Passive forensics in image and video using noise features: A review

Due to present of enormous free image and video editing software on the Internet, tampering of digital images and videos have become very easy. Validating the integrity of images or videos and detecting any attempt of forgery without use of active forensic technique such as Digital Signature or Digital Watermark is a big challenge to researchers. Passive forensic techniques, unlike active techniques, do not need any preembeded information about the image or video. The proposed paper presents a comprehensive review of the recent developments in the field of digital image and video forensic using noise features. The previously existing methods of image and video forensics proved the importance of noises and encourage us for the study and perform extensive research in this field. Moreover, in this paper, forensic task cover mainly source identification and forgery detection in the image and video using noise features. Thus, various source identification and forgery detection methods using noise features are reviewed and compared in this paper for image and video. The overall objective of this paper is to give researchers a broad perspective on various aspects of image and video forensics using noise features. Conclusion part of this paper discusses about the importance of noise features and the challenges encountered by different image and video forensic method using noise features.     

Selection of image features for steganalysis based on the Fisher criterion

A steganalytic feature selection method based on the Fisher criterion used in pattern recognition is proposed in this paper in order to reduce effectively the high dimensionality of the statistical features used in state-of-the-art steganalysis. First, the separability of each single-dimension feature in the feature space is evaluated using the Fisher criterion, and these features are reordered in descending order of separability. Then, starting from the first dimension of the reordered features, as the dimension increases, the separability of each feature component is analyzed using the Fisher criterion combined with the Euclidean distance. Finally, the feature components with the best separability are selected as the final steganalytic features. Experimental results based on the selection of SPAM (Subtractive Pixel Adjacency Matrix) features in spatial-domain steganalysis and CC-PEV (Cartesian Calibrated feature extracted by PEVný) features in DCT-domain steganalysis show that the proposed method can not only reduce the dimensionality of the features efficiently while maintaining the accuracy of the steganalysis, but also greatly improve the detection efficiency.     

Detection of copy-move forgery using a method based on blur moment invariants

In our society digital images are a powerful and widely used communication medium. They have an important impact on our life. In recent years, due to the advent of high-performance commodity hardware and improved human-computer interfaces, it has become relatively easy to create fake images. Modern, easy to use image processing software enables forgeries that are undetectable by the naked eye. In this work we propose a method to automatically detect and localize duplicated regions in digital images. The presence of duplicated regions in an image may signify a common type of forgery called copy-move forgery. The method is based on blur moment invariants, which allows successful detection of copy-move forgery, even when blur degradation, additional noise, or arbitrary contrast changes are present in the duplicated regions. These modifications are commonly used techniques to conceal traces of copy-move forgery. Our method works equally well for lossy format such as JPEG. We demonstrate our method on several images affected by copy-move forgery.     

Image copy-move forgery detection based on polar cosine transform and approximate nearest neighbor searching

Copy-move is one of the most commonly used image tampering operation, where a part of image content is copied and then pasted to another part of the same image. In order to make the forgery visually convincing and conceal its trace, the copied part may subject to post-processing operations such as rotation and blur. In this paper, we propose a polar cosine transform and approximate nearest neighbor searching based copy-move forgery detection algorithm. The algorithm starts by dividing the image into overlapping patches. Robust and compact features are extracted from patches by taking advantage of the rotationally-invariant and orthogonal properties of the polar cosine transform. Potential copy-move pairs are then detected by identifying the patches with similar features, which is formulated as approximate nearest neighbor searching and accomplished by means of locality-sensitive hashing (LSH). Finally, post-verifications are performed on potential pairs to filter out false matches and improve the accuracy of forgery detection. To sum up, the LSH based similar patch identification and the post-verification methods are two major novelties of the proposed work. Experimental results reveal that the proposed work can produce accurate detection results, and it exhibits high robustness to various post-processing operations. In addition, the LSH based similar patch detection scheme is much more effective than the widely used lexicographical sorting.     

Organizing crime: A classificatory scheme based on offense transitions

An approach to classification of major offenses and of offenders based on regularities of transition among offenses is examined in a construction sample of 1523 male recidivists and a validation sample of 5636 male recidivists. Results indicate that the category of prior offense is a moderately efficient predictor of the category of subsequent offense. Categories resembling person and property groupings found in earlier cluster analyses are also found here. Classificatory schemes based on regularities in transitions among offenses may offer a useful research tool.     

A survey of image processing techniques and statistics for ballistic specimens in forensic science

This paper provides a review of recent investigations on the image processing techniques used to match spent bullets and cartridge cases. It is also, to a lesser extent, a review of the statistical methods that are used to judge the uniqueness of fired bullets and spent cartridge cases. We review 2D and 3D imaging techniques as well as many of the algorithms used to match these images. We also provide a discussion of the strengths and weaknesses of these methods for both image matching and statistical uniqueness. The goal of this paper is to be a reference for investigators and scientists working in this field.     

Modern ships Voyage Data Recorders: A forensics perspective on the Costa Concordia shipwreck

International regulations about the safety of ships at sea require every modern vessel to be equipped with a Voyage Data Recorder to assist investigations in the event of an accident. As such, these devices are the primary means for acquiring reliable data about an accident involving a ship, and so they must be the first targets in an investigation. Although regulations describe the sources and amount of data to be recorded, they say nothing about the format of the recording. Because of this, nowadays investigators are forced to rely solely on the help of the builder of the system, which provides proprietary software to “replay” the voyage recordings. This paper delves into the examination of data found in the VDR from the actual Costa Concordia accident in 2012, and describes the recovery of information useful for the investigation, both by deduction and by reverse engineering of the data, some of which were not even shown by the official replay software.     

基于模糊集值统计方法的城市应急资源保障能力评价探讨

本文从城市应急系统的结构出发,结合城市应急的特点,构建了一个具有十五项评价指标的城市应急资源保障能力评价指标体系,利用模糊集值统计方法对各指标的权值和评价分值加以分析,建立了城市应急资源保障能力综合评价模型.传统的专家判断法主要是令专家直接给出指标权值和评价值,本文利用模糊集值统计方法将专家给出各指标权值和评价值的描述范围进行整合运算,得出各指标的权值和评价值,能够减少主观随意性,提高评价的可靠性和客观性,为提高城市应急资源保障能力提供决策依据.     

Personal identification based on radiographic vertebral features

Personal identification of human remains constitutes about 10% of the normal caseload of any forensic medicine practice. Identification can be achieved by a variety of methods, one of which is the comparison of antemortem and postmortem radiographs. There are numerous accounts of cranial and dental radiographic features useful for identification, whereas the availability of postcranial radiographs and especially plates that depict the vertebral column is less widespread among the forensic community. The authors here review the various vertebral features instrumental in positive identification that can be identified on radiographs of the spine.     

基于点云数据的瘢痕长度测量方案

瘢痕鉴定是法医工作中重要的一项任务,对瘢痕的纹理、位置和长度等信息都有着细致的规定和要求。通过三维扫描仪可以便捷地获取点云数据,还原瘢痕区域的具体结构,为瘢痕鉴定提供新的工具。本文基于三维点云数据,提取瘢痕的趋势线,进行瘢痕长度测量。该方案首先对三维瘢痕数据进行投影,在二维平面上提取瘢痕的端点和关键点。然后在三维曲面上通过近邻搜索和向量内积的方法,依次连接所有关键点得到沿瘢痕表面的趋势线,计算瘢痕的长度。本文实验中使用的三维瘢痕点云来自某法医司法鉴定中心的工作内容,通过三维扫描仪提取。在实验数据上的应用结果显示,提取的趋势线在瘢痕表面贴合程度较好,可以跟随曲面进行弯折,可靠性很高。以点为核心的计算方法,在后续测量功能改进中也有较大的空间。     

A note on quetelet and the development of criminological statistics

This Note clarifies several ambiguities in the claims that Salas and Surette (1984) have made about the Belgian criminologist Adolphe Quetelet. Specifically, it suggests that Quetelet (1) never articulated a concept of political relations or of the political state; (2) consistently rejected the need for ‘theoretical’ interpretation of empirical ‘data,’ (3) borrowed the notion of ‘statistique morale’ from French and German moral statisticians, and (4) vacillated between the poles of determinism and free-will philosophy.     

运用局部形态SIFT描述法过滤网络淫秽图像方法的研究

各国政府和警方目前使用的传统淫秽图像检测方法主要以皮肤检测结果为基础,提取低层特征进行判断,在获得高正检率的同时也导致了大量的误检。为此,本文的方法从获得更直观和高层的语义知识着手,首先检测图像中局部形态变化突出的位置,并建立关于该区域形态的SIFT描述向量。把这些描述向量抽象地看作视觉“单词”,并收集淫秽图像中常见的单词。依据图像中单词出现的情况,来检测是否包含淫秽成分。结合传统检测方法,仅使用简单的Bayes规则判断,在不降低正检率的前提下,使非淫秽图像的误检率得到显著的下降。     

Forensic discrimination of blue ballpoint pen inks based on thin layer chromatography and image analysis

This article aims to provide a new and fast method for differentiation of inks on a questioned document. The data acquisition was carried out by designing specific image analysis software for evaluating thin layer chromatograms (TLC-IA). The ink spot was extracted from the document using methanol and separated by TLC using plastic sheet silica gel 60 without fluorescent indicator, and a mixture of ethyl acetate, ethanol, and water (70:35:30, v/v/v) as mobile phase. To discriminate between different pen inks, new software was designed on the basis of intensity profile of red, green, and blue (RGB) characteristic. In practice, after development of chromatogram, the chromatograms were scanned by ordinary office scanner, intensity profiles of RGB characteristics on the development straight of each sample were produced and compared with the mentioned software. RGB profiles of ballpoint inks from various manufacturers showed that the patterns in most cases were distinctly different from each other. This new method allowed discriminating among different pen inks with a high reliability and the discriminating power of 92.8%. Blue ballpoint pen inks of 41 different samples available on the local market were successfully analyzed and discriminated.     

A demonstration of spermatozoa on vaginal swabs after complete destruction of the vaginal cell deposits

The proteolytic enzyme, proteinase K, has been found to destroy all vaginal cells though it does not have the same effect on spermatozoa. In cases of sexual offenses, in which a swab has been used to wipe out the vagina, the female cells and their nuclei on that swab may also contain the heads of spermatozoa. After as short a time as 30 min of proteinase K treatment, the spermatozoa that had separated from the enzymatically destroyed vaginal cells were recovered. This proteinase destruction furnishes some spermatozoa with deformed heads and a somewhat greater number of isolated tails though a sufficient number of spermatozoan heads still remain for a reliable diagnosis. For detection of spermatozoa from a vaginal swab after proteinase K pretreatment, the heads of the spermatozoa are distinctly stained by Oppitz's method. Further, on prior treatment with proteinase K, the ABO blood grouping of the spermatozoa could also be determined on the vaginal swab by using the absorption-elution technique. The resistance of the spermatozoa to proteinase K is the basis for this method.     

A discussion on the usefulness of a shared European ballistic image database

The introduction of electronic systems into the comparison of weapon marks in the mid 1990s caused a revolution in the discipline of “forensic ballistics”. Most European states now use this technology to search their national open case files.Globalisation of crime and the loss of effective border controls have made the idea of a unified European ballistic system seem logical.The article critically considers the requirements and possible outcomes of such a system. Based on the experience of forensic practitioners it seems probable that a shared European electronic ballistic system will be of a very limited value at present. Further improvements of existing systems to reach compatibility are encouraged.     

A study on JPEG steganalytic features: Co-occurrence matrix vs. Markov transition probability matrix

Statistical feature selection is a key issue affecting the performance of steganalytic methods. In this paper, a performance comparison method for different types of image steganalytic features was proposed firstly based on the changing rates. Then, for two types of typical steganalytic features – co-occurrence matrix and Markov transition probability matrix, the performances of them were discussed and theoretically compared for detecting two types of well-known JPEG steganography that preserve DCT coefficients histogram and lead the histogram to shrink respectively. At last, a conclusion on the sensitivity comparison between components of these two types of features was derived: for the steganography that preserve the histogram, their sensitivities are comparable to each other; whereas for the other one (such as the steganography that subtract 1 from absolute value of the coefficient), different feature components have different sensitivities, on the basis of that, a new steganalytic feature could be obtained by fusing better components. Experimental results based on detection of three typical JPEG steganography (F5, Outguess and MB1) verified the theoretical comparison results, and showed that the detection accuracy of the fused new feature outperforms that of existing typical features.     

聚焦警察形象建设——第一届警察公共关系论坛综述

21世纪,面对中国改革开放和社会主义现代化建设的快速发展,中国的警察应该是什么形象,如何树立警察形象?基于这样的主题,由中国人民公安大学主办、公安部宣传局、人民公安报、江苏省公安厅联办的第一届警察公共关系论坛于2002年10月29日-31日在北京举行。由于各有关方面的充分重视和支持,经过两年多的筹备,来自全国18个省、市、自治区和港澳特别行政区以及韩国警界的共48位代表参加了第一届警察公共关系论坛。中国国际公关协会、中国行政管理学会的负责人和专家也参加了论坛。     

新西兰白兔死亡后颅脑CT检查与死亡时间关系的研究

目的采用CT扫描动态观察新西兰白兔死亡后脑组织变化,建立利用CT值、脑组织/颅腔面积比,推断死亡时间(PM I)的研究方法。方法通过耳缘静脉注射空气,建立新西兰白兔死亡模型;于死亡后0~120h,运用CT进行头颅平描;选取颅顶面层测定脑组织CT值、脑组织/颅腔面积比。结果死亡后兔脑组织CT值呈双峰样上升、脑组织/颅腔面积比呈不断下降趋势;建立与死亡时间的回归方程:CT值=47.4780-0.1768T+0.0049T2(T/h,CT值/HU)、面积比=99.7368+0.3098T-0.0118T2/100(T/h)。结论CT扫描检查可准确显示兔脑的死后变化;脑组织消失之前,综合运用CT检查指标可用于准确推断死亡时间。     

Photoshop图像分析法在不规则瘢痕鉴定中应用

目的 探讨photoshop图像分析方法在不规则瘢痕鉴定中的应用价值.方法 用photoshop图像分析方法和数格法对30种不规则瘢痕进行面积计算,并对其准确性和实用性进行比较.结果 photoshop图像分析方法与数格法所计算出的面积之间无明显差异(P =0.960 7),而在检测时间和过程等方面photoshop图像分析方法明显优于数格法.结论 photoshop图像分析法用于不规则瘢痕的面积计算,具有既准确又节省时间的优点,可以在不规则瘢痕的法医学鉴定中选择使用.