xg_clip_contours — 2D `xldgeom` op

• Data kinds: contour → contour

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

xg_clip_contours: input → output

*The figure is the actual output on a synthetic 128×128 input. Left: input, right: output. Point clouds are drawn as a top-down scatter (brightness = z), 1-D series as a line plot, volumes as the maximum-intensity projection along z, videos as the middle frame, complex images as magnitude; return values that are not pictures are shown as the values themselves.*

Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):

▸ xg_clip_contours: knob a sweep (docs site)

*Knob b does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*

Stages (the ops that come before → this op, left to right):

▸ xg_clip_contours: stages (docs site)

On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):

▸ xg_clip_contours: other inputs (docs site)

Usage

Drop contours whose polyline length is below a * max-length (a in [0,1]).

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

各輪郭の折れ線長(隣接点間のユークリッド距離の和)を求め、最長の輪郭の長さ

`L_max に対して length >= a * L_max を満たす輪郭だけ残す。a` は

[0,1] に clip され、`a=0 で全輪郭を残し、a=1` で最長の輪郭(同長なら

複数)だけ残す。`b` は未使用。

返り値は入力と同じ `{"shape", "cs"}` 形式の輪郭辞書(点配列はコピー)。

輪郭が無ければ `cs は空。L_max <= 1e-12`(全輪郭が 1 点)なら全輪郭を

そのまま返す。しきい値が画像サイズでなく「最長輪郭に対する相対値」なので、

最長の輪郭が変わると選別基準も動く(点数の絶対値で選ぶなら

`select_contours_xld`)。名前から想像される矩形での切り取りではなく、

長さによる選別である(矩形で切るのは `xg_crop_contours / hx_clip_contours`)。

閉輪郭の重複終点も長さに含むが、0 長の辺なので影響しない。

Detailed usage guide

• gallery2d_geometry 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.

Try it in Studio

The program below has been verified to run (same input as the figure). In Studio's help this block becomes buttons that load and run it on the spot.

threshold 0.50 0.50
sk_find_contours 0.50 0.50
xg_clip_contours 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_geometry — py -3.11 examples/gallery2d_geometry.py

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

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

Same category (`xldgeom`)

xg_moments · xg_area_center · xg_eccentricity · xg_orientation · xg_elliptic_axis · xg_height_width_ratio · xg_regress_contours · xg_gen_polygons

*Provenance: ops.py — 2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

xg_clip_contours — 2D xldgeom op