Automatic Calibration of a Multiple-Projector Spherical Fish Tank VR Display
Bibliographic record
Abstract
We describe a novel automatic calibration method using a single camera for a multiple-projector spherical Fish Tank Virtual Reality (FTVR) display. Modeling the projector as an inverse camera, we estimate the intrinsic and extrinsic projector parameters automatically using a set of projected images on the spherical screen. A calibrated camera is placed beneath to observe partially visible projected patterns. Using the correspondence between the observed pattern and the projected pattern, we reconstruct the shape of the spherical display and finally recover the 3D position of each projected pixel on the display. Additionally we present a practical calibration evaluation method that estimates on-surface accuracy using the single camera. We use point mismatch as a metric to describe misalignment and line mismatch to describe distortion. We demonstrate our automatic approach can achieve an on-surface point mismatch less than 1mm and line mismatch less than 1 on a 30cm diameter spherical screen. Taken together, our calibration approach and evaluation method are automatic and accurate for a desktop spherical FTVR and can be applied to other multiple-projector displays with curved screens.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".