rotational_symmetry — AOI `symmetry` op

• Data kinds: image2d → table

• Call: import fullseye as fs; fs.ledger.rotational_symmetry(image, max_order=12, angular_samples=720, score_threshold=0.18) (to call the implementation directly, import symmetry2d; symmetry2d.rotational_symmetry(image, max_order=12, angular_samples=720, score_threshold=0.18); from the registry, opsaoi.get("rotational_symmetry"))

• GPU: none (CPU reference implementation only)

Usage

Returns the 180-degree point-symmetry centre and the rotational order from polar autocorrelation.

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

Parameters

image : array-like, shape (H, W)

グレー画像または region。

max_order : int, default 12

調べる最大次数。範囲は [2, 36]。

angular_samples : int, default 720

極座標の角度標本数。範囲は [180, 2880] で、2..max_order の公倍数を推奨。

score_threshold : float, default 0.18

正規化 RMS 差を対称とみなす上限。範囲は (0, 1)。

Returns

dict

center=(row,col)、point_symmetric、order、各次数の polar

autocorrelation と差を持つ table。order=1 は非回転対称を表す。

Notes

中心は外側エッジ対から推定し、その中心で極座標画像を作る。角度方向に 360/n 度循環シフトした自己相関を測り、しきい値を満たす最大 n を次数とする。定数入力、中心が求まらない入力は ValueError。同心円のように連続回転対称な像、角度標本数で割り切れない次数、中心から画像端まで対象が切れる像では次数は多義または不安定になる。

Loy and Zelinsky, Fast radial symmetry for detecting points of interest, IEEE TPAMI 25(8), 2003; Liu et al., FnT CGV 5(1-2), 2010.

Detailed usage guide

• aoi_frontend 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)

• poc_symmetry_self_reference_inspection — py -3.11 examples/poc_symmetry_self_reference_inspection.py

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

symmetry_difference_map · symmetry_score

Same category (`symmetry`)

center_from_symmetric_edges · reflection_axis · symmetry_difference_map · symmetry_score

*Provenance: symmetry2d.py — AOI operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

rotational_symmetry — AOI symmetry op