Filter

Filtration is a physical process that separates solid matter and fluid from a mixture. Filter, filtering, filters or filtration may also refer to:

Science and technology

Computing Filter (higher-order function), in functional programming Filter (software), a computer program to process a data stream Filter (video), a software component that performs some operation on a multimedia stream Information filtering system Email filtering, the processing of email to organize it according to specified criteria Content-control software also known as an Internet filter Wordfilter, a script typically used on Internet forums or chat rooms Berkeley Packet Filter, filter expression used in the qualification of network data DSL filter, a low-pass filter installed between analog devices and a telephone line Helicon Filter, a raster graphics editor Filter (large eddy simulation), a mathematical operation intended to remove a range of small scales from the solution to the Navier-Stokes equations Kalman filter, an approximating algorithm in optimal control applications and problems Filter (social media), an appearance-altering digital image effect for social media

Device Filter (chemistry), a device which separates solids from fluids (liquids or gases) by adding a medium through which only the fluid can pass Filter (aquarium), critical components of both freshwater and marine aquaria Filter paper, a semi-permeable paper barrier placed perpendicular to a liquid or air flow. It is used to separate fine solids from liquids or air Air filter, a device composed of fibrous materials which removes solid particulates such as dust, pollen, mold, and bacteria from the air Oil filter, a filter to remove contaminants from engine oil, transmission oil, lubricating oil, or hydraulic oil Pneumatic filter, a device which removes contaminants from a compressed air stream Water filter, removes impurities from water by means of a fine physical barrier, a chemical process or a biological process Cigarette filter, a part of a cigarette intended to filter the smoke inhaled by a smoker Coffee filter, a utensil used to separate coffee grounds from liquid coffee Fuel filter, found in most internal combustion engines Filtration (wine) Sieve or macroscopic filter, a device for separating wanted elements from unwanted material

Mathematics Filter (mathematics), a special subset of a partially ordered set. Filter on a set, a special family of subsets that forms an (order theoretic) filter with respect to set inclusion Filters in topology, the use of collections of subsets to describe convergence. Filtering problem (stochastic processes), a mathematical model for a number of filtering problems in signal processing and the like. Filtration (mathematics), an indexed set of subobjects of a given algebraic structure S.

Optics Optical filter, selectively transmits light of different wavelengths Interference filter, reflects one or more spectral bands or lines and transmits others, while maintaining a nearly zero coefficient of absorption for all wavelengths of interest Dichroic filter, a very accurate color filter used to selectively pass light of a small range of colors while reflecting other colors Hydrogen-alpha filter, an optical filter that transmits a narrow bandwidth of light centred on the H-alpha wavelength Photographic filter, a camera accessory consisting of an optical filter that can be inserted in the optical path Infrared cut-off filter, designed to reflect or block mid-infrared wavelengths while passing visible light Chelsea filter, a dichromatic optical filter used for identifying coloured stones Astronomical filter, a telescope accessory used to enhance the details of celestial objects

Signal processing Filter (signal processing) Electronic filter, an electronic circuit which processes signals, for example to remove unwanted frequency components Digital filter, a system that performs mathematical operations to reduce or enhance certain aspects of a signal Analogue filter, a basic building block of signal processing much used in electronics Filters used in digital image processing

Arts and entertainment Filter (TV series), a show on the G4 channel Filter (magazine), an indie music magazine Filter Theatre, a British theatre company The Filter, a digital content services company based in England Filter (band), an American rock band "Filter", a song from the album Bend by 8stops7 "Filter", a song from the album Map of the Soul: 7 by BTS "Filter", a song from the album Ruby by Jennie

Other uses Biofilter, a pollution control technique using a bioreactor containing living material to capture and biologically degrade pollutants Filtering (housing), the process of housing units becoming more affordable with age Category-based filtering of perception, according to (objectivist interpretations of) Kant Affective filter, an impediment to learning or acquisition caused by negative emotional ("affective") responses to one's environment Lane splitting, a practice that cyclists use to pass slow or stopped congested traffic The ability of a person to self-censor themselves (their thoughts) whilst speaking

See also Filter coffee, a method for preparing coffee Filter feeder, an animal that strains food particles from water Filtration camp (disambiguation) Lifter (signal processing) Philtre (disambiguation) Separation process Ultrafilter