features op• Data kinds: region → feature
• Call: fullseye.apply(img, "elliptic_axis", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: elliptic_axis (the HALCON reference is a useful guide to its meaning and parameters)
Returns the ratio (aspect ratio) of the major to minor axis of the equivalent ellipse (the ellipse with matching moment of inertia) of the region. Computed from `skimage.measure.regionprops's axis_major_length/axis_minor_length`, then divided by 10 to bring it roughly into the [0,1] scale (this is not true normalization, so it can exceed 1 for very elongated regions). a and b are unused.
> The detailed description below is the original text — the summary and the headings are translated.
HALCON の `elliptic_axis（等価楕円の長半径・短半径そのもの 2 つの長さを返す演算）とは異なり、この実装は長さではなく比（アニソメトリー、anisometry` と同じ metric）だけを 1 スカラーで返す近似。
• 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.
• 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.