contour op• Data kinds: image → contour
• Call: fullseye.apply(img, "lines_gauss", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: lines_gauss (the HALCON reference is a useful guide to its meaning and parameters)
Line (ridge) structure detection. Binarizes the response of `skimage.filters.frangi (a vessel-like ridge-enhancement filter) with a threshold (0.1+0.4*a) and returns the connected components as contour point sets. This is simplified to thresholding the ridge-enhanced image, rather than the "line centerline + width estimation" that HALCON's lines_gauss` (Detect lines and their width.) originally performs (an approximation in which line-width information is not returned).
> The detailed description below is the original text — the summary and the headings are translated.
`a がリッジ検出のしきい値を振る。b` は未使用。skimage が無い環境
ではこの分岐は呼べない。
• 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
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 · edges_sub_pix · 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.