NakedSignal OS

Site fit

Check whether a certificate's evidence covers the scanner you would actually run it on.

How site fit works

A site fingerprint is 38 physics features measured from a site’s own images — noise, sharpness, response, contrast, SNR, quantisation and geometry — each one a median with a distribution-free 95% interval around it. There is no model on that path and no labels: it is a feature vector, an ascending sort, four order statistics and one square root. It is produced by variation/fingerprint.py, run on the site’s own machine, and this page takes the resulting JSON.

An acquisition envelope is the band each of those 38 features occupied across the acquisition conditions the certificate’s evidence covers. This one is axial -> coronal— the span of two reconstruction planes’ central tendency, graded PAIRED_CLASS. It is signed inside the certificate, so it cannot be edited without breaking the signature.

The comparison is interval against interval, not point against interval: your 95% interval must sit inside the band, and a parameter whose interval straddles a boundary is reported as not placed at this sample size rather than guessed at. Outside the band there is a grace margin of edge_tolerance × (ci_high − ci_low) — 0.25 here, read off the envelope rather than chosen by this page, because a tolerance the gated party could pick would make the gate negotiable after the fact.

And within is the absence of every other state, never a count of the features inside the band. S6.2's structural finding: a condition that DEFINES a band endpoint cannot reliably certify as `inside` against it. Held-out sagittal reads inside on 22 of 38 against the envelope fitted on axial and sagittal, while coronal — which that envelope does NOT cover — reads 29. A gate that scored coverage by counting `inside` would rank the uncovered condition above the covered one. So `within` is the ABSENCE of every other state, and it means `nothing here places this site outside the conditions the evidence covers` rather than `this site is certified covered`. Your browser ran the operator; nothing was uploaded, and there is no server behind this page to upload to.

Synthetic variation

1 · Your site

A site fingerprint is 38 physics features measured from the site’s own images — a median and a distribution-free 95% interval for each, with no model and no labels anywhere on the path. Nothing you drop here leaves this tab.

Constructed — not measurements of anywhere
2 · The certificate

The acquisition envelope inside a signed certificate: the band of physical acquisition conditions the evidence was measured under. Not the same thing as the request envelope on Deployment gate, which is a deployment context.