gray_opening — 2D morphology op

• Data kinds: image → image

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

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

Usage

Grayscale opening (erosion followed by dilation with the same structuring element). It removes small bright protrusions and thin lines while roughly preserving the overall brightness distribution. Equivalent to HALCON's `gray_opening` (Perform a gray value opening on an image.).

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

`a が矩形構造要素のサイズを {3,5,7,9} で振る。b` は未使用。

Detailed usage guide

• gallery2d_morphology 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_morphology — py -3.11 examples/gallery2d_morphology.py

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

identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter

Same category (morphology)

gerode · gdilate · gopen · gclose · tophat · bothat · morph_grad · sk_area_opening

*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.