Centrality of the Fingerprint Core Location
Laurenz Ruzicka Bernhard Strobl Bernhard Kohn Clemens Heitzinger
Fingerprints have long been recognized as a unique and reliable means of
personal identification. Central to the analysis and enhancement of
fingerprints is the concept of the fingerprint core. Although the location of
the core is used in many applications, to the best of our knowledge, this study
is the first to investigate the empirical distribution of the core over a
large, combined dataset of rolled, as well as plain fingerprint recordings. We
identify and investigate the extent of incomplete rolling during the rolled
fingerprint acquisition and investigate the centrality of the core. After
correcting for the incomplete rolling, we find that the core deviates from the
fingerprint center by 5.7% $\pm$ 5.2% to 7.6% $\pm$ 6.9%, depending on the
finger. Additionally, we find that the assumption of normal distribution of the
core position of plain fingerprint recordings cannot be rejected, but for
rolled ones it can. Therefore, we use a multi-step process to find the
distribution of the rolled fingerprint recordings. The process consists of an
Anderson-Darling normality test, the Bayesian Information Criterion to reduce
the number of possible candidate distributions and finally a Generalized Monte
Carlo goodness-of-fit procedure to find the best fitting distribution. We find
the non-central Fischer distribution best describes the cores' horizontal
positions. Finally, we investigate the correlation between mean core position
offset and the NFIQ 2 score and find that the NFIQ 2 prefers rolled fingerprint
recordings where the core sits slightly below the fingerprint center.