Nyquist sampling
The Nyquist-Shannon sampling theorem defines a minimum sampling rate required to observe a signal feature as twice the spatial or temporal frequency of that feature. For example, to properly image a periodic grating with 1 µm spacing, each pixel must cover 0.5 µm or less (projected in the object plane). In practice, a minimum 2.3X sampling rate is recommended.
Synonyms: Nyquist-Shannon sampling , Nyquist criterion