Yannis Avrithis
Yannis Avrithis
Research Scientist
Inria Rennes-Bretagne Atlantique, France

Working on computer vision and machine learning

News

Oct 22, 2020
Bill Psomas defends his MSc thesis on Deep Metric Learning
Oct 11, 2020
Two papers accepted at ICPR 2020: Few-Shot Few-Shot Learning and Local Propagation
Oct 01, 2020
Felipe Torres Figueroa begins his PhD thesis on Interpretable Visual Recognition
Sep 10, 2020
Oriane Siméoni defends her PhD thesis on Visual Search, Discovery and Recognition
Sep 01, 2020
Deniz Engin begins her PhD thesis on Multimodal Question Answering
Sep 01, 2020
Research grant MQA begins
Sep 01, 2020
Timothée Neitthoffer defends his MSc thesis on Neural Architecture Search
Aug 09, 2020
Paper accepted at TIFS: Boundary Projection Attack
Jul 03, 2020
HDR Thesis thesis defended at University of Rennes 1: Exploring and Learning from Visual Data
Jul 02, 2020
Paper accepted at ECCV 2020: Few Clean and Many Noisy Labels
Jun 29, 2020
Preprint released at arXiv: Asymmetric Metric Learning
Jun 22, 2020
Paper accepted at ICPR 2020: Deep Active Learning
Apr 01, 2020
Research grant MEERQAT begins
Feb 18, 2020
Paper accepted at JIS: Smooth Adversarial Examples
Feb 18, 2020
Preprint released at arXiv: Few-Shot Few-Shot Learning
Feb 17, 2020
I begin teaching the 2nd iteration of Computer Vision at NKUA
Jan 01, 2020
Research grant UNLIR begins
Dec 04, 2019
Preprint released at arXiv: Boundary Projection Attack
Dec 01, 2019
Preprint released at arXiv: Nano-Supervised Object Detection
Dec 01, 2019
Research grant GRAPES begins
Nov 19, 2019
Preprint released at arXiv: Rethinking Deep Active Learning
Nov 18, 2019
I begin teaching the 3th iteration of Deep Learning for Vision at UR1
Oct 01, 2019
Preprint released at arXiv: Few Clean and Many Noisy Labels
Sep 06, 2019
I become a father for a second time
Aug 05, 2019
I am an Outstanding Reviewer of ICCV 2019
Jul 13, 2019
Two research grants accepted: MEERQAT and UNLIR
May 15, 2019
Preprint released at arXiv: Deep Spatial Matching
May 15, 2019
Research grant GRAPES accepted
Apr 22, 2019
I am a Senior Member of IEEE
Apr 10, 2019
Preprint released at arXiv: Deep Label Propagation

About me

Since 2016 I am a research scientist in LinkMedia team of Inria Rennes-Bretagne Atlantique, carrying out research on computer vision and machine learning, and teaching Deep Learning for Vision. I enjoy working on learning visual representations from data, with as little supervision as possible. My recent work is focusing on exploring the manifold structure of data and, apart from image retrieval, using it for unsupervised, semi-supervised and few-shot learning. I am also working on adversarial examples and on investigating the sparsity of convolutional activations, applied to spatial matching and unsupervised object discovery.

In 2015 I have been at the Laboratory of Algebraic and Geometric Algorithms (ΕρΓΑ) of National and Kapodistrian University of Athens (NKUA), where I have worked on large-scale clustering and nearest neighbor search with Ioannis Emiris. An achievement of this period has been Web-Scale Image Clustering.

Between 2001 and 2015 I have been at the Image, Video and Multimedia Systems Laboratory (IVML) of the National Technical University of Athens (NTUA). In the latter part of this period, since 2008, I have been leading the Image and Video Analysis (IVA) team. We have worked on a diverse set of problems including local feature and salient region detection, spatial and spatiotemporal visual representation and matching, object recognition and tracking, action recognition in video, scene classification, image/video indexing, retrieval and summarization.

In 2015 I have been at the Laboratory of Algebraic and Geometric Algorithms (ΕρΓΑ) of National and Kapodistrian University of Athens (NKUA), where I have worked on large-scale clustering and nearest neighbor search with Ioannis Emiris. An achievement of this period has been Web-Scale Image Clustering.

Between 2001 and 2015 I have been at the Image, Video and Multimedia Systems Laboratory (IVML) of the National Technical University of Athens (NTUA). In the latter part of this period, since 2008, I have been leading the Image and Video Analysis (IVA) team. We have worked on a diverse set of problems including local feature and salient region detection, spatial and spatiotemporal visual representation and matching, object recognition and tracking, action recognition in video, scene classification, image/video indexing, retrieval and summarization.

A large body of this work has focused on local feature/descriptor representations. In this context, we have delivered repeatable feature detection, extremely fast spatial matching, geometry indexing, multi-view and single-view feature selection, approximate nearest neighbor search for large scale clustering and vocabulary construction, and mining 3d scenes from millions of images. Examples of this work are Hough Pyramid Matching (HPM), the Aggregated Selective Match Kernel (ASMK), and Locally Optimized Product Quantization (LOPQ). In 2017, using a CNN image representation, Yahoo! Research has chosen LOPQ to index and provide a similar image search functionality on its entire Flickr collection. A flagship product of this period has been our unique application Visual Image Retrieval and Localization (VIRaL).

In the preceding period before 2008, I have worked on problems related to object detection and image understanding. This includes regions-of-interest for generic object detection, semantic segmentation, integrated segmentation and region labeling, spatio-temporal object segmentation and tracking, image classification, as well as the use of visual context and prior knowledge.

While at NTUA, I have had the opportunity to collaborate with a large number of researchers across Europe by participating in Networks of Excellence Muscle and K-Space and Integrated Projects like aceMedia and WeKnowIt. I have developed a number of activities including being the Program Chair or General Chair of workshops and conferences in the field of multimedia like WIAMIS, CBMI, MMM and CIVR. For several years I have been teaching Signals and Systems and Image and Video Analysis.

Between 1996 and 2001 I have been working on my Ph.D. at NTUA with Stefanos Kollias, studying visual representations for video sequence analysis. I have investigated accurate spatio-temporal segmentation by fusing color, motion and depth, as well as a region-based representation for retrieval and summarization in the form of key-frames. I have designed an affine-invariant representation of object contours for shape-based object classification and retrieval. Finally, I have studied temporal segmentation and parsing of broadcast news based on human face detection.

In 1993-1994 I completed a M.Sc. with Distinction in Communications and Signal Processing at Imperial College, University of London. As part of my Masters thesis, I have worked on communications and investigated the capacity of a cellular CDMA system with Athanassios Manikas.

Between 1998 and 1993 I have studied Electrical and Computer Engineering at NTUA. As part of my Diploma thesis, I have worked on analog electronics and developed a hardware implementation of a fuzzy logic processor with Yannis Tsividis. Before that, my first exposure to computer vision and machine learning has been the study of an invariant representation for optical character recognition with Anastasios Delopoulos, leading to a conference publication before my Diploma.

Recent publications

Smooth Adversarial Examples
H. Zhang, Y. Avrithis, T. Furon, L. Amsaleg
JIS, In press
Local Propagation for Few-Shot Learning
Y. Lifchitz, Y. Avrithis, S. Picard
ICPR 2020
Few-Shot Few-Shot Learning and the Role of Spatial Attention
Y. Lifchitz, Y. Avrithis, S. Picard
ICPR 2020
Rethinking Deep Active Learning: Using Unlabeled Data at Model Training
O. Siméoni, M. Budnik, Y. Avrithis, G. Gravier
ICPR 2020
Graph-Based Particular Object Discovery
O. Siméoni, A. Iscen, G. Tolias, Y. Avrithis, O. Chum
Revisiting the Medial Axis for Planar Shape Decomposition
N. Papanelopoulos, Y. Avrithis, S. Kollias
Label Propagation for Deep Semi-Supervised Learning
A. Iscen, G. Tolias, Y. Avrithis, O. Chum
Dense Classification and Implanting for Few-Shot Learning
Y. Lifchitz, Y. Avrithis, S. Picard, A. Bursuc
Hybrid Diffusion: Spectral-Temporal Graph Filtering for Manifold Ranking
A. Iscen, Y. Avrithis, G. Tolias, T. Furon, O. Chum
Mining on Manifolds: Metric Learning without Labels
A. Iscen, G. Tolias, Y. Avrithis, O. Chum
Revisiting Oxford And Paris: Large-Scale Image Retrieval Benchmarking
F. Radenović, A. Iscen, G. Tolias, Y. Avrithis, O. Chum
Fast Spectral Ranking for Similarity Search
A. Iscen, Y. Avrithis, G. Tolias, T. Furon, O. Chum
Unsupervised Object Discovery for Instance Recognition
O. Siméoni, A. Iscen, G. Tolias, Y. Avrithis, O. Chum
Automatic Discovery of Discriminative Parts as a Quadratic Assignment Problem
R. Sicre, J. Rabin, Y. Avrithis, T. Furon, F. Jurie, E. Kijak
Unsupervised Part Learning for Visual Recognition
R. Sicre, Y. Avrithis, E. Kijak, F. Jurie
Panorama to Panorama Matching for Location Recognition
A. Iscen, G. Tolias, Y. Avrithis, T. Furon, O. Chum
$\alpha$-Shapes for Local Feature Detection
C. Varytimidis, K. Rapantzikos, Y. Avrithis, S. Kollias
Dithering-Based Sampling and Weighted $\alpha$-Shapes for Local Feature Detection
Varytimidis, C., Rapantzikos, K., Avrithis, Y., Kollias, S.
Web-Scale Image Clustering Revisited
Y. Avrithis, Y. Kalantidis, E. Anagnostopoulos, I. Z. Emiris
Planar Shape Decomposition Made Simple
N. Papanelopoulos, Y. Avrithis
Towards Large-Scale Geometry Indexing by Feature Selection
G. Tolias, Y. Kalantidis, Y. Avrithis, S. Kollias
Improving Local Features by Dithering-Based Image Sampling
C. Varytimidis, K. Rapantzikos, Y. Avrithis, S. Kollias
Multimodal Saliency and Fusion for Movie Summarization Based on Aural, Visual, and Textual Attention
G. Evangelopoulos, A. Zlatintsi, A. Potamianos, P. Maragos, K. Rapantzikos, G. Skoumas, Y. Avrithis