Dec 12, 1998

The Ames room is built using perspective cues to fool the eye of the observer. The illusion best works when the viewer positions his/her head near the Camera Station planned in the design of the illusion. It is a good example to test our algorithm and verify that we do reconstruct the 3D illusory model, as the brain does ...

Due to the assumed perspective, the observer "builds" a cubical room, while the real room is physically made with a tilted back-wall (and a trapezoidal distorted checkerboard, which looks like a normal squared checkerboard when viewed near the CS locus). Thus, in the example here, the boy on the RHS looks like a pygmy in comparison to his "giant sister" on the LHS (in reality, she is much closer to the CS/us than the perspective cues let us assume).

The following images illustrate the 3 steps used in SkiP to:

1. Retrieve camera parameters from perspective cues (phase 1a) and specify a reference frame and metric length (phase 1b).
2. Initialize 3D reconstruction and verify/adjust camera parameters (how good a fit do we observe) - phase 2.
3. Pursue 3D reconstruction with fixed camera parameters - phase 3.

   Phase 1a: retrieve perspective cues for 1PtP	Phase 1b: Position reference frame and input metric.

   Phase 2: Built the central column.	Phase 2: Added a floor, back-wall & door.

   Camera parameters look fine: proceed to phase 3 (freeze the camera calibration for the CS).

   Phase 3: Added a ceiling, built the door (CSG).	Phase 3: More columns, walls; roam around.

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   Page created & maintained by Frederic Leymarie, 1998.
   Comments, suggestions, etc., mail to: leymarie@lems.brown.edu