fullseye

projection_angles — TOMOGRAPHY layout op

• データ種: なし → signal(引数だけで決まる op —— 画像やデータの入力を取らない)
• 呼び出し: import fullseye as fs; fs.ledger.projection_angles(n_angles=180, span_deg=180.0, scheme='uniform', start_deg=0.0) (実装を直接呼ぶなら import tomography; tomography.projection_angles(n_angles=180, span_deg=180.0, scheme='uniform', start_deg=0.0)、台帳から引くなら opstomography.get("projection_angles"))

使い方

The angle sequence of a scan, in degrees, as a 1-D float64 array.

Three schemes, and the difference between them is what happens when a scan is cut short:

• "uniform" — start + span * k / n. The textbook scan. A prefix of it covers only a wedge, so an interrupted uniform scan is a limited-angle scan.

• "golden" — increments of 180/phi = 111.246... degrees, wrapped into [start, start+span). Every prefix is near-uniform, so an interrupted golden scan is a sparse scan, which is a far easier problem. Largest angular gap left by a scan that stops early, measured:

  scheme after 32 of 180 all 180 uniform 149.000 deg 1.000 deg golden 10.031 deg 1.464 deg bit-reversed 8.000 deg 1.000 deg

  Uniform’s 149-degree hole is the entire limited-angle problem arriving by accident. Bit-reversed is the only one of the three that is good at both ends; golden’s price for working at every prefix length rather than only at powers of two is a completed set 1.46x less even than the grid.

• "bit-reversed" — the uniform grid, visited in bit-reversed order. Same guarantee as golden for power-of-two prefixes and exactly uniform at the end, which golden is not.

span_deg is the total angular range. 180 degrees is the complete data set for parallel beam — projections at theta and theta+180 are mirror images and carry no new information — so a 360-degree span is redundancy, not resolution, and anything under 180 is the limited-angle problem.

:param n_angles: number of views, 1 .. 65536. :param span_deg: total angular range in degrees, > 0. :param scheme: one of :data:ANGLE_SCHEMES. :param start_deg: angle of the first view. :returns: (n_angles,) float64 array of degrees. :raises ValueError: on a non-int count, a non-positive span, a non-finite start, or an unknown scheme.

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)

• ct_reconstruction — py -3.11 examples/ct_reconstruction.py
• poc_battery_ct_degradation — py -3.11 examples/poc_battery_ct_degradation.py
• poc_ct_fidelity — py -3.11 examples/poc_ct_fidelity.py
• tomography_reconstruct — py -3.11 examples/tomography_reconstruct.py

型が繋がる次の op(signal を入力に取れる)

—

同カテゴリ(layout)

sinogram_design

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Provenance: tomography.py — TOMOGRAPHY 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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