Testing the reliability of hands and ears as biometrics: the importance of viewpoint.

Sarah V Stevenage,Sue M Black,Greg J Neil,Catherine Walpole

doi:10.1007/s00426-014-0625-x

Sarah V Stevenage, Sue M Black + Show 2 more

Open Access

https://doi.org/10.1007/s00426-014-0625-x

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Abstract

Two experiments are presented to explore the limits when matching a sample to a suspect utilising the hand as a novel biometric. The results of Experiment 1 revealed that novice participants were able to match hands at above-chance levels as viewpoint changed. Notably, a moderate change in viewpoint had no notable effect, but a more substantial change in viewpoint affected performance significantly. Importantly, the impact of viewpoint when matching hands was smaller than that when matching ears in a control condition. This was consistent with the suggestion that the flexibility of the hand may have minimised the negative impact of a sub-optimal view. The results of Experiment 2 confirmed that training via a 10-min expert video was sufficient to reduce the impact of viewpoint in the most difficult case but not to remove it entirely. The implications of these results were discussed in terms of the theoretical importance of function when considering the canonical view and in terms of the applied value of the hand as a reliable biometric across viewing conditions.Electronic supplementary materialThe online version of this article (doi:10.1007/s00426-014-0625-x) contains supplementary material, which is available to authorized users.

Highlights

Whilst criminals have learned to hide their face, or disguise their voice, their hands may provide an Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.S
The results of Experiment 2 confirmed that training via a 10-min expert video was sufficient to reduce the impact of viewpoint in the most difficult case but not to remove it entirely. The implications of these results were discussed in terms of the theoretical importance of function when considering the canonical view and in terms of the applied value of the hand as a reliable biometric across viewing conditions
The visibility and identification of unique cues within the hand, such as vein patterns and skin features (Black, Mallett, Rynn & Duffield, 2009; Black, MacDonald-McMillan & Mallett, 2013; Black, MacDonald-McMillan, Rynn & Jackson, 2013; Jackson & Black, 2013), have been sufficient to support a number of recent criminal convictions

Summary

Introduction

Whilst criminals have learned to hide their face, or disguise their voice, their hands may provide an Electronic supplementary material The online version of this article (doi:10.1007/s00426-014-0625-x) contains supplementary material, which is available to authorized users. The purpose of the present paper is to investigate the limits of the hand as a biometric cue through exploring the ability of viewers to match images as viewpoint changes. Key in this enquiry is the concept of the ‘canonical view’. It may be predicted that hands may not have as strong a preference for a single canonical view, and may survive presentation across a range of views, compared to a more rigid object To test this prediction, the processing of hand images was compared here to the processing of ear images. The present study is grounded in the predictions of canonicality across rigid and non-rigid cues, but provides an important test of the limits of the hand as a forensic biometric

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