The effects of shadows on depth perception in augmented reality on a mobile device

Abstract: In the visual perception of depth in computer graphics, people rely on a number of cues, including depth of field, relative size of objects in perspective, and shadows. This work focuses on shadows in Augmented Reality. An experiment was performed in order to measure the effects of having virtual objects cast shadows on real objects. Users performed the task of placing a virtual object on a physical table, in an Augmented Reality environment displayed on a mobile device. The virtual object was either a cube or a sphere. The effects of having shadows enabled was measured by time to task completion and the positional error. Qualitative measurements of the user experience were also made, through the use of questionnaires. The results showed a decrease in both positional error and time to task completion when shadows were enabled. The results also indicated that users placed the objects with a higher degree of certainty when shadows were enabled. The quantitative and qualitative results of the experiment showed that users found it easier to perceive the position of the virtual object with respect to the physical object when the virtual object cast shadows.