Proof · how we test

Tested on signatures it has never seen.

We test nib v2.2 on public signature datasets, straight out of the box: no training on the test data, one policy for everyone. Results will be published once the dataset owners have agreed.

CEDAR

Latin 55 writers · sealed set

Hindi

Devanagari 160 writers · sealed set

Bengali

Bengali 100 writers · development set

RESULTS TO FOLLOW

01 · What we measure

What happens to a skilled forgery.

A skilled forgery is made by someone who studied the real signature. It is the hard case, and the one that matters in fraud, so it is what we measure first.

  • Skilled forgeries approved

    Of the forgeries made by someone who studied the real signature, how many the default policy would approve.

  • Equal error rate

    The point where false accepts and false rejects are equally likely. Lower is better.

  • Genuine signatures approved automatically

    How many real signatures go straight through, and how many are sent to a person.

02 · More references

Tested with few references, and with many.

For each writer we draw 3, 5 and 10 reference signatures at random, then check the rest. 10 is the most a check uses. Each run is repeated with 3 different draws.

  • references 3
  • references 5
  • references 10

03 · The honest part

We’d rather ask a person than wave a forgery through.

Nib is tuned to be strict. The default policy approves only from 0.95; anything less sure goes to a person. Nothing in FLAG or FAILED is approved without a person.

  • APPROVEfiled
  • FLAGto a person
  • FAILEDto a person

04 · How we test

Rules we hold ourselves to.

  • Out of the box

    No training on any benchmark signature. One default policy for every dataset, never tuned per set.

  • Sealed sets

    CEDAR and Hindi are sealed: we only ever see headline summaries, never individual results.

  • One dev set

    Bengali is our development set. We say so, so you can weigh its results accordingly.

  • Every run logged

    Each sealed run is recorded with its date and version. CEDAR’s flags were viewed once, before these rules existed.

Datasets

DatasetScriptWritersRole
CEDARLatin55sealed
BHSig260-HindiDevanagari160sealed
BHSig260-BengaliBengali100development

The fine print

nib v2.2 · default policy (default@1). Each run averages 3 random draws of reference signatures per writer. Definitions and limits are in the whitepaper.

Results will be published once the dataset owners have agreed.

Try it on your own signatures.