Biometrics

Can I access pen events from the Signature SDK?

The Signature SDK is a high-level SDK which does not provide access to individual pen events - it is designed to provide a standardised signature capture window and return the entire signature in the form of an image (or a text string or binary array representing the image).

If you need direct access to pen events you will need to use the STU SDK or Wintab interface.

Please see also Capture biometric data such as pressure and timing.

Capture biometric data such as pressure and timing

STU SDK - Windows and Linux

Using our low-level STU SDK you can capture pen data directly from the signature pad.
For all our pads this includes x and y co-ordinates plus pressure and timing information.
With our latest pads there is also a sequence number and a date/time stamp.

Signature SDK (Signature Library) - Windows, iOS and Android

Using our Signature SDK you can encode the biometric data of the captured signature within the signature image - we provide samples illustrating how to do this.
The full version of the Signature SDK (known simply as the "Signature Library") allows the export of the biometric information in one of the following two standard ISO formats:

  • ISO 19785 - XML
  • ISO 19794-7 - binary data

Please note that the full Signature Library is a fee-paid product - for details of costs please contact your regional Wacom Business Development Manager.
If you are using the "Lite" version of the SDK the only way to access the biometric data is to transfer the signature into one of our analysis tools (see below) for examination.

DTU Tablets

If you are using DTU tablets to capture signatures you can access the biometric data using the Signature Library as explained above.
Alternatively you can use the Wintab API (supplied with the tablet driver) to access the pen data in real time, i.e. as it is being generated by the tablet.
Further information on Wintab is available from the Wacom Device Kit sections.

iOS Devices

Using our Signature SDK for iOS you can encode biometric data captured with one of our Bluetooth Styluses within the signature image - we provide both objective C and Swift examples of how to achieve this.
For lower level access or to construct your own format of biometric data it would be feasible to use our Bluetooth Stylus SDK in combination with the UITouch framework to construct data, however use of the Signature SDK on this platform is the recommended approach.

ANALYSIS TOOLS

GSV (General Signature Verification) SDK

This tool allows you build up a template of six signatures or more against which future signatures are to be compared. A new candidate signature is compared against the six existing ones and a score is given indicating its compatibility.

Signatures can be captured dynamically from a pad or imported from an existing file; FSS files can be dragged and dropped onto the sample app.
The GSV supersedes the SSV and DSV mentioned below, although both are still available if needed.
For more information please see Github  

SSV (Static Signature Verification) SDK

The SSV is designed to compare two signatures images scanned from paper originals. Scanned signatures can also be compared against dynamic signature data captured using the Signature SDKs.
 

DSV (Dynamic Signature Verification) SDK

This tool allows you to compare the biometric data of two signatures and gives a score indicating how similar they are where a value of 1 is a complete match.
Signatures can be captured dynamically from a pad, opened from an existing file or copy/pasted from sign pro PDF or our Signature SDK.
 

SignatureScope

This comprehensive analysis tool allows you to examine in detail the biometric data of a signature which has been captured using either sign pro PDF or one of our Signature SDKs.
Two versions are available - the demo version is available on request and enables a signature to be analysed which is captured directly from the user; it does not allow signatures to be opened from other sources such as a file or the clipboard.

The full (FDE) version of SignatureScope allows the user to analyse in detail a signature from any of the following sources:

  1. Dynamic input by the user
  2. A file created by our Signature SDK
  3. Copy/pasting from sign pro PDF or the Signature SDK.

Please note that this full version is only issued to qualified Forensic Document Examiners (FDEs) after signing of a non-disclosure agreement.

Save signature biometric data for later validation or analysis

  1. Using sign pro PDF the biometric data is automatically incorporated within the signature and can be copy/pasted into any of our analysis tools.
     

  2. With our Signature SDK you must use the RenderEncodeData option with RenderBitMap when saving the signature as an image.
    (For more information please see section 3.1.2.6 of the Signature SDK components reference manual).
    The image file can subsequently be opened and examined from Signature Scope or from our DSV SDK.
     

  3. With our STU SDK you can save the biometric data in your own chosen format but you are limited to our STU range of signature pads.
    In addition the signatures cannot be examined with our analysis tools because they use a proprietary format for the biometric data which we cannot disclose.

Signature data format

The Signature SDK generates the signature data in a proprietary Wacom format which we do not disclose, partly in order to prevent forgery.
If you want to capture the biometric data within the signature image this can be done by encoding that data in the signature image using the RenderEncodeData flag.

There are sample programs showing how to do this, e.g. CaptureImage.js in the JScript folder of the Signature SDK samples on GitHub.

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