fullseye

quaternion_to_rgb — QUAT convert op

• データ種: qimage → rgbimage
• 呼び出し: import fullseye as fs; fs.ledger.quaternion_to_rgb(qimage, allow_scalar: 'bool' = False) -> 'np.ndarray' (実装を直接呼ぶなら import quatimage; quatimage.quaternion_to_rgb(qimage, allow_scalar: 'bool' = False) -> 'np.ndarray'、台帳から引くなら opsquat.get("quaternion_to_rgb"))

使い方

Vector part of a quaternion image, as linear RGB. → (H, W, 3).

The inverse of :func:rgb_to_quaternion — and, by default, a checked inverse. A quaternion image that picked up a scalar component somewhere (a Hamilton product with a non-pure quaternion, a monogenic signal handed here by mistake) is refused rather than silently truncated, because dropping the w component is exactly the kind of loss that produces a plausible picture from the wrong data. Pass allow_scalar=True to opt in to the truncation when it is what you meant.

The tolerance is relative to the field’s own peak modulus (:data:_MONOGENIC_K_TOL, 1e-9): a quaternion image that really is pure carries |w| at the 1e-17 level after a round trip through two FFTs, and anything with a meaningful scalar part is many orders above that. Nothing real lives in between.

Raises ValueError: qimage is not a finite (H, W, 4) array; or it has a non-negligible scalar part and allow_scalar is False.

詳しい使い方ガイド

• quaternion_monogenic ファミリ ガイド

参考(サンプルデータ・文献)

• サンプルデータ カタログ(DL URL / ライセンス) — 2-D は skimage.data(BSD/public)+ 合成、3-D は実データ源(Stanford/PDS 等)の DL URL。
• 演算子の来歴・参考文献 — この op 族の元になった研究/手法の出典。
• アルゴリズムの正典(著者・年)と用途は上記ファミリ使い方ガイドに記載。

実行できる例(この op を実際に呼ぶ検証済みサンプル)

• quaternion_monogenic — py -3.11 examples/quaternion_monogenic.py

型が繋がる次の op(rgbimage を入力に取れる)

rgb_to_quaternion

同カテゴリ(convert)

rgb_to_quaternion · quat_norm

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Provenance: quatimage.py — QUAT operator registry. この per-op ノートは tools/opdocs.py md が自動生成(手編集しない)。

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.

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