Background
Projection technologies have enabled projectors to become not only smaller but also cheaper and less power-hungry, which may solve this ``small screen'' limitation of handheld devices. Mounting a projector on a mobile device will make it possible to create a larger information display without external equipment, by projecting images onto surfaces such as walls, the ceiling, or the floor. In fact, Siemens' researchers have developed a mobile phone featuring a built-in projector system. Moreover, palm-sized and battery-powered commercial projectors, which use low-power LED lighting are already available.
Some researchers have proposed interactive systems using handheld projectors. They focus on interaction techniques such as manipulations using fingers on a projected display and stabilizing projected images. However, they have not sufficiently taken advantage of a projected display that users can move flexibly and easily in real time. A handheld projector offers the possibility of manipulating real movable objects such as robots intuitively and visually, in dynamic environments.
Manipulation by Projection
We propose the ``manipulation by projection'' technique that allows users to visually and intuitively control a robot using their projectors. By projecting a variety of information including the robot's state, its surroundings, and human commands to the robot via a handheld projector, users can confirm their commands and the reactions of the robot. Although a user could perform a similar task by using a Head-Mounted Display (HMD), the proposed technique also allows other users to see the information, and these users can interact with the robot without conflict.