AliasingArtefakte

AliasingArtefakte are distortions that occur when a signal is sampled or processed at a rate insufficient to capture its frequency content, causing high-frequency components to masquerade as lower-frequency ones. This phenomenon, rooted in the Nyquist-Shannon sampling theorem, leads to spectral folding where frequencies above half the sampling rate (the Nyquist frequency) are reflected into the observable spectrum. In practice, aliasing manifests as visual artifacts or audio glitches that do not exist in the original signal.

In digital imaging and graphics, AliasingArtefakte can appear as jagged edges along diagonal or curved contours (aliasing in rasterized lines), moiré patterns on finely striped textures, and false color artifacts in color channels. In audio and signal processing, aliasing can produce distorted tonal components, fluttering, or metallic timbres when high-frequency content is folded into the audible range, especially during resampling, synthesis, or bit-crushing processes.

Causes of AliasingArtefakte include insufficient sampling rate relative to signal bandwidth, absence of proper anti-aliasing filtering before sampling, and improper resampling or downsampling algorithms. Mitigation strategies emphasize increasing the sampling rate, applying effective low-pass anti-aliasing filters before sampling or during resampling, and using high-quality resampling algorithms with prefiltering. In digital media workflows, oversampling and careful signal processing design reduce the occurrence of these artifacts while preserving fidelity.

See also: Nyquist frequency, anti-aliasing, resampling, moiré pattern, undersampling.