vol_fft_highpass — 3D `frequency` op

• Data kinds: voxel → voxel

• Call: import fullseye as fs; fs.ledger.vol_fft_highpass(vol, cutoff, spacing=None) (to call the implementation directly, import volfreq; volfreq.vol_fft_highpass(vol, cutoff, spacing=None); from the registry, ops3d.get("vol_fft_highpass"))

Usage

Gaussian high-pass — the exact complement `1 - lowpass` (the two sum

> The detailed description below is the original text — the summary and the headings are translated.

to the input to float precision, proven in tests). Removes the DC level and

slow drift, keeps edges/texture. Output is signed (mean ~ 0).

伝達関数は `1 - exp(-|f|^2 / (2 cutoff^2))。DC(f = 0`)は係数 0 なので平均

輝度は完全に落ち、`|f| = cutoff で 1 - 0.61 ≈ 0.39`、高周波ほど 1 に近づく。

返り値は入力と同じ `(D, H, W)` の float64 で 符号付き(負の値を含む)。

`[0, 1] 前提の後段(表示・vol_window_level 等)に渡すなら vol_stretch` で

正規化するか、`vol + highpass` の形で使う。

引数: `cutoff は正の有限値。spacing=None で cycles/voxel、spacing`

(`(sz, sy, sx) または volio.VolumeMeta`)を渡すと cycles/mm。

検証(`ValueError): vol_fft_lowpass` と同じ(3-D でない / NaN・Inf /

`MAX_VOXELS` 超 / cutoff・spacing 不正)。

使いどころ: 照明むら・厚みドリフト・背景勾配の除去(`vol_fft_lowpass` の結果を

引くのと同値)。周期的とみなす FFT の性質上、面どうしの輝度差は wrap で漏れる。

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

Runnable examples (verified samples that actually call this op)

• deconv_fft_restore — py -3.11 examples_3d/deconv_fft_restore.py

Ops the type connects to (they accept `voxel` as input)

voxel_to_mips · voxel_to_mesh · signed_distance_field · to_points · sobel3d · hessian3d · curvature_maps · edt_jfa

Same category (`frequency`)

vol_fft_lowpass · vol_fft_bandpass

*Provenance: volfreq.py — 3D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

vol_fft_highpass — 3D frequency op