features op• Data kinds: image → feature
• Call: fullseye.apply(img, "xsk_orb_count", 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).*
Number of ORB (Oriented FAST and Rotated BRIEF) keypoints detected.
> The detailed description below is the original text — the summary and the headings are translated.
skimage.feature.ORB で検出・記述を行い、実際に検出できたキーポイント
数を返す(feature 出力)。
`a が要求する最大キーポイント数 n_keypoints` を 50〜450 の範囲で
振る(上限であり、画像のコントラストや構造が乏しいと実際の検出数は
それより少なくなる)。`b` は未使用。テクスチャの豊富さ・特徴点密度の
目安として使える。
• 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.
xsk_orb_count 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.