contour op• Data kinds: color → contour
• Call: fullseye.apply(img, "lines_color", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: lines_color (the HALCON reference is a useful guide to its meaning and parameters)
Detects lines (ridges) in a color image. Claimed to correspond to HALCON's `lines_color` (detects color lines and their width), but it does not estimate line width -- it only thresholds the Laplacian-of-Gaussian response on the luminance image into a binary image and returns the connected components as contours; it has no output corresponding to the line width that HALCON returns.
> The detailed description below is the original text — the summary and the headings are translated.
`_rgb_to_gray で輝度化した後、scipy.ndimage.gaussian_laplace` を
シグマ `0.5 + 2.5 * a` でかけて絶対値を最大値正規化し、
`0.2 + 0.4 * b` でしきい値二値化して 8 連結ラベリングする。
a はリッジの太さ（LoG のスケール）、b は検出しきい値を振る。
3 画素未満の成分は捨てる。
• 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 · lines_gauss · select_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.