Search Results for author: Laurent Najman

Found 30 papers, 10 papers with code

FLIM-based Salient Object Detection Networks with Adaptive Decoders

1 code implementation29 Apr 2025 Gilson Junior Soares, Matheus Abrantes Cerqueira, Jancarlo F. Gomes, Laurent Najman, Silvio Jamil F. Guimarães, Alexandre Xavier Falcão

We compare FLIM models with adaptive decoders for two challenging SOD tasks with three lightweight networks from the state-of-the-art, two FLIM networks with decoders trained by backpropagation, and one FLIM network whose labeled markers define the decoder's weights.

object-detection Object Detection +1

Intuitive physics understanding emerges from self-supervised pretraining on natural videos

1 code implementation17 Feb 2025 Quentin Garrido, Nicolas Ballas, Mahmoud Assran, Adrien Bardes, Laurent Najman, Michael Rabbat, Emmanuel Dupoux, Yann Lecun

We investigate the emergence of intuitive physics understanding in general-purpose deep neural network models trained to predict masked regions in natural videos.

Video Prediction

Shape Transformation Driven by Active Contour for Class-Imbalanced Semi-Supervised Medical Image Segmentation

1 code implementation18 Oct 2024 Yuliang Gu, Yepeng Liu, Zhichao Sun, Jinchi Zhu, Yongchao Xu, Laurent Najman

The significant size differences among various organs in the human body lead to imbalanced class distribution, which is a major challenge in the real-world application of these SSL approaches.

Data Augmentation Image Segmentation +2

Evolutionary Retrofitting

no code implementations15 Oct 2024 Mathurin Videau, Mariia Zameshina, Alessandro Leite, Laurent Najman, Marc Schoenauer, Olivier Teytaud

AfterLearnER (After Learning Evolutionary Retrofitting) consists in applying non-differentiable optimization, including evolutionary methods, to refine fully-trained machine learning models by optimizing a set of carefully chosen parameters or hyperparameters of the model, with respect to some actual, exact, and hence possibly non-differentiable error signal, performed on a subset of the standard validation set.

Code Translation Image Generation

Log-normal Mutations and their Use in Detecting Surreptitious Fake Images

no code implementations23 Sep 2024 Ismail Labiad, Thomas Bäck, Pierre Fernandez, Laurent Najman, Tom Sander, Furong Ye, Mariia Zameshina, Olivier Teytaud

We apply the log-normal method to the attack of fake detectors, and get successful attacks: importantly, these attacks are not detected by detectors specialized on classical adversarial attacks.

Reasoning with trees: interpreting CNNs using hierarchies

1 code implementation19 Jun 2024 Caroline Mazini Rodrigues, Nicolas Boutry, Laurent Najman

We introduce a framework that uses hierarchical segmentation techniques for faithful and interpretable explanations of Convolutional Neural Networks (CNNs).

Decision Making Segmentation

Quantile Activation: Correcting a Failure Mode of ML Models

no code implementations19 May 2024 Aditya Challa, Sravan Danda, Laurent Najman, Snehanshu Saha

In this article, we propose a simple activation function, quantile activation (QACT), that addresses this problem without significantly increasing computational costs.

Learning and Leveraging World Models in Visual Representation Learning

no code implementations1 Mar 2024 Quentin Garrido, Mahmoud Assran, Nicolas Ballas, Adrien Bardes, Laurent Najman, Yann Lecun

Joint-Embedding Predictive Architecture (JEPA) has emerged as a promising self-supervised approach that learns by leveraging a world model.

Representation Learning

A Novel Approach to Regularising 1NN classifier for Improved Generalization

no code implementations13 Feb 2024 Aditya Challa, Sravan Danda, Laurent Najman

In this paper, we propose a class of non-parametric classifiers, that learn arbitrary boundaries and generalize well.

Clustering Dynamics for Improved Speed Prediction Deriving from Topographical GPS Registrations

no code implementations12 Feb 2024 Sarah Almeida Carneiro, Giovanni Chierchia, Aurelie Pirayre, Laurent Najman

A persistent challenge in the field of Intelligent Transportation Systems is to extract accurate traffic insights from geographic regions with scarce or no data coverage.

Clustering

Bridging Human Concepts and Computer Vision for Explainable Face Verification

no code implementations30 Jan 2024 Miriam Doh, Caroline Mazini Rodrigues, Nicolas Boutry, Laurent Najman, Matei Mancas, Hugues Bersini

With Artificial Intelligence (AI) influencing the decision-making process of sensitive applications such as Face Verification, it is fundamental to ensure the transparency, fairness, and accountability of decisions.

Decision Making Explainable artificial intelligence +3

Transforming gradient-based techniques into interpretable methods

no code implementations25 Jan 2024 Caroline Mazini Rodrigues, Nicolas Boutry, Laurent Najman

The explication of Convolutional Neural Networks (CNN) through xAI techniques often poses challenges in interpretation.

Dual Structure-Aware Image Filterings for Semi-supervised Medical Image Segmentation

no code implementations12 Dec 2023 Yuliang Gu, Zhichao Sun, Tian Chen, Xin Xiao, Yepeng Liu, Yongchao Xu, Laurent Najman

In this paper, we propose novel dual structure-aware image filterings (DSAIF) as the image-level variations for semi-supervised medical image segmentation.

Image Segmentation Segmentation +2

PrivacyGAN: robust generative image privacy

no code implementations19 Oct 2023 Mariia Zameshina, Marlene Careil, Olivier Teytaud, Laurent Najman

Classical techniques for protecting facial image privacy typically fall into two categories: data-poisoning methods, exemplified by Fawkes, which introduce subtle perturbations to images, or anonymization methods that generate images resembling the original only in several characteristics, such as gender, ethnicity, or facial expression. In this study, we introduce a novel approach, PrivacyGAN, that uses the power of image generation techniques, such as VQGAN and StyleGAN, to safeguard privacy while maintaining image usability, particularly for social media applications.

Data Poisoning Image Generation

SWMLP: Shared Weight Multilayer Perceptron for Car Trajectory Speed Prediction using Road Topographical Features

no code implementations2 Oct 2023 Sarah Almeida Carneiro, Giovanni Chierchia, Jean Charléty, Aurélie Chataignon, Laurent Najman

One concern is that, although there are studies that give good results for these data, the data from these regions may not be sufficiently representative to describe all the traffic patterns in the rest of the world.

Unsupervised discovery of Interpretable Visual Concepts

1 code implementation31 Aug 2023 Caroline Mazini Rodrigues, Nicolas Boutry, Laurent Najman

Attribution maps from xAI techniques, such as Integrated Gradients, are a typical example of a visualization technique containing a high level of information, but with difficult interpretation.

Self-supervised learning of Split Invariant Equivariant representations

1 code implementation14 Feb 2023 Quentin Garrido, Laurent Najman, Yann Lecun

We hope that both our introduced dataset and approach will enable learning richer representations without supervision in more complex scenarios.

Self-Supervised Learning

Fairness in generative modeling

no code implementations6 Oct 2022 Mariia Zameshina, Olivier Teytaud, Fabien Teytaud, Vlad Hosu, Nathanael Carraz, Laurent Najman, Markus Wagner

We design general-purpose algorithms for addressing fairness issues and mode collapse in generative modeling.

Fairness

RankMe: Assessing the downstream performance of pretrained self-supervised representations by their rank

no code implementations5 Oct 2022 Quentin Garrido, Randall Balestriero, Laurent Najman, Yann Lecun

Joint-Embedding Self Supervised Learning (JE-SSL) has seen a rapid development, with the emergence of many method variations but only few principled guidelines that would help practitioners to successfully deploy them.

Self-Supervised Learning

On the duality between contrastive and non-contrastive self-supervised learning

no code implementations3 Jun 2022 Quentin Garrido, Yubei Chen, Adrien Bardes, Laurent Najman, Yann Lecun

Recent approaches in self-supervised learning of image representations can be categorized into different families of methods and, in particular, can be divided into contrastive and non-contrastive approaches.

Self-Supervised Learning

Some equivalence relation between persistent homology and morphological dynamics

no code implementations25 May 2022 Nicolas Boutry, Laurent Najman, Thierry Géraud

In Mathematical Morphology (MM), connected filters based on dynamics are used to filter the extrema of an image.

Relation Topological Data Analysis

Assessing hierarchies by their consistent segmentations

1 code implementation11 Apr 2022 Zeev Gutman, Ritvik Vij, Laurent Najman, Michael Lindenbaum

We found that the obtainable segmentation quality varies significantly depending on the way that the segments are specified by the hierarchy elements, and that representing a segmentation with only a few hierarchy elements is often possible.

Math Segmentation

Rethinking Interactive Image Segmentation: Feature Space Annotation

1 code implementation12 Jan 2021 Jord{ã}o Bragantini, Alexandre X Falc{ã}o, Laurent Najman

This strategy is in stark contrast to existing interactive segmentation methodologies, which perform annotation in the image domain.

Foreground Segmentation Image Segmentation +4

VOIDD: automatic vessel of intervention dynamic detection in PCI procedures

no code implementations12 Oct 2017 Ketan Bacchuwar, Jean Cousty, Régis Vaillant, Laurent Najman

We present the automatic VOIDD algorithm to detect the vessel of intervention which is going to be treated during the procedure by combining information from the vessel image with contrast agent injection and images acquired during guidewire tip navigation.

Hierarchical image simplification and segmentation based on Mumford-Shah-salient level line selection

no code implementations15 Mar 2016 Yongchao Xu, Thierry Géraud, Laurent Najman

Many image simplification and segmentation methods are driven by the optimization of an energy functional, for instance the celebrated Mumford-Shah functional.

Attribute Segmentation

New characterizations of minimum spanning trees and of saliency maps based on quasi-flat zones

no code implementations27 May 2015 Jean Cousty, Laurent Najman, Yukiko Kenmochi, Silvio Guimarães

We study three representations of hierarchies of partitions: dendrograms (direct representations), saliency maps, and minimum spanning trees.

A graph-based mathematical morphology reader

no code implementations30 Apr 2014 Laurent Najman, Jean Cousty

This survey paper aims at providing a "literary" anthology of mathematical morphology on graphs.

Survey

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