morphology op• Data kinds: image → image
• Call: fullseye.apply(img, "gray_erosion", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: gray_erosion (the HALCON reference is a useful guide to its meaning and parameters)

*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).*
Grayscale erosion (`ndimage.grey_erosion). Replaces each pixel with the minimum value within a rectangular structuring element (default shape="rect"), eroding bright details. Equivalent to HALCON's gray_erosion` (Perform a gray value erosion on an image.).
> The detailed description below is the original text — the summary and the headings are translated.
`a が構造要素のサイズを {3,5,7,9}(_k(a)、矩形)で振る。b` は
このバックエンドの全グレーモルフォロジー op に共通して未使用。円形
構造要素が欲しい場合は `gray_erosion` ではなく形状指定つきの派生
(`*_shape`)を使う。
• gallery2d_morphology family guide
• 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.
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.
gray_erosion 0.35 0.50
▸ Load this pipeline · Load & run
• gallery2d_morphology — py -3.11 examples/gallery2d_morphology.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
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.