r3_region_features — 2D `region` op

• Data kinds: region → feature

• Call: fullseye.apply(img, "r3_region_features", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

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

r3_region_features: 入力 → 出力

*The figure is the real output on a synthetic 128×128 input. Left: input, right: output (a non-image return value is shown as the value itself).*

Usage

Returns one shape feature of the region (implements part of HALCON `region_features`).

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

`a < 0.5 なら正規化面積（前景画素数/全画素数）、a >= 0.5 なら真円度の逆数にあたるコンパクトネス P^2 / (4*pi*A)（P は 4 連結境界の周囲長。円で 1、正方形で約 1.27、細長いほど大きくなる）を返す。b` は未使用。領域が空なら 0.0。

Detailed usage guide

• gallery2d_region 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
r3_region_features 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_region — py -3.11 examples/gallery2d_region.py

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

identity

Same category (`region`)

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

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

r3_region_features — 2D region op