MATLAB functions for computing image spectra
Bibliographic record
Abstract
This capsule provides two different MATLAB functions for computing the mean spectrum of an image in both the horizontal and vertical directions. The first function (img_spectra_1) uses the Welch's method and the second function (img_spectra_2) uses the 2D Fourier transform. The main script calls sequentially these two functions that are fed with an image of Degas's painting entitled 'A Woman Seated Beside a Vase of Flowers' and a graphical comparison is made. The two methods give essentially the same result. The result shows that the slope of the spectrum, when examined in the logarithmic space, is close to -5/3, that is the slope expected for fully developed turbulent flow following Kolmogorov's law of turbulence. These codes were written as part of a study to demonstrate, with a counterexample, that the slope alone of a power spectrum is a poor indicator of turbulence.
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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 | 0.011 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.167 | 0.125 |
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".