monogenic_amplitude — QUAT riesz op

• データ種: qimage → image2d

• 呼び出し: import quatimage; quatimage.monogenic_amplitude(qimage) -> 'np.ndarray' (または opsquat.get("monogenic_amplitude"))

使い方

Local amplitude `sqrt(f^2 + R1^2 + R2^2)` of a monogenic signal. → (H, W).

The local contrast at the signal's scale, and the confidence map for

:func:monogenic_phase / :func:monogenic_orientation, which mean nothing

where this is at the rounding floor. Raw / unnormalised (a contrast is a

metric quantity), in the same spirit as `complexops.cx_magnitude`.

For a unit-contrast grating at the band centre it is exactly 1.0 (measured

spread 8.9e-16 over a 64x64 frame) and, unlike a squared oriented-filter

response, it is *isotropic*: rotating the grating does not change it.

Measured over eight grid-exact orientations the amplitude spans

`[0.99999999999999911, 1.0000000000000011]` — a total spread of 2.0e-15

across all of them, which is the isotropy claim as a number.

Raises `ValueError`: the input is not a valid quaternion field, or its

`k component is non-zero (see :func:_require_monogenic`).

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(image2d を入力に取れる)

riesz_transform · monogenic_signal

同カテゴリ(riesz)

riesz_transform · monogenic_signal · monogenic_phase · monogenic_orientation

*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.