DOI: 10.5281/zenodo.1195799
title: Trigraphslant - Benchmark Set For Writer Identification - Writers Were Asked To Write In Unnatural Slant

description: <br>
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*                                                                             *<br>
*                                                                             *<br>
*   This is the TrigraphSlant (Img version) Distribution, release 18/3/2011   *                                 *<br>
*                                                                             *<br>
*   This distribution contains 188 images of scanned handwritten text,        *<br>
*   scanned at resolution 300dpi Canon LiDE 25, grey scale,                   *<br>
*   by 47 Dutch writers, four pages per writer, from four                     *<br>
*   writing conditions, one condition per page. The conditions are:           *<br>
*   1. [AN] Copy text A in your natural handwriting.                          *<br>
*   2. [BN] Copy text B in your natural handwriting.                          *<br>
*   3. [BL] Copy text B and slant your handwriting to the                     *<br>
*           left as much as possible.                                         *<br>
*   4. [BR] Copy text B and slant your handwriting to the                     *<br>
*           right as much as possible.                                        *<br>
*   The codes AN, BN, BL and BR refer to subsets into which the collected     *<br>
*   pages of the writers were subdivided. AN represents a collection of       *<br>
*   authentic documents; BN, BL and BR can be seen as collections of          *<br>
*   questioned documents. To avoid structural effects of fatigue, the order   *<br>
*   of item 3 and 4 was randomized at each collection: half of the subjects   *<br>
*   wrote the BR page before the BL page. The data were collected at three    *<br>
*   sites, in three cities: The Hague: NFI (N...), Donders Institute for      *<br>
*   Brain, Cognition and Behaviour, Radboud University Nijmegen (D...)        *<br>
*   and the Artificial Intelligence Dept. of University of Groningen (R...)   *<br>
*                                                                             *<br>
*   Copyright The International Unipen Foundation, 2010, All rights reserved  *<br>
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*     DATA.                                                                   *<br>
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*  4) THE USER SHOULD REFER TO THE FOLLOWING ARTICLE ON THIS DATA SET:        *<br>
*                                                                             *<br>
* A.A. Brink, R.M.J. Niels, R.A. van Batenburg, C.E. van den Heuvel,          *<br>
* L.R.B. Schomaker, Towards robust writer verification by correcting          *<br>
* unnatural slant, Pattern Recognition Letters, Volume 32, Issue 3,           *<br>
* 1 February 2011, Pages 449-457, ISSN 0167-8655,                             *<br>
* DOI: 10.1016/j.patrec.2010.10.010.                                          *<br>
*                                                                             *<br>
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*  RESEARCHERS TO HTTP://UNIPEN.ORG FOR OBTAINING THEIR OWN COPY.             *<br>
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Abstract<br>
 <br>
Towards robust writer verification by correcting unnatural slant<br>
 <br>
A.A. Brink, , R.M.J. Niels, R.A. van Batenburg, C.E. van den Heuvel,   <br>
and L.R.B. Schomaker,  <br>
 <br>
a Institute of Artificial Intelligence and Cognitive Engineering (ALICE),  <br>
  University of Groningen, P.O. Box 407, 9700 AK Groningen, The Netherlands<br>
   <br>
b Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen,  <br>
  P.O. Box 9104, 6500 HE Nijmegen, The Netherlands<br>
   <br>
c Netherlands Forensic Institute, P.O. Box 24044, 2490 AA Den Haag, The Netherlands<br>
 <br>
Received 11 September 2009.  Available online 30 October 2010.<br>
 <br>
Slant is a salient feature of Western handwriting and it is considered to be an<br>
important writer-specific feature. In disguised handwriting however, slant is<br>
often modified. It was tested whether slant is indeed an important factor and it<br>
was tested whether the distorting effect of deliberate slant change can be<br>
countered by a simple shear transform. This was done in two off-line writer<br>
verification experiments in image processing conditions of slant elimination and<br>
slant correction. The experiments were performed using three features based on<br>
statistical pattern recognition, including the state-of-the-art features<br>
Fraglets and Hinge. A new public dataset was created and used, containing<br>
natural and slanted handwriting by 47 writers. A striking result is that the<br>
average natural slant value is much less important for biometric systems than is<br>
usually assumed: eliminating slant yields just a 1-5% performance loss. A<br>
second result is that the effects of deliberate slant change cannot be fully<br>
countered by a simple shear transform: it raises performance on the distorted<br>
handwriting from 53-68% to 64-90%, but this is still lower than normal<br>
operation on natural handwriting: 97-100%.<br>
 <br>
Research highlights<br>
- The value of slant as a writer identification feature has been overrated.  <br>
- Deliberate slant change can be partly countered by the shear transform.  <br>
- Deliberate slant change introduces non-affine distortions to the handwriting.  <br>
- A new dataset of deliberately slanted handwriting was introduced.<br>
 <br>
Keywords: Handwriting biometrics; Writer verification; Slant; Disguise; Statistical<br>
pattern recognition
description: {"references": ["A.A. Brink, R.M.J. Niels, R.A. van Batenburg, C.E. van den Heuvel,   L.R.B. Schomaker, Towards robust writer verification by correcting   unnatural slant, Pattern Recognition Letters, Volume 32, Issue 3,  1 February 2011, Pages 449-457, ISSN 0167-8655,  DOI: 10.1016/j.patrec.2010.10.010."]}