Eliminating the effect of bulk scattering when measuring skin surface roughness using speckle contrast: a skin phantom study
Bibliographic record
Abstract
We have been investigating the quantification of skin surface roughness by polychromatic speckle contrast. Speckle contrast, being a measure of light coherence, decreases as coherence decays when low coherent light is reflected from a rough surface. The main constraint of applying the technique to skin is the presence of bulk scattering along with surface reflection. Bulk scattering also decays coherence and is a source of noise. To examine the effect of bulk contribution, we studied speckle patterns generated by silicone phantoms with controllable roughness and optical parameters in the range of human skin. We discovered that using the theoretical curve plotting speckle contrast vs. surface roughness as a calibration curve overestimates the phantom surface roughness. We propose to use the effective calibration curve for the proper skin roughness measurements. The effective calibration curve was obtained experimentally taking the advantage of its weak dependence on phantom's attenuation 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 | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| 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".