Japanese researchers from the Koike Laboratory at Tokyo’s University of Electro-Communications have used a Kinect depth sensor and a projector to create the AquaTop Display. By adding bath salts to a tub, they found that the opaque water could be used as a projector screen.
Combined with the depth sensor, the water transformed into a touchscreen display, enabling users to interact with virtual objects using their hands. The system allows the user’s limbs to freely move through, under and over the projection surface.
It detects input to allow for interactions such as protruding fingers out from under the water and scooping it up with both hands, which aren’t possible with current impenetrable rigid surfaces. By floating their limbs on the water surface, it is also possible to fuse the user’s body with the displayed objects for further augmented interaction by “becoming one” with the screen. You can check out the AquaTop Display in the video below: