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'''Image processing''' is the application of [[signal processing]]
techniques to the domain of [[images]] — two-dimensional [[signal]]s such as [[photography|photographs]] or [[video]].


Most of the signal processing concepts that apply to one-dimensional signals — such as [[Image_resolution | resolution]], [[dynamic range]], [[bandwidth]], [[filter (signal processing)| filtering]], etc. — extend naturally to images as well. However, image processing brings some new concepts — such as [[connected|connectivity]] and [[rotational invariance]] — that are meaningful or useful only for two-dimensional signals. Also, certain one-dimensional concepts — such as [[differential operators]], [[edge detection]], and [[domain modulation]] — become substantially more complicated when extended to two dimensions.

A few decades ago, image processing was done largely in the [[analog (signal)|analog]] domain, chiefly by [[optics|optical]] devices. Optical methods are inherently [[parallel]], and for that reason they are still essential to [[holography]] and a few other applications. However, as [[computers]] keep getting faster, analog techniques are being increasingly replaced by [[digital image processing]] techniques — which are more versatile, reliable, accurate, and easier to implement.


'''Image processing''' is the study of [[algorithm]]s applied to [[digital image]]s. Typical problems covered by this field include
* [[Euclidean geometry|geometric transformation]]s such as enlargement, reduction, and rotation;
* [[Color]] corrections such as brightness and contrast adjustments, [[quantization (signal processing)|quantization]], or conversion to a different [[color space]];
* Combination of two or more images, e.g. into an average, blend, difference, or [[image composite]].
* Interpolation, demosaicing, and recovery of a full image from a [[mosaic (digital image)|mosaic]] image (e.g. a Bayer pattern, etc.);
* [[Noise reduction]] and other types of [[digital filter|filter]]ing, and signal averaging;
* [[Edge detection]] and other local [[operator]]s;
* [[Segmentation (image processing)|Segmentation]] of the image into regions;
* [[2D computer graphics|image editing]] and digital retouching;
* Extending dynamic range by combining differently exposed images ([[generalized signal averaging]] of [[Wyckoff sets]]).

and many more.

Besides static two-dimensional images, the field also covers the processing of three-dimensional signals such as [[digital video]] and the output of [[tomography|tomographic]] equipment. Some techniques, such as [[morphological image processing]], are specific to [[binary image|binary]] or [[grayscale|grayscale image]]s.

The name 'image processing' is most appropriate when both inputs and outputs are images. The extraction of arbitrary information from images is the domain of [[image analysis]], which includes [[pattern recognition]] when the patterns to be identified are in images. In [[computer vision]] one seeks to extract more abstract information, such as the 3D description of a scene from video footage of it. The tools and concepts of image processing are also relevant to [[image synthesis]] from more abstract models, which is a major branch of [[computer graphics]].

Some applications are:
* [[Digital photography]] and printing
* Satellite image processing
* [[Medical image processing]]
* [[Face detection]], feature detection, face identification
* [[Microscope image processing]]

Some related concepts are:
* [[Classification]]
* [[Feature extraction]]
* [[Pattern recognition]]
* [[Projection]]
* [[Multi-scale signal analysis]]
* [[Principal components analysis]]
* [[Independent component analysis]]
* [[Self organizing map]]
* [[Hidden Markov model]]
* [[Neural networks]]

== See also ==
* [[Computer graphics]]
* [[Computer vision]]
* [[GPGPU]]
* [[optics]]
* [[photography]]
* [[imaging]]
* [[digitizing]]
* [[super-resolution]]
{{wikicities|computervision|Computer Vision}}


==External links==
*[http://image-processing-algo.blogspot.com/ Image Processing Algorithms]
*[http://homepages.inf.ed.ac.uk/rbf/HIPR2/ Hypermedia Image Processing Reference]
*[http://www.emva.org/ EMVA - European Machine Vision Association]
*[http://www.mvtec.com Software for Image Processing and Machine Vision]
* [http://computervision.wikicities.com/wiki/Main_Page Computer vision wikicity]

{{wikicities|computervision|Computer Vision}}
[[Category:Computer vision]]
[[Category:Image processing]]
[[Category:Image processing]]

[[de:Bildverarbeitung]]
[[fr:Traitement d'image]]
[[ja:コンピュータビジョン]]
[[nl:Beeldbewerking]]
[[th:การประมวลผลภาพ]]
[[zh:图像处理]]

Latest revision as of 11:12, 12 November 2022