Surround Viewer
MCVL Homepage	Department of Computer Engineering and Computer Science

Contact Information:

K. Palaniappan
Department of Computer Engineering and Computer Science
University of Missouri-Columbia
Columbia, MO 65211

The Surround View is software which is being developed by students working in the Multimedia Communications and Visualization Laboratory at the University of Missouri, at Columbia's Department of Computer Engineering and Computer Science. The Surround Viewer software will put the user in the middle of a virtual world made up of a 360 degree video image. The user will be able to rotate the direction of view to look at the virtual world around him.

The Surround Viewer's virtual world is constructed by mapping a 360 degree video image onto the inner surface of a cylinder. For this mapping, the program makes use of OpenGL texture mapping . One advantage of this approach is that it can use hardware accelerated texture mapping to achievessary for achieve the performance necessary to render the 360 degree, active environment. Performance is further enhance by the use of look up tables and algorithms which take advantage of the incremental nature of rendering scan lines.

The software make use of a 360 degree real time video image captured by an Omnicam, a viewing device developed at Columbia University.

The Omnicam uses a parabloid shaped mirror to reflect light coming from all directions onto the imaging surface of a camera. Unlike the more common parabolic mirror, the reflecting surface of the omnicam's mirror is on the outside, rather than the inside, of the parabolid shaped surface.

The use of a parabloid shaped mirror gives the omnicam a single effective center of projection. A two-dimensional cross section of the mirror shows that the effective center of projection (where the light rays would come together if they were not reflected by the mirror), is at the vertex of the parabola. This single effective center of projection makes it possible to construct distortion-free images from any portion of the image.

A parabloid shaped mirror has the added advantage of reflecting all of the rays of light that strike it in the same direction.

When rays of light strike a parabolic mirror and are reflected to the imaging surface of the camera, they travel parallel to one another until they strike the imaging surface.

Because the reflected rays travel parallel to one another, the distance between the lens and mirror and their alignment is not critical. A camera that used a mirror that did not have this characteristic would require careful calibration of the alignment of the imaging surface and the mirror.

Below is one version of the Omnicam. This one can sit on a desk or table top. The glass bubble around the parabloid mirror is used to hold the camera above the mirror without obstructing any of the surrounding 360 degree view.

One of the omnicam's many uses is in video conferenceing. As shown below, at each locality where there are conference participants, one camera can be placed in the middle of the participants. This gives remote participants the ability to view each of the participants with the use of only one camera.

Further details on the omnicam are available at Columbia Universities's Computer Science web site.

CECS Multimedia Communications and Visualization Laboratory