ellipse — ANNOTATE shape op

Data kinds: image2dimage2d

Call: import fullseye as fs; fs.ledger.ellipse(img, center, radii, angle_deg=0.0, color='neutral', width=2, fill=False, alpha=1.0, scheme='okabe_ito') (to call the implementation directly, import annotate; annotate.ellipse(img, center, radii, angle_deg=0.0, color='neutral', width=2, fill=False, alpha=1.0, scheme='okabe_ito'); from the registry, opsannotate.get("ellipse"))

Usage

An ellipse (rotated by `angle_deg, filled with fill=True`).

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

Raises

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ValueError

半径が非正、非有限、alpha が [0,1] の外。

描画: 画素を `angle_deg だけ回した局所座標 (u, v)` に写し、

`q = (u/ra)^2 + (v/rb)^2 で判定する。fill=Trueq <= 1`、

`fill=False|sqrt(q) - 1| <= max(1, width) / (2 min(ra, rb))` の帯

(アンチエイリアス無し)。帯の幅を短軸で正規化しているので、扁平な楕円では

長軸の端ほど線が太く見える(近似)。

• `center: (x, y)`、x = 列・y = 行。画像外でもよい。

• `radii: (ra, rb) [px]。raangle_deg 方向、rb` がその直交方向。

両方とも正。

• `angle_deg`: 回転角 [度]。x 軸から時計回り(画面座標、y が下向き)。

• `width: 線幅 [px] (fill=False` のとき)。

• `img / color / alpha / scheme の扱いは rounded_rect` と同じ

(float64 複製、`[0, 1]`、役割名か RGB)。

• 返り値: 入力と同形の float64。

`ra == rb なら円。計測結果(楕円フィットの row, col, phi, ra, rb`)を

重ねるときは `center=(col, row)angle_deg=degrees(phi)` に読み替える。

Detailed usage guide

figure_annotation family guide

Background guides (the physics and conventions behind this op)

dataset_conventions — 学習データセット規約の知識 — COCO / YOLO / VOC と外観検査での落とし穴

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)

annotate_gallerypy -3.11 examples/annotate_gallery.py

poc_dimensional_inspectionpy -3.11 examples/poc_dimensional_inspection.py

poc_machine_condition_fusionpy -3.11 examples/poc_machine_condition_fusion.py

Ops the type connects to (they accept image2d as input)

text_box · arrow · leader_line · label_points · crosshair · legend_box · color_bar · scale_bar

Same category (shape)

rounded_rect · filled_polygon · arc


*Provenance: annotate.py — ANNOTATE 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.