Egocentric distance perception in real and HMD-based virtual environments: the effect of limited scanning method

We conducted four experiments on egocentric depth perception using blind walking with a restricted scanning method in both the real and a virtual environment. Our viewing condition in all experiments was monocular. We varied the field of view (real), scan direction (real), blind walking method (real and virtual), and self-representation (virtual) over distances of 4 meters to 7 meters. The field of view varied between 21.1° and 13.6°. The scan direction varied between near-to-far scanning and far-to-near scanning. The blind walking method varied between direct blind walking and an indirect method of blind walking that matched the geometry of our laboratory. We varied self-representation between having a self-avatar (a fully tracked, animated, and first-person perspective of the user), having a static avatar (a mannequin avatar that did not move), to having no avatar (a disembodied camera view of the virtual environment). In the real environment, we find an effect of field of view; participants performed more accurately with larger field of view. In both real and virtual environments, we find an effect of blind walking method; participants performed more accurately in direct blind walking. We do not find an effect of distance underestimation in any environment, nor do we find an effect of self-representation.