contour op• Data kinds: image → contour
• Call: fullseye.apply(img, "edges_sub_pix", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: edges_sub_pix (the HALCON reference is a useful guide to its meaning and parameters)
Sub-pixel-accurate edge point extraction. Computes the gradient and its normal direction (`gradient_normals), forms connected components from pixels exceeding a threshold (0.15+0.5*a), and then refines each point to sub-pixel position by parabola fitting (subpixel_refine_edges, an implementation shared with the same-named op on the ops side -- a 2026-09-02 fix made this genuinely sub-pixel; the old implementation simply returned integer pixel coordinates). Equivalent to HALCON's edges_sub_pix` (Extract sub-pixel precise edges using Deriche, Lanser, Shen, or Canny filters.).
> The detailed description below is the original text — the summary and the headings are translated.
`a がエッジ強度のしきい値を振る。b` は未使用。
• gallery2d_contour_measure 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_contour_measure — py -3.11 examples/gallery2d_contour_measure.py
• quickstart — py -3.11 examples/quickstart.py
contour as input)identity · select_contours · smooth_contours · fit_line_contours · contours_to_region · count_contours · total_length · select_contours_xld
contour)select_contours · smooth_contours · fit_line_contours · contours_to_region · sk_find_contours · lines_gauss · select_contours_xld · smooth_contours_xld
*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.