Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?
Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur GraphSearch.
Concept
Zoom numérique
Résumé
Digital zoom is a method of decreasing the precise angle of view of a digital photograph or video image. It is accomplished by an image down to an area with the same as the original, and scaling the image up to the dimensions of the original. The camera's optics are not adjusted. It is accomplished electronically, so no optical resolution is gained. Digital zooming may be enhanced by computationally expensive algorithms which sometimes involves artificial intelligence.
In cameras that perform lossy compression, digital zoom is preferred to enlargement in post-processing, as the zooming may be applied before detail is lost to compression. In cameras that save in a lossless format, resizing in post-production yields results equal or superior to digital zoom.
Lower-end camera phones use only digital zoom and do not have optical zoom, while many higher-end phones have additional rear cameras, including fixed telephoto lenses that allow for the simulation of optical zoom. Full-sized cameras generally have an optical zoom lens, but some apply digital zoom automatically once the longest optical focal length possible has been reached. Professional cameras generally do not feature digital zoom.
An optical zoom camera can be zoomed to its optical limit, and further zooming is sometimes allowed by digital zoom. Digital zoom uses the centre area of the optical image to enlarge the image. By reducing the image size, digital zoom occurs without image deterioration of the output image, and some cameras have a "not-deteriorated image" mode or an image deterioration indicator.
The table below shows the not-deteriorated zoom limit for some megapixel (MP) image sizes of a particular camera with optical zoom 24x, and digital zoom 4x for its maximum capability:
File:Zoom10x.JPG|Handheld. Zoom 10×, Optical zoom 10×, 2 MP from 16 MP maximum, ISO 800, 1/420, F/14.0, image is clear
File:Zoom28x.JPG|Handheld. Zoom 28×, Optical zoom 10×, and Digital zoom 2.8×, 2 MP from 16 MP maximum, ISO 800, 1/420, F/14.
Source officielle
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.