16 research outputs found
On the Generation of Synthetic Fingerprint Alterations
No full textIn this paper we propose some techniques to generate synthetic altered fingerprints and prove the utility of the generated datasets for developing, tuning and evaluating algorithms for altered fingerprint detection/matching. Due to the lack of public databases of altered fingerprints the generation tool proposed (and made freely available) can be a valid instrument to boost research on these challenging problems
Printed artificial sweat as replacement for natural fingermarks: Qualitative and quantitative approach considering an amino acid reagent.
No full textThe study presented in this paper aims at assessing how printed fingermarks can be used to generate realistic latent marks bearing varying quantities of materials to be detected. Considering dilution series of artificial sweat (eccrine secretion) and 1,2-indanedione/zinc as amino acid reagent, we assessed how printed marks behave in comparison to natural fingermarks provided by a set of 30 donors. The results were assessed in terms of relative intensity (contrast, luminescence) and expert grading (ridge details, overall quality). With regards to the set of 30 donors, this study brought a quantitative look to the influence of intra- and inter-variability on the relative intensity values observed when processing natural fingermarks. This provided new data to further understand the concept of "donorship". With regards to the use of printed marks, it has been illustrated how dilution series of a concentrated solution allows covering a range of cases: unnatural marks (intensity values well above those obtained with donors), rich marks (corresponding to fingermarks left by good donors), and faint marks (associated with the kind of results observed with poor donors). Such a range of detection performance offers the possibility to generate fine-tuned detection exercises of varying difficulty levels. Printed items made of artificial sweat could hence constitute a valuable alternative to natural secretions in the context of education and proficiency testing
Automatic assessment of fingermarks quality: Exploration of the possible application in the context of detection and comparison with human examiners
No full textIn forensic science, particularly in the context of latent fingermarks detection, forensic scientists are often faced with the need to assess the quality of the detected fingermarks to quantitatively interpret their results and express conclusions. Today this process is mainly carried out by human examiners referring to guidelines or provided quality scales. The largest the set of fingermarks (e.g., hundreds, thousands), the longest and the most labor-intensive this task becomes. Moreover, it is difficult to guarantee a fully objective process since the subjectivity of each individual is almost impossible to avoid, especially with regards to the interpretation of the quality scale levels or when facing fingermarks detected in an inhomogeneous manner. In this paper, the possibility of automatizing the quality assessment step is explored. The choice has been made to consider the use of quality assessment algorithms currently applied in an identification context. 150 natural fingermarks from ten donors were deposited on three different supports. These marks were detected using 1,2-indanedione/zinc or cyanoacrylate fumigation depending on the support. Then, their quality was assessed by five examiners, according to the UNIL scale, and by seven algorithms (i.e., Lights Out, Latent Fingerprint Image Quality 1 and 2, Latent Quality Metric, Expected Score Likelihood Ratio, NIST Fingerprint Image Quality, MINDTCT). Spearman and Pearson correlations were calculated, and the distribution of scores for each algorithm was charted (using boxplots) against the results provided by the human examiners. The most promising results were obtained with the LQM algorithm, more specifically with the fingermark clarity metric
Benchmarking of proficiency tests for the fingerprint field
No full textSince 2015, European fingerprint service providers carrying out laboratory activities must be EN ISO/IEC 17025 accredited. Consequently, relevant and reliable proficiency tests are required by those accredited forensic laboratories to regularly assess and certify their analytical capabilities. In this context, Work package #10 of the ENFSI-EU funded project named "Competency, Education, Research, Testing, Accreditation, and Innovation in Forensic Science" (Grant #101051099) aimed at proposing guidance to forensic laboratories for the selection of proficiency tests in the fields of fingermark visualization, imaging, and comparison/identification. In this paper, the methodology that has been set and followed is described, and the resulting guidance document presented. Additionally, a critical overview of the current market of commercial proficiency tests dedicated to the fingerprint field is proposed
Level 3 details and their role in fingerprint identification:A survey among practitioners
No full textLevel 3 details are used in fingerprint comparison by fingerprint examiners to reach a conclusion as to the identity of a person from a latent impression recovered from a crime scene. Level 3 details are usually used in a holistic way, mainly by members of the fingerprint community who are not subjected to a numerical standard rule. Although the term Level 3 detail is well known, a survey performed by the authors suggests that there is no clear consensus on the classification, reproducibility, and individual value of Level 3 details.</p
Investigation of the reproducibility of third-level characteristics
No full textThe process of comparing a fingermark recovered from crime scene with the fingerprint taken from a known individual involves the characterization and comparison of different ridge details on both the mark and the print. Fingerprint examiners commonly classify these characteristics into three different groups, depending on their level of discriminating power. It is commonly considered that the general pattern of the ridge f low constitutes first-level detail, specific ridge f low and minutiae (e.g., ending ridges, bifurcations) constitutes second-level detail, and fine ridge details (e.g., pore positions and shapes) are described as third-level detail. In this study, the reproducibility of a selection of third-level chacteristics is investigated. The reproducibility of these features is examined on several recordings of a same finger, first acquired using only optical visualization techniques and second on impressions developed using common fingermark development techniques. Prior to the evaluation of the reproducibility of the considered characteristics, digital images of the fingerprints were recorded at two different resolutions (1000 and 2000 ppi). This allowed the study to also examine the inf luence of higher resolution on the considered characteristics. It was observed that the increase in the resolution did not result in better feature detection or comparison between images. The examination of the reproducibility of a selection of third-level characteristics showed that the most reproducible features observed were minutiae shapes and pore positions along the ridges.</p
