sk_clear_border — 2D region op

Data kinds: regionregion

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

sk_clear_border: input → output

*The figure is the actual output on a synthetic 128×128 input. Left: input, right: output. Point clouds are drawn as a top-down scatter (brightness = z), 1-D series as a line plot, volumes as the maximum-intensity projection along z, videos as the middle frame, complex images as magnitude; return values that are not pictures are shown as the values themselves.*

*Knob a does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*

*Knob b does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*

Stages (the ops that come before → this op, left to right):

sk_clear_border: stages (docs site)

On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):

sk_clear_border: other inputs (docs site)

Usage

Removal of components touching the image border. Drops all connected components of the foreground region that touch the image's outer edge back to background -- a standard preprocessing step for excluding objects cut off at the edge of the field of view (not fully captured) from analysis.

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

HALCON に直接対応するものは無い。実装は `segmentation.clear_border(binm(v))`。a, b は未使用 —— 除去判定に使う縁の幅(buffer_size)は既定の 0(画像端そのものに触れている成分のみ対象)。

Border handling: replicate the edge pixel (nearest neighbour) (measured; tools/impl2/border_probe.py).

Detailed usage guide

gallery2d_region 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.

threshold 0.50 0.50
sk_clear_border 0.50 0.50

▸ Load this pipeline  ·  Load & run

Runnable examples (verified samples that actually call this op)

gallery2d_regionpy -3.11 examples/gallery2d_region.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 (region)

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


*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.