Modeling the Critical Flicker Fusion Frequency in the Human Visual System

The temporal resolving power of the visual system is essential for the perception of the objective world. The lowest sampling rate of a sequence of images at which perception becomes fused is called the critical flicker fusion frequency (CFFF). A variety of experimental data on critical frequency thresholds can be explained from the viewpoint of a model of the contrast sensitivity of the visual system that is based on the tremor modulation signal (TMS). The model describes how the critical frequency depends on the stimulus brightness, adaptation brightness, and the duration and angular size of the stimulus. The model demonstrates that critical frequency values lie in a range up to 1000 Hz for bright stimuli of a short duration and a large angular size, that a frame rate of 300–500 Hz should be considered optimal for the visual system, and that the critical frequency lies in a low-frequency region for small-sized angular stimuli. Differences in the rate of flicker fusion can be explained by temporal sensitivity of magnocellular and parvocellular neurons.