Perceptual modelling in 3D

You will need red-green 3D glasses such as those available from "Worldwide Co" to see the images in this article. (http://www.npw-usa.com or http://www.npw.co.uk ).

The phi phenomenon is clear in 3D:

There is also a depth version of the phi phenomenon:

The disk moves behind then level with the grid in a continuous pumping motion. The duration of the disk outlines is 250ms and the duration of the blank space is 90ms.  Unlike the 2D phi effect the 3D version ceases to be clear if the blank period is more than about 200ms (the 2D phi ceases at about 400ms):

The image above has a 200ms blank period and 250ms duration disks.  The disks must also be present for more than about 100ms for the 3D phi to occur:

The image above has 90ms blank period and 90ms display of the disks. There is very little pulsing in and out of the disk, all that occurs is a sort of fluttering.  Interestingly the 2D Phi in a 3D setting works fine with 90ms intervals and durations:

It should be stressed that the term "3D" is used colloquially above, of course, none of the images are actually viewed three dimensionally because we cannot see behind them from a constant location.  However, each eye has a slightly different view that is not shared by the other and it is this dual view that seems like "looking behind".