Summary of full paper, presented at IWAR'99, San Francisco, October 20-21, 1999
The full article is published in the printed "Proceedings of the 2nd IWAR'99" and copyright protected by IEEE Computer Society.

Registration with a Zoom Lens Camera for Augmented Reality Applications

Gilles Simon, Marie-Odile Berger


We focus in this paper on the problem of adding computer-generated objects in video sequences that have been shot with a zoom lens camera. While numerous papers have been devoted to registration with fixed focal length, little attention has been brought to zoom lens cameras. In this paper, we propose an efficient two-stage algorithm for handling zoom changing which are are likely to happen in a video sequence. We first attempt to partition the video into camera motions and zoom variations. Then, classical registration methods are used on the image frames labeled {\em camera motion} while keeping the internal parameters constant, whereas the zoom parameters are only updated for the frames labeled {\em zoom variations}. Results are presented demonstrating registration on various sequences. Augmented video sequences are also shown.

Copyright (c) 1999 IEEE. Reprinted, with permission, from IWAR'99 proceedings.

  1. The cottage sequence

  2. Key-points correspondences between frames (arrows join the previous image key-points to the current image corresponding key-points).

    Model free-form curves tracked over the sequence (2D features are drawn in yellow, projections of the 3D corresponding features in green).

    Reprojection of the wireframe model.

    Virtual objects are added in the real scene.

  3. The Loria sequence

  4. Key-points correspondences.

    Tracked features.

    Reprojection of the wireframe model.

    The sequence is augmented with the well known sculpture " La femme à la chevelure défaite" realized by Miro. The camera trajectory is somewhat jagged. We currently investigate methods to incorporate regularity constraints on the trajectory inside the registration process.
Our previous works concerning Augmented Reality are described here

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