features op• Data kinds: region → feature
• Call: fullseye.apply(img, "connect_and_holes", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: connect_and_holes (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).*
Counts the number of connected components in the region (8-connectivity, the same `count branch of _sh_region_feat used by count_obj`). a and b are unused.
> The detailed description below is the original text — the summary and the headings are translated.
HALCON の `connect_and_holes（連結成分数と穴の数の 2 つを同時に返す演算）のうち**連結成分数だけ**を返す近似 —— feature sort は 1 スカラーしか運べないため、穴の数は含まれない（area_holes` が穴の面積比を別途計算する）。
• gallery2d_features 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 connect_and_holes 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_features — py -3.11 examples/gallery2d_features.py
feature as input)features)blob_count · area_frac · count_contours · total_length · vol_count · sk_euler · sk_entropy_feat · sk_blur_effect
*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.