StreamFog: Using ultrasonic streaming for controlling aerosols in fog-based displays

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.