A Novel Method for the Photographic Recovery of Fingermark Impressions from Ammunition Cases Using Digital Imaging

The photographic preservation of fingermark impression evidence found on ammunition cases remains problematic due to the cylindrical shape of the deposition substrate preventing complete capture of the impression in a single image. A novel method was developed for the photographic recovery of fingermarks from curved surfaces using digital imaging. The process involves the digital construction of a complete impression image made from several different images captured from multiple camera perspectives. Fingermark impressions deposited onto 9‐mm and 0.22‐caliber brass cartridge cases and a plastic 12‐gauge shotgun shell were tested using various image parameters, including digital stitching method, number of images per 360° rotation of shell, image cropping, and overlap. The results suggest that this method may be successfully used to recover fingermark impression evidence from the surfaces of ammunition cases or other similar cylindrical surfaces.     

Digital camera identification using PRNU: A feature based approach

Source camera identification is one of the emerging field in digital image forensics, which aims at identifying the source camera used for capturing the given image. The technique uses photo response non-uniformity (PRNU) noise as a camera fingerprint, as it is found to be one of the unique characteristic which is capable of distinguishing the images even if they are captured from similar cameras. Most of the existing PRNU based approaches are very sensitive to the random noise components existing in the estimated PRNU, and also they are not robust when some simple manipulations are performed on the images. Hence a new feature based approach of PRNU is proposed for the source camera identification by choosing the features which are robust for image manipulations. The PRNU noise is extracted from the images using wavelet based denoising method and is represented by higher order wavelet statistics (HOWS), which are invariant features for image manipulations and geometric variations. The features are fed to support vector machine classifiers to identify the originating source camera for the given image and the results have been verified by performing ten-fold cross validation technique. The experiments have been carried out using the images captured from various cell phone cameras and it demonstrated that the proposed algorithm is capable of identifying the source camera of the given image with good accuracy. The developed technique can be used for differentiating the images, even if they are captured from similar cameras, which belongs to same make and model. The analysis have also showed that the proposed technique remains robust even if the images are subjected to simple manipulations or geometric variations.     

人体体表损伤法医学鉴定软件开发及应用

通过运用人体体表损伤法医学鉴定软件,进行各种体表损伤和瘢痕面积、长度、骨折畸形愈合角度和关节活动度等测算。用于人体轻伤和重伤、交通事故损伤、工伤、军人伤残、意外伤害保险等损伤程度的法医学鉴定,亦可用于临床烧烫伤等损伤面积和程度准确计算。本软件基于 Windows平台,应用 Visual Basic6.0编程,设计了扫描照片、数码照相、联机摄象和鼠标多种录入损伤图象路径,打印输出图文格式化鉴定书。测算结果具客观性和重复性好,克服了传统方法的弊端。软硬件环境通用,界面友好,简单易学。经数家法医学鉴定机构 3年多的两百多例实际检案应用,取得了较好的社会效益。     

Source Camera Identification for Heavily JPEG Compressed Low Resolution Still Images*

Abstract: In this research, we examined whether fixed pattern noise or more specifically Photo Response Non‐Uniformity (PRNU) can be used to identify the source camera of heavily JPEG compressed digital photographs of resolution 640 × 480 pixels. We extracted PRNU patterns from both reference and questioned images using a two‐dimensional Gaussian filter and compared these patterns by calculating the correlation coefficient between them. Both the closed and open‐set problems were addressed, leading the problems in the closed set to high accuracies for 83% for single images and 100% for around 20 simultaneously identified questioned images. The correct source camera was chosen from a set of 38 cameras of four different types. For the open‐set problem, decision levels were obtained for several numbers of simultaneously identified questioned images. The corresponding false rejection rates were unsatisfactory for single images but improved for simultaneous identification of multiple images.     

Characterization of Digital Cameras for Reflected Ultraviolet Photography; Implications for Qualitative and Quantitative Image Analysis During Forensic Examination

Reflected ultraviolet imaging techniques allow for the visualization of evidence normally outside the human visible spectrum. Specialized digital cameras possessing extended sensitivity can be used for recording reflected ultraviolet radiation. Currently, there is a lack of standardized methods for ultraviolet image recording and processing using digital cameras, potentially limiting the implementation and interpretation. A methodology is presented for processing ultraviolet images based on linear responses and the sensitivity of the respective color channels. The methodology is applied to a FujiS3 UVIR camera, and a modified Nikon D70s camera, to reconstruct their respective spectral sensitivity curves between 320 and 400 nm. This method results in images with low noise and high contrast, suitable for qualitative and/or quantitative analysis. The application of this methodology is demonstrated in the recording of latent fingerprints.     

GrinLine Identification Using Digital Imaging and Adobe Photoshop*

Abstract: The purpose of this study was to outline a method by which an antemortem photograph of a victim can be critically compared with a postmortem photograph in an effort to facilitate the identification process. Ten subjects, between 27 and 55 years old provided historical pictures of themselves exhibiting a broad smile showing anterior teeth to some extent (a grin). These photos were termed “antemortem” for the purpose of the study. A digital camera was used to take a current photo of each subject’s grin. These photos represented the “postmortem” images. A single subject’s “postmortem” photo set was randomly selected to be the “unknown victim.” These combined data of the unknown and the 10 antemortem subjects were digitally stored and, using Adobe Photoshop software, the images were sized and oriented for comparative analysis. The goal was to devise a technique that could facilitate the accurate determination of which “antemortem” subject was the “unknown.” The generation of antemortem digital overlays of the teeth visible in a grin and the comparison of those overlays to the images of the postmortem dentition is the foundation of the technique. The comparisons made using the GrinLine Identification Technique may assist medical examiners and coroners in making identifications or exclusions.     

Background correction in forensic photography. I. Photography of blood under conditions of non-uniform illumination or variable substrate color--theoretical aspects and proof of concept

The combination of photographs taken at two or three wavelengths at and bracketing an absorbance peak indicative of a particular compound can lead to an image with enhanced visualization of the compound. This procedure works best for compounds with absorbance bands that are narrow compared with "average" chromophores. If necessary, the photographs can be taken with different exposure times to ensure that sufficient light from the substrate is detected at all three wavelengths. The combination of images is readily performed if the images are obtained with a digital camera and are then processed using an image processing program. Best results are obtained if linear images at the peak maximum, at a slightly shorter wavelength, and at a slightly longer wavelength are used. However, acceptable results can also be obtained under many conditions if non-linear photographs are used or if only two wavelengths (one of which is at the peak maximum) are combined. These latter conditions are more achievable by many "mid-range" digital cameras. Wavelength selection can either be by controlling the illumination (e.g., by using an alternate light source) or by use of narrow bandpass filters. The technique is illustrated using blood as the target analyte, using bands of light centered at 395, 415, and 435 nm. The extension of the method to detection of blood by fluorescence quenching is also described.     

Contactless Visualization of Latent Fingerprints on Nonporous Curved Surfaces of Circular Cross Section

Nondestructive techniques for gathering evidence are important in the field of forensics. Due to the geometry of the substrates, nondestructive visualization of fingermarks on curved surfaces remains challenging. A novel contactless technique was developed for visualizing and recording fingermark patterns on nonporous curved surfaces of circular cross section. The technique utilizes a plane mirror to transmit rays from a light source to illuminate the area of interest for fingermark visualization. The fingermark acquisition system consists of a digital single‐lens reflex (SLR) camera, a plane mirror, and a white light source. Mathematical equations are used to calculate the mirror size. Experiments were performed on various curved surfaces to determine the feasibility and effectiveness of the technique. Spectral Image Validation and Verification (SIVV) was used to analyze the captured images. The results of this study indicate that the technique described here is able to reveal fingermark patterns on curved surfaces of circular cross section.     

Assessing age-related morphology of the pubic symphysis from digital images versus direct observation

The increasingly global role of a forensic anthropologist necessitates a proper means for archiving evidence for re-examination. Large quantities of evidence can be stored and be made readily accessible through digital imaging. This study focuses on age assessment from digital photographs for personal identity reconstructions. A comparison of 52 Suchey-Brooks scores assigned to digital images and actual bone revealed that age assessment from digital images can be completed with accuracy. Coefficients of concordance imply that there significant agreement between osteological assessment of aging criteria from digital images and direct observation-greater than random change alone (p < 0.05). However, assessments from images should be approached with caution since there are inherent limitations of the naked eye in identifying morphological changes in certain skeletal features, especially where older adults are concerned. Although there is no replacement for a hands-on physical assessment, a digital archive may facilitate the global needs of the forensic anthropologist.     

PRNU based source camera attribution for image sets anonymized with patch-match algorithm

Patch-Match is an efficient algorithm used for structural image editing and available as a tool on popular commercial photo-editing software. The tool allows users to insert or remove objects from photos using information from similar scene content. Recently, a modified version of this algorithm was proposed as a counter-measure against Photo-Response Non-Uniformity (PRNU) based Source Camera Identification (SCI). The algorithm can provide anonymity at a great rate (97%) and impede PRNU based SCI without the need of any other information, hence leaving no-known recourse for the PRNU-based SCI. In this paper, we propose a method to identify sources of the Patch-Match-applied images by using randomized subsets of images and the traditional PRNU based SCI methods. We evaluate the proposed method on two forensics scenarios in which an adversary makes use of the Patch-Match algorithm and distorts the PRNU noise pattern in the incriminating images she took with his camera. Our results show that it is possible to link sets of Patch-Match-applied images back to their source camera even in the presence of images that come from unknown cameras. To our best knowledge, the proposed method represents the very first counter-measure against the usage of Patch-Match in the digital forensics literature.     

Forensic applications of infrared imaging for the detection and recording of latent evidence

We report on a simple method to record infrared (IR) reflected images in a forensic science context. Light sources using ultraviolet light have been used previously in the detection of latent prints, but the use of infrared light has been subjected to less investigation. IR light sources were used to search for latent evidence and the images were captured by either video or using a digital camera with a CCD array sensitive to IR wavelength. Bloodstains invisible to the eye, inks, tire prints, gunshot residue, and charred document on dark background are selected as typical matters that may be identified during a forensic investigation. All the evidence types could be detected and identified using a range of photographic techniques. In this study, a one in eight times dilution of blood could be detected on 10 different samples of black cloth. When using 81 black writing inks, the observation rates were 95%, 88% and 42% for permanent markers, fountain pens and ball-point pens, respectively, on the three kinds of dark cloth. The black particles of gunshot residue scattering around the entrance hole under IR light were still observed at a distance of 60 cm from three different shooting ranges. A requirement of IR reflectivity is that there is a contrast between the latent evidence and the background. In the absence of this contrast no latent image will be detected, which is similar to all light sources. The use of a video camera allows the recording of images either at a scene or in the laboratory. This report highlights and demonstrates the robustness of IR to detect and record the presence of latent evidence.     

An innovative method for human height estimation combining video images and 3D laser scanning

Digitalization has increased the number of video surveillance systems that sometimes capture crime images. Traditional methods of human height estimation use projective geometry. However, sometimes they cannot be used because the video camera surveillance system is not available or has been moved and there are no reference lines on the frame. Scientific studies have developed a new method for human height estimation using 3D laser scanning. This model necessarily requires a series of approximations, which increase the final measurement error. To overcome this problem, in the present study, images of a subject are projected directly on the 3D model, estimating the height of the subject. This article describes the methodological approach adopted through the analysis of a real case study in a controlled environment executed by Carabinieri Forensic Investigation Department (Italy). The aim is to obtain a human anthropometric measure derived from frames extracted from the videos associated with the digital survey of the framed area obtained with 3D laser scanning and point cloud analysis. The result is the height estimation of five subjects filmed by a camera obtained through the combination of 2D images extracted by a DVR/surveillance systems with 3D laser scanning. Results show that most estimated measurements are less than the real measurement of the subject; it also depends on the posture of the subject while walking. Furthermore, results shows the differences between the real height and the estimated height with a statistical approach.     

Camera/video phones in schools: law and practice

The emergence of mobile phones with built-in digital cameras is creating legal and ethical concerns for school systems throughout the world. Users of such phones can instantly email, print or post pictures to other MMS1 1. MMS stands for Multimedia Messaging Services. MMS is frequently used to send photos from camera phones to other MMS phones or email addresses. View all notes phones or websites. Local authorities and schools in Britain, Europe, USA, Canada, Australia and elsewhere have introduced outright bans on their use because of the problems or risks they pose if misused. Risks concerned with pupils surreptitiously photographing other pupils in changing rooms or photographing examination papers are obvious examples. The article examines some worldwide examples of the misuse of camera phones in schools and the issues and problems that emerged. A landmark decision concerning the European Data Privacy Directive (Directive 95/46/EC) in the case of Bodil Lindqvist by the European Court of Justice is explored and the implications for camera phones considered. The article concludes by stating that because of their ubiquity and social potency, it is probably a mistake and an overreaction for education authorities or schools to introduce blanket bans on the possession of camera phones. Rather they need to devise sensible agreements and policies on camera phone usage.     

Photographic evidence protocol: the use of digital imaging methods to rectify angular distortion and create life size reproductions of bite mark evidence

Bite mark evidence seen in skin injuries or objects is commonly photographed for evidentiary documentation, preservation, and analysis. Distortion in forensic evidence photographs diminishes the outcome of analytical procedures available to the forensic odontologist. Inaccurate positioning of the evidence, camera, or measurement reference scale creates perspective and parallax distortion of the captured image. These variables must be eliminated, if possible, to ensure reliable results derived from comparison of the suspect teeth and the bite mark. Detection and measurement of camera/evidence/scale misalignment is the threshold step in evidence evaluation, and is possible through digital imaging methods coupled with established methods. Correction (rectification) of perspective distortion is possible through the application of additional digital editing techniques. This study establishes type categories of perspective and parallax distortion seen in bite mark evidence, validates the use of the digital imaging tools of Adobe Photoshop to correct certain types of distortion, and establishes a forensic protocol to verify the accuracy of evidence photographs requiring dimensional accuracy.     

Tibia and Fibula Stature Formulae for Modern Female Populations Based on Digital Radiographic Measurements

Abstract: This study demonstrates the feasibility of creating bone lengths and stature databases of significant size for modern living human populations from digital radiographic archives and medical records. Tibia and fibula lengths were taken from digital radiographic images of 250 women. The images, drawn from the University of California, Los Angeles Medical Center’s Radiology Department’s General Electric Picture Archiving and Communication System, were taken between 2003 and 2007. Stature measurements were obtained from medical records on 83 individuals, 50 of which were used to regress stature equations for the tibia and fibula. Bone lengths obtained from radiographic images are almost 3 cm longer than those obtained from skeletalized collections. The formulae produce ranges up to 10 cm lower than current formulae. Accuracy could be improved as methods are developed to correct for the small magnification produced by digital images.     

Using anisotropic diffusion for efficient extraction of sensor noise in camera identification

Each digital camera has an intrinsic fingerprint that is unique to each camera. This device fingerprint can be extracted from an image and can be compared with a reference device fingerprint to determine the device origin. The complexity of the filters proposed to accomplish this is increasing. In this note, we use a relatively simple algorithm to extract the sensor noise from images. It has the advantages of being easy to implement and parallelize, and working faster than the wavelet filter that is common for this application. In addition, we compare the performance with a simple median filter and assess whether a previously proposed fingerprint enhancement technique improves results. Experiments are performed on approximately 7500 images originating from 69 cameras, and the results are compared with this often used wavelet filter. Despite the simplicity of the proposed method, the performance exceeds the common wavelet filter and reduces the time needed for the extraction.     

Dental identification using digital images via computer network

Dental identification is a useful scientific method. In Japan, however, there are only a few forensic odontologists; moreover, until now, forensic dental services have only been offered by general dentists. These dentists may not be able to offer such forensic services during office time. For a quick comparison, the authors tried sending digital photos, taken with a 2-million-pixel digital camera, to dental offices via the Internet. If a dental office has Internet access, it is possible for dental charting to be sent directly to the autopsy room. Of course, digital images only provide the first outline. However, when antemortem dental records of the person in question are available at autopsy, a quick comparison can be made.     

Digital imaging methods as an aid in dental identification of human remains

The physical comparison of known (K) and questioned (Q) evidence samples is an accepted tool in numerous forensic identification disciplines (1). A subset of this process is the use of antemortem and postmortem dental radiographs to identify unidentified human remains. This method has been generally accepted for decades (2). The outcome is performed with a considerable degree of accuracy, due in part to a finite pool of possible candidates for identification derived via the NCIC database, passenger lists, and law enforcement Missing Persons reports. This paper describes a dental identification comparison protocol that incorporated digital imaging technology in this process. The computer was used to create digital exemplars of the K and Q evidence that were spatially and quantitatively compared (3). The digital mode allowed direct metric and morphologic comparison through the aid of a digital camera, desktop computer, monitor, and printer. The well-known computer program Adobe Photoshop 5.0 (4) was used to process the digital information in two forensic cases described in this paper. It is a commercially available digital imaging editing program that is operated on laptop and desktop computers possessing sufficient chip speed and RAM (Pentium II or equivalent and at least 76MB RAM) to open the large-size files generated by high-resolution digital capture devices. This program accepts raster-based image formats (e.g. .JPG, .BMP). Photoshop is noted for its diverse imaging functions, which allow the computer monitor to be used as a comparison microscope when Q and K sample images are tiled side-by-side and/or superimposed. Two and three-dimensional Q and K evidence samples can be individually digitized and then independently resized to allow two-dimensional comparison. The investigator also has the ability to create magnified images (200% to 300%) when the original digital image has been captured at near photoquality resolution (300 dpi). The visual comparison of physical features on the computer monitor permits a large field of view and robust digital control over image quality. Photographic measurement and enhancement features of Adobe Photoshop mimics and in some circumstances surpasses the historic use of conventional photographic manipulation in forensic casework. This paper presents two cases processed via routine forensic odontology identification protocols. These protocols had minimal results due to limitations described in the case histories. The additional application of digital methods proved useful in the ultimate identification of these human remains.