Spatial anti-aliasing

In <a href="/facts/Digital_signal_processing/PEG7azr8">digital signal processing</a>, spatial anti-aliasing is a technique for minimizing the distortion artifacts (<a href="/facts/Aliasing/Pzg84HL0">aliasing</a>) when representing a high-resolution image at a lower resolution. <a href="/facts/Anti-aliasing/m3Ew0TQ6">Anti-aliasing</a> is used in <a href="/facts/Digital_photography/a2UfweJh">digital photography</a>, <a href="/facts/Computer_graphics/lapBE8wv">computer graphics</a>, <a href="/facts/Digital_audio/PgugcLAI">digital audio</a>, and many other applications.
Anti-aliasing means removing signal components that have a higher <a href="/facts/Frequency/QUSbPaW8">frequency</a> than is able to be properly resolved by the recording (or sampling) device. This removal is done before (re)sampling at a lower resolution. When sampling is performed without removing this part of the signal, it causes undesirable artifacts such as black-and-white noise.
In signal acquisition and audio, anti-aliasing is often done using an analog <a href="/facts/Anti-aliasing_filter/PqhNr0FQ">anti-aliasing filter</a> to remove the out-of-band component of the input signal prior to sampling with an <a href="/facts/Analog-to-digital_converter/8YYNsMFg">analog-to-digital converter</a>. In digital photography, optical anti-aliasing filters made of <a href="/facts/Birefringent/J4lLuR3a">birefringent</a> materials smooth the signal in the spatial optical domain. 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 <a href="/facts/Pixel_pitch/G6h5eyK4">pixel pitch</a>, the lower the achievable resolution at the sensor level).

Spatial anti-aliasing open-in-new

Spatial anti-aliasing