region op• Data kinds: region → region
• Call: fullseye.apply(img, "convex_fill", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: shape_trans (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).*
Fills holes and indentations to approximate a convex-hull-like shape (an approximation via closing). Intended to correspond to the convex hull transform of HALCON's `shape_trans` (Transform the shape of a region.), but the implementation is a closing with many iterations, not an exact convex hull computation (an approximation).
> The detailed description below is the original text — the summary and the headings are translated.
`a が反復回数を 3〜6(_it(a)+2)に振る。b は未使用。border_value=1` の二値クロージングを掛けるだけなので、反復回数を超える大きさのくびれ・穴は埋まらない(真の凸包なら必ず埋まる)。
• gallery2d_region 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.
threshold 0.50 0.50 convex_fill 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_region — py -3.11 examples/gallery2d_region.py
region as input)identity · reg_erode · reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small
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.