Colour contrast can facilitate perceived 3D shape-from-shading
Bibliographic record
Abstract
It has been suggested that one of the purposes of colour vision is to help disambiguate material and illumination changes in naturals scenes, since whereas an intensity change might be due to either a change in material or a change in illumination, a colour change is invariably due to a change in material. Here we demonstrate a compelling phenomenon that can be explained by just such a role for colour vision. A plaid made from two otherwise identical orthogonal sine-wave luminance gratings appears corrugated in depth when colour contrast is added to one of the gratings. The perceived depth corrugation follows the pure luminance grating. A plausible explanation is that the mixed colour-plus-luminance grating is interpreted as a material surface and the pure luminance grating as shading. We measured the perceived depth of the corrugation for various amounts of added colour contrast by adjusting the amplitude of a textured disparity grating to match the corrugation, and found a monotonic relationship between colour contrast and perceived depth. We also report estimates of the degree to which the illusory depth in the plaid is paralleled by a perceptual ‘flattening’ of the luminance contrast in the coloured grating, as measured using a matching technique. We conclude that colour vision can play an important role in helping to decompose the visual scene into its illumination and material laye rs, or ‘intrinsic images’.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| 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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.022 | 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 teacher head, 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".