segmentation op• Data kinds: image → region
• Call: fullseye.apply(img, "adaptive_gauss_thresh", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: local_threshold (the HALCON reference is a useful guide to its meaning and parameters)
Adaptive thresholding based on a locally Gaussian-smoothed mean. Equivalent to HALCON's `local_threshold` (Segment an image using local thresholding.).
> The detailed description below is the original text — the summary and the headings are translated.
`a が基準を作るガウシアンの σ を 1.0〜4.0 に、b がオフセットを -0.15〜+0.15（(b-0.5)*0.3）に振る。v > gaussian_filter(v, σ) + offset を満たす画素を前景にする。照明ムラがある画像で大域しきい値（_threshold/_otsu）より安定する。近い op に _dyn_threshold があるが、そちらは箱型平均（uniform_filter）を基準にし、オフセット幅も異なる（±0.2`）——同じ「適応的しきい値」でも基準の平滑化方式とパラメータ範囲が違う別実装。
• gallery2d_segmentation family guide
• 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.
• gallery2d_segmentation — py -3.11 examples/gallery2d_segmentation.py
region as input)identity · reg_erode · reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small
segmentation)threshold · otsu · canny · sk_otsu · sk_li · sk_yen · sk_sauvola · sk_niblack
*Provenance: ops.py — 2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.