Interactions between viewing from above and global convexity priors in the interpretation of depth-ambiguous shape-from-contour drawings
Bibliographic record
Abstract
The ‘Viewing from Above’ prior (VFA) guides visual perception of ambiguous stimuli in shape-from-shading and shape-from-contour tasks (Reichel & Todd, 1990). Accordingly, the typical Necker cube tends to be reliably perceived from above, particularly for short presentations, although viewing-from-below is equally valid (e.g., Troje, 2010). Initial observations indicated that shape influences the reliability of the VFA: a ‘diamond’ stimulus (i.e., two attached square-base pyramids) is less likely to be perceived in one consistent orientation. We compared perception of diamond and Necker cube ambiguous line-drawings with four shapes that shared related features: point-up or point-down square-based pyramids and point-up or point-down pyramids attached to a Necker cube. The Necker cube was viewed from above (97%) significantly more often than the diamond (86%). The point-up pyramid was also viewed from above (97%) more often than the point-down pyramid (84%). We also found the point-up pyramid attached to the Necker cube was viewed from above (98%) more often than the same stimulus when inverted (87%). We suggest that a strong VFA prior mediated by a weaker prior for global convexity are generally consistent with the results. The finding contrasts with research that found equal strength for the two priors in shape-from-shading (Langer & Bulthoff, 2001), but supports research on the unequal strength of the two priors in line drawings (Mamassian & Landy, 1998). Specifically, all stimuli tended to be viewed from above; and the point-up and point-down pyramids adhere to a convexity towards the viewer if they are perceived from above and from below, respectively. The same is true for the pyramids attached to Necker cubes. However, the finding that the diamond stimulus is seen less often from above than other stimuli cannot be explained. Meeting abstract presented at VSS 2015
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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 | 0.021 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".