texture op• Data kinds: image → image
• Call: fullseye.apply(img, "sk_shape_index", 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).*
Shape index. Represents local surface shape as a single scalar from -1 (spherical cup/pit) through 0 (saddle point) to +1 (spherical cap/dome), derived from the eigenvalues of the Hessian matrix -- a descriptor that summarizes the "orientation" of curvature.
> The detailed description below is the original text — the summary and the headings are translated.
HALCON に直接対応するものは無い。実装は `feature.shape_index(v, sigma=0.5+2.0*a) の NaN(平坦領域で未定義になる)を 0 に置き換えてから signed01(符号付き応答の 0 を 0.5 に写像し、±最大値を 0/1 に写像する)で [0,1]` へ写した値 —— a は Hessian を計算する際のガウス微分の σ を 0.5〜2.5 に振る。b は未使用。
• gallery2d_texture_freq 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.
sk_shape_index 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_texture_freq — py -3.11 examples/gallery2d_texture_freq.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
texture)std_filter · gabor · sk_frangi · sk_meijering · sk_hessian · sk_gabor · sk_lbp · sk_entropy
*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.