View source for Image differencing

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'''Image differencing''' is an [[Image processing|image processing]] technique used to determine changes between images. The difference between two images is calculated by finding the difference between each pixel in each image, and generating an image based on the result. For this technique to work, the two images must first be aligned so that corresponding points coincide, and their [[Physics:Photometry (optics)|photometric]] values must be made compatible, either by careful calibration, or by post-processing (using [[Color mapping|color mapping]]). The complexity of the pre-processing needed before differencing varies with the type of image.

Image differencing techniques are commonly used in [[Astronomy:Astronomy|astronomy]] to locate objects that fluctuate in brightness or move against the star field.

The [[Hutchinson metric]] can be used to "measure of the discrepancy between two [[Image|image]]s for use in [[Fractal|fractal]] [[Image processing|image processing]]".<ref> [http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1355938 Efficient computation of the Hutchinson metric between digitized images] abstract</ref><ref> [http://isis.pub.ro/iafa2003/files/3-5.pdf HUTCHINSON METRIC IN FRACTAL DNA ANALYSIS -- A NEURAL NETWORK APPROACH] {{webarchive |url=https://web.archive.org/web/20110818165407/http://isis.pub.ro/iafa2003/files/3-5.pdf |date=August 18, 2011 }}</ref>

== See also ==
* [[Astronomy:Blink comparator|Blink comparator]]
* Difference matte
* Image stabilization
* [[Image subtraction]]

==Sources and notes==
{{Reflist}}

== External links ==
* Sussex Computer Vision webpage: [http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/YOUNG/vision6.html Use of motion information in computer vision]


[[Category:Image processing]]

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