region op• Data kinds: region → region
• Call: fullseye.apply(img, "r3_clip_region", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: clip_region (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):
▸ r3_clip_region: knob a sweep (docs site)
Sweeping knob b (0.1 / 0.5 / 0.9, the other knob at its default):
▸ r3_clip_region: knob b sweep (docs site)
Stages (the ops that come before → this op, left to right):
▸ r3_clip_region: stages (docs site)
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ r3_clip_region: other inputs (docs site)
Clips the region with a rectangular window centred on the image (equivalent to HALCON `clip_region`).
> The detailed description below is the original text — the summary and the headings are translated.
`a は残す高さの割合（0〜1）、b` は残す幅の割合（0〜1）。窓は画像の中心に置かれ、窓の外側の領域画素はすべて消される。
窓の大きさは `wh = max(1, round(a*H)) 行 × ww = max(1, round(b*W)) 列で、左上を ((H-wh)//2, (W-ww)//2) に置く（端数は上・左に寄る）。a, b は [0,1] に clip、非有限なら 0.5。a=b=1 で入力そのまま、a=b=0 でも中央の 1 画素は残る（全零にはならない）。入力は > 0.5` で前景マスクに直すため、グレー値や NaN は背景扱い。
返り値は入力と同形の float64 0/1 マスク。窓は領域の外接矩形ではなく画像全体を基準にする点に注意（領域が画像の隅にあると `a=b=0.5 で丸ごと消えることがある）。領域基準で相対クリップしたいなら hx_clip_region_rel。窓の外を消すのであって窓自体を前景にはしない（領域が無い所は 0 のまま）。画像側で同じ中央窓を切るのは it_crop_domain（こちらは a 1 つで縦横同じ割合）、輪郭の点を窓で残すのは xg_crop_contours`。例外時は0 マスクに落ち、backend_safe の台帳に記録される（strict モードでは再送出）。
• 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 r3_clip_region 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.