Publications from the Center of Mathematical Morphology

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S. Dubuisson, I. Bloch, G. Franchi, E. Aldea (2019): Crowd Behavior Characterization for Scene Tracking. 2019 16th IEEE International Conference on Advanced Video and Signal Based Surveillance (AVSS), Taipei (Taiwan) 1—8.
In this work, we perform an in-depth analysis of the specific difficulties a crowded scene dataset raises for tracking algorithms. Starting from the standard characteristics depicting the crowd and their limitations, we introduce six en-tropy measures related to the motion patterns and to the appearance variability of the individuals forming the crowd, and one appearance measure based on Principal Component Analysis. The proposed measures are discussed on synthetic configurations and on multiple real datasets. These criteria are able to characterize the crowd behavior at a more detailed level...

B. Figliuzzi (2019): Eikonal-based models of random tessellations. Image Analysis and Stereology 38(1) 15.
In this article, we propose a novel, efficient method for computing a random tessellation from its vectorial representation at each voxel of a discretized domain. This method is based upon the resolution of the Eikonal equation and has a complexity in O(N log N), N being the number of voxels used to discretize the domain. By contrast, evaluating the implicit functions of the vectorial representation at each voxel location has a complexity of O(N²) in the general case. The method also enables us to consider the generation of tessellations with rough interfaces between cells by simulating the...

J. Angulo (2019): Hierarchical Laplacian and Its Spectrum in Ultrametric Image Processing. International Symposium on Mathematical Morphology and Its Applications to Signal and Image Processing ISMM 2019, Saarbrücken (Germany) 11564 29—40.
The Laplacian of an image is one of the simplest and useful image processing tools which highlights regions of rapid intensity change and therefore it is applied for edge detection and contrast enhancement. This paper deals with the definition of the Laplacian operator on ultrametric spaces as well as its spectral representation in terms of the corresponding eigenfunctions and eigenvalues. The theory reviewed here provides the computational framework to process images or signals defined on a hierarchical representation associated to an ultrametric space. In particular, image regularization by...

J. Angulo (2019): Minkowski Sum of Ellipsoids and Means of Covariance Matrices. International Conference on Geometric Science of Information GSI 2019, Toulouse (France) 11712 107—115.
The Minkowski sum and difference of two ellipsoidal sets are in general not ellipsoidal. However, in many applications, it is required to compute the ellipsoidal set which approximates the Minkowski operations in a certain sense. In this study, an approach based on the so-called ellipsoidal calculus, which provides parameterized families of external and internal ellipsoids that tightly approximate the Minkowski sum and difference of ellipsoids, is considered. Approximations are tight along a direction l in the sense that the support functions on l of the ellipsoids are equal to the support...

A. Serna, B. Marcotegui, E. Decencière (2019): Segmenting junction regions without skeletonization using geodesic operators and the max-tree. 14th International Symposium on Mathematical Morphology and Its Applications to Signal and Image Processing, Saarbrücken (Germany).
In a 2D skeleton, a junction region indicates a connected component (CC) where a path splits into two or more different branches. In several real applications, structures of interest such as vessels, cables, fibers, wrinkles, etc. may be wider than one pixel. Since the user may be interested in the junction regions but not in the skeleton itself (e.g. in order to segment an object into single branches), it is reasonable to think about finding junction regions directly on objects avoiding skeletoniza-tion. In this paper we propose a solution to find junction regions directly on objects, which...

T. Asplund, A. Serna, B. Marcotegui, R. Strand, C. Luengo Hendriks (2019): Mathematical Morphology on Irregularly Sampled Data Applied to Segmentation of 3D Point Clouds of Urban Scenes. 14th International Symposium on Mathematical Morphology and Its Applications to Signal and Image Processing, Saarbrücken (Germany).
This paper proposes an extension of mathematical morphology on irregularly sampled signals to 3D point clouds. The proposed method is applied to the segmentation of urban scenes to show its applicability to the analysis of point cloud data. Applying the proposed operators has the desirable side-effect of homogenizing signals that are sampled heterogeneously. In experiments we show that the proposed segmenta-tion algorithm yields good results on the Paris-rue-Madame database and is robust in terms of sampling density, i.e. yielding similar labelings for more sparse samplings of the same scene.

W. Alves, C. Gobber, D. Da Silva, A. Morimitsu, R. Hashimoto, B. Marcotegui (2019): Ultimate levelings with strategy for filtering undesirable residues based on machine learning. 14th International Symposium on Mathematical Morphology and Its Applications to Signal and Image Processing, Saarbrücken (Germany).
Ultimate levelings are operators that extract important image contrast information from a scale-space based on levelings. During the residual extraction process, it is very common that some residues are selected from undesirable regions, but they should be filtered out. In order to avoid this problem some strategies can be used to filter residues extracted by ultimate levelings. In this paper, we introduce a novel strategy to filter undesirable residues from ultimate levelings based on a regression model that predicts the correspondence between objects of interest and residual regions. In...

A. Fehri, S. Velasco-Forero, F. Meyer (2019): Prior-based Hierarchical Segmentation Highlighting Structures of Interest. Math. Morphol. Theory Appl 3 29 — 44.
Image segmentation is the process of partitioning an image into a set of meaningful regions according to some criteria. Hierarchical segmentation has emerged as a major trend in this regard as it favors the emergence of important regions at different scales. On the other hand, many methods allow us to have prior information on the position of structures of interest in the images. In this paper, we present a versatile hierarchical segmentation method that takes into account any prior spatial information and outputs a hierarchical segmentation that emphasizes the contours or regions of interest...

E. Decencière, A. Belhedi, S. Koudoro, F. Flament, G. François, V. Rubert, I. Pécile, J. Pierre (2019): A 2.5d approach to skin wrinkles segmentation. Image Analysis and Stereology 38(1) 75.
Wrinkles or creases are common structures on surfaces. Their detection is often challenging, and can be an important step for many different applications. For instance, skin wrinkle segmentation is a crucial step for quantifying changes in skin wrinkling and assessing the beneficial effects of dermatological and cosmetic anti-ageing treatments. A 2.5D approach is proposed in this paper to segment individual wrinkles on facial skin surface described by 3D point clouds. The method, based on mathematical morphology, only needs a few physical parameters as input, namely the maximum wrinkle width,...

B. Laÿ, R. Danno, G. Quellec, E. Decencière, A. Erginay, P. Massin, A. Le Guilcher, M. Lamard, B. Cochener, R. Alais (2019): RetinOpTIC-Automatic Evaluation of Diabetic Retinopathy. ARVO, Vancouver (Canada).
Purpose: The RetinOpTIC project performs mass screening of color fundus images and assesses image quality and Diabetic Retinopathy (DR) grade. Algorithm performance is evaluated on the Messidor-2 image database. Methods: Based on artificial intelligence (AI) solutions, referable DR is detected using convolutional neural networks (CNNs). The solution includes first the automatic assessment of the quality of the photography, and then the DR grade

F. Willot, R. Brenner, H. Trumel (2019): Elastostatic field distributions in polycrystals and cracked media. Philosophical Magazine.
This work addresses the problem of the reconstruction of the local fields distribution occurring in heterogeneous linear elastic solids. The constitutive heterogeneities are crystals and cracks. Through comparisons with FFT computations, it is shown that self-consistent estimates together with an assumption of normal distribution at the phase scale provide an accurate description of the elastostatic field histograms in polycrystals without cracks. In the case of inter and transgranular cracks, full-field FFT simulations indicate that the field histograms present van Hove singularities. Their...

M. Neumann, O. Stenzel, F. Willot, L. Holzer, V. Schmidt (2019): Quantifying the influence of microstructure on effective conductivity and permeability: Virtual materials testing. International Journal of Solids and Structures 184 211—220.
Effective conductivity and permeability of a versatile, graph-based model of random structures are investigated numerically. This model, originally introduced in Gaiselmann et al. (2014) allows one to simulate a wide class of realistic materials. In the present work, an extensive dataset of two-phase microstructures with wide-ranging morphological features is used to assess the relationship between microstructure and effective transport properties, which are computed using Fourier-based methods on digital images. Our main morphological descriptors are phase volume fractions, mean geodesic...

F. Willot (2019): The effective conductivity of strongly nonlinear media: The dilute limit. International Journal of Solids and Structures 184 287—295.
This work is a combined numerical and analytical investigation of the effective conductivity of strongly nonlinear media in two dimensions. The nonlinear behavior is characterized by a threshold value for the maximal absolute current. Our main focus is on random media containing an infinitesimal proportion f≪1 of insulating phase. We first consider a random conducting network on a square grid and establish a relationship between the length of minimal paths spanning the network and the network's effective response. In the dilute limit f≪1, the network's effective conductivity scales, to...

S. Forest, F. Willot (2019): Preface to a Special Issue of the International Journal of Solids and Structures on Physics and Mechanics of Random Structures: From Morphology to Material Properties In honor of Professor Dominique Jeulin (Mines ParisTech). International Journal of Solids and Structures 184 1—2.
This volume gathers contributions presented at the International Workshop on Physics and Mechanics of Random Structures: From Morphology to Material Properties held on the Ile d’Oléron (Atlantic coast, France), June 17–22, 2018 (Willot and Forest, 2018; Oleron, 2019). This exceptional workshop was organized on the occasion of the (official) retirement of Prof. Dominique Jeulin from his position at Mines ParisTech, where he has been working for more than 30 years to the development of mathematical morphology and physics and mechanics of random media.

F. Cadiou, A. Etiemble, T. Douillard, F. Willot, O. Valentin, J.C. Badot, B. Lestriez, E. Maire (2019): Numerical Prediction of Multiscale Electronic Conductivity of Lithium-Ion Battery Positive Electrodes. Journal of The Electrochemical Society 166(8) A1692—A1703.
The electronic conductivity, at the multiscale, of lithium-ion positive composite electrodes based on LiNi_{1/3}Mn_{1/3}Co_{1/3}O_2 and/or carbon-coated LiFePO_4, carbon black and poly(vinylidene fluoride) mixture is modeled. The electrode microstructures are acquired numerically in 3D by X-ray tomography and FIB/SEM nanotomography and numerically segmented to perform electrostatic simulations using Fast Fourier Transform (FFT) method. Such simulations are easy and quick to perform because they are directly computed on the grid represented by the voxels in the 3D volumes. Numerical results...

L. Lacourt, S. Forest, F. N'Guyen, D. Ryckelynck, F. Willot, S. Flouriot, V. De Rancourt, A. Thomas (2019): Étude numérique de la nocivité des défauts dans les soudures. Rupture des matériaux et structures – Mécanismes et modélisations face aux applications industrielles, Aussois (France).

L. Lacourt, S. Forest, D. Ryckelynck, F. Willot, S. Flouriot, V. De Rancourt (2019): Étude numérique de la nocivité des défauts dans les soudures. 14e Colloque National en Calcul des Structures, Presqu’île de Giens (France).

F. Rabette, H. Trumel, F. Willot (2019): Modélisation multiéchelle par champ de phase de la microfissuration d'un polycristal organique de forte anisotropie cristalline par FFT. 14e Colloque National en Calcul des Structures, Presqu’île de Giens (France).

D. Jeulin (2019): Some dense random packings generated by the dead leaves model. Image Analysis and Stereology 38(1) 3.
The intact grains of the dead leaves model enables us to generate random media with non overlapping grains. Using the time non homogeneous sequential model with convex grains, theoretically very dense packings can be generated, up to a full covering of space. For these models, the theoretical volume fraction, the size distribution of grains, and the pair correlation function of centers of grains are given.

H. Trumel, F. Rabette, F. Willot, R. Brenner, E. Ongari, M. Biessy, D. Picart (2019): Understanding the thermomechanical behavior of a TATB-based explosive via microstructure-level simulations. Part I: Microcracking and viscoelasticity. Europyro 44th International Pyrotechnics Seminar, Tours (France).
In view of a better understanding of the thermomechanical behavior of pressed explosives, a Fourier-based computational tool is used to perform numerical homogenization and compare predictions to experimental macroscopic properties. This is first done in a purely thermoelastic context on simplified polycrystalline virtual microstructures, then extended to cracked polycrystalline ones. A further extension is proposed, aiming at predicting the nucleation and propagation of (micro)-cracks. Besides, a mean-field (self-consistent) approach is also followed, providing accurate thermoelastic...

F. Rabette, F. Willot, H. Trumel (2019): Homogénéisation en champs complets par FFT pour un matériau énergétique à forte anisotropie cristalline : prise en compte de la microfissuration par une méthode de champ de phase. Colloque National MECAMAT 2019: Rupture des Matériaux et des Structures, Aussois (France).

H. Thomas, C.R. Qi, J.E. Deschaud, B. Marcotegui, F. Goulette, L.J. Guibas (2019): KPConv: Flexible and Deformable Convolution for Point Clouds. The IEEE International Conference on Computer Vision (ICCV), Séoul (South Korea).
We present Kernel Point Convolution (KPConv), a new design of point convolution, i.e. that operates on point clouds without any intermediate representation. The convolution weights of KPConv are located in Euclidean space by kernel points, and applied to the input points close to them. Its capacity to use any number of kernel points gives KPConv more flexibility than fixed grid convolutions. Furthermore, these locations are continuous in space and can be learned by the network. Therefore, KPConv can be extended to deformable convolutions that learn to adapt kernel points to local geometry....

D. Duque-Arias, S. Velasco-Forero, F. Goulette, J.E. Deschaud, B. Marcotegui (2019): A graph-based color lines model for image analysis. International Conference on Image Analysis and Processing, Trento (Italy).
This paper addresses the problem of obtaining a concise description of spectral representation for color images. The proposed method is a graph-based formulation of the well-known Color Lines model. It generalizes the lines to piece-wise lines, been able to fit more complex structures. We illustrate the goodness of proposed method by measuring the quality of the simplified representations in images and videos. The quality of video sequences reconstructed by means of proposed color lines extracted from the first frame demonstrates the robustness of our representation. Our formalism allows to...

E. Bazan, P. Dokládal, E. Dokladalova (2019): Quantitative Analysis of Similarity Measures of Distributions. British Machine Vision Conference (BMVC), Cardiff (United Kingdom).
There are many measures of dissimilarity that, depending on the application, do not always have optimal behavior. In this paper, we present a qualitative analysis of the similarity measures most used in the literature and the Earth Mover's Distance (EMD). The EMD is a metric based on the theory of optimal transport with interesting geometrical properties for the comparison of distributions. However, the use of this measure is limited in comparison with other similarity measures. The main reason was, until recently, the computational complexity. We show the superiority of the EMD through three...

S. Velasco-Forero, B. Ponchon, S. Blusseau, J. Angulo, I. Bloch (2019): On approximating mathematical morphology operators via deep learning techniques. 15th International Congress for Stereology and Image Analysis, Aarhus (Denmark) 51.
Mathematical Morphology (MM) is a well-established discipline whose aim is mainly to provide tools to characterise complex object via their shape/size features. This study addresses the problem of robust approximation of mathematical morphology (MM) operators by deep learning methods. We present two cases, (a) Asymmetric autoencoders for part-based approximations of classical MM in the sense of [1] and, (b) image-to-image translation networks [2] to produce robust MM operators in presence of noise.

S. Blusseau, Y. Zhang, S. Velasco-Forero, I. Bloch, J. Angulo (2019): Pruning neural networks thanks to morphological layers. 15th International Congress for Stereology and Image Analysis, Aarhus (Denmark) 17.
Motivated by recent advances in morphological neural networks, we further study the properties of morphological units when incorporated in layers of conventional neural networks. We confirm and extend the observation that a Max-plus layer can be used to select relevant filters and reduce redundancy in its previous layer, without incurring performance loss. We present several experiments in image processing, showing that this filter selection property seems efficient and robust. We also point out the close connection between Maxout networks and our pruned Max-plus networks. The code related to...

Y. Yan, P.H. Conze, E. Decencière, M. Lamard, G. Quellec, B. Cochener, G. Coatrieux (2019): Cascaded multi-scale convolutional encoder-decoders for breast mass segmentation in high-resolution mammograms. IEEE International Engineering in Medicine and Biology Conference, Berlin (Germany).

Y. Xiao, E. Decencière, S. Velasco-Forero, H. Burdin, T. Bornschlögl, F. Bernerd, E. Warrick, T. Baldeweck (2019): A new color augmentation method for deep learning segmentation of histological images. 2019 IEEE 16th International Symposium on Biomedical Imaging (ISBI), Venise (France).
This paper addresses the problem of labeled data insufficiency in neural network training for semantic segmentation of color-stained histological images acquired via Whole Slide Imaging. It proposes an efficient image augmentation method to alleviate the demand for a large amount of labeled data and improve the network's generalization capacity. Typical image augmentation in bioimaging involves geometric transformation. Here, we propose a new image augmentation technique by combining the structure of one image with the color appearance of another image to construct augmented images on-the-fly...

R. Rodriguez Salas, E. Dokladalova, P. Dokládal (2019): Rotation invariant CNN using scattering transform for image classification. IEEE International Conference on Image Processing (ICIP), Taipei (Taiwan).
Deep convolutional neural networks accuracy is heavily impacted by rotations of the input data. In this paper, we propose a convolutional predictor that is invariant to rotations in the input. This architecture is capable of predicting the angular orientation without angle-annotated data. Furthermore, the predictor maps continuously the random rotation of the input to a circular space of the prediction. For this purpose, we use the roto-translation properties existing in the Scattering Transform Networks with a series of 3D Convolutions. We validate the results by training with upright and...

P. Cettour-Janet, C. Cazorla, V. Machairas, Q. Delannoy, N. Bednarek, F. Rousseau, E. Decencière, N. Passat (2019): Watervoxels. Image Processing On Line 9 317—328.
In this article, we present the $n$-dimensional version of the waterpixels, namely the watervoxels. Waterpixels constitute a simple, yet efficient alternative to standard superpixel paradigms, initially developed in the field of computer vision for reducing the space cost of input images without altering the accuracy of further image processing / analysis procedures. Waterpixels were initially proposed in a 2-dimensional version. Their extension to 3-dimensions---and more generally $n$-dimensions---is however possible, in particular in the Cartesian grid. Indeed, waterpixels mainly rely on a...

Kaeshammer, P. Dokládal, F. Willot, B. Erzar, S. Belon, L. Borne (2019): A Morphological Study of Energetic Materials: Analysis of Micro-computed Tomography Images to Generate Representative Microstructures. Europyro 2019 44th International Pyrotechnics Seminar, Tours (France).
In previous work, impact experiments were performed at ISL on three energetic materials composed of 70% in weight of RDX particles embedded in a wax matrix. These materials differ by the microstructural properties of the explosive particles. The experimental results reveal that the detonation thresholds, and so the sensitivity to shock, are different for each sample. To better understand these results, we characterize the microstructural properties of these compositions and generate virtual microstructures representative of the real microstructures. First, the microstructures of the three...

Kaeshammer, P. Dokladal, F. Willot, S. Belon, L. Borne (2019): Generation of Virtual Microstructures of Energetic Materials Based on Micro-computed Tomography Images Analysis. 50th International Annual Conference of the Fraunhofer ICT, Karlsruhe (Germany).
Impact experiments were performed at the french-german research Institute of Saint-Louis on three energetic materials composed of 70 % in weight of RDX particles embedded in a wax matrix. These materials differ by the microstructural properties of the explosive particles. The experimental results reveal that the detonation thresholds, and so the sensitivity to shock, are different for each sample. To better understand these results, we characterize the microstructural properties of these compositions. The microstructures of the three materials are imaged with micro-computed tomography (µCT)...

M. Neumann, B. Abdallah, L. Holzer, F. Willot, V. Schmidt (2019): Stochastic 3D Modeling of Three-Phase Microstructures for Predicting Transport Properties: A Case Study. Transport in Porous Media 128(1) 179—200.
We compare two conceptually different stochastic microstructure models , i.e., a graph-based model and a pluri-Gaussian model, that have been introduced to model the transport properties of three-phase microstructures occurring, e.g., in solid oxide fuel cell electrodes. Besides comparing both models, we present new results regarding the relationship between model parameters and certain mi-crostructure characteristics. In particular, an analytical expression is obtained for the expected length of triple phase boundary per unit volume in the pluri-Gaussian model. As a case study, we consider...

J. Serra, F. Willot (2019): Special topic on multiscale modeling of granular media: a tribute to Prof. Dominique Jeulin. Image Analysis and Stereology 38(1) 1.
A few words on the present special topic, devoted to the multiscale modeling of granular media, and published in honor of Prof. Dominique Jeulin's enduring contribution to the wide field of image analysis, random structures and material science.

B. Ponchon, S. Velasco-Forero, S. Blusseau, J. Angulo, I. Bloch (2019): Part-based approximations for morphological operators using asymmetric auto-encoders. International Symposium on Mathematical Morphology, Saarbrücken (Germany).
This paper addresses the issue of building a part-based representation of a dataset of images. More precisely, we look for a non-negative, sparse decomposition of the images on a reduced set of atoms, in order to unveil a morphological and interpretable structure of the data. Additionally, we want this decomposition to be computed online for any new sample that is not part of the initial dataset. Therefore, our solution relies on a sparse, non-negative auto-encoder where the encoder is deep (for accuracy) and the decoder shallow (for interpretability). This method compares favorably to the...

Y. Zhang, S. Blusseau, S. Velasco-Forero, I. Bloch, J. Angulo (2019): Max-plus Operators Applied to Filter Selection and Model Pruning in Neural Networks. International Symposium on Mathematical Morphology, Saarbrücken (Germany).
Following recent advances in morphological neural networks, we propose to study in more depth how Max-plus operators can be exploited to define morphological units and how they behave when incorporated in layers of conventional neural networks. Besides showing that they can be easily implemented with modern machine learning frameworks , we confirm and extend the observation that a Max-plus layer can be used to select important filters and reduce redundancy in its previous layer, without incurring performance loss. Experimental results demonstrate that the filter selection strategy enabled by...

F. Willot, H. Trumel, D. Jeulin (2019): The thermoelastic response of cracked polycrystals with hexagonal symmetry. Philosophical Magazine 99(5) 606—630.
The influence of a population of randomly-oriented cracks on the macroscopic thermal and linear-elastic response of a hexagonal polycrystal is addressed using a self-consistent method. Coupling between micro-cracks and crystal anisotropy is taken into account through the effective medium where all inhomogeneities are embedded. In the absence of cracks, the proposed approach reduces to the self-consistent estimate of Berryman (2005). The accuracy of the present method is first assessed using numerical, Fourier-based computations. In the absence of crystal anisotropy, the estimates for the...

E.H. Diop, J. Angulo (2019): Levelings based on Spatially-Adaptive Scale-Spaces using Local Image Features. IET Image Processing 13(10) 1597—1607.

A. Borocco, B. Marcotegui (2019): Non-rigid shape registration using curvature information. 14th International Conference on Computer Vision Theory and Applications, Prague (Czech Republic).
This paper addresses a registration problem for an industrial control application: it meets the need to registrate a model on an image of a flexible object. We propose a non-rigid shape registration approach that deals with a great disparity of the number of points in the model and in the manufactured object. We have developed a method based on a classical minimization process combining a distance term and a regularization term. We observed that, even if the control points fall on the object boundary, the registration failed on high curvature points. In this paper we add a curvature-based...

R.B. Metcalf, M. Meneghetti, C. Avestruz, F. Bellagamba, C.R. Bom, E. Bertin, R. Cabanac, F. Courbin, A. Davies, E. Decencière, R. Flamary, R. Gavazzi, M. Geiger, P. Hartley, M. Huertas-Company, N. Jackson, C. Jacobs, E. Jullo, J.P. Kneib, L.V.E. Koopmans, F. Lanusse, C.L. Li, Q. Ma, M. Makler, N. Li, M. Lightman, C.E. Petrillo, S. Serjeant, C. Schäfer, A. Sonnenfeld, A. Tagore, C. Tortora, D. Tuccillo, M.B. Valentín, S. Velasco-Forero, G.A. Verdoes Kleijn, G. Vernardos (2019): The Strong Gravitational Lens Finding Challenge. Astron.Astrophys. 625 A119.
Large-scale imaging surveys will increase the number of galaxy-scale strong lensing candidates by maybe three orders of magnitudes beyond the number known today. Finding these rare objects will require picking them out of at least tens of millions of images, and deriving scientific results from them will require quantifying the efficiency and bias of any search method. To achieve these objectives automated methods must be developed. Because gravitational lenses are rare objects, reducing false positives will be particularly important. We present a description and results of an open...

F. Willot (2019): Localization in random media and its effect on the homogenized behavior of materials.
The present manuscript is submitted in partial fulfillment of my application to the degree of ``Habilitation à diriger des recherches'' at Sorbonne University. Its main contribution is a study in theoretical mechanics devoted to homogenization problems in the context of degenerate (non-strictly convex) local response of one of the phases, which can serve as idealized models for porous or rigidly-reinforced materials exhibiting perfectly-plastic behavior. In these situations plastic flow preferentially concentrates along shear bands; as a result the material effective response is governed by...

S. Blusseau (2019): Mathematical morphology in non-Euclidean spaces and medical images -Technical report.

K. Chang, B. Figliuzzi (2019): Fast Marching Based Superpixels Generation. Burgeth B., Kleefeld A., Naegel B., Passat N., Perret B. (eds) Mathematical Morphology and Its Applications to Signal and Image Processing. ISMM 2019. Lecture Notes in Computer Science, vol 11564. Springer, Cham 350—361.

R. Rodriguez Salas, P. Dokládal, E. Dokladalova (2019): RED-NN: Rotation-Equivariant Deep Neural Network for Classification and Prediction of Rotation.
In this work, we propose a new Convolutional Neural Network (CNN) for classification of rotated objects. This architecture is built around an ordered ensemble of oriented edge detectors to create a roto-translational space that transforms the input rotation into translation. This space allows the subsequent predictor to learn the internal spatial and angular relations of the objects regardless of their orientation. No data augmentation is needed and the model remains significantly smaller. It presents a self-organization capability and learns to predict the class and the rotation angle...

J. DIRRENBERGER, S. FOREST, D. Jeulin (2019): Computational Homogenization of Architectured Materials. Architectured Materials in Nature and Engineering 89—139.

S. Bancelin, B. Lynch, C. Bonod-Bidaud, P. Dokládal, F. Ruggiero, J.M. Allain, M.C. Schanne-Klein (2019): Combination of Traction Assays and Multiphoton Imaging to Quantify Skin Biomechanics. Collagen : Methods and Protocols 1944 145—155.
An important issue in tissue biomechanics is to decipher the relationship between the mechanical behavior at macroscopic scale and the organization of the collagen fiber network at microscopic scale. Here, we present a protocol to combine traction assays with multiphoton microscopy in ex vivo murine skin. This multiscale approach provides simultaneously the stress/stretch response of a skin biopsy and the collagen reorganization in the dermis by use of second harmonic generation (SHG) signals and appropriate image processing.

R. Rodriguez Salas, P. Dokládal, E. Dokladalova (2019): Rotation-invariant NN for learning naturally un-oriented data.
Deep convolutional neural networks accuracy is heavily impacted by the rotations of the input data. In this paper, we propose a convolutional predictor that is invariant to rotations in the input. This architecture is capable of predicting the angular orientation without angle-annotated data. Furthermore, the predictor maps continuously the random rotation of the input to a circular space of the prediction. For this purpose, we use the roto-translation properties existing in the Scattering Transform Networks with a series of 3D Convolutions. We validate the results by training with upright...

E. Bazan, P. Dokládal, E. Dokladalova (2019): Quantitative Analysis of Similarity Measures of Distributions.
The Earth Mover's Distance (EMD) is a metric based on the theory of optimal transport that has interesting geometrical properties for distributions comparison. However, the use of this measure is limited in comparison with other similarity measures as the Kullback-Leibler divergence. The main reason was, until recently, the computation complexity. In this paper, we present a comparative study of the dissimilarity measures most used in the literature for the comparison of distributions through a color-based image classification system and other simple examples with synthetic data. We show that...


List of all publications from the CMM, recorded on the HAL depository under the tag ENSMP_CMM.

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