calibration op• Data kinds: signal → table
• Call: import fullseye as fs; fs.ledger.null_distribution(values) (to call the implementation directly, import imgforensics; imgforensics.null_distribution(values); from the registry, opsimgforensics.get("null_distribution"))
Summarise the null distribution of the evidence statistic from samples known to be untampered.
This family consistently returns no verdicts. That is correct, but as it stands the user is handed a number like PCE 1832 and has no means of interpreting it. Yet bundling a threshold would be a lie ―― the separation point moves with the number of images, resolution, compression ratio and subject, so it is not a value that can be fixed at shipping time.
Hence the distribution is measured from the user's own clean data. What is bundled is not "a threshold" but "how to measure a threshold", and that stays correct even when the conditions change.
values : array_like
Evidence quantities measured on pairs known to be untampered (hash_distance or
fingerprint_correlate()["pce"] etc.). Collect them under the same conditions.
dict
n / mean / std / min / max / quantiles
(5, 25, 50, 75, 95, 99th percentiles). With few samples the tails cannot be measured,
so n < 20 is reported in caveats (no silent extrapolation).
• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).
• Operator provenance and references — the sources of the research/methods this op family came from.
• The canonical algorithm (author, year) and its uses are named in the family usage guide above.
• image_forensics_audit — py -3.11 examples/image_forensics_audit.py
• poc_prnu_camera_fingerprint — py -3.11 examples/poc_prnu_camera_fingerprint.py
table as input)calibration)*Provenance: imgforensics.py — IMGFORENSICS operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.