Ubiquitous computing
is a concept of computers fading into the background of the applications
they are running.
Ubiquitous video, is likewise, the use of data
streamed from video without the perception of the presence of video
cameras.
This is achieved by having clusters of networked cameras in the
real world, transmitting their feeds back to a central source.
If all these streams are viewed simultaneously, the information
would overload the viewer. The answer, is to use these feeds to
provide a virtual environment in which the viewer can be immersed.
How Ubiquitous Video Works
Assuming an infinite number of cameras, and interpreting the location
of the user,
Immerse the user in the environment, having them move from camera
to camera. As the user changes position or direction in the environment,
the appropriate camera feeds are changed to provide the user relative
imaging. The user needs to be able to move naturally through the
environment, as if they were present in the real environment. They
should see an accurate rendering of the environment from any point
in space. This needs abstraction, having a camera at every point
of orientation.
One application that makes this possible in Reality FlyThrough.
Reality FlyThrough
Realityflythrough is a telepresence/tele-reality system that works
in the dynamic, uncalibrated environments typically associated with
ubiquitous computing.
By harnessing networked mobile video cameras, it allows a user
to remotely and immersively explore a physical space.
RealityFlythrough creates the illusion of complete live camera
coverage in a physical environment.
This video describes the architecture of RealityFlythrough, and
evaluates it along three dimensions:
its support of the abstractions for infinite camera coverage,
its scalability, and
its robustness to changing user requirements
An Abstraction for Ubiquitous Video[8:17]
Telereality
Having an infinite number of cameras is not feasible, however,
by having a high number of cameras, the application is able to interpolate
between the camera views to create 'novel' views. This is known
as Telereality. Accurate telereality requires the precise location
of the cameras and the optical properties of the camera lenses.
The outcome is the virtualization of cameras, the perception that
there are cameras located in every location directed at every perspective.
Building A Ubiquitous Video Environment
Reality FlyThrough creates this illusion of infinite camera coverage.
This is created by:
Simplify three-dimensional space
If you know the location and orientation in the real space,
you can create a representation of this camera in the corresponding
position in virtual space.
Project the image onto a virtual wall which is located some
distance away from the camera.
When the users virtual position matches that of the camera,
the entire screen is covered with the image. This results in a
2D simplification of the 3D space. Near objects are pushed out
on to the image plane, and distant objects pulled in to the image
plane.
As the user moves, the users location is moved from the point
of location of the source camera, to the point of location of
the destination camera, whlist the virtual walls are displayed
in perspective.
The overlapping portions of the image are blended using the
alpha blend.
Transitions are using motion as a substitute for infinite cameras.
This works due to the human ability to make sense of incomplete
information. Our visual cortex is able to smoothly interlace inaccurate
images to blend into an accurate image.
By only selecting new images, when the current images are no
longer in view, the human transition is more able to process the
multiple streams of data.
Uses For Ubiquitous Video
There are many potential uses for ubiquitous video, for example:
Remote exploration
First response information from head mounted video cameras of
first responders. This data can be fed back to central command,
to give them significantly more information on disaster sites
than is currently provided.
Virtual tourism - maintaining databases of tourists photos,
videos and live web feeds
Real Estate Walk Throughs -
Driving Directions
Watching Sports Games
Virtual Shopping
Virtual Mobility - for the disabled, giving them a sense of
the experience enjoyed by fully ambulatory users.