Image processing considerations for simple real-time restrictometric fluid-based user interfaces

The FUNtain (TM) is a new input device in which a user inputs data by direct interaction with fluid, such as with one or more air or water jets. There is usually a (re)strictometer for each jet that measures the degree of restriction of fluid flow for that jet, such that the time-varying changes in restrictometric quantities provide an input to another process. For example, 61 restrictometers are used to provide a directacting waterpipe organ as a musical instrument in which notes are played by blocking fluid (air or water) emerging from each of the 61 holes spaced along a copper pipe that forms the housing for the musical instrument. When used with liquids, such a fluid-user interface based on the image processing of water sprays is proposed to create a new form of input device. In particular, the methodology exploits the unique optical properties of fluids that become manifest when a fountain or spray is illuminated as it would typically be for an exhibit, display, or performance. Most notably, the form of illumination that is most desirable for aesthetic reasons turns out to assist simple image processing of the water flow. In this way, an interactive performance environment is created that is ideally suited to real-time image processing as a means of data input. The resulting methodology gives rise to a liquid-user-interface, played by one or more people, interacting with water jets, such as by blocking, partially blocking, diverting, or otherwise engaging with the spray.