3D fog display using parallel linear motion platforms

Fog screens have been widely used in theme parks and exhibition halls for entertainment and advertising purposes as the semi-transparent images suspending in the mid-air can create impressive pseudo 3D effect. However, conventional fog screens are flat and the projected images are not true 3D in nature. This paper suggests a new 3D fog display that exploits spatial projection mapping technique on a non-planar, reconfigurable fog screen to display volumetric data in real 3D space. The fog screen is composed of columns of upward-flowing laminar fog that are traveling on a set of linear motion platforms. The light beams from the projector are scattered at different depth positions on the fog screen, thus allowing the viewers to perceive three-dimensionality intuitively. The 3D fog display does not require any headgears or eye-tracking equipment while allowing full color 3D image to be observed by multiple simultaneous viewers. The immaterial nature of fog screens can also facilitate interesting tangible interactions in three physical dimensions. We have constructed a prototype display unit and developed a software platform to render the projection video and control the stepper motors of the linear motion platforms in order to synchronize the fog screen with the projection. The performance of the proposed display is verified by a number of real display examples.