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Reactive control of zoom while fixating using perspective and affine cameras
1Active Vision Laboratory, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK. bjt@robots.ox.ac.uk
IEEE Transactions on Pattern Analysis and Machine Intelligence
|September 24, 2004
Summary
This study presents two visual methods for active camera zoom control to maintain object fixation. One method uses perspective projection and self-calibration, while the other employs affine projection for more general camera movement.
Area of Science:
- Computer Vision
- Robotics
- Image Processing
Background:
- Controlling active camera zoom for object fixation is crucial in various applications.
- Existing methods often require explicit scene geometry or calibration.
Purpose of the Study:
- To develop and evaluate reactive visual methods for controlling active camera zoom while fixating on an object.
- To enable self-calibration and robust fixation under different projection models.
Main Methods:
- Perspective projection method: Adjusts zoom by preserving focal length to scene depth ratio, uses planar structure from motion for depth recovery, and exploits interimage homographies for segmentation and fixation update.
- Affine projection method: Employs factorization for affine structure recovery, requires no self-calibration, and allows general camera motion for fixation update.
Main Results:
- The perspective method demonstrates effectiveness on real imagery for planar scenes but faces challenges with general 3D structures under noise.
- The affine method shows promise for general camera movement and achieves zoom control by unifying affine bases across views.
Conclusions:
- Both methods offer viable approaches to reactive visual zoom control for active cameras.
- The affine projection method provides greater flexibility for camera movement and eliminates the need for self-calibration.