In the areas of computer vision, and signal processing, the notion of scale-space representation is used for processing measurement data at multiple scales, and specifically enhance or suppress image features over different ranges of scale (see the article on scale space). A special type of scale-space representation is provided by the Gaussian scale space, where the image data in N dimensions is subjected to smoothing by Gaussian convolution. Most of the theory for Gaussian scale space deals with continuous images, whereas one when implementing this theory will have to face the fact that most measurement data are discrete. Hence, the theoretical problem arises concerning how to discretize the continuous theory while either preserving or well approximating the desirable theoretical properties that lead to the choice of the Gaussian kernel (see the article on scale-space axioms). This article describes basic approaches for this that have been developed in the literature. The Gaussian scale-space representation of an N-dimensional continuous signal, is obtained by convolving fC with an N-dimensional Gaussian kernel: In other words: However, for implementation, this definition is impractical, since it is continuous. When applying the scale space concept to a discrete signal fD, different approaches can be taken. This article is a brief summary of some of the most frequently used methods. Using the separability property of the Gaussian kernel the N-dimensional convolution operation can be decomposed into a set of separable smoothing steps with a one-dimensional Gaussian kernel G along each dimension where and the standard deviation of the Gaussian σ is related to the scale parameter t according to t = σ2. Separability will be assumed in all that follows, even when the kernel is not exactly Gaussian, since separation of the dimensions is the most practical way to implement multidimensional smoothing, especially at larger scales. Therefore, the rest of the article focuses on the one-dimensional case.

À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.
Cours associés (8)
MICRO-512: Image processing II
Study of advanced image processing; mathematical imaging. Development of image-processing software and prototyping in Jupyter Notebooks; application to real-world examples in industrial vision and bio
EE-550: Image and video processing
This course covers fundamental notions in image and video processing, as well as covers most popular tools used, such as edge detection, motion estimation, segmentation, and compression. It is compose
MICRO-511: Image processing I
Introduction to the basic techniques of image processing. Introduction to the development of image-processing software and to prototyping using Jupyter notebooks. Application to real-world examples in
Afficher plus
Séances de cours associées (35)
Apprendre le noyau : l’optimisation convexe
Explore l'apprentissage de la fonction du noyau en optimisation convexe, en se concentrant sur la prédiction des sorties à l'aide d'un classificateur linéaire et en sélectionnant les fonctions optimales du noyau par validation croisée.
Traitement d'image I : filtres et transformations
Explore la moyenne mobile et les filtres exponentiels, le filtrage gaussien et les concepts d'espace d'échelle linéaire dans le traitement d'images.
Forme à partir de Stereo-2
Explore les concepts de vision stéréoscopique tels que les occlusions, l'impact de la taille de la fenêtre, la stéréo multivue, la reconstruction dynamique de la forme et la segmentation basée sur des graphiques.
Afficher plus
Publications associées (164)
Concepts associés (5)
Gaussian blur
In , a Gaussian blur (also known as Gaussian smoothing) is the result of blurring an by a Gaussian function (named after mathematician and scientist Carl Friedrich Gauss). It is a widely used effect in graphics software, typically to reduce and reduce detail. The visual effect of this blurring technique is a smooth blur resembling that of viewing the image through a translucent screen, distinctly different from the bokeh effect produced by an out-of-focus lens or the shadow of an object under usual illumination.
Filtre de Gauss
Le filtre de Gauss est, en électronique et en traitement du signal, un filtre dont la réponse impulsionnelle est une fonction gaussienne. Le filtre de Gauss minimise les temps de montée et de descente, tout en assurant l'absence de dépassement en réponse à un échelon. Cette propriété est étroitement liée au fait que le filtre de Gauss présente un retard de groupe minimal. En mathématiques, le filtre de Gauss modifie le signal entrant par une convolution avec une fonction gaussienne ; cette transformation est également appelée transformation de Weierstrass.
Multi-scale approaches
The scale space representation of a signal obtained by Gaussian smoothing satisfies a number of special properties, scale-space axioms, which make it into a special form of multi-scale representation. There are, however, also other types of "multi-scale approaches" in the areas of computer vision, and signal processing, in particular the notion of wavelets. The purpose of this article is to describe a few of these approaches: For one-dimensional signals, there exists quite a well-developed theory for continuous and discrete kernels that guarantee that new local extrema or zero-crossings cannot be created by a convolution operation.
Afficher plus

Graph Chatbot

Chattez avec Graph Search

Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.

AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.