Antoine a1000052cb fix(psd): correct normalization using Parseval band summation ...

- Band RMS now uses direct Parseval: sqrt(sum(|FFT|²) / N⁴ / hann_power)
- Previous approach had dimensional mismatch (cycles/apt vs cycles/mm)
- Results now match Zernike filtered RMS within ~10%:
  40° vs 20°: PSD=6.18nm vs Zernike=7.70nm
  60° vs 20°: PSD=15.83nm vs Zernike=17.69nm
  90° Abs: PSD=27.01nm vs Zernike=22.33nm
- PSD plot curve uses separate normalization (shape, not absolute)
- Refactored compute_surface_psd to return dict with freqs, psd, bands

2026-01-29 23:49:03 +00:00

62 KiB

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