counting op• Data kinds: image2d → table
• Call: import fullseye as fs; fs.ledger.photon_statistics(counts) (implementation को सीधे call करना हो तो import photoncount; photoncount.photon_statistics(counts), registry से लेना हो तो opsphoton.get("photon_statistics"))
photon-count frame के Poisson statistics: क्या यह सच में shot-noise limited है?
> नीचे का विस्तृत विवरण मूल text में है — सारांश और headings का अनुवाद हो चुका है।
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 family guide
• Sample data catalog (DL URL / license) — 2-D के लिए skimage.data (BSD/public) + synthetic, 3-D के लिए real data sources (Stanford/PDS आदि) के DL URL।
• Operators का स्रोत और संदर्भ — इस op family के मूल research/methods के स्रोत।
• Algorithm का मानक स्रोत (लेखक, वर्ष) और उपयोग ऊपर की family usage guide में दिए गए हैं।
• photon_timeresolved — py -3.11 examples/photon_timeresolved.py
table को input के रूप में लेते हैं)—
counting)photon_sample · photon_uncertainty
*Provenance: photoncount.py — PHOTON operator registry. यह per-op note tools/opdocs.py md से अपने-आप generate होता है (हाथ से edit न करें)।*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.