Panoramic depth imaging with a single standard camera 

                        Peter Peer

                  Computer Vision Laboratory
                   University of Ljubljana
                   peter.peer@fri.uni-lj.si

I will present a panoramic depth imaging system. The system is
mosaic-based which means that we use a single rotating camera and
assemble the captured images in a mosaic. Due to a setoff of the
camera's optical center from the rotational center of the system we
are able to capture the motion parallax effect which enables stereo
reconstruction. The camera is rotating on a circular path with a step
defined by the angle, equivalent to one pixel column of the captured
image.

The equation for depth estimation can be easily extracted from the
system geometry. To find the corresponding points on a stereo pair of
panoramic images the epipolar geometry needs to be determined.  It can
be shown that the epipolar geometry is very simple if we are doing the
reconstruction based on a symmetric pair of stereo panoramic images.
We get a symmetric pair of stereo panoramic images when we take
symmetric pixel columns on the left and on the right side from the
captured image center column. Epipolar lines of the symmetrical pair
of panoramic images are image rows.

The search space on the epipolar line can be additionaly constrained.
The focus of the presentation is mainly on the system analysis.
Results of the stereo reconstruction procedure and quality evaluation
of generated depth images are quite promissing.

The system performs well for reconstruction of small indoor spaces.
Our finall goal is to develop a system for automatic navigation of a
mobile robot in a room.