A transitory image sequence is one in which no scene element
is visible through the entire sequence.
When a camera system scans a scene which cannot be
covered by a single view, the image sequence is transitory.
This project deals with some major theoretical and
algorithmic issues associated with the task of estimating structure and motion
from transitory image sequences. It is shown that integration
with a transitory sequence has properties that are very different from
those with a non-transitory one.
Two representations, world-centered (WC) and camera-centered (CC),
behave very differently with a transitory sequence.
The asymptotical error rates derived
in this article indicate that one representation
is significantly superior to the other, depending on whether one needs
camera-centered or world-centered estimates. Using Cramer-Rao lower error
bound, the paper also shows that these error rates are not only
the rates obtained by the proposed algorithm, but also the best rates possible.
Based on the error rate analysis, we introduce an efficient ``cross-frame''
estimation technique for the CC representation.
For the WC representation, our
analysis indicates that a good technique should be based on
camera global pose instead of interframe motions.
In addition to testing with synthetic data,
rigorous experiments were conducted with real-image sequences taken by a fully
calibrated camera system. The comparison of the experimental results
with the ground truth has demonstrated that a good accuracy
can be obtained from transitory image sequences.
J. Weng, Y. Cui and N. Ahuja, ``Transitory Image Sequences, Asymptotic
Properties, and Estimation of Motion and Structure,''
IEEE Trans. on Pattern Analysis and Machine Intelligence, vol. 19, no. 5, pp. 451-464, 1997.
Down load PDF
file.
J. Weng, Y. Cui, N. Ahuja and A. Singh, ``Integration of Transitory
Image Sequences,'' in Proc. IEEE Conf. Computer Vision and
Pattern Recognition, Seattle, Washington, pp. 966-969, June 20-23, 1994.
J. Weng and Y. Cui, ``Transitory Image Sequences and Their Integration,''
Technical Report
CPS-95-4, Department of Computer Science, MSU, March 1995.
To Weng's Home Page: http://web.cps.msu.edu/~weng/