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Measuring what latent fingerprint examiners consider sufficient information for individualization determinations.

Ulery BT, Hicklin RA, Roberts MA, Buscaglia J - PLoS ONE (2014)

Bottom Line: Latent print examiners use their expertise to determine whether the information present in a comparison of two fingerprints (or palmprints) is sufficient to conclude that the prints were from the same source (individualization).Examiners' counts of corresponding minutiae were strongly associated with their own determinations; however, due to substantial variation of both annotations and determinations among examiners, one examiner's annotation and determination on a given comparison is a relatively weak predictor of whether another examiner would individualize.The extensive variability in annotations also means that we must treat any individual examiner's minutia counts as interpretations of the (unknowable) information content of the prints: saying "the prints had N corresponding minutiae marked" is not the same as "the prints had N corresponding minutiae." More consistency in annotations, which could be achieved through standardization and training, should lead to process improvements and provide greater transparency in casework.

View Article: PubMed Central - PubMed

Affiliation: Noblis, Falls Church, Virginia, United States of America.

ABSTRACT
Latent print examiners use their expertise to determine whether the information present in a comparison of two fingerprints (or palmprints) is sufficient to conclude that the prints were from the same source (individualization). When fingerprint evidence is presented in court, it is the examiner's determination--not an objective metric--that is presented. This study was designed to ascertain the factors that explain examiners' determinations of sufficiency for individualization. Volunteer latent print examiners (n = 170) were each assigned 22 pairs of latent and exemplar prints for examination, and annotated features, correspondence of features, and clarity. The 320 image pairs were selected specifically to control clarity and quantity of features. The predominant factor differentiating annotations associated with individualization and inconclusive determinations is the count of corresponding minutiae; other factors such as clarity provided minimal additional discriminative value. Examiners' counts of corresponding minutiae were strongly associated with their own determinations; however, due to substantial variation of both annotations and determinations among examiners, one examiner's annotation and determination on a given comparison is a relatively weak predictor of whether another examiner would individualize. The extensive variability in annotations also means that we must treat any individual examiner's minutia counts as interpretations of the (unknowable) information content of the prints: saying "the prints had N corresponding minutiae marked" is not the same as "the prints had N corresponding minutiae." More consistency in annotations, which could be achieved through standardization and training, should lead to process improvements and provide greater transparency in casework.

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Example annotation of a mated image pair.Corresponding features are indicated here in red, unassociated features in yellow, and debatable correspondences with question marks. This examiner marked 8 corresponding minutiae, 2 debatable correspondences, individualized, and assessed it as very difficult. Determinations by the 9 examiners assigned this image pair: 5 NV, 4 VID (1 changed to NV during Comparison); 1 inconclusive, 2 individualization.
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pone-0110179-g002: Example annotation of a mated image pair.Corresponding features are indicated here in red, unassociated features in yellow, and debatable correspondences with question marks. This examiner marked 8 corresponding minutiae, 2 debatable correspondences, individualized, and assessed it as very difficult. Determinations by the 9 examiners assigned this image pair: 5 NV, 4 VID (1 changed to NV during Comparison); 1 inconclusive, 2 individualization.

Mentions: The software application used for our experiment is a variant of the FBI's Universal Latent Workstation's Comparison Tool [45]. It included tools for annotating the fingerprints, simple image processing, and recording the examiners' determinations. Fingerprint annotations complied with the ANSI/NIST-ITL 1-2011 standard [22] (using Extended Feature Set features); the test instructions were derived in part from [23]. In the Analysis phase, the examiners provided the following annotations pertaining to the latent: local clarity map (produced by “painting” the images using six colors denoting defined levels of clarity [46], [22]); locations of features; types of features (minutiae, cores, deltas, and “other” points (nonminutia features such as incipient ridges, ridge edge features, or pores)); and value determination (VID, VEO, or NV). If the latent print was determined to be VEO or VID, the examiner provided the following annotations during the Comparison/Evaluation phase (Figure 2): latent and exemplar clarity; latent and exemplar features, as well as correspondences (definitive and debatable) and discrepancies; latent and exemplar value determinations; comparison determination (individualization, exclusion, or inconclusive); and comparison difficulty (very easy/obvious, easy, moderate, difficult, very difficult).


Measuring what latent fingerprint examiners consider sufficient information for individualization determinations.

Ulery BT, Hicklin RA, Roberts MA, Buscaglia J - PLoS ONE (2014)

Example annotation of a mated image pair.Corresponding features are indicated here in red, unassociated features in yellow, and debatable correspondences with question marks. This examiner marked 8 corresponding minutiae, 2 debatable correspondences, individualized, and assessed it as very difficult. Determinations by the 9 examiners assigned this image pair: 5 NV, 4 VID (1 changed to NV during Comparison); 1 inconclusive, 2 individualization.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4221158&req=5

pone-0110179-g002: Example annotation of a mated image pair.Corresponding features are indicated here in red, unassociated features in yellow, and debatable correspondences with question marks. This examiner marked 8 corresponding minutiae, 2 debatable correspondences, individualized, and assessed it as very difficult. Determinations by the 9 examiners assigned this image pair: 5 NV, 4 VID (1 changed to NV during Comparison); 1 inconclusive, 2 individualization.
Mentions: The software application used for our experiment is a variant of the FBI's Universal Latent Workstation's Comparison Tool [45]. It included tools for annotating the fingerprints, simple image processing, and recording the examiners' determinations. Fingerprint annotations complied with the ANSI/NIST-ITL 1-2011 standard [22] (using Extended Feature Set features); the test instructions were derived in part from [23]. In the Analysis phase, the examiners provided the following annotations pertaining to the latent: local clarity map (produced by “painting” the images using six colors denoting defined levels of clarity [46], [22]); locations of features; types of features (minutiae, cores, deltas, and “other” points (nonminutia features such as incipient ridges, ridge edge features, or pores)); and value determination (VID, VEO, or NV). If the latent print was determined to be VEO or VID, the examiner provided the following annotations during the Comparison/Evaluation phase (Figure 2): latent and exemplar clarity; latent and exemplar features, as well as correspondences (definitive and debatable) and discrepancies; latent and exemplar value determinations; comparison determination (individualization, exclusion, or inconclusive); and comparison difficulty (very easy/obvious, easy, moderate, difficult, very difficult).

Bottom Line: Latent print examiners use their expertise to determine whether the information present in a comparison of two fingerprints (or palmprints) is sufficient to conclude that the prints were from the same source (individualization).Examiners' counts of corresponding minutiae were strongly associated with their own determinations; however, due to substantial variation of both annotations and determinations among examiners, one examiner's annotation and determination on a given comparison is a relatively weak predictor of whether another examiner would individualize.The extensive variability in annotations also means that we must treat any individual examiner's minutia counts as interpretations of the (unknowable) information content of the prints: saying "the prints had N corresponding minutiae marked" is not the same as "the prints had N corresponding minutiae." More consistency in annotations, which could be achieved through standardization and training, should lead to process improvements and provide greater transparency in casework.

View Article: PubMed Central - PubMed

Affiliation: Noblis, Falls Church, Virginia, United States of America.

ABSTRACT
Latent print examiners use their expertise to determine whether the information present in a comparison of two fingerprints (or palmprints) is sufficient to conclude that the prints were from the same source (individualization). When fingerprint evidence is presented in court, it is the examiner's determination--not an objective metric--that is presented. This study was designed to ascertain the factors that explain examiners' determinations of sufficiency for individualization. Volunteer latent print examiners (n = 170) were each assigned 22 pairs of latent and exemplar prints for examination, and annotated features, correspondence of features, and clarity. The 320 image pairs were selected specifically to control clarity and quantity of features. The predominant factor differentiating annotations associated with individualization and inconclusive determinations is the count of corresponding minutiae; other factors such as clarity provided minimal additional discriminative value. Examiners' counts of corresponding minutiae were strongly associated with their own determinations; however, due to substantial variation of both annotations and determinations among examiners, one examiner's annotation and determination on a given comparison is a relatively weak predictor of whether another examiner would individualize. The extensive variability in annotations also means that we must treat any individual examiner's minutia counts as interpretations of the (unknowable) information content of the prints: saying "the prints had N corresponding minutiae marked" is not the same as "the prints had N corresponding minutiae." More consistency in annotations, which could be achieved through standardization and training, should lead to process improvements and provide greater transparency in casework.

Show MeSH