On the Determinants of Size-Constancy in a Virtual Environment
Résumé
—An important aspect of a subject’s perception of
virtual objects in a virtual environment is whether the size of the
object is perceived as it would be in the physical world, which is
named size-constancy. The ability of subjects to appreciate
size-constancy in an immersive virtual environment was studied
while scene complexity, stereovision and motion parallax visual
factors were manipulated resulting in twelve different viewing
conditions. Under each visual condition, 18 subjects made size
judgments of a virtual object displayed at five different distances
from them. Responses from the majority of our population
demonstrated that scene complexity and stereovision have a
significant impact on subjects’ ability to appreciate size-constancy.
In contrast, motion parallax produced by moving the virtual
environment or by the movements of the observer alone proved
not to be a significant factor in determining size-constancy
performance. Consequently, size-constancy is best obtained when
scene complexity and stereovision are components of the viewing
conditions.