gen_region_polygon_xld — 2D contour op

Data kinds: contourregion

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

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

gen_region_polygon_xld: 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):

gen_region_polygon_xld: 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):

gen_region_polygon_xld: stages (docs site)

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

gen_region_polygon_xld: other inputs (docs site)

Usage

Converts an XLD contour (a polygon's vertex sequence) into a region (pixel mask). Plots contour points onto the nearest pixels, then thickens and connects the lines with `1+2a` rounds of binary dilation. b is unused.

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

HALCON の `gen_region_polygon_xld`(XLD 多角形の内部を塗りつぶした region を生成する演算)とは異なり、この実装は多角形の内部を塗りつぶすのではなく、輪郭線そのものを膨張させて太らせるだけの近似 —— 閉じていない輪郭や自己交差する輪郭では本来の内部塗りつぶしと結果が食い違う。

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.

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
gen_region_polygon_xld 0.50 0.50

▸ Load this pipeline  ·  Load & run

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 region as input)

identity · reg_erode · reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small

Same category (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.