748, ISSN: 1063-6919

CONFERENCE PAPER

Sagonas C, Panagakis Y, Zafeiriou S, Pantic Met al., 2017, Robust Statistical Frontalization of Human and Animal Faces, INTERNATIONAL JOURNAL OF COMPUTER VISION, Vol: 122, Pages: 270-291, ISSN: 0920-5691

JOURNAL ARTICLE

Sagonas C, Ververas E, Panagakis Y, Zafeiriou SPet al., 2017, Recovering Joint and Individual Components in Facial Data, IEEE Transactions on Pattern Analysis and Machine Intelligence, ISSN: 0162-8828

IEEE A set of images depicting faces with different expressions or in various ages consists of components that are shared across all images (i.e., joint components) and imparts to the depicted object the properties of human faces and individual components that are related to different expressions or age groups. Discovering the common (joint) and individual components in facial images is crucial for applications such as facial expression transfer. The problem is rather challenging when dealing with images captured in unconstrained conditions and thus are possibly contaminated by sparse non-Gaussian errors of large magnitude (i.e., sparse gross errors) and contain missing data. In this paper, we investigate the use of a method recently introduced in statistics, the so-called Joint and Individual Variance Explained (JIVE) method, for the robust recovery of joint and individual components in visual facial data consisting of an arbitrary number of views. Since, the JIVE is not robust to sparse gross errors, we propose alternatives, which are 1) robust to sparse gross, non-Gaussian noise, 2) able to automatically find the individual components rank, and 3) can handle missing data. We demonstrate the effectiveness of the proposed methods to several computer vision applications, namely facial expression synthesis and 2D and 3D face age progression in-the-wild.

JOURNAL ARTICLE

Trigeorgis G, Bousmalis K, Zafeiriou S, Schuller BWet al., 2017, A Deep Matrix Factorization Method for Learning Attribute Representations, IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE, Vol: 39, Pages: 417-429, ISSN: 0162-8828

JOURNAL ARTICLE

Trigeorgis G, Snape P, Kokkinos I, Zafeiriou Set al., 2017, Face Normals "in-the- wild" using Fully Convolutional Networks, 30th IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), Publisher: IEEE, Pages: 340-349, ISSN: 1063-6919

CONFERENCE PAPER

Tzirakis P, Trigeorgis G, Nicolaou MA, Schuller BW, Zafeiriou Set al., 2017, End-to-End Multimodal Emotion Recognition Using Deep Neural Networks., J. Sel. Topics Signal Processing, Vol: 11, Pages: 1301-1309

JOURNAL ARTICLE

Wang M, Panagakis Y, Snape P, Zafeiriou Set al., 2017, Learning the Multilinear Structure of Visual Data, 30th IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR), Publisher: IEEE, Pages: 6053-6061, ISSN: 1063-6919

CONFERENCE PAPER

Xue N, Panagakis Y, Zafeiriou S, 2017, Side Information in Robust Principal Component Analysis: Algorithms and Applications, 16th IEEE International Conference on Computer Vision (ICCV), Publisher: IEEE, Pages: 4327-4335, ISSN: 1550-5499

CONFERENCE PAPER

Zafeiriou S, Trigeorgis G, Chrysos G, Deng J, Shen Jet al., 2017, The Menpo Facial Landmark Localisation Challenge: A step towards the solution, 30th IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW), Publisher: IEEE, Pages: 2116-2125, ISSN: 2160-7508

CONFERENCE PAPER

Antonakos E, Snape P, Trigeorgis G, Zafeiriou Set al., 2016, ADAPTIVE CASCADED REGRESSION, 23rd IEEE International Conference on Image Processing (ICIP), Publisher: IEEE, Pages: 1649-1653, ISSN: 1522-4880

CONFERENCE PAPER

Booth J, Roussos A, Zafeiriou S, Ponniah A, Dunaway Det al., 2016, A 3D Morphable Model learnt from 10,000 faces, 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Publisher: IEEE, Pages: 5543-5552, ISSN: 1063-6919

CONFERENCE PAPER

Gligorijevic V, Panagakis Y, Zafeiriou S, 2016, Fusion and Community Detection in Multi-layer Graphs, 23rd International Conference on Pattern Recognition (ICPR), Publisher: IEEE COMPUTER SOC, Pages: 1327-1332, ISSN: 1051-4651

CONFERENCE PAPER

Hong X, Zhao G, Zafeiriou S, Pantic M, Pietikainen Met al., 2016, Capturing correlations of local features for image representation, NEUROCOMPUTING, Vol: 184, Pages: 99-106, ISSN: 0925-2312

JOURNAL ARTICLE

Hovhannisyan V, Parpas P, Zafeiriou S, 2016, MAGMA: Multilevel Accelerated Gradient Mirror Descent Algorithm for Large-Scale Convex Composite Minimization, SIAM JOURNAL ON IMAGING SCIENCES, Vol: 9, Pages: 1829-1857, ISSN: 1936-4954

JOURNAL ARTICLE

Kampouris C, Zafeiriou S, Ghosh A, Malassiotis Set al., 2016, Fine-Grained Material Classification Using Micro-geometry and Reflectance, 14th European Conference on Computer Vision (ECCV), Publisher: SPRINGER INT PUBLISHING AG, Pages: 778-792, ISSN: 0302-9743

CONFERENCE PAPER

Panagakis Y, Nicolaou MA, Zafeiriou S, Pantic Met al., 2016, Robust Correlated and Individual Component Analysis, IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE, Vol: 38, Pages: 1665-1678, ISSN: 0162-8828

JOURNAL ARTICLE

Sagonas C, Antonakos E, Tzimiropoulos G, Zafeiriou S, Pantic Met al., 2016, 300 Faces In-The-Wild Challenge: database and results, IMAGE AND VISION COMPUTING, Vol: 47, Pages: 3-18, ISSN: 0262-8856

JOURNAL ARTICLE

Sagonas C, Panagakis Y, Arunkumar S, Ratha N, Zafeiriou Set al., 2016, Back to the Future: A Fully Automatic Method for Robust Age Progression, 23rd International Conference on Pattern Recognition (ICPR), Publisher: IEEE COMPUTER SOC, Pages: 4226-4231, ISSN: 1051-4651

CONFERENCE PAPER

Snape P, Pszczolkowski S, Zafeiriou S, Tzimiropoulos G, Ledig C, Rueckert Det al., 2016, A robust similarity measure for volumetric image registration with outliers, IMAGE AND VISION COMPUTING, Vol: 52, Pages: 97-113, ISSN: 0262-8856

JOURNAL ARTICLE

Trigeorgis G, Nicolaou MA, Schuller BW, Zafeiriou Set al., 2016, Deep Canonical Time Warping, 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Publisher: IEEE, Pages: 5110-5118, ISSN: 1063-6919

CONFERENCE PAPER

Trigeorgis G, Ringeval F, Brueckner R, Marchi E, Nicolaou MA, Shuller B, Zafeiriou Set al., 2016, ADIEU FEATURES? END-TO-END SPEECH EMOTION RECOGNITION USING A DEEP CONVOLUTIONAL RECURRENT NETWORK, IEEE International Conference on Acoustics, Speech, and Signal Processing, Publisher: IEEE, Pages: 5200-5204, ISSN: 1520-6149

CONFERENCE PAPER

Trigeorgis G, Snape P, Nicolaou MA, Antonakos E, Zafeiriou Set al., 2016, Mnemonic Descent Method: A recurrent process applied for end-to-end face alignment, 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Publisher: IEEE, Pages: 4177-4187, ISSN: 1063-6919

CONFERENCE PAPER

Zafeiriou L, Antonakos E, Zafeiriou S, Pantic Met al., 2016, Joint Unsupervised Deformable Spatio-Temporal Alignment of Sequences, 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR), Publisher: IEEE, Pages: 3382-3390, ISSN: 1063-6919

CONFERENCE PAPER

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