Investigating the effect of pictorial depth cues on distance perception in a virtual environment

In the last years, many experiments about distance perception in virtual environments (VEs) have been undertaken. Aim of these researches was to study the effect of different depth cues in estimating the distances. Many theories have been proposed regarding the relation between different cues; but none of them seems to be conclusive. However, a common conclusion is that observers underestimate long distances in VEs. In this work, we present the results of experiments considering different pictorial cues (shadows, reflections, and texture gradients). The observers' task was to estimate the distance of a sphere floating inside a VE in the action space. After 15 s, the sphere was moved to another position, and the observer was asked to move it, by means of a gamepad, to the previous position. The apparatus used for the experiments is the Virtual Theater of the Milan University , an installation of virtual reality characterized by a large semicylindrical screen that covers 120° of field of view. The results seem to suggest that shadows and texture gradients could improve distance estimations inside the VE. The implications of the results will be discussed within the relevant literature