| ISLE | Chapter 1
| Optic Flow
The direct perception view was developed by American husband and wife team J. J. and Eleanor Gibson, who were both professors at Smith College in Northampton, Massachusetts (E. Gibson, 2001). The Gibsons emphasized that the information in the sensory world is complex and abundant, and therefore, the perceptual systems need only to directly perceive such complexity. In this view, the senses do not send to the brain incomplete and inaccurate information about the world that needed to be reasoned about to generate a perception. In the direct perception view, the world generates rich sources of information that the senses merely need to pick up directly. This module is a demonstration of optic flow, one of the key contributions of this approach.
However, optic flow refers to our perception of objects as we move forward or backward in a scene (Gibson, 1955). Imagine now that you are driving down a straight country road. As you move forward, the world rushes by you in the opposite direction. In front of you, however, the world is still coming toward you and getting larger as it does. We can determine depth from optical flow because faraway objects appear to move slower relative to more close objects, which appear to rush up to you faster. Indeed, extremely large faraway objects may appear essentially fixed in position. If you are looking backwards, not advised while driving, the situation is the opposite. Optic flow is often used to convey depth information in movies. Think of the words flowing through space that give you the background for a Star Wars movie. The flow of words creates an optic flow, which allows you to judge the relative distance of different parts of the story.
To see the illustration in full screen, which is recommended, press the Full Screen button, which appears at the top of the page.
On the Illustration tab, you can adjust these parameters:
Move/Stop: this starts or stops demonstration.Pressing this button restores the settings to their default values.