Multi-scale shape prior using wavelet packet representation and independent component analysis
Bibliographic record
Abstract
Statistical shape priors try to faithfully represent the full range of biological variations in anatomical structures. These priors are now widely used to restrict shapes; obtained in applications like segmentation and registration; to a subspace of plausible shapes. Principle component analysis (PCA) is commonly used to represent modes of shape variations in a training set. In an attempt to face some of the limitations in the PCA-based shape model, this paper describes a new multi-scale shape prior using independent component analysis (ICA) and adaptive wavelet decomposition. Within a best basis selection framework, the proposed method benefits from the multi-scale nature of wavelet packets, and the capability of ICA to capture higher order statistics in wavelet subspaces. The proposed approach is evaluated using contours from digital x-ray images of five vertebrae of human spine. We demonstrate the ability of the proposed shape prior to capture both local and global shape variations, even with limited number of training samples. Our results also show the performance gains of the ICA-based analysis for the wavelet sub-spaces, as compared to PCA-based analysis approach.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".