typed op• データ種: qimage → image
• 呼び出し: fullseye.apply(img, "tb_monogenic_orientation", a=0.5, b=0.5) (2-D は 1 画像 + 2 スカラつまみ a,b∈[0,1] のモデル)
*図は合成の入力 128×128 で実際に走らせた出力。左が入力、右が出力。点群は上から見た散布(明るさ = z)、1-D 列は折れ線、体積は z 方向の最大値投影、動画は中央フレーム、複素画像は振幅、絵にならない返り値は値そのもの。*
*出力は viridis 風の疑似カラー(暗い紫 = 小、黄 = 大)。距離・位相・向き・深度のような「量の場」を読むため。*
*つまみ a は出力を変えない(実測: 0.1 / 0.5 / 0.9 で同一)。*
*つまみ b は出力を変えない(実測: 0.1 / 0.5 / 0.9 で同一)。*
段階(前置きの op → この op。左から順):
▸ tb_monogenic_orientation: stages (docs site)
別の画像でも(合成シーン / 写真 / 硬貨。上段が入力、下段がその出力。つまみは既定):
▸ tb_monogenic_orientation: other inputs (docs site)
Local orientation `atan2(R2, R1)` of a monogenic signal. → (H, W).
Radians in `[0, pi): an orientation is defined modulo pi` (a grating at
10 degrees and one at 190 degrees are the same grating), and the value is
folded into that range rather than left in `(-pi, pi]` where the same
structure would read as two different numbers on either side of a contrast
reversal. `display=True maps it to [0, 1]`.
Continuous, not quantised — the angle is read directly from two filters,
for any angle, where a steerable bank with `K` orientations interpolates
between its `K`. Measured against eight grid-exact grating orientations the
error is at most 3.6e-15 rad, including the obliques. (Whether that
buys anything downstream is a separate question, and the measured answer is
mostly *no* — see :func:riesz_displacement.)
Where it is undefined, and the mask is not the one you expect. The
orientation dies where the *Riesz vector* dies, which is at every
even-symmetric point — local phase 0 or pi, the crest of a bright or dark
line — and the amplitude is at full strength there. Measured on a 45-degree
grating, the worst orientation error over the whole frame is 0.2764 rad, at a
pixel where `|R| = 6.8e-16 and :func:monogenic_amplitude` reads
`1.0000`. So masking on the amplitude does not protect you; mask on
`hypot(q[..., 1], q[..., 2])`, the Riesz magnitude. With that mask the
error over the same eight orientations is at most 3.6e-15 rad.
Where the Riesz vector is exactly zero, `atan2(0, 0) = 0` is returned —
a *value*, not a measurement.
Raises `ValueError`: the input is not a valid quaternion field, or its
`k` component is non-zero; *display* is not a bool.
Typed bridge of the quat op `monogenic_orientation into the 2-D evolution registry: the same implementation, called under the op(v, a, b) convention. This op has no tunable parameter; a and b` are unused.
• 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。
下のプログラムは実際に走ることを確かめてある(図と同じ入力)。Studio のヘルプではこのブロックがボタンになり、その場で読み込んで実行できる。
img_to_monogenic 0.50 0.50 tb_monogenic_orientation 0.50 0.50
▸ Load this pipeline · Load & run
次の例は元の台帳 op monogenic_orientation を呼ぶもの。この橋渡し op は同じ実装を fn(v, a, b) 規約に合わせただけなので、挙動はそのまま当てはまる(呼び出し形だけ違う)。
• quaternion_monogenic — py -3.11 examples/quaternion_monogenic.py
image を入力に取れる)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
typed)tb_points_to_voxel · tb_estimate_point_normals · tb_iss_keypoints · tb_project_points · tb_render_point_depth · tb_statistical_outlier_removal · tb_radius_outlier_removal · tb_voxel_grid_downsample
*Provenance: ops.py — 2D 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.