fullseye

spad_deadtime_apply — PHOTON spad op

• データ種: countrate → countrate
• 呼び出し: import fullseye as fs; fs.ledger.spad_deadtime_apply(rate_hz, dead_time_ns=50.0, paralyzable=False) (実装を直接呼ぶなら import photoncount; photoncount.spad_deadtime_apply(rate_hz, dead_time_ns=50.0, paralyzable=False)、台帳から引くなら opsphoton.get("spad_deadtime_apply"))

使い方

Distort a true photon rate by the detector’s dead time (counts lost).

After every detection a SPAD is blind for a recharge (dead) time tau, so the measured rate m is always below the true incident rate n. Two classical laws, and this op implements both:

• non-paralysable (default) — an arriving photon during the dead time is simply lost: m = n / (1 + n*tau). Monotonic, saturating at 1/tau.
• paralysable (paralyzable=True) — an arriving photon restarts the dead time: m = n * exp(-n*tau). This law peaks at n = 1/tau (where m = 1/(e*tau)) and then falls, so a bright scene can read darker than a dim one. That is why no inverse op exists for it (see :func:spad_deadtime_correct).

rate_hz is a 1-D array of true rates in counts per second; dead_time_ns is the dead time in nanoseconds, defaulting to 50 — the middle of the 10-100 ns range a passively quenched SPAD occupies, and a placeholder to be replaced by the datasheet value, never a measurement of your detector. Returns the measured rates as a float64 1-D array of the same length.

Ground truth (pinned in the tests): at n = 1/tau the non-paralysable law gives exactly n/2; the paralysable law’s maximum is exactly 1/(e*tau) at n = 1/tau; both reduce to m = n as n*tau -> 0.

Raises ValueError: negative, non-finite or non-1-D rate_hz, a non-positive dead_time_ns, and a non-bool paralyzable.

詳しい使い方ガイド

• photon_timeresolved 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)

• photon_timeresolved — py -3.11 examples/photon_timeresolved.py

型が繋がる次の op(countrate を入力に取れる)

spad_deadtime_correct

同カテゴリ(spad)

spad_deadtime_correct · tcspc_coates_correct

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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.

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