Fog screens are a projection medium for mid-air graphics, they are see-through and reach-through. Fog screens are traditionally generated by laminar flows coming out of linear outlets and thus are usually static. Here, we show that ultrasonic beams create a streaming field of constrained airflow that direct aerosols in a fast and controllable way. We characterize various aerosols under streaming and optical diffusion, and evaluate control methods for obtaining different aerosol shapes. Aerosol columns are raised, moved and pushed in a few hundred milliseconds to serve as a projection medium. Hands and other objects do not disturb the fog columns significantly, allowing for direct interaction. We showcase applications by projecting on multiple columns that can be moved continuously within the display volume, reach-through interactions and mixed-reality for tabletop games.

International audience

A laser pointer is a commonly used device that does not require communication with the display system or modifications on the applications, the presenter can just take a pointer and start using it. When a laser pointer is used on a volumetric display, a line rather than a point appears, making it not suitable for pointing at 3D locations. PointerVol is a modified laser pointer that allows users to point to 3D positions inside a swept volumetric display. We propose two PointerVol implementations based on timing and distance measurements, we evaluate the pointing performance using them. Finally, we present other features such as multi-user pointing, line patterns and a multi-finger wearable. PointerVol is a simple device that can help to popularize volumetric displays, or at least to make them more usable for presentations with true-3D content.