Feature-Based Sequence-to-Sequence Matching
Yaron Caspi, Denis Simakov and Michal Irani

Paper: "Feature-Based Sequence-to-Sequence Matching"
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  Yaron   Denis   Michal
Our affiliation:
  Computer Vision Group
  Faculty of Mathematics and Computer Science
  Weizmann Institute of Science
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This paper studies the problem of matching two unsynchronized video sequences of the same dynamic scene, recorded by different stationary uncalibrated video cameras. The matching is done both in time and in space, where the spatial matching can be modeled by a 2D homography or a (3D) fundamental matrix. Our approach is based on matching space-time trajectories of moving objects, in contrast to matching interest points (e.g., corners), as done in regular feature-based image-to-image matching techniques. The sequences are matched in space and time by enforcing consistent matching of all points along corresponding space-time trajectories.
    By exploiting the dynamic properties of these space-time trajectories, we obtain sub-frame temporal correspondence (synchronization) between the two video sequences. Furthermore, using trajectories rather than feature-points significantly reduces the combinatorial complexity of the spatial point-matching problem when the search space is large. This benefit allows to match information across sensors in situations which are extremely difficult when only image-to-image matching is used, including:   (a) matching under large scale (zoom) differences,   (b) very wide base-line matching,   and   (c) matching across different sensing modalities (e.g., IR and visible-light cameras).     We show examples of recovering homographies and fundamental matrices under such conditions.

Experiments preview

1) Alignment of sequences with large zoom difference
Large zoom difference experiment
2) Multi-sensor alignment (infra-red vs. visible light)
Muli-sensor experiment
3) Wide base-line matching, basketball experiment
Basketball wide base-line experiment
4) Wide base-line matching, hall experiment
Hall wide base-line experiment

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