Diorama |
 |
Diorama |
|
Diorama is an augmented reality system. It enables one to populate a physical space with three-dimensional virtual objects. It consists of two components: authoring tools and viewing tools. The authoring tools provide a means for placing and manipulating objects in the physical space. It also provides for attributing simple behaviors to objects. For example, a virtual object might be created as a guide to lead one to a certain location; a virtual tree might be created that grows every time you make a bank deposit.
The viewing system consists of a hand-held lens. This currently exists in the form of a laptop. As the user moves the lens, they see the physical world with an overlay of virtual three-dimensional objects. These objects are rendered accordingly as the user maneuvers the lens.
The conceptual mapping is simple. A virtual camera is directly linked to a physical camera; a virtual coordinate system is directly linked to a physical coordinate system. However, there exist technical issues which make this mapping a challenge in practice.
The position and orientation of the lens must be known to a high degree of precision in order to render the objects in the correct location. This calibration is currently done using orientation sensors mounted upon the top left corner of the viewing lens. Position is currently handled at certain specified nodal points. Originally, we began position sensing using an IR sensor grid. We have since moved on to consider an RF approach analogous to GPS.
Within the realm of the current system, we have experimented with different forms of rendering as the user moves the screen. In one mode, as the screen is in motion, the objects all appear in wireframe mode. As the user settles into a location, the objects slowly evolve into their complete structure. The following two mpegs show the lens apparatus in use and a view from the lens, respectively [lens mpeg][display mpeg].
We have also experimented with certain perceptual issues with regard to rendering. This work involves the blending of an abstract representation of the physical world with virtual elements. Using such methods, we can impose constraints in an evironment with many degrees of freedom.
Behaviors in this system can be triggered by direct interaction with the viewing apparatus, outside stimuli connected to the objects, a reach of the hand recognized through vision, etc. The presence of a person (or persons) alone can be a catalyst for such communication.
This section briefly explains some of the conceptual issues we are exploring within the Diorama environment.
The system also provides a playground for privacy issues. Notions of privacy and publicity will have to be rethought to account for this new dynamic space. The boundary of a physical wall does not stop virtual perception. Public and private spaces will overlap at different levels as the complexity of perceptual filters advances.
Ownership of objects and of physical and virtual space create interesting dilemmas. Perhaps one has write permissions in their personal office. What about common hallways? Can anyone who can see these objects move them or remove them completely?
The "value" of the real estate of these layered spaces is also novel. Virtual objects might have no correlation whatsoever to the value of the physical space they occupy.
Also, it allows for people to use communicative objects to provide visual information as well as for users to communicate with each other through this medium.