Virtual Shadows - Enhanced Interaction in Mixed Reality Environment

We propose the concepts of Virtual Light and Virtual Shadow with the aim of achieving a Mixed Reality Environment focused on shadows. In this proposal, we divide the concept of Virtual Shadow into four categories, and among them, implement four types of interactive applications: ( a) real to virtual shadow for rigid objects, (b) real to virtual shadow for non-rigid objects, ( c ) image-based virtual to virtual shadow, and (d) virtual to real shadow. In these applications, we can see the shadow of a real object projected onto the virtual world and vice versa. These proposed concepts should contribute to the realization of a Mixed Reality Environment that provides a novel sense ofinteraction. 2. Virtual Light An ordinary flashlight emits light and can therefore be used to illuminate space as desired. If, however, we were to know the position and direction of a flashlight that a user is holding and then project the corresponding image on a screen, the user could experience the same visual effect as a flashlight even if the flashlight is not actually emitting light. Here, the interface that provides the same or even better visual effect of a flashli~t, regardless of whether the flashlight is emitting light, IS called "Virtual Light." We can consider some types of Virtual Light device. T:YPe (a) is a 3D sensor for measuring 3D position and direction that a user can hold like a flashlight. T:YPe (b) embeds a CCD camera in the 3D sensor so as to capture images of the real world. T:YPe (c ) uses a projector to project a virtual object's shadow onto the real world.