Personal Identification by Morphometric Analyses of Intra‐Oral Radiographs of Unrestored Teeth*

Abstract: The aim of this study was to work out a biometric method for personal identification by comparing simulated antemortem and postmortem digital radiographs of unrestored teeth. Intra‐oral radiographs of the inferior right first molar, without restorations, were acquired at two different times in 70 subjects using a standardized technique followed by a morphometric analysis. The program automatically supplied values of the absolute distances, relative distances, shape factors, moments, perimeter values, and the areas of the triangles, which were obtained by joining key reference points. The values for the homologous samples were compared with the heterologous samples. Statistical analysis was then carried out, resulting in a section point value of 0.9992. Higher correlation coefficients indicate positive identification, with less than 2% risk of false positives, and approximately 3% of false negatives. We have also tested the method on dental records from 30 patients in order to demonstrate the specificity and sensitivity of the system.     

A Set of Handwriting Features for Use in Automated Writer Identification,

A writer's biometric identity can be characterized through the distribution of physical feature measurements (“writer's profile”); a graph‐based system that facilitates the quantification of these features is described. To accomplish this quantification, handwriting is segmented into basic graphical forms (“graphemes”), which are “skeletonized” to yield the graphical topology of the handwritten segment. The graph‐based matching algorithm compares the graphemes first by their graphical topology and then by their geometric features. Graphs derived from known writers can be compared against graphs extracted from unknown writings. The process is computationally intensive and relies heavily upon statistical pattern recognition algorithms. This article focuses on the quantification of these physical features and the construction of the associated pattern recognition methods for using the features to discriminate among writers. The graph‐based system described in this article has been implemented in a highly accurate and approximately language‐independent biometric recognition system of writers of cursive documents.     

The Possibilities and Limitations of Forensic Hand Comparison

On recordings of certain crimes, the face is not always shown. In such cases, hands can offer a solution, if they are completely visible. An important aspect of this study was to develop a method for hand comparison. The research method was based on the morphology, anthropometry, and biometry of hands. A new aspect of this study was that a manual and automated test were applied, which, respectively, assess many features and provide identification rates quickly. An important observation was that good quality images can provide sufficient hand details. The most distinctive features were the length/width ratio, the palm line pattern and the quantity of highly distinctive features present, and how they are distributed. The results indicate that experience did not improve the identification rates, while the manual test did. Intra‐observer variability did not influence the results, whereas hands of relatives were frequently misjudged. Both tests provided high identification rates.     

Analysis of Frontal Sinuses for Personal Identification in a Chinese Sample Using a New Code Number

The study of frontal sinuses for personal identification is a considered approach in the forensic field. In Yoshino's system, the frontal sinus patterns of a given person were formulated as a code number (codY) obtained by arranging the class numbers in each classification item. The aim of this work was to use a new code number (codC) with eight digits that includes other two continuous variables obtained as ratios SOR₁ (left frontal sinus area/left orbit area) and SOR₂ (right frontal sinus area/right orbit area), comparing the results with that of Yoshino. Digital radiographic images of the skulls of 150 Chinese people were analyzed. Spearman's partial correlation coefficients were evaluated between variables characterizing frontal sinus patterns. We used a maximum-weight dependence tree for statistical analysis. Results demonstrated that codC significantly reduced the probability of having the same personal code number compared with codY. Our scientific approach results valid for personal identification purposes.     

The Reliability of Visually Comparing Small Frontal Sinuses*

Abstract: Several studies have investigated frontal sinus comparison for personal identification. One study addressed the statistical reliability of correct identification using automated digital methods and resulted in a 96% accuracy rate. Missed matches with the digital methods generally involved small, less featured sinuses. This study investigates the hypothesis that human examiners may be able to more accurately identify correct matches than digital methods, even when the comparisons involve small frontal sinuses. Participants were provided two sets of 28 radiographs and were instructed to identify matching radiographs and list the radiographs that did not have a corresponding match. Overall, error rates were low, with correct associations identified at a rate of 0.983. No incorrect associations (“false positives”) were made. Correct association rates were highest among participants “experienced” examining radiographs. Results support previous assertions that frontal sinus radiographs are a reliable means of personal identification even when the frontal sinuses are small.     

Visualization of gunshot residue patterns on dark clothing

ABSTRACT: Determination of the muzzle‐to‐target distance is often a critical factor in criminal and civil investigations involving firearms. However, seeing and recording gunshot residue patterns can be difficult if the victim's clothing is dark and/or bloodstained. Trostle reported the use of infrared film for the detection of burn patterns. However, only after the film is developed are the results visible and multiple exposures at different settings may be needed. The Video Spectral Comparator^? 2000 (Foster & Freeman Ltd., Evesham, Worcestershire, U.K.) is an imaging instrument routinely used by forensic document examiners. Without use of specialized film could the VSC 2000 (at appropriate instrument settings) quickly, easily, and reliably provide instantaneous viewing, saving, and printing of gunshot residue patterns on dark and/or blood soaked clothing? At muzzle‐to‐target distances of 6, 12, and 18 in., test fires were made into five different types of dark clothing using eight different handguns of different calibers. Gunshot residues were detected for all eight calibers, and powder burn patterns were seen on dark clothing for all three target distances and calibers except 0.22 long rifle and 0.25 ACP. Bloodstains did not preclude the viewing of these patterns.     

A View to the Future: A Novel Approach for 3D–3D Superimposition and Quantification of Differences for Identification from Next‐Generation Video Surveillance Systems

Techniques of 2D–3D superimposition are widely used in cases of personal identification from video surveillance systems. However, the progressive improvement of 3D image acquisition technology will enable operators to perform also 3D–3D facial superimposition. This study aims at analyzing the possible applications of 3D–3D superimposition to personal identification, although from a theoretical point of view. Twenty subjects underwent a facial 3D scan by stereophotogrammetry twice at different time periods. Scans were superimposed two by two according to nine landmarks, and root‐mean‐square (RMS) value of point‐to‐point distances was calculated. When the two superimposed models belonged to the same individual, RMS value was 2.10 mm, while it was 4.47 mm in mismatches with a statistically significant difference (p < 0.0001). This experiment shows the potential of 3D–3D superimposition: Further studies are needed to ascertain technical limits which may occur in practice and to improve methods useful in the forensic practice.     

The Reliability of Facial Recognition of Deceased Persons on Photographs

In humanitarian emergencies, such as the current deceased migrants in the Mediterranean, antemortem documentation needed for identification may be limited. The use of visual identification has been previously reported in cases of mass disasters such as Thai tsunami. This pilot study explores the ability of observers to match unfamiliar faces of living and dead persons and whether facial morphology can be used for identification. A questionnaire was given to 41 students and five professionals in the field of forensic identification with the task to choose whether a facial photograph corresponds to one of the five photographs in a lineup and to identify the most useful features used for recognition. Although the overall recognition score did not significantly differ between professionals and students, the median scores of 78.1% and 80.0%, respectively, were too low to consider this method as a reliable identification method and thus needs to be supported by other means.     

A new approach to amino acid racemization in enamel: testing of a less destructive sampling methodology

Aspartic acid racemization has been found to be an accurate measure of age at death for recent forensic material. This paper examines the practicality of using acid etching of the tooth surface to extract amino acids from the enamel for racemization analysis. By serial etching of the tooth and contamination of the teeth with bovine serum albumin prior to etching, the ability of etching to remove contamination was assessed. The destructiveness of the method was visualized and quantified using micro-computed tomography (micro-CT). By bleaching the teeth and by deeper etching it was possible to obtain more consistent values. While etching had little effect on the enamel at the macroscale, it did have an impact at the microscale. The quantities of enamel removed varied depending upon the tooth morphology, but were not large. Acid etching of enamel thus appears to be a promising new method for extracting proteins for amino acid racemization age estimation noninvasively.     

Identification of Bodies by Unique Serial Numbers on Implanted Medical Devices

Visual identification is the most common identification method used by medical examiners but is not always possible. Alternative methods include X‐ray, fingerprint, or DNA comparison, but these methods require additional resources. Comparison of serial numbers on implanted medical devices is a rapid and definitive method of identification. To assess the practicality of using this method, we reviewed 608 consecutive forensic autopsies performed at a regional medical examiner office. Of these, 56 cases required an alternative method of identification due to decomposition (n = 35), gunshot wound (n = 9), blunt trauma (n = 6), or charring (n = 6). Of these 56 cases, eight (14.3%) were known to have an implanted medical device. Of these eight cases, five (63%) could be positively identified by comparing serial numbers. If an implanted medical device is known to be present, and medical records are available, identification by medical device serial number should be a first‐line method.     

Percentage of body recovered and its effect on identification rates and cause and manner of death determination

Anthropologists frequently encounter cases in which only partial human remains are recovered. This study reports how the percentage of the body recovered affects identification (ID) rates and cause and manner of death determination. A total of 773 cases involving anthropology consults were drawn from the New Mexico medical examiner's office (1974-2006). Results indicate a significant correlation between body percent recovered and ID rates, which ranged from 89% for complete bodies to 56% when less than half the body was present. Similar patterns were evident in cause/manner determination, which were the highest (83% and 79%, respectively) in complete bodies but declined to 40% when less than half the body was found. The absence of a skull also negatively impacted ID and ruling rates. Findings are compared with general autopsy ID rates (94-96%) and cause/manner determination rates (96-99%) as well as prior published rates for individual casework and mass death events.     

Anthropological and Radiographic Comparison of Antemortem Surgical Records for Identification of Skeletal Remains*

Abstract: This case review illustrates the important contributions of forensic archeological methods and forensic anthropological analysis to the identification of found skeletal remains. After reassociation of skeletal remains found in two locations, anthropological analysis provided the basis for a presumptive identification and a request for antemortem medical records. Partial DNA profiles were supportive but not conclusive and antemortem dental records were not available. Comparison of antemortem traumas, skeletal morphology, and surgical artifacts with antemortem radiographs and surgical records led to positive identification of an individual missing for almost a decade.     

Speech Watermarking: An Approach for the Forensic Analysis of Digital Telephonic Recordings*

Abstract: In this article, the authors discuss the problem of forensic authentication of digital audio recordings. Although forensic audio has been addressed in several articles, the existing approaches are focused on analog magnetic recordings, which are less prevalent because of the large amount of digital recorders available on the market (optical, solid state, hard disks, etc.). An approach based on digital signal processing that consists of spread spectrum techniques for speech watermarking is presented. This approach presents the advantage that the authentication is based on the signal itself rather than the recording format. Thus, it is valid for usual recording devices in police‐controlled telephone intercepts. In addition, our proposal allows for the introduction of relevant information such as the recording date and time and all the relevant data (this is not always possible with classical systems). Our experimental results reveal that the speech watermarking procedure does not interfere in a significant way with the posterior forensic speaker identification.     

The use of material culture to establish the ethnic identity of victims in genocide investigations: a validation study from the American Southwest*

Successful prosecution of genocide requires that the victims constitute one of four protected groups: national, religious, ethnic, or racial. Establishing victim identity in prior trials has relied on positive identification of decedents, been largely presumptive, or was based on untested methodology. This report details a validation study of one untested method: the use of material culture in establishing ethnic identity. Classes of clothing and personal effects were scored on 3,430 individuals of known Hispanic or White ancestry from autopsy records in New Mexico. Significant differences were seen in evidence of language, nationality, and religious affiliation between the two groups, as well as clothing types and currency. Predictive models used to estimate ethnic identity in random, blind subsets produced an overall accuracy of 81.5% and estimates of 61-98% in specific subsets. Results suggest material culture, when present, can provide reliable evidence of ethnic affinity in genocide investigations.     

Anthropological and radiographic comparison of vertebrae for identification of decomposed human remains

This case study demonstrates the importance of involving an anthropologist in forensic situations with decomposed remains. Anthropological consultation was used in conjunction with the comparison of antemortem and postmortem radiographs to establish positive identification of unknown, decomposed remains. The remains had no traditional identifying features such as fingerprints or dental. Through anthropological analysis, it was determined the decedent was male, between 20 and 23 years at time of death and c. 5'2' tall. This information allowed for a presumptive identification and a request for antemortem radiographs. The missing person was identified comparing the spinous processes of the cervical and thoracic vertebrae between ante- and postmortem radiographs.     

Variability and Similarity of Gait as Evaluated by Joint Angles: Implications for Forensic Gait Analysis

Closed‐circuit television (CCTV) footage is used in criminal investigations to compare perpetrators with suspects. Usually, incomplete gait cycles are collected, making evidential gait analysis challenging. This study aimed to analyze the discriminatory power of joint angles throughout a gait cycle. Six sets from 12 men were collected. For each man, a variability range VR (mean ± 1SD) of a specific joint angle at a specific time point (a gait cycle was 100 time points) was calculated. In turn, each individual was compared with the 11 others, and whenever 1 of these 11 had a value within this individual's VR, it counted as positive. By adding the positives throughout the gait cycle, we created simple bar graphs; tall bars indicated a small discriminatory power, short bars indicated a larger one. The highest discriminatory power was at time points 60–80 in the gait cycle. We show how our data can assess gait data from an actual case.     

正面照片面部特征指标用于个人识别的选择及评价

目的研究中国汉族成人正面照片,优选出面部特征指标建立分型特征标准,考察面部特征的个人识别能力。方法确定27项面部特征指标及分型标准,观察254张中国汉族成人正面照片,通过统计分析观察数据结果及计算个人识别能力评价指标和分型标准。结果 13项指标性别差异显著;联合所选择的27个面部特征指标,男性TDP(tolal discrimination power,累计个人识别能力)=0.999 999 909 08,女性TDP=0.999 999 919 82,总体TDP=0.999 999 868。结论正面照片面部特征指标越多、分型的多态性及量化程度越高,个人识别能力越高。     

Three-dimensional surface topography acquisition and analysis for firearm identification

In the last decade, computer-based systems for the comparison of microscopic firearms evidence have been the subject of considerable research work because of their expected capability of supporting the firearms examiner through the automated analysis of large amounts of evidence. The Integrated Ballistics Identification System, which is based on a two-dimensional representation of the specimen surface, has been widely adopted in forensic laboratories worldwide. More recently, some attempts to develop systems based on three-dimensional (3D) representations of the specimen surface have been made, both in the literature and as industrial products, such as BulletTRAX-3D, but fundamental limitations in achieving fully automated identification remain. This work analyzes the advantages and disadvantages of a 3D-based approach by proposing an approach and a prototype system for firearms evidence comparison that is based on the acquisition and analysis of the 3D surface topography of specimens, with particular reference to cartridge cases. The concept of 3D virtual comparison microscope is introduced, whose purpose is not to provide fully automated identification, but to show how the availability of 3D shape information can provide a whole new set of verification means, some of them being described and discussed in this work, specifically, visual enhancement tools and quantitative measurement of shape properties, for supporting, not replacing, the firearm examiner in reaching the final decision.     

Application of the Iscan method to two- and three-dimensional imaging of the sternal end of the right fourth rib

Age determination is a major field of interest in physical and forensic anthropology. Among the different methods based on macroscopic skeletal study, the Iscan method, which analyzes the sternal end of the right fourth rib, is one of the most reliable. We applied the Iscan method to two- and three-dimensional multislice computed tomography (MSCT) reconstructions of the sternal end of the right fourth rib on 39 ribs. The intra-observer variability on MSCT reconstructions was good (gamma coefficient equal to 0.86; value of the Krippendorff's alpha reliability equal to 0.79); inter-observer variability on MSCT reconstructions was also good (gamma coefficient ranging from 0.82 to 0.88; value of the Krippendorff's alpha reliability ranging from 0.78 to 0.86). We demonstrated excellent agreement between the results of analysis of bone samples and those of the two- and three-dimensional images, in particular regarding bone projections, morphology of the pit and of its rim. The accuracy of age estimation did not significantly differ between the Iscan method applied to dry bones and the same method applied to MSCT images. Determination of the Krippendorff's alpha reliability coefficient for the inter-error method confirmed the agreement between phase estimations obtained with the two methods (ranging from 0.55 to 0.71). The real civil age was comprised in 21 cases out of 36 for assessment performed on dry bones and in 23 cases out of 36 on MSCT reconstructions, which represented 58.3% and 63.9%, respectively. Use of MSCT reconstructions in forensic anthropology offers many advantages: no bone preparation, no damage to bone material, and the possibility of application to living individuals.     

An Assessment of How Facial Mimicry Can Change Facial Morphology: Implications for Identification

The assessment of facial mimicry is important in forensic anthropology; in addition, the application of modern 3D image acquisition systems may help for the analysis of facial surfaces. This study aimed at exposing a novel method for comparing 3D profiles in different facial expressions. Ten male adults, aged between 30 and 40 years, underwent acquisitions by stereophotogrammetry (VECTRA‐3D ^® ) with different expressions (neutral, happy, sad, angry, surprised). The acquisition of each individual was then superimposed on the neutral one according to nine landmarks, and the root mean square (RMS) value between the two expressions was calculated. The highest difference in comparison with the neutral standard was shown by the happy expression (RMS 4.11 mm), followed by the surprised (RMS 2.74 mm), sad (RMS 1.3 mm), and angry ones (RMS 1.21 mm). This pilot study shows that the 3D–3D superimposition may provide reliable results concerning facial alteration due to mimicry.