fit_line_contours — 2D contour op

Data kinds: contourcontour

Call: fullseye.apply(img, "fit_line_contours", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

HALCON equivalent: fit_line_contour_xld (the HALCON reference is a useful guide to its meaning and parameters)

Usage

Approximates each XLD contour with a single straight line. Equivalent to HALCON's `fit_line_contour_xld` (Approximate XLD contours by line segments.).

> The detailed description below is the original text — the summary and the headings are translated.

`a, b` は未使用。輪郭点群の重心を通り、SVD(特異値分解)で求めた第一主成分方向を直線の向きとして採用し(全点との距離二乗和を最小化する直線)、元の点群の射影範囲に等間隔に打ち直した点列に置き換える。HALCON 版は折れ線(複数線分)に分割できるが、この実装は輪郭全体を 1 本の直線にする点が異なる。点が 2 点未満の輪郭はそのまま返す。

Detailed usage guide

gallery2d_contour_measure family guide

References (sample data, literature)

• 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.

Runnable examples (verified samples that actually call this op)

gallery2d_contour_measurepy -3.11 examples/gallery2d_contour_measure.py

Ops the type connects to (they accept contour as input)

identity · select_contours · smooth_contours · contours_to_region · count_contours · total_length · select_contours_xld · smooth_contours_xld

Same category (contour)

select_contours · smooth_contours · contours_to_region · sk_find_contours · edges_sub_pix · 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.