Jacques-Olivier Lachaud

Professor of Computer Science

I am Professor of Computer Science at University Savoie Mont Blanc. I do my research in the Laboratory of Mathematics. I teach in the Computer Science department of UFR Science and Montagne. I was co-chair of the thematic year “Geometry” of the GdR IFM and IGRV during 2023-2024. I was head of the Cursus Master en Ingénierie Informatique till August 2024. My research interests include digital geometry and topology, image segmentation and analysis, geometry processing, variational models, and discrete calculus. Albeit not an expert, I am also quite fond of arithmetic, word combinatorics, computational geometry, combinatorial topology, differential geometry and I often use several related results in my research.

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Interests

Digital Geometry
Image analysis
Geometry processing
Variational models
Discrete calculus

Education

HDR in Computer science (Habilitation à Diriger des Recherches), 2006
University Bordeaux 1
PhD in Computer Science, 1998
University Joseph Fourier
MSc in Computer Science, 1994
University Joseph Fourier
Engineer in Applied Mathematics and Computer Science, 1994
ENSIMAG School of Engineering

Featured Publications

Digital Geometry

2D Bijective rigid rotation: quantitative and qualitative study

Stéphane Breuils

• Jul 4, 2025

Digital Calculus

Corrected Laplace-Beltrami Operators for Digital Surfaces

Colin Weill-Duflos

• Mar 7, 2025

Digital Geometry

Recognition of Pieces of Arithmetic Hyperplanes Using the Stern-Brocot Tree

Bastien Laboureix

• Mar 7, 2025

Digital Geometry

New Properties for Full Convex Sets and Full Convex Hulls

Fabien Feschet

• Jan 25, 2025

Geometric Inference

Lightweight Curvature Estimation on Point Clouds with Randomized Corrected Curvature Measures

Jacques-Olivier Lachaud

• Jul 2, 2023

Digital Geometry

An Alternative Definition for Digital Convexity

Jacques-Olivier Lachaud

• Jan 1, 2022

Recent Publications

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Stéphane Breuils, David Coeurjolly, Jacques-Olivier Lachaud (2025). 2D Bijective rigid rotation: quantitative and qualitative study. J. Math. Imaging Vis., 67(4): 37, 2025..

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Colin Weill-Duflos, David Coeurjolly, Jacques-Olivier Lachaud (2025). Corrected Laplace-Beltrami Operators for Digital Surfaces. J. Math. Imaging Vis., 67(2): 11, 2025..

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Bastien Laboureix, Alban Mattei, Jacques-Olivier Lachaud, Isabelle Debled-Rennesson (2025). Recognition of Pieces of Arithmetic Hyperplanes Using the Stern-Brocot Tree. J. Math. Imaging Vis., 67(2): 15, 2025..

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Fabien Feschet, Jacques-Olivier Lachaud (2025). New Properties for Full Convex Sets and Full Convex Hulls. J. Math. Imaging Vis., 67(1): 8, 2025..

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Jui-Ting Lu, Tristan Roussillon, Jacques-Olivier Lachaud, David Coeurjolly (2024). Delaunay property and proximity results of the L-algorithm for digital plane probing. Theoretical Computer Science, 1011: 114719, 2024.

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Stéphane Breuils, David Coeurjolly, Jacques-Olivier Lachaud (2024). Construction of Fast and Accurate 2D Bijective Rigid Transformation. In: Brunetti, S., Frosini, A., Rinaldi, S. (eds) Discrete Geometry and Mathematical Morphology. DGMM 2024, volume 14605 of Lecture Notes in Computer Science, pp 80-92, 2024. Springer, Cham.

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Colin Weill-Duflos, David Coeurjolly, Jacques-Olivier Lachaud (2024). Digital Calculus Frameworks and Comparative Evaluation of Their Laplace-Beltrami Operators. In: Brunetti, S., Frosini, A., Rinaldi, S. (eds) Discrete Geometry and Mathematical Morphology. DGMM 2024, volume 14605 of Lecture Notes in Computer Science, pp 93-106, 2024. Springer, Cham.

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Fabien Feschet, Jacques-Olivier Lachaud (2024). New characterizations of full convexity. In: Brunetti, S., Frosini, A., Rinaldi, S. (eds) Discrete Geometry and Mathematical Morphology. DGMM 2024, volume 14605 of Lecture Notes in Computer Science, pp 41-53, 2024. Springer, Cham.

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Fabien Feschet, Jacques-Olivier Lachaud (2023). An Envelope Operator for Full Convexity to Define Polyhedral Models in Digital Spaces. J. Math. Imaging Vis., 65(5): 754-769, 2023.

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Jacques-Olivier Lachaud, David Coeurjolly, Céline Labart, Pascal Romon, Boris Thibert (2023). Lightweight Curvature Estimation on Point Clouds with Randomized Corrected Curvature Measures. Comput. Graph. Forum, (Proc. of Symposium on Geometry Processing, SGP2023, Genova, Italy)), 42(5): e14910, 2023.

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Colin Weill-Duflos, David Coeurjolly, Fernando De Goes, Jacques-Olivier Lachaud (2023). Joint optimization of distortion and cut location for mesh parameterization using an Ambrosio-Tortorelli functional. Computer Aided Geometric Design, Proc. International Conference on Geometric Modeling and Processing (GMP 2023), Genoa, Italy. 102231, 2023..

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Daniel Martins Antunes, Jacques-Olivier Lachaud, Hugues Talbot (2023). Elastica Energy Regularization via Graph Cuts. Research report, hal-04421328, 2024.

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David Coeurjolly, Jacques-Olivier Lachaud (2022). A Simple Discrete Calculus for Digital Surfaces. Discrete Geometry and Mathematical Morphology - Second International Joint Conference, DGMM 2022, Strasbourg, France, Oct 24-27, 2022, Proceedings, pp 341-353, volume 13493 of Lecture Notes in Computer Science, 2022, Springer, Cham..

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Jacques-Olivier Lachaud (2022). An Alternative Definition for Digital Convexity. J. Math. Imaging Vis., 64(7): 718-735, 2022.

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Jacques-Olivier Lachaud, Pascal Romon, Boris Thibert (2022). Corrected Curvature Measures. Discret. Comput. Geom., 68(2): 477–524, 2022.

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Fabien Feschet, Jacques-Olivier Lachaud (2022). Full convexity for polyhedral models in digital spaces. Discrete Geometry and Mathematical Morphology - Second International Joint Conference, DGMM 2022, Strasbourg, France, Oct 24-27, 2022, Proceedings, pp 98-109, volume 13493 of Lecture Notes in Computer Science, 2022, Springer, Cham..

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Daniel Martins Antunes, Jacques-Olivier Lachaud, Hugues Talbot (2021). A Maximum-Flow Model for Digital Elastica Shape Optimization. Discrete Geometry and Mathematical Morphology - First International Joint Conference, DGMM 2021, Uppsala, Sweden, May 24-27, 2021, Proceedings.

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Jacques-Olivier Lachaud (2021). An Alternative Definition for Digital Convexity. Discrete Geometry and Mathematical Morphology - First International Joint Conference, DGMM 2021, Uppsala, Sweden, May 24-27, 2021, Proceedings, volume 12708 of Lecture Notes in Computer Science, pp 269–282, 2021. Springer.

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Daniel Martins Antunes, Jacques-Olivier Lachaud, Hugues Talbot (2021). An Elastica-Driven Digital Curve Evolution Model for Image Segmentation. J. Math. Imaging Vis., 63(1): 1-17, 2021.

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David Coeurjolly, Jacques-Olivier Lachaud, Pierre Gueth (2021). Digital Surface Regularization With Guarantees. IEEE Trans. Vis. Comput. Graph., 27(6): 2896-2907, 2021.

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Jacques-Olivier Lachaud, Jocelyn Meyron, Tristan Roussillon (2020). An Optimized Framework for Plane-Probing Algorithms. J. Math. Imaging Vis., 62(5): 718-736, 2020.

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Jacques-Olivier Lachaud, Pascal Romon, Boris Thibert, David Coeurjolly (2020). Interpolated corrected curvature measures for polygonal surfaces. Comput. Graph. Forum, 39(5): 41-54, 2020.

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Mouhammad Said, Jacques-Olivier Lachaud (2019). Analytical description of digital intersections: Minimal parameters and multiscale representation. Theoretical Computer Science, 784: 99-112, 2019.

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Johanna Delanoy, David Coeurjolly, Jacques-Olivier Lachaud, Adrien Bousseau (2019). Combining voxel and normal predictions for multi-view 3D sketching. Computers & Graphics, 82: 65-72, 2019.

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D. Antunes, Jacques-Olivier Lachaud, H. Talbot (2019). Digital Curvature Evolution Model for Image Segmentation. International Conference on Discrete Geometry for Computer Imagery (DGCI'2019), Marne-la-Vallée, France.

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Recent & Upcoming Talks

Talk

Corrected curvature measures

Invited talk at NII Shonan Meeting 226, Japan.

Jacques-Olivier Lachaud

• May 20, 2025

Talk

Around global and local convexity in digital spaces

Invited talk at Meeting on Tomography and Applications 2025

Jacques-Olivier Lachaud

• May 7, 2025

Talk

Année "Géométrie" 2023-2024 : bilan et prospective

Invited talk at JNIFM 2025

Jacques-Olivier Lachaud

• Mar 26, 2025

Talk

Introduction to digital geometry

Tutorial talk, DGMM2024, Firenze, Italy.

David Coeurjolly

• Apr 15, 2024

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Recent events

Event

Journées du GT GDMM / Workshop of GDMM workgroup

Co-chair of the organization committee.

Stéphane Breuils

• Jul 9, 2025

Event

Thematic year "Geometry" of GDR IFM and IGRV

Chair (with M. Desbrun) of Thematic year on "Geometry"

Jacques-Olivier Lachaud

• Jan 1, 2023

Event

Conference on Digital Geometry and Discrete Variational Calculus

Chair of the organization committee.

Jacques-Olivier Lachaud

• Mar 29, 2021

Event

Cross Border Meeting on Discrete and Computational Geometry and Applications

Organizer.

Jacques-Olivier Lachaud

• Nov 9, 2015

Projects

Fun

AlgoSurfer

implicit/algebraic surface viewer (project for pedagogy and fun) Mar. 2024 - May. 2024 / Creator

May 30, 2024

Digital Geometry

StableProxies

Stable Geometry Processing and High Performance Calculus on Heterogeneous Geometrical Data (ANR project ANR-22-CE46) Feb. 2023 - Jan. 2028 / Team Leader LAMA

Sep 1, 2022

Plane Probing

PARADIS

PARameter-free Analysis of DIgital Surfaces (ANR JCJC project ANR-18-CE23-0007-01) Dec. 2018 - Mar. 2024 / Member

Dec 1, 2018

Digital Geometry

CoMeDiC

Convergent Metrics for Digital Calculus (ANR project ANR-15-CE40-0006) Oct. 2015 - Jul. 2021 / Principal Investigator

Oct 1, 2015

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Gallery

features-AT — Extraction of sharp features along digital surfaces, undamaged or noisy, using a discrete calculus formulation of the Ambrosio-Tortorelli functional.

Pacific Graphics 2016

Shortest paths along a digital surface using tangency property given by full convexity. Note that induced distances are Euclidean in every planar (even slanted) parts of the digital surface. JMIV 2022 DGMM 2021	Delaunay complex of a set of lattice points randomly generated within a ball of radius 10. Note that co-sphericities of more than 4 points are quite frequent in lattice spaces, and Delaunay cells may thus not be tetrahedra. Module Quickhull of DGtal allows you to compute the Delaunay complex of lattice/rational points in arbitrary dimension.
3D Convex hull a digital ball of radius 50. Note that co-sphericities of more than 4 points are quite frequent in lattice spaces, and the convex hull has many non triangular faces. Module Quickhull of DGtal allows you to compute the convex hull of lattice/rational points in arbitrary dimension.	Estimated principal directions of curvature on a digitized Stanford bunny shape (resolution 64x64x64) using corrected curvature measures; principal curvatures are depicted using colors (blue is very low negative, cyan is low negative, black is zero, yellow is high positive, red is very high positive). Discrete & Computational Geometry 2022
Multigrid convergence of mean curvature estimator based on Corrected Normal Current. The finer the sampling, the more stable are the curvature estimations. Discrete & Computational Geometry 2022	Multigrid convergence of Gaussian curvature estimator based on Corrected Normal Current. The finer the sampling, the more stable are the curvature estimations. Discrete & Computational Geometry 2022
Lowest principal curvatures on a “Murex” point cloud, estimated using randomized corrected curvature measures. Computer Graphics Forum 2023 (SGP2023)	Highest principal curvatures on a “Murex” point cloud, estimated using randomized corrected curvature measures. Computer Graphics Forum 2023 (SGP2023)
Depixelizing pixel art: 16 x zoomed bitmap image using Geometric Total Variation. ACPR2019	Depixelizing pixel art: 16 x zoomed bitmap image using Geometric Total Variation. ACPR2019
Vision of Kleinian surface AlgoSurfer	View of mean curvatures onto Kleinian surface AlgoSurfer