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Proceedings Paper

A Contour-Based Recovery Of Optical Flows By Iterative Improvement
Author(s): Kwangyoen Wohn; Jian Wu; Roger Brockett
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Paper Abstract

We present an iterative algorithm for the computation of motion parameters which characterize the motion in the image plane, given a sequence of contours which change in time due to motion in space. Our method is based on the observation due to Waxman and Ullman (1985) that the second-order polynomial approximation of optical flow in the image coordinates provides sufficient information for 3-D motion computation. The use of an explicit flow model enables us to improve normal flow estimates through an iterative process. The algorithm has been tested on the synthetic time-varying images. The optical flows recovered from this scheme are accurate enough to be used for 3-D structure and motion computation. We also discuss the (in)variance of the zerocrossings of the Laplacian operating on the image intensities with respect to motion. The change of perspective view due to relative motion results certain zerocrossings not being preserved as image evolves, thereby deteriorating the accuracy of 2-D motion obtained by analyzing such zero-crossing contours. We present a theorem which relates true local measurement of zerocrossings to the tolerance of optical flow vector. Such analysis suggests an effective way to prevent "unstable" zerocrossings from being used for the matching process of motion computation.

Paper Details

Date Published: 20 November 1986
PDF: 7 pages
Proc. SPIE 0707, Visual Communications and Image Processing, (20 November 1986); doi: 10.1117/12.937243
Show Author Affiliations
Kwangyoen Wohn, Harvard University (United States)
Jian Wu, Harvard University (United States)
Roger Brockett, Harvard University (United States)


Published in SPIE Proceedings Vol. 0707:
Visual Communications and Image Processing
T. Russell Hsing, Editor(s)

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