PennOffice: Experiment Description

A bit of warning: this is a rather technical description which serves as experiment documentation and is not intended for general public. It is still incomplete and will be updated. Any comments are welcome.

Contents

  1. Purpose
  2. Hardware Equipment
  3. Camera Calibration
  4. Scan Plan
  5. Landmark Calibration
  6. Scanning
  7. Stereo Matching and Reconstruction
  8. What Was Difficult?
  9. What is Important for Future Experiments?
  10. References

Purpose

This experiment shows what geometric precision can be achieved in 3D reconstruction from many images for indoor static scenes when illumination is under full control and data-acquisition is not time-limited.

The experiment has shown that as many as 58 partial views can successfully be registered with high precision in a common coordinate system without any prior knowledge of the camera motion parameters if suitable landmarks and simple registration aids are used.

The goal of this experiment was not to obtain any sort of surface (manifold) representations. That is the topic for our ongoing research.

There is no limitation on the number of partial views that can be processed (except for computer disk space and processing time, which both scale linearly with increasing number of views).

Hardware Equipment

We used four b/w Sony XC-77CE cameras with 16mm Cosmicar lenses and one Sony XC-007 3 chip color camera with a Canon 25mm lens. The images from the b/w cameras were digitized by a DataTranslation DT1451 frame-grabber (clock 10MHz) and the color images were digitized by a TIM-40 RGB video frame-grabber from Traquair Data Systems.

stereo setup

The four b/w cameras are mounted on a frame 125 x 80 mm apart from each other and the color camera is mounted off-center. The two horizontal pairs of b/w cameras are slightly verging.

The wider field of view of the b/w cameras was necessary to provide some view overlap necessary for successful view registration. Only the b/w cameras were used for reconstruction, the color camera was only used for "coloring" the reconstructed points. In the color camera AGC was switched off to get consistent colors over all partial scans.

The dataset (the total of 904 b/w and 60 color images) was processed on a SUN Sparc station with 250 MB of main memory.


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Radim Sara
Last modified: Wed Nov 5 14:52:02 MET 1997