Filtre de PrewittLe filtre de Prewitt est utilisé en pour la détection de contours. Il tient son nom de Judith M. S. Prewitt. En termes simples, le filtre calcule le gradient d'intensité lumineuse de l'image à chaque point, donnant la direction et le taux de la plus grande décroissance. Le résultat nous indique les changements abrupts de luminosité de l'image et donc exhibe les contours probables de celle-ci. En pratique cette technique est plus fiable et facile à mettre en œuvre qu'un algorithme plus direct.
Roberts crossThe Roberts cross operator is used in and computer vision for edge detection. It was one of the first edge detectors and was initially proposed by Lawrence Roberts in 1963. As a differential operator, the idea behind the Roberts cross operator is to approximate the gradient of an image through discrete differentiation which is achieved by computing the sum of the squares of the differences between diagonally adjacent pixels.
Blob detectionIn computer vision, blob detection methods are aimed at detecting regions in a that differ in properties, such as brightness or color, compared to surrounding regions. Informally, a blob is a region of an image in which some properties are constant or approximately constant; all the points in a blob can be considered in some sense to be similar to each other. The most common method for blob detection is convolution.
Total variation denoisingIn signal processing, particularly , total variation denoising, also known as total variation regularization or total variation filtering, is a noise removal process (filter). It is based on the principle that signals with excessive and possibly spurious detail have high total variation, that is, the integral of the absolute is high. According to this principle, reducing the total variation of the signal—subject to it being a close match to the original signal—removes unwanted detail whilst preserving important details such as .
Image numériqueL'appellation d'image numérique désigne toute (dessin, icône, photographie...) acquise, créée, traitée et stockée sous forme binaire : acquise par des convertisseurs analogique-numérique situés dans des dispositifs comme les scanners, les appareils photo ou les caméscopes numériques, les cartes d’acquisition vidéo (qui numérisent directement une source comme la télévision) créée directement par des programmes informatiques, grâce à une souris, des tablettes graphiques ou par de la modélisation 3D (ce que l’on appelle, par abus de langage, les « images de synthèse ») ; traitée grâce à des outils graphiques, de façon à la transformer, à en modifier la taille, les couleurs, d’y ajouter ou d'en supprimer des éléments, d’y appliquer des filtres variés stockée sur un support informatique (clé USB, SSD, disque dur, CD-ROM.
Anisotropic diffusionIn and computer vision, anisotropic diffusion, also called Perona–Malik diffusion, is a technique aiming at reducing without removing significant parts of the image content, typically edges, lines or other details that are important for the interpretation of the image. Anisotropic diffusion resembles the process that creates a scale space, where an image generates a parameterized family of successively more and more blurred images based on a diffusion process.
Corner detectionCorner detection is an approach used within computer vision systems to extract certain kinds of features and infer the contents of an image. Corner detection is frequently used in motion detection, , video tracking, image mosaicing, panorama stitching, 3D reconstruction and object recognition. Corner detection overlaps with the topic of interest point detection. A corner can be defined as the intersection of two edges. A corner can also be defined as a point for which there are two dominant and different edge directions in a local neighbourhood of the point.
Image gradientAn image gradient is a directional change in the intensity or color in an image. The gradient of the image is one of the fundamental building blocks in . For example, the Canny edge detector uses image gradient for edge detection. In graphics software for , the term gradient or color gradient is also used for a gradual blend of color which can be considered as an even gradation from low to high values, as used from white to black in the images to the right. Another name for this is color progression.
