Polarization enhancement of contrast through a water surface
Bibliographic record
Abstract
When imaging underwater scenes from above the water surface, the reflection from the air-water interface creates an obscuring background that varies with illumination and viewing angles. It is well known that the reflected light is horizontally polarized, and using a vertically transmitting polarizing filter is a common technique to improve the contrast of underwater scenes. However, to our knowledge, no quantitative measurements of polarization-enabled contrast enhancement have been reported in the literature. In this work, panchromatic and RGB division-of-focal-plane polarization cameras were used to record images of black and white tiles submerged in water for determining contrast as a function of viewing angle, both without a polarizer and with a vertical polarizer. Experiments were conducted in two outdoor locations and in a black tub indoors with controlled color and brightness of the reflected background. The maximum contrast through a vertical polarizer occurred near the Brewster angle, but the amount of contrast enhancement (the ratio of contrast through a polarizer to contrast without a polarizer) was found to increase until much larger angles. Also, the observed changes in contrast resulting from changing properties of the reflected background were consistent with the Fresnel reflection coefficients.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".