counting op• データ種: image2d → table
• 呼び出し: import fullseye as fs; fs.ledger.photon_statistics(counts) (実装を直接呼ぶなら import photoncount; photoncount.photon_statistics(counts)、台帳から引くなら opsphoton.get("photon_statistics"))
光子計数フレームのポアソン統計: 本当にショット雑音律速か?
> 以下の詳細説明は原文のままです —— 要約と見出しは訳出済み。
Returns a dict: mean · variance (population, ddof=0) · fano_factor = variance / mean (1 for a Poisson process) · snr_poisson = sqrt(mean) (the theoretical photon-limited SNR) · snr_measured = mean / std (what this frame actually achieved) · total_counts · n_samples · zero_fraction (the fraction of pixels that saw no photon at all — the honest measure of "photon starved"; exp(-lambda) for a flat field) · max_counts.
The Fano factor is evidence of Poisson statistics only on a flat field. On a structured scene the scene's own spatial variance dominates and the ratio is large and meaningless — this op computes the number, it cannot tell you which situation you are in. Measured on the test scenes: a flat lambda = 100 field (512x512, seed 0) gives 1.001089; the same detector looking at a linear ramp from 20 to 180 photons gives 22.4102. Both are "correct" and only one of them means anything.
Raises ValueError: negative, non-finite or non-2-D *counts*, fewer than 2 pixels (no variance), an all-zero frame (fano_factor would be 0/0 — say "no photons were detected" instead of returning NaN), and a frame with exactly zero variance (snr_measured would be inf; for n >= 2 a constant frame is not a Poisson realisation but a synthetic constant, i.e. an input mistake).
• photon_timeresolved ファミリ ガイド
• 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。
• photon_timeresolved — py -3.11 examples/photon_timeresolved.py
table を入力に取れる)—
counting)photon_sample · photon_uncertainty
*Provenance: photoncount.py — PHOTON 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.