When time-varying information is sampled at a rate R, the highest frequency that can be recovered without alias is limited to R/2.

Aliasing may be generated by under sampling temporally in frame rate, or vertically in lines allocated to image height, or horizontally in analog bandwidth or in pixel allocation. Intermodulations prior to band limiting may “preserve” some distracting effects of aliasing in the final display. Note: Sampling at a rate below the Nyquist limit permits mathematical confirmation of the frequencies present (as for example in a Fourier analysis of recorded motion). If the sampling window is very small (as in synchronized flash exposure), however, it may become a subjective judgment whether strobing is perceived in the image for motion approaching the limiting velocity (frequency).