Spatial anti-aliasing

anti-aliasinganti-aliasedantialiasinganti-aliasFSAAAAAntialiasedfull-scene anti-aliasingmorphological anti-aliasinganti-aliasing levels
In digital signal processing, spatial anti-aliasing is a technique for minimizing the distortion artifacts known as aliasing when representing a high-resolution image at a lower resolution.wikipedia
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Aliasing

aliasaliasedtemporal aliasing
In digital signal processing, spatial anti-aliasing is a technique for minimizing the distortion artifacts known as aliasing when representing a high-resolution image at a lower resolution.
For spatial anti-aliasing, the types of anti-aliasing include fast sample anti-aliasing (FSAA), multisample anti-aliasing, and supersampling.

Subpixel rendering

BGRBGR (subpixels)GBR (subpixels)
Particularly with fonts displayed on typical LCD screens, it is common to use subpixel rendering techniques like ClearType.
It takes advantage of the fact that each pixel on a color LCD is actually composed of individual red, green, and blue or other color subpixels to anti-alias text with greater detail or to increase the resolution of all image types on layouts which are specifically designed to be compatible with subpixel rendering.

Anti-aliasing

antialiasingAnti-aliasing (disambiguation)anti-aliased
Anti-aliasing is used in digital photography, computer graphics, digital audio, and many other applications.

Jaggies

jaggednessjagginessjaggyness
In computer graphics, anti-aliasing improves the appearance of "jagged" polygon edges, or "jaggies", so they are smoothed out on the screen. Super sampling anti-aliasing (SSAA), also called full-scene anti-aliasing (FSAA), is used to avoid aliasing (or "jaggies") on full-screen images.
The effect of jaggies can be reduced somewhat by a graphics technique known as spatial anti-aliasing.

Computer font

fontfontsoutline font
Particularly with fonts displayed on typical LCD screens, it is common to use subpixel rendering techniques like ClearType.
The latter is anti-aliased.

Bicubic interpolation

bi-cubicbicubiccubic
For more sophisticated shapes, the algorithm may be generalized as rendering the shape to a pixel grid with higher resolution than the target display surface (usually a multiple that is a power of 2 to reduce distortion), then using bicubic interpolation to determine the average intensity of each real pixel on the display surface.
Images resampled with bicubic interpolation are smoother and have fewer interpolation artifacts.

Supersampling

supersampledantialiasingfull-scene anti-aliasing
Super sampling anti-aliasing (SSAA), also called full-scene anti-aliasing (FSAA), is used to avoid aliasing (or "jaggies") on full-screen images.
Supersampling is a spatial anti-aliasing method, i.e. a method used to remove aliasing (jagged and pixelated edges, colloquially known as "jaggies") from images rendered in computer games or other computer programs that generate imagery.

Multisample anti-aliasing

MSAAanti-aliasedanti-aliasing
But due to its tremendous computational cost and the advent of multisample anti-aliasing (MSAA) support on GPUs, it is no longer widely used in real time applications.
Multisample anti-aliasing (MSAA) is a type of spatial anti-aliasing, a technique used in computer graphics to improve image quality.

Anti-aliasing filter

anti-aliasinganti-aliasing (AA) filteroptical low-pass filter
In signal acquisition and audio, anti-aliasing is often done using an analogue anti-aliasing filter to remove the out-of-band component of the input signal prior to sampling with an analogue-to-digital converter.

Texture filtering

filteredbilinear and trilinear filteringBilinear texture filtering
Mipmapping is generally combined with various forms of texture filtering in order to improve the final result.
Depending on the situation texture filtering is either a type of reconstruction filter where sparse data is interpolated to fill gaps (magnification), or a type of anti-aliasing (AA), where texture samples exist at a higher frequency than required for the sample frequency needed for texture fill (minification).

Font hinting

hintinghintedhints
In these cases, a prior grid-fitting step may be useful (see hinting).
It can be accompanied by antialiasing and (on liquid crystal displays) subpixel rendering for further clarity.

Nyquist–Shannon sampling theorem

sampling theoremNyquist-Shannon sampling theoremNyquist theorem
The goal of an anti-aliasing filter is to greatly reduce frequencies above a certain limit, known as the Nyquist frequency, so that the signal will be accurately represented by its samples, or nearly so, in accordance with the sampling theorem; there are many different choices of detailed algorithm, with different filter transfer functions.
When the area of the sampling spot (the size of the pixel sensor) is not large enough to provide sufficient spatial anti-aliasing, a separate anti-aliasing filter (optical low-pass filter) may be included in a camera system to reduce the MTF of the optical image.

Mipmap

mipmappingMIP mappingMIP-Mapping
There is also an approach specialised for texture mapping called mipmapping, which works by creating lower resolution, pre-filtered versions of the texture map.
If using a limited number of texture samples per display pixel (as is the case with bilinear filtering) then artifacts are reduced since the mipmap images are effectively already anti-aliased.

Font rasterization

font renderingantialiasedantialiased font
This often involves some anti-aliasing on screen text to make it smoother and easier to read.

Temporal anti-aliasing

TSSAA
In spatial anti-aliasing it is possible to determine the image intensity function by supersampling.

Digital signal processing

DSPsignal processingdigital
In digital signal processing, spatial anti-aliasing is a technique for minimizing the distortion artifacts known as aliasing when representing a high-resolution image at a lower resolution.

Digital photography

digital photodigitaldigital photograph
Anti-aliasing is used in digital photography, computer graphics, digital audio, and many other applications.

Computer graphics

graphicsCGCG artwork
Anti-aliasing is used in digital photography, computer graphics, digital audio, and many other applications.

Digital audio

digital musicdigitalaudio
Anti-aliasing is used in digital photography, computer graphics, digital audio, and many other applications.

Frequency

frequenciesperiodperiodic
Anti-aliasing means removing signal components that have a higher frequency than is able to be properly resolved by the recording (or sampling) device.

Analog-to-digital converter

ADCanalog to digital converteranalog-to-digital conversion
In signal acquisition and audio, anti-aliasing is often done using an analogue anti-aliasing filter to remove the out-of-band component of the input signal prior to sampling with an analogue-to-digital converter.

Birefringence

birefringentdouble refractionbiaxial
In digital photography, optical anti-aliasing filters made of birefringent materials smooth the signal in the spatial optical domain.

Dot pitch

pixel pitchDPLCD screen pixel sizes
The anti-aliasing filter essentially blurs the image slightly in order to reduce the resolution to or below that achievable by the digital sensor (the larger the pixel pitch, the lower the achievable resolution at the sensor level).

Video card

graphics cardgraphics cardsvideo cards
However, it incurs a performance cost for the graphics card and uses more video memory.