What is spatial frequency theory?

The spatial-frequency theory refers to the theory that the visual cortex operates on a code of spatial frequency, not on the code of straight edges and lines hypothesised by Hubel and Wiesel on the basis of early experiments on V1 neurons in the cat.

Spatial frequency describes the periodic distributions of light and dark in an image. High spatial frequencies correspond to features such as sharp edges and fine details, whereas low spatial frequencies correspond to features such as global shape .10 Ara 2015

Low spatial frequencies (LSF), conveyed by fast magnocellular pathways, provide a coarse information about a visual stimulus (e.g., the global shape and structure of a scene), whereas high spatial frequencies (HSF), conveyed more slowly by the parvocellular pathways, provide finer information about the stimulus (e.g., …7 May 2014

Sensitivity falls off for lower spatial frequencies and rapidly falls off for higher spatial frequencies . Eventually a high spatial frequency is reached that requires a contrast of 1.0 to detect (the high frequency cutoff). Spatial frequencies higher than this cutoff frequency cannot be detected by an observer.