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[[File:Nikon D90 - board 0 - Nikon Expeed EI-149-1769.jpg|thumb|[[EXPEED|Nikon EXPEED]], a [[system on a chip]] including an [[Color image pipeline|image processor]], [[Video_scaler#Video_processor|video processor]], [[digital signal processor]] (DSP) and a [[32-bit]] [[microcontroller]] controlling the chip]]
An '''image processor''', also known as an '''image processing engine''', '''image processing unit''' ('''IPU'''), or '''image signal processor''' ('''ISP'''), is a type of [[media processor]] or specialized [[digital signal processor]] (DSP) used for [[image processing]], in [[digital camera]]s or other devices.<ref>[http://www.robots.ox.ac.uk/~sjrob/Teaching/B4_SP/b4_sp.pdf DIGITAL SIGNAL & IMAGE PROCESSING]</ref><ref>[http://homepages.inf.ed.ac.uk/rbf/BOOKS/VERNON/Chap004.pdf Fundamentals of digital image processing]</ref>
Image processors often employ [[parallel computing]] even with [[Single instruction, multiple data|SIMD]] or [[Multiple instruction, multiple data|MIMD]] technologies to increase speed and efficiency.<ref>{{Cite journal |
To increase the system integration on [[Embedded system|embedded devices]], often it is a [[system on a chip]] with [[multi-core processor]] architecture.
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=== Demosaicing ===
As stated above, the image processor evaluates the color and [[brightness]] data of a given pixel, compares them with the data from neighboring pixels, and then uses a [[demosaicing]] algorithm to produce an appropriate color and brightness value for the pixel.<ref>{{Cite journal |last=Chang |first=Lanlan |date=Mar 2006 |title=Hybrid color filter array demosaicking for effective artifact suppression |url=http://www3.ntu.edu.sg/home5/CHAN0069/JEI013003.pdf |journal=Journal of Electronic Imaging |volume=15 |issue=1 |pages=013003-1 - 013003-17|doi=10.1117/1.2183325 |bibcode=2006JEI....15a3003C |archive-url=https://web.archive.org/web/20091229063407/http://www3.ntu.edu.sg/home5/CHAN0069/JEI013003.pdf |archive-date=29 December 2009 }}</ref> The image processor also assesses the whole picture to guess at the correct distribution of [[Contrast (vision)|contrast]]. By adjusting the [[Gamma correction|gamma]] value (heightening or lowering the contrast range of an image's mid-tones), subtle tonal gradations, such as in [[human skin]] or the blue of the [[sky]], become much more realistic.
=== Noise reduction ===
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