power_ln — 2D `frequency` op

• Data kinds: image → image

• Call: fullseye.apply(img, "power_ln", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

• HALCON equivalent: power_ln (the HALCON reference is a useful guide to its meaning and parameters)

Usage

> This operator's description has not been translated yet. The original text follows as it is.

複素画像のパワースペクトルの代役。実装は fft_generic と同一で、入力画像に自前で FFT をかけてから振幅の対数 `log1p(|F|) を最大値正規化して返す（_sh_freq の fft_power` 分岐を共有）。a, b は未使用。

HALCON の `power_ln`（複素画像のパワースペクトルを返す演算、通常は fft_generic 等が出力した複素画像を入力に取る）とは異なり、この実装は複素入力を受け取らず実画像から自前で FFT を計算する簡略近似。fft_generic とは実装上区別がない。

Detailed usage guide

• gallery2d_texture_freq family guide

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.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• gallery2d_texture_freq — py -3.11 examples/gallery2d_texture_freq.py

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

identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter

Same category (`frequency`)

lowpass · highpass · sk_butterworth · fft_image · power_real · power_byte · phase_rad · highpass_image

*Provenance: ops.py — 2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

power_ln — 2D frequency op