highpass_image — 2D `frequency` op

• Data kinds: image → image

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

• HALCON equivalent: highpass_image (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.

周波数領域で低域(半径 `<= 0.02+0.3*a`)を遮断し、残りを逆 FFT で

実空間に戻したハイパスフィルタ。零平均の符号つき応答になるため

`signed01` で [0,1] に写像している(0.5 がゼロ、つまり画素の約半分が

0.5 未満になるのが正常)。HALCON の `highpass_image`（Extract high

frequency components from an image.）に相当。

`a が遮断半径(カットオフ周波数)を振る。b` は未使用。単純に

`> 0.5` で二値化するとほぼ半分の画素が黒に潰れるので注意(詳細は

`_sh_freq` の docstring)。

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 · bandpass_image

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

highpass_image — 2D frequency op