sk_otsu — 2D `segmentation` op

• Data kinds: image → region

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

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

sk_otsu: 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

Global thresholding by Otsu's method (discriminant analysis). Automatically selects the threshold that maximizes between-class variance, splitting the whole image into foreground/background.

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

HALCON の binary_threshold(Segment an image using binary thresholding.)に相当。実装は `v > filters.threshold_otsu(v)` —— a, b は未使用(しきい値は完全自動)。双峰性(2 山)のヒストグラムを持つ画像で最もうまく働き、コントラストが低い/単峰の画像では境界がずれやすい。

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.

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.

sk_otsu 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

• poc_cell_counting — py -3.11 examples/poc_cell_counting.py

• poc_nuclei_ploidy — py -3.11 examples/poc_nuclei_ploidy.py

• poc_vegetation_cover — py -3.11 examples/poc_vegetation_cover.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_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).*

sk_otsu — 2D segmentation op