sk_canny — 2D segmentation op

Data kinds: imageregion

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

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

Usage

Canny edge detection (region version). Finds edge pixels through the classic multi-stage pipeline -- Gaussian smoothing -> gradient computation -> non-maximum suppression -> hysteresis thresholding -- and returns them as a boolean region.

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

HALCON の edges_image に相当。実装は `feature.canny(v, sigma=0.5+2.0*a)` —— a は前段のガウス平滑化の σ を 0.5〜2.5 に振る(大きいほど細かいノイズ由来のエッジが消え、太い輪郭だけ残る)。b は未使用 —— ヒステリシスの低/高しきい値は skimage が画像から自動推定した値のまま(明示指定していない)。

Detailed usage guide

gallery2d_segmentation 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_segmentationpy -3.11 examples/gallery2d_segmentation.py

Ops the type connects to (they accept region as input)

identity · reg_erode · reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small

Same category (segmentation)

threshold · otsu · canny · adaptive_gauss_thresh · sk_otsu · sk_li · sk_yen · sk_sauvola


*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.