Add artwork feature extractor and fix spectral centroid bug#51
Merged
exdysa merged 3 commits intodarkshapes:mainfrom Mar 22, 2026
Merged
Add artwork feature extractor and fix spectral centroid bug#51exdysa merged 3 commits intodarkshapes:mainfrom
exdysa merged 3 commits intodarkshapes:mainfrom
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The fourier_discrepancy method used log_mag.T which creates a (w,h) matrix that can't be added to the (h,w) log_mag matrix when h != w. Split into separate row/col contributions to avoid the broadcast.
Implements the 39-feature extraction pipeline from Li & Stamp (2025) "Detecting AI-generated Artwork" (arXiv:2504.07078), extended with 10 FFT/DCT spectral analysis features for frequency-domain artifact detection. Features: brightness (2), color (23), texture (6), shape (6), noise (2), frequency (10). All CPU-only, no pretrained models required. Includes benchmark tests with SVM/MLP/XGBoost ensemble achieving 95%+ accuracy with calibrated thresholds and abstention for uncertain images.
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Summary
fourier_discrepancythat crashed on non-square images (affected all inference on real-world images)Features added
49 image features extracted without GPU or pretrained models:
Benchmark results
5-fold cross-validation on WikiArt (human) vs AI-generated images:
Test plan
pytest tests/test_chip.py tests/test_dataset.py tests/test_load_spec.py)pytest tests/test_artwork_accuracy.py -v -s)python tests/generate_results_pdf.py)