The Assessment of Fingerprint Quality for a More Effective Match Score in Minutiae-Based Matching Performers

One of the most common types of evidence recovered from a crime scene are latent fingerprints, however these impressions are often of low quality. The quality of a latent fingerprint is described as the degree to which the ridge details can be observed. If the quality of the latent fingerprint is very clear, a minutiae-based matching algorithm with automatic extraction may detect and utilize the minutiae that are truly present in the fingerprint. However, if the impression is of poor quality, the minutiae-based matching algorithm\u27s automatic extraction may detect fewer features and could completely miss features resulting in the return of an unrelated candidate. The aim of this research was to determine a method to improve the match score of latent fingerprints by removing the bad quality regions, where both a subjective and objective methods were utilized. The subjective method utilized the predetermined quality categories of good, bad or ugly to assign a latent fingerprint. After classification, each impression was processed by AdobeRTM PhotoshopRTM and four quality areas were serially removed. In the objective method, each latent fingerprint was assessed with NFIQ algorithm and then MINDTCT algorithm. The MINDTCT algorithm provided a quality map that was used to remove successive portions of each latent fingerprint. The resulting new images from both methods were compared to a database using the two different minutiae-based matching algorithms: AFIX TrackerRTM and BOZORTH3.;The results were examined utilizing the statistical methods of receiver operator characteristic (ROC) curves, area under the ROC curve (AUC), cumulative match characteristic (CMC) curve, Wilcoxon signed-rank test, Spearman\u27s rank correlation and the comparison of the removal methods. ROC curves and the resulting AUC were able to determine that the AFIX TrackerRTM program is a reliable performer with high AUC values, while the BOZORTH3 minutiae-based algorithm did not perform well with low AUC scores of around 0.5. The results produced from the CMC curves showed that the subjective method produced higher rank 1 and top 10 rank identification than the objective method, contrary to what was hypothesized. The correlation scores showed the manual and automatic extraction were weakly correlated to one another. However, a very weak to no correlation between the algorithms of the BOZORTH3 and AFIX Tracker R was observed. The comparison between the subjective and objective methods of removal showed the examiner allowed for a more conservative removal of the fingerprint than the objective method. With this result in connection with the CMC curve results shows that being more conservative produces higher rank 1 and top ten rank identification scores

Quantifying the Reliability of Latent Fingerprint Matching via Signal Detection Theory

The definition of standards in fingerprint identification is currently an issue of discussion in the field. Quantitative standards have been used in the past to provide justifications for conclusions; however, a scientific basis for relying on numerical standards alone currently does not exist. The tradeoff for this combined approach is that conclusions are based on a conclusion that is left to the judgment of the examiner and may not be repeatable. To test the implementation of thresholds for conclusion, this research studied the effects of only considering concrete data in quantitative form. In this case, signal detection theory is applied to latent fingerprint matching by using automated fingerprint identification systems from two different program vendors. By searching a test set of fingerprints multiple times with a wide range of detail entered, values for the number of system-matched minutiae and computed match scores can be studied to determine threshold limits based on the amount of the search returns. This in turn allows for the generation of receiver operating characteristic curves that directly measure the reliability of the system. The results show that the ability of the system to distinguish matches and non-matches properly is partly based on the method by which the searches are evaluated. Furthermore, the searched area of the fingerprint and the size of the database play roles in determining how well the system is able to discriminate between states. Through future comparison against results submitted by latent fingerprint examiners, inferences can be drawn as to the reliability of conclusions based on varying levels of available detail

Preliminary Study on the Reliability of AFIX Tracker for Lip Print Examination

Lip prints have been proposed as a type of impression evidence with similar issues as fingerprints, but with greater scrutiny by the forensic community due to a lack of history in using this type of impression as evidence. A survey of 11 questions about lip print examination was sent to 63 members of the Chesapeake Bay Division of the International Association for Identification (CBD-IAI) to gather opinions from active forensic scientists in determining an appropriate direction for this study. The responses were presented at the spring CBD-IAI 2009 conference to generate more discussion and to achieve greater awareness. A method including glass slides, magnetic black powder with photography and tape lifting resulted. Phase I focused on intervariability with the collection of 300 impressions from 100 individuals. Phase II focused on intravariability. The 49 best donors from Phase I were selected for the collection of 6 lip prints on 5 different dates throughout 2 different seasons, fall and winter. In total, 1770 lip prints were collected in this study. In addition to promoting awareness for lip prints, the purpose of this study was to test the reliability of AFIX Tracker, a minutiae based system, for lip print individualization. Reproducible rules of mark-up were established for lip prints based on the author\u27s classification systems, frequency analyses, and experience with AFIX Tracker for fingerprint examination. Preliminary analysis resulted in the detection of 4 potentially useful minutiae , or unique identifying characteristics: bifurcations, diamonds, triangles, and middle horizontals. Each minutiae Type was tested via AFIX Tracker by the analysis of 10 individuals from Phase I. Focus was placed on the number of matched minutiae and match score corresponding to where False Positives (Type I errors) decrease and where False Negatives (Type II errors) increase. As a preliminary study, it cannot be said if all individuals produced different lip prints. In addition, the author cannot say if changes did or did not occur in lip print patterns with change in time. Future analysis will involve a more thorough approach to these issues

AFIS Based Likelihood Ratios for Latent Fingerprint Comparisons

Latent fingerprints are one of the most common pieces of evidence found on a crime scene and represent accidental or unintentional prints collected as part of a criminal investigation. They are caused when the friction ridge skin comes in contact with a surface, and thus requires the use of chemical processing to be visualized with the naked eye. The comparison and identification of fingerprints depends on various factors such as the substrate quality, surface, duration, environmental factors and examiner experience. These factors can result in reduced clarity or content, and can even cause distortions as compared to a fingerprint taken under controlled conditions. Since the release of the National Academy of Sciences (NAS) report in 2009, the field of fingerprint analysis has come under much scrutiny. Specifically, the need for more research into the determination of the accuracy and reliability of the identifications made by fingerprint examiners has been raised.;One such method used for the comparison of latent fingerprint to known prints is through an Automated Fingerprint Identification System (AFIS). The AFIS used in this research was the AFIX Tracker R where where variables were assessed: match score, match minutiae, match status, delta match score and marked minutiae, to determine which variable(s) was a better indicator of a true match. Bayesian networks were then constructed to compute the likelihood ratios to evaluate the dependency of the variables on one another,where the performance of the likelihood ratios in determining the identity of the unknown latent was assessed using Tippett and ECE plots. Receiver Operating Characteristic (ROC) curves and Bayesian networks were constructed to perform statistical analysis of the matches obtained while comparing a latent print to a ten-print card. A combination of Tippett and Empirical Cross Entropy (ECE) plots were used to assess the performance of the AFIX Tracker R in classifying unknown prints. It was observed that a match minutiae of 15 or higher resulted in a 100% true match result whereas for the non-matches,no more than 13 match minutiae were found. Moreover, the delta match scores difference between the matches and non-matches were notable (delta score of 0.1-153 for matches compared to a score of 0-0.1 for the non-matches). Overall, it was determined that approximately 87% of the time a randomly selected known match would have a higher number of match minutiae as compared to a non-match

Differences In Latent Fingerprints of Caucasian Children

It is already known that the latent fingerprints of adults and the latent fingerprints of prepubescent children are different from each other in chemical makeup. This study compares the latent fingerprints of prepubescent children to each other—specifically attempting to determine if there are any noticeable differences between the latent prints of Caucasian male and female children using the processing methods of ninhydrin and indane dione. The latent fingerprints included in the study were processed and graded. Two independent t-tests as well as a factorial ANOVA were performed on the acquired data. It was found that there is not a significant difference between the fingerprints of the males and the females with either method. As well, no significant difference was found between the two processing methods. Thus, according to this study, a latent fingerprint of a Caucasian prepubescent child, regardless of gender, should develop equally well with ninhydrin or indane dione

A Comprehensive Study of the Effects of Chemotherapy on Friction Ridge Detail

Past research and case studies have shown that chemotherapy drugs appear to lessen the quality of friction ridge skin, thereby impacting cancer patients who are already experiencing a number of unpleasant side effects. Palmar-plantar erythrodysaesthesia, more commonly referred to as Hand-Foot Syndrome (HFS), is a common side effect of many chemotherapy agents and includes redness, swelling, and peeling of the skin of the hands and feet. This syndrome has been linked to a number of cases involving fingerprint loss, including a prior longitudinal study that evidenced degradation in response to capecitabine, a common chemotherapy agent. This research builds upon the prior study by assessing the effects of taxane class drugs and doxorubicin on the fingerprints. Impressions were collected from seven patients, five of which were prescribed taxane class drugs, and two of which were administered doxorubicin. Data was collected prior to treatment and at the three-month mark, which represents the halfway point of the general six-month administration cycle. Impressions were inputted into AFIX Tracker software to determine the number of minutiae points by way of the Smart-Extract feature. The data suggests no definitive decrease between taxane class drugs and the quality of the impressions. A singular patient who had been prescribed doxorubicin, however, experienced quality decrease, and may have been affiliated with HFS. No other significant HFS was discovered with any of the patients, which further certifies the link between HFS and ridge degradation

Analyzing Palm Print Shapes with Pressure and Distortion

While much research exists on latent fingerprints, there is a lack of research on palm prints. This study aims to discover how the variable of pressure affects the distortion of latent palm prints recovered from a crime scene. This study used various development techniques to extract prints from aluminum Coca-Cola cans, white copy paper, and household steak knives. The collected prints were scanned into the AFIX Tracker system and an auto-extract number, based on the number of minutiae points, was generated automatically from the system. These auto-extract numbers were then compared to a baseline, which consisted of an average of 400 perfectly rolled unknown palm prints. There was a significantly lower number of minutiae points from the partial prints that were lifted than the average of the 400 that were perfectly rolled. The analysis of the collected data revealed that, for the most part, when a medium amount of pressure is applied to an object, it yields a higher auto-extract number than when a low or high amount of pressure is applied

Capecitabine Induced Hand and Foot Syndrome and the Reproducibility of Friction Skin

In 2008, a 62 year old male was detained by United States Customs and Immigration officials when attempting to enter the United States because his fingerprints were not detectable. It was later reported by his medical doctor in Singapore that the individual suffered from Hand and Foot Syndrome (palmar-plantar erythrodysaesthesia) as a result of his cancer treatment of capecitabine (N4-pentyloxycarbonyl-5-deoxy-5- fluorocytidine) which causes interruptions to the normal growth of keratinocytes in the friction skin. Capecitabine is a recently developed, orally administered fluoropyrimidine prodrug designed to generate 5-fluorouracil through a three-step enzymatic process giving it antineoplastic properties to combat cancerous tumor growth in a number of different cancers, including adjuvant colon cancer, metastatic colorectal cancer, and metastatic breast cancer. This study consisted of a 253-day evaluation of the physiological effects to the friction ridge skin from an individual undergoing capecitabine chemotherapy treatment. The results indicate the quality of the friction ridge skin impressions decreased by 32% and to a degree which may impair the ability to positively identify individuals using friction skin impressions alone while undergoing this type of treatment and experiencing hand and foot syndrome. Following cessation of capecitabine treatment, normal growth of keratinocytes resumed returning the skin to a normal state with no indication of damage thus demonstrating the persistency of the friction ridge skin despite the temporary toxicity of capecitabine

Evidence Utility in Forensic Intelligence Models

Forensic intelligence is the accurate, timely, and useful product of logically processing forensic case data for investigation and/or intelligence purposes. The most important facet of any investigation is the decision making process due to significant influence and direction of the downstream investigation. Wrong decisions can lead to an unsolved case or implication of an innocent individual. Accurate decision making can be reinforced by linkages or relationships uncovered within a case. Analysis of evidence can also create a link between cases leading to more effective case closure. Application of forensic intelligence seeks to rectify this problem; more open and fluid communication across all law enforcement agencies will uncover more inter and intra-case linkages. Graphical distribution of evidence enhances this process and creates a user-friendly interface analytical environment for investigators. Meaningful utilization of forensic intelligence at all levels of a given investigation serves to close more cases, provide case assessment/interpretation of all evidence, and give investigators higher confidence for testimony in court.;In order achieve a forensic intelligence case assessment model, the linkage analysis software IBMRTM i2RTM Analyst\u27s NotebookRTM was employed. Analyst\u27s NotebookRTM is a visual intelligence analysis environment that enables the user to quickly collate, analyze, and visualize data from numerous sources while reducing the time required to discover key information. The application of the resulting model within the software delivers timely, actionable intelligence to help identify, predict, prevent, and disrupt criminal, terrorist, and fraudulent activities based upon evidentiary value. Additionally, this software can be used in conjunction with an agency\u27s current database or information repository to develop critical linkages between criminal activity.;Import specification models were developed and refined throughout the course of this project. The three step model serves to compile case information automatically and draw links for the investigator. Firstly, a model was developed as an import mechanism for case files into an intelligence network within Analyst\u27s NotebookRTM. The significance of an import mechanism is that case files can be incorporated to the network in order to develop a repository of case files. Secondly, import specifications were developed to integrate articles of evidence with the case file. Finally, AFIS, CODIS, and IBIS database search results were incorporated with the cases and evidence already present in the forensic intelligence network. Complete integration of database results can be utilized for case assessment and interpretation by the investigator, and also to draw linkages with other cases in the network in a multi-case approach

Comparison of the Biological Attributes, First and Second Level of Detail of Friction Ridge Skin of the Palms and Fingers

Since the case of Daubert v. Merrell Dow Pharmaceuticals, the Daubert criteria is nothing new to forensic science. Today\u27s practices and techniques presented in a court of law are held to high scientific scrutiny. For nearly 100 years, expert witness testimony concerning fingerprint identification has been allowed into courts with little challenge, as it is supported by several areas of research that acknowledge that no two fingerprints are the same; they will remain unchanged during an individuals lifetime, and that fingerprints have a general systematic classification system. In the past, the assumption was always made that palm prints adhered to this criteria as well. In fact, very little research has been conducted that supports all the premises of fingerprints, with this lack of support also being applicable to palm prints. Thus, there is an aim to establish a biological foundation that fingerprints and palm prints can be equated biologically, and therefore it is necessary to conduct vast amounts of research to demonstrate a correlation between second level minutia detail as it exists in fingerprints and palm prints