Aliasing

Aliasing

Aliasing is a phenomenon in digital signal processing, particularly in computer graphics and digital audio, where a high-frequency signal is misinterpreted as a lower-frequency signal due to insufficient sampling rate. It occurs when the sampling frequency is less than twice the highest frequency component in the original signal, violating the Nyquist-Shannon sampling theorem. In visual media, aliasing manifests as jagged edges or moiré patterns on curved or diagonal lines, creating a staircase effect. This is caused by the pixelation of the image, where the resolution is not high enough to accurately represent the smooth edges. In digital audio, aliasing can introduce distortion and artifacts, such as high-frequency harmonics that were not present in the original sound. To mitigate aliasing, various techniques are employed, including anti-aliasing filters, supersampling, and higher sampling rates. Anti-aliasing techniques in computer graphics involve smoothing the edges by blending the colors of adjacent pixels, creating a more visually appealing result. In digital audio, oversampling and low-pass filtering are used to remove high-frequency components before the signal is downsampled to the desired rate.

Jagged edges, Moiré patterns, Pixelation, Sampling rate, Nyquist-Shannon theorem, Anti-aliasing, Supersampling

— John Armstrong

CITATION : "John Armstrong. 'Aliasing.' Design+Encyclopedia. https://design-encyclopedia.com/?E=433059 (Accessed on July 26, 2024)"