Relative Motion

Monocular Cues: Relative Motion

As we move, objects that are stationary appear to move.  Objects closer than the fixation point appear to move backwards.  The closer the object is to you, the faster it appears to move.  Objects beyond the fixation point appear to move with you, the farther away those objects are, the faster they appear to move.

Because the trees and setting around it is blurred, the illusion that the train is still while the world around it moves. We know that the train is the moving object because of our knowledge of the world, even though it is the object that is clear (not the trees).

Motion Parallax:

When you are moving, you use the speed of passing objects to estimate the distance of the objects. Nearby objects seem to zip by faster than do distant objects.

      

A picture of  a sign would zip right past us in the car whereas the moon is too far for us to pass so it remains semi-stationary in the sky allowing us to take a better picture.





When driving to the right the objects appear to move to the left.  Also the objects in the foreground will appear to move almost three times as fast as the objects in the background.