Anti-aliasing may refer to any of a number of techniques to combat the problems of aliasing in a sampled signal such as a digital image or digital audio recording.
Specific topics in anti-aliasing include:
Temporal anti-aliasing has two meanings. It is currently commonly and widely used to describe a technique for realtime spatial anti-aliasing, usually in computer and video games, described in detail here. It is also formally used to describe techniques for reducing aliasing in the time dimension - that is, aliasing due to under-sampling in the time dimension. Temporal aliasing in video applications is caused by the sampling rate (i.e. number of frames per second) of a scene being too low compared to the transformation speed of objects inside of the scene; this causes objects to appear to jump or appear at a location instead of giving the impression of smoothly moving towards it. To avoid aliasing artifacts, the sampling rate of a scene must be at least twice as high as the fastest moving object.[3] The shutter behavior of the sampling system (typically a camera) strongly influences aliasing, as the overall shape of the exposure over time determines the band-limiting of the system before sampling, an important factor in aliasing. A temporal anti-aliasing filter can be applied to a camera to achieve better band-limiting.[4] A common example of temporal aliasing in film is the appearance of vehicle wheels travelling backwards, the so-called wagon-wheel effect.
In cel animation, animators can either add motion lines or create an object trail to give the impression of movement. To solve the wagon-wheel effect without changing the sampling rate or wheel speed, animators could add a broken or discolored spoke to force viewer's visual system to make the correct connections between frames.