What is Frame Rate?
Frame rate, also known as frame frequency, is the frequency (rate) at which an imaging device displays consecutive images called frames. The term applies equally to film and video cameras, computer graphics, and motion capture systems. Frame rate is expressed in frames per second (FPS).
The human eye and its brain interface, the human visual system, can process 10 to 12 separate images per second, perceiving them individually. The threshold of human visual perception varies depending on what is being measured. When looking at a lighted display, people begin to notice a brief interruption of darkness if it is about 16 milliseconds or longer. Observers can recall one specific image in an unbroken series of different images, each of which lasts as little as 13 milliseconds. When given very short single-millisecond visual stimulus people report a duration of between 100 ms and 400 ms due to persistence of vision in the visual cortex. This may cause images perceived in this duration to appear as one stimulus, such as a 10 ms green flash of light immediately followed by a 10 ms red flash of light perceived as a single yellow flash of light. Persistence of vision may also create an illusion of continuity, allowing a sequence of still images to give the impression of motion.