bin_threshold — 2D segmentation op

Data kinds: imageregion

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

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

bin_threshold: 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

Automatic threshold binarization using Otsu's method. Shares the `otsu branch of _sh_threshold with binary_threshold/auto_threshold`; a and b are unused. Pixels brighter than the threshold become the foreground (1). In environments without skimage, it falls back to using the image mean as the threshold.

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

HALCON の `bin_threshold`(複数の自動しきい値決定アルゴリズムから選んで二値化する演算、既定は最大分離度=大津法相当)に相当する近似で、大津法のみをサポートし他のアルゴリズム選択肢は無い。

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.

bin_threshold 0.50 0.50

▸ Load this pipeline  ·  Load & run

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.