The Development of Multi-Depth Pepper's Ghost Display for Mixed Reality System

Pepper's ghost is a well known technique in theater productions that allows the appearance of a semi- transparent and perhaps flying ghost on the stage. This technique has also been used with digital display to create a mixed reality (MR) system, where dynamic virtual objects are presented together with the static diorama. The usual pepper's ghost setup does not allow the presentation of the virtual objects in different z location. This paper describes the development of a pepper's ghost MR system that is able to display the virtual objects in varying z locations. In this implementation, we used six layers of polymer dispersed liquid crystal (PDLC) as the projection screens. By adjusting the on/off status of the PDLC layer, we were able to present objects at different depths.