** Next:** Prediction of Disocclusion
**Up:** The Predictivity Principle:
** Previous:** The Predictivity Principle:

Taken as a starting point, this simple yet powerful
predictivity principle has surprisingly rich implications. Suppose
that we want to design a visual system that generates accurate
predictions of the occlusion sequence in
Figure 1a--d. If the depth relation
between the rectangular occluder and the moving circle is known, then
it is easy to predict the disappearance of the circle; the system
would have to know only the location and velocity of the circle and of
the occluder.
The reappearance of the circle (Figure 1d) is harder
to predict; Figure 1c contains no direct evidence that
a circle is about to appear anywhere. Nevertheless, if the visual
system * can* predict accurately the reappearance of the circle,
then it would more completely satisfy the predictivity principle. We
therefore conclude that the predictivity principle implies that the
visual system * should* predict disocclusion events like the
reappearance of the circle in Figure 1d, as well as
occlusion events.

** Next:** Prediction of Disocclusion
**Up:** The Predictivity Principle:
** Previous:** The Predictivity Principle: