Fermi filter

{{distinguish|Great Filter}}

{{refimprove|date=April 2021}}

The Fermi filter is a common image processing filter that uses the Fermi–Dirac distribution in the frequency domain to perform a low-pass filter{{cite web | title=img.alg - Image Processing Algorithms: FermiLowPassFilter | website=OpenStructure | url=https://openstructure.org/docs/2.2/img/alg/alg/#ost.img.alg.FermiLowPassFilter | access-date=2021-07-03}} or high-pass filter{{cite web | title=img.alg - Image Processing Algorithms: FermiHighPassFilter | website=OpenStructure | url=https://openstructure.org/docs/2.2/img/alg/alg/#ost.img.alg.FermiHighPassFilter | access-date=2021-07-03}} similar to a Gaussian blur, but the harshness can be scaled.{{cite web | title=SPIDER: FQ NP (Filter - Quick Fourier, High, low pass, etc) | website=SPIDER | url=https://spider.wadsworth.org/spider_doc/spider/docs/man/fqnp.html | access-date=2021-07-03}}