region op• Data kinds: region → region
• Call: fullseye.apply(img, "r2_inner_rectangle1", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: inner_rectangle1 (the HALCON reference is a useful guide to its meaning and parameters)
*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.*
Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):
▸ r2_inner_rectangle1: knob a sweep (docs site)
*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):
▸ r2_inner_rectangle1: stages (docs site)
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ r2_inner_rectangle1: other inputs (docs site)
Largest axis-aligned inscribed rectangle (a shrinks the drawn rect; a=0=exact).
> The detailed description below is the original text — the summary and the headings are translated.
領域に内接する軸並行矩形のうち面積最大のものをマスクとして描く。前景マスク
(`> 0.5`)に対し、行ごとに各列の連続前景高さを積み、単調スタックで最大
長方形を求めるヒストグラム法(O(H*W))で厳密解を得る。同面積の候補が複数
あるときは走査順で最初に見つかったものを採る。
`a は描く矩形を内側へ縮める割合で、f = 0.3*a` として高さを
`round(hh*f/2) 行ずつ、幅を round(ww*f/2) 列ずつ両側から削る。a=0` で
厳密な最大内接矩形、`a=1` で各辺が約 15% ずつ縮む(面積ではおよそ半分)。
縮めすぎて辺が潰れる場合は中央の 1 行 / 1 列に丸める。`b` は未使用。
返り値は入力と同形の float64 0/1 マスク。前景が無ければ全零。矩形は画素境界に
そろうため `a=0 の出力は必ず領域に含まれる(r2_inner_circle` と異なり
はみ出さない)。孔のある領域では孔を避けた矩形になるので、孔を無視したい
ときは前段に `fill_up`。回転した矩形は扱えない(軸並行のみ)。外接側の
軸並行矩形は `r2_smallest_rectangle1`。
• 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 r2_inner_rectangle1 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.