We systematically analyse the binocular disparity field under various eye, head
and stimulus positions and orientations. From the literature we know that
certain classes of disparity which involve the entire disparity field (such as
those caused by horizontal lateral shift, differential rotation, horizontal scale
and horizontal shear between the entire half-images of a stereogram) lead to
relatively poor depth perception in the case of limited observation periods.
These classes of disparity are found to be similar to the classes of disparities
which are brought about by eye and head movements. Our analysis supports
the suggestion that binocular depth perception is based primarily (for the
first few hundred milliseconds) on classes of disparity that do not change as a
result of ego-movement