canny — 2D `segmentation` op

• Data kinds: image → region

• Call: fullseye.apply(img, "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)

canny: 入力 → 出力

*The figure is the real output on a synthetic 128×128 input. Left: input, right: output (a non-image return value is shown as the value itself).*

Usage

Simplified Canny-style edge detection (returns a region). Mapped to HALCON's `edges_image` (Extract edges using Deriche, Lanser, Shen, or Canny filters.), but this is a simplified version (an approximation) that does not perform non-maximum suppression or hysteresis thresholding.

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

`a が事前平滑化のガウシアン σ を 0.5〜2.0 に、b がしきい値を 0.1〜0.6 に振る。ガウシアンでぼかした画像に Sobel 勾配強度を掛け、正規化した値を b` で二値化するだけ——本家 Canny の細線化（1画素幅への収束）は無いため、エッジは本来の Canny より太く、複数画素にまたがって残る。

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.

Try it in Studio

The program below has been verified to run (same input as the figure). In Studio's help this block becomes buttons that load and run it on the spot.

canny 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_segmentation — py -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 · adaptive_gauss_thresh · 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).*

canny — 2D segmentation op