spad opcountrate → countrateimport fullseye as fs; fs.ledger.spad_deadtime_correct(measured_hz, dead_time_ns=50.0) (実装を直接呼ぶなら import photoncount; photoncount.spad_deadtime_correct(measured_hz, dead_time_ns=50.0)、台帳から引くなら opsphoton.get("spad_deadtime_correct"))Recover the true photon rate from a dead-time-distorted measured rate.
The exact inverse of the non-paralysable law of
:func:spad_deadtime_apply::
n = m / (1 - m*tau)
A round trip apply -> correct is exact to machine precision (measured max
elementwise relative error 6.0e-16 over 2000 rates spanning 1e3 to 5e7 Hz at
tau = 50 ns, where the measured rate reaches 71.4% of the 20 MHz
saturation rate).
There is deliberately no paralysable inverse. m = n*exp(-n*tau) is not
injective — every measured rate below the maximum 1/(e*tau) corresponds to
two true rates, one below and one above 1/tau — so returning one of them
would be a fabrication dressed as a correction. Resolve the branch with an
independent measurement (e.g. an attenuator step) and invert it yourself.
measured_hz is a 1-D array of measured rates in counts per second;
dead_time_ns the dead time in nanoseconds (default 50, the same
placeholder :func:spad_deadtime_apply uses — replace it with the
datasheet value). Returns the corrected true rates as a float64 1-D array.
Raises ValueError: negative, non-finite or non-1-D measured_hz, a
non-positive dead_time_ns, and — instead of returning inf or a negative
rate — any measured rate at or above the saturation rate 1/tau, which no
non-paralysable detector can ever produce.
py -3.11 examples/photon_timeresolved.pycountrate を入力に取れる)spad)spad_deadtime_apply · tcspc_coates_correct
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.