segment op• Data kinds: image → region
• Call: fullseye.apply(img, "sg_normalized_cut_2", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
*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).*
Splits the image into two regions (bright / dark) using normalized cut on the intensity graph (spectral 2-way partitioning, Shi & Malik; no corresponding HALCON operator).
> The detailed description below is the original text — the summary and the headings are translated.
計算量を抑えるため画像を `sdim = round(10+b*14) 程度まで間引いてから、輝度差と距離で重みを決めたアフィニティグラフを作り、一般化固有値問題 (D-W)y = lambda*D*y の第 2 固有ベクトル（Fiedler ベクトル）を中央値でしきい値化して 2 群に分ける。a（0〜1）は輝度方向の帯域幅sig_i = 0.05 + a*0.5 を振り、b`（0〜1）は間引きの解像度を振る。明るい方の群を最近傍で元解像度に拡大して region として返す。
• gallery2d_segmentation 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.
sg_normalized_cut_2 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_segmentation — py -3.11 examples/gallery2d_segmentation.py
region as input)identity · reg_erode · reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small
segment)sg_slic_superpixels · sg_felzenszwalb · sg_gmm_segment · sg_kmeans_intensity · sg_region_growing_seeded · sg_watershed_gradient
*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.