Artifacts are changes of signals, representations or information from the original state. Such changes occur in technical, medical, social, and photographic fields and can affect the original signals in form and content.
Artifacts occur wherever a signal, photograph, or information is processed by electronic circuitry. In electronics, for example, artifacts appear as distorted partial signals, due to interference signals, noise or voltage spikes. In transmission technology, it is reflections, interference, coding and compression that cause artifacts of audio and video. Typical compression artifacts are small squares that become visible in MPEG compression. In display technology, artifacts are due to the display techniques used. For example, various displays and projectors have a very fine grid that can only be seen when viewed up close or with a magnifying glass.
The effects of artifacts show up in false images, double images or other phenomena, in the rainbow effect and the fly screen effect, in small squares, in grids or in some other distortion or disturbance.