Editing Moiré pattern (section)

{{short description|Interference pattern}}
{{redirect2|Moiré|Moire||Moire (disambiguation)}}
{{multiple image
| total_width = 320
| align = right
| image1 = Moiré pattern.svg
| alt1 = 
| caption1 = A moiré pattern formed by two units of parallel lines, one unit rotated 5° clockwise relative to the other
| image2 = Divers - Illustrated London News Feb 6 1873-2.PNG
| alt2 = 
| caption2 = The fine lines that make up the sky in this image create moiré patterns when shown at some resolutions for the same reason that photographs of televisions exhibit moiré patterns: the lines are not absolutely level.
| footer = 
}}
[[File:Moire-bridge-picket-fence.jpg|thumb|Difference in distance of the front and rear picket fence on a bridge create moiré patterns.]]
[[File:Moiré pattern.png|thumb|Moiré pattern appearing on scaled camera captures of LCD screen]]
[[File:ShadingNetMoiree.webm|thumb|Moiré pattern of double layered shading net]]

In mathematics, physics, and art, '''moiré patterns''' ({{IPAc-en|UK|'|m|w|ɑː|r|eɪ}} {{respell|MWAH|ray}}, {{IPAc-en|US|m|w|ɑː|ˈ|r|eɪ}} {{respell|mwah|RAY}},<ref>{{cite encyclopedia |last=Wells|first=John |author-link=John C. Wells |title=Longman Pronunciation Dictionary |publisher=Pearson [[Longman]] |edition=3rd |date=3 April 2008 |isbn=978-1-4058-8118-0}}</ref> {{IPA|fr|mwaʁe|lang|LL-Q150 (fra)-Lyokoï-moiré.wav}}) or '''moiré fringes'''<ref name="SIMicroscopy">{{cite journal | last=Gustafsson|first=M. G. L. |title=Surpassing the lateral resolution limit by a factor of two using structured illumination microscopy |journal=[[Journal of Microscopy]] |doi=10.1046/j.1365-2818.2000.00710.x |pmid=10810003 |volume=198 |issue=2 |year=2000 |pages=82–87 |s2cid=9257781 |doi-access=free}}</ref> are large-scale [[wave interference|interference patterns]] that can be produced when a partially opaque [[grating|ruled pattern]] with transparent gaps is overlaid on another similar pattern. For the moiré interference pattern to appear, the two patterns must not be completely identical, but rather displaced, rotated, or have slightly different pitch.

Moiré patterns appear in many situations. In printing, the printed pattern of dots can interfere with the image. In television and digital photography, a pattern on an object being photographed can interfere with the shape of the light sensors to generate unwanted artifacts. They are also sometimes created deliberately; in [[micrometer (device)|micrometers]], they are used to amplify the effects of very small movements.

In physics, its manifestation is [[wave interference]] like that seen in the [[double-slit experiment]] and the [[Beat (acoustics)|beat phenomenon]] in [[acoustics]].