Didier Verna

Interactive and real-time typesetting for demonstration and experimentation: <span style="font-variant:small-caps;">ETAP</span>

By Didier Verna

2023-09-01

In TUGboat

Abstract In general, typesetting experimentation is not a very practical thing to do. WYSIWYG typesetting systems are very reactive but do not offer highly configurable algorithms, and TeX, with its separate development / compilation / visualization phases, is not as interactive as its WYSIWYG competitors. Being able to experiment with typesetting algorithms interactively and in real-time is nevertheless desirable, for instance for demonstration purposes, or for rapid prototyping and debugging of new ideas.

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Structural analysis of the additive noise impact on the $\alpha$-tree

By Baptiste Esteban, Guillaume Tochon, Edwin Carlinet, Didier Verna

2023-06-30

In Proceedings of the 20th international conference on computer analysis of images and patterns (CAIP)

Abstract Hierarchical representations are very convenient tools when working with images. Among them, the $\alpha$-tree is the basis of several powerful hierarchies used for various applications such as image simplifi- cation, object detection, or segmentation. However, it has been demon- strated that these tasks are very sensitive to the noise corrupting the image. While the quality of some $\alpha$-tree applications has been studied, including some with noisy images, the noise impact on the whole struc- ture has been little investigated.

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A MOP-based implementation for method combinations

By Didier Verna

2023-04-01

In ELS 2023, the 16th european lisp symposium

Abstract In traditional object-oriented languages, the dynamic dispatch algorithm is hardwired to select and execute the most specific method in a polymorphic call. In CLOS, the Common Lisp Object System, an abstraction known as “method combinations” allows the programmer to define their own dispatch scheme. When Common Lisp was standardized, method combinations were not mature enough to be fully specified.In 2018, using SBCL as a research vehicle, we analyzed the unfortunate consequences of this under-specification and proposed a layer on top of method combinations designed to both correct a number of observed behavioral inconsistencies, and propose an extension called “alternative combinators”.

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The cost of dynamism in static languages for image processing

By Baptiste Esteban, Edwin Carlinet, Guillaume Tochon, Didier Verna

2022-10-10

In Proceedings of the 21st international conference on generative programming: Concepts & experiences (GPCE 2022)

Abstract Generic programming is a powerful paradigm abstracting data structures and algorithms to improve their reusability, as long as they respect a given interface. Coupled with a performance-driven language, it is a paradigm of choice for scientific libraries where the implementation of manipulated objects may change depending on their use case, or for performance purposes. In those performance-driven languages, genericity is often implemented statically to perform some optimization. This does not fit well with the dynamism needed to handle objects which may only be known at runtime.

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Estimation de la fonction de niveau de bruit pour des images couleurs en utilisant la morphologie mathématique

By Baptiste Esteban, Guillaume Tochon, Edwin Carlinet, Didier Verna

2022-06-15

In 28e colloque sur le traitement du signal et des images

Abstract Le niveau de bruit est une information importante pour certaines applications de traitement d’image telles que la segmentation ou le débruitage. Par le passé, nous avons proposé une méthode pour estimer ce niveau de bruit en s’adaptant au contenu d’une image en niveau de gris et nous avons montré que ses performances dépassent celle de l’état de l’art. Dans cet article, nous proposons une extension de cette méthode aux images couleurs dont les valeurs multivariées, dénuées de relation d’ordre naturelle, impliquent de nouvelles problématiques.

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Généricité dynamique pour des algorithmes morphologiques

By Baptiste Esteban, Edwin Carlinet, Guillaume Tochon, Didier Verna

2022-06-15

In 28e colloque sur le traitement du signal et des images

Abstract La généricité est un paradigme puissant dont l’usage permet d’implémenter un unique algorithme et de l’exécuter sur différents types de données. De ce fait, il est très utilisé lors du développement d’une bibliothèque scientifique, notamment en traitement d’images où les algorithmes peuvent s’appliquer à différents types d’images. Le langage C++ est un langage de choix pour ce genre de bibliothèque. Il supporte ce paradigme et ses applications sont performantes compte tenu de sa nature compilée.

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Analyse structurelle de l’influence du bruit sur l’arbre alpha

By Baptiste Esteban, Guillaume Tochon, Edwin Carlinet, Didier Verna

2022-06-14

In 29e colloque sur le traitement du signal et des images

Abstract L’arbre alpha est une représentation hiérarchique utilisée dans divers traitements d’une image tels que la segmentation ou la simplification. Ces traitements sont néanmoins sensibles au bruit, ce qui nécessite parfois de les adapter. Or, l’influence du bruit sur la structure de l’arbre alpha n’a été que peu étudiée dans la littérature. Ainsi, nous proposons une étude de l’impact du bruit en fonction de son niveau sur la structure de l’arbre.

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Estimation of the noise level function for color images using mathematical morphology and non-parametric statistics

By Baptiste Esteban, Guillaume Tochon, Edwin Carlinet, Didier Verna

2022-04-08

In Proceedings of the 26th international conference on pattern recognition

Abstract Noise level information is crucial for many image processing tasks, such as image denoising. To estimate it, it is necessary to find homegeneous areas within the image which contain only noise. Rank-based methods have proven to be efficient to achieve such a task. In the past, we proposed a method to estimate the noise level function (NLF) of grayscale images using the tree of shapes (ToS). This method, relying on the connected components extracted from the ToS computed on the noisy image, had the advantage of being adapted to the image content, which is not the case when using square blocks, but is still restricted to grayscale images.

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ETAP: Experimental typesetting algorithms platform

By Didier Verna

2022-03-01

In ELS 2022, the 15th european lisp symposium

Abstract We present the early development stages of ETAP, a platform for experimenting with typesetting algorithms. The purpose of this platform is twofold: while its primary objective is to provide building blocks for quickly and easily designing and testing new algorithms (or variations on existing ones), it can also be used as an interactive, real time demonstrator for many features of digital typography, such as kerning, hyphenation, or ligaturing.

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A corpus processing and analysis pipeline for Quickref

By Antoine Hacquard, Didier Verna

2021-05-01

In ELS 2021, the 14th european lisp symposium

Abstract Quicklisp is a library manager working with your existing Common Lisp implementation to download and install around 2000 libraries, from a central archive. Quickref, an application itself written in Common Lisp, generates, automatically and by introspection, a technical documentation for every library in Quicklisp, and produces a website for this documentation. In this paper, we present a corpus processing and analysis pipeline for Quickref. This pipeline consists of a set of natural language processing blocks allowing us to analyze Quicklisp libraries, based on natural language contents sources such as README files, docstrings, or symbol names.

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