In the late 1960's, Blakemore and Campbell
(1969) suggested that the neurons in the visual cortex might process **spatial
frequencies** instead of particular **features** of the visual world. In English,
this means that instead of piecing the visual world together like a puzzle, the brain
performs something akin to the mathematical technique of **Fourier Analysis** to detect
the form of objects. While this analogy between the brain and the mathematical procedure
is at best a loose one (since the brain doesn't really "do" a Fourier Analysis),
whatever the brain actually does when we see an object is easier to understand within this
context. Thus, a review of the basic concepts of Fourier Analysis will be very helpful.

Several topics are covered within this tutorial. Simply click on the topic that you are interested in to begin the tutorial.

- Basics of Gratings (sinewave and square-wave)
- Fourier Analysis of a Square-Wave Grating

Here is a collections of links with more sites dealing with Fourier Analysis.

This tutorial is copyrighted 1994 by John H. Krantz, all rights reserved. It was last updated on May, 1999.