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.     

伪造信用卡犯罪中的伪造行为内涵与对象研究

刑法中伪造信用卡犯罪中的伪造不仅包括仿制其物理外观的形式伪造,还应包括将权利人信息写入磁条介质、芯片等的内容伪造。作为伪造对象的信用卡应当是具有物理载体的实体卡片,事实上不存在对虚拟信用卡的伪造。以虚假身份骗领无对应实体卡的虚拟信用卡应视为妨害信用卡管理罪中的骗领信用卡行为;利用权利人既有实体卡信息,复制虚拟信用卡的行为系对他人信用卡信息资料的非法使用而非伪造。有关伪造信用卡犯罪刑法规定的立法原意并不包含伪造空白信用卡,伪造空白信用卡具有严重的社会危害性,理应将其纳入刑法规制范围,以保持与妨害信用卡管理罪刑法规定的协调。不能通过司法解释改变立法原意,现行刑法中伪造信用卡犯罪的伪造含义应有相应的调整。     

Image region duplication detection based on circular window expansion and phase correlation

Region duplication forgery is one of the tampering techniques that are frequently used, where a part of an image is copied and pasted into another part of the same image. In this paper, a phase correlation method based on polar expansion and adaptive band limitation is proposed for region duplication forgery detection. Our method starts by calculating the Fourier transform of the polar expansion on overlapping windows pair, and then an adaptive band limitation procedure is implemented to obtain a correlation matrix in which the peak is effectively enhanced. After estimating the rotation angle of the forgery region, a searching algorithm in the sense of seed filling is executed to display the whole duplicated region. Experimental results show that the proposed approach can detect duplicated region with high accuracy and robustness to rotation, illumination adjustment, blur and JPEG compression while rotation angle is estimated precisely for further calculation.     

论刑法中的无形伪造--以文书为视角

各国立法中的伪造包括有形伪造和无形伪造两种情况.有形伪造是指无制作权限人非法制作文书的行为;无形伪造是指有制作权限者制作内容虚伪文书的行为.有形伪造与无形伪造的区别在于"名义人与制作人之间的人格是否具有一致性".处罚无形伪造的宗旨在于其侵犯文书的证据力.我国刑法中的伪造包含有形伪造和无形伪造两种含义,司法实践存在处罚无形伪造行为的案件.     

Identification of document paper using hybrid feature extraction

Document forgery is a significant issue in Korea, with around ten thousand cases reported every year. Analyzing paper plays a crucial role in examining questionable documents such as marketable securities and contracts, which can aid in solving criminal cases of document forgery. Paper analysis can also provide essential insights in other types of criminal cases, serving as an important clue for solving cases such as the source of a blackmail letter. The papermaking process generates distinct forming fabric marks and formations, which are critical features for paper classification. These characteristics are observable under transmitted light and are created by the forming fabric pattern and the distribution of pulp fibers, respectively. In this study, we propose a novel approach for paper identification based on hybrid features. This method combines texture features extracted from images converted using the gray-level co-occurrence matrix (GLCM) approach and a convolutional neural network (CNN), with another set of features extracted by the CNN using the same images as input. We applied the proposed method to classification tasks for seven major paper brands available in the Korean market, achieving an accuracy of 97.66%. The results confirm the applicability of this method for visually inspecting paper products and demonstrate its potential for assisting in solving criminal cases involving document forgery.     

Blind Detection of Region Duplication Forgery Using Fractal Coding and Feature Matching

Digital image forgery detection is important because of its wide use in applications such as medical diagnosis, legal investigations, and entertainment. Copy–move forgery is one of the famous techniques, which is used in region duplication. Many of the existing copy–move detection algorithms cannot effectively blind detect duplicated regions that are made by powerful image manipulation software like Photoshop. In this study, a new method is proposed for blind detecting manipulations in digital images based on modified fractal coding and feature vector matching. The proposed method not only detects typical copy–move forgery, but also finds multiple copied forgery regions for images that are subjected to rotation, scaling, reflection, and a mixture of these postprocessing operations. The proposed method is robust against tampered images undergoing attacks such as Gaussian blurring, contrast scaling, and brightness adjustment. The experimental results demonstrated the validity and efficiency of the method.     

德国法律对艺术伪造行为的规制——兼与我国相关法律的比较

对艺术伪造的理解在德国有广义和狭义之分.广义的艺术伪造包括艺术模仿、艺术篡改和艺术诈骗.狭义的艺术伪造则与广义的艺术伪造中的艺术诈骗是一致的,都与被署名人的作品无关.不过,从德国法律适用的角度看,艺术伪造主要分为两类:一类是与被署名人作品无关的艺术伪造；另一类则是与被署名人作品有关的艺术伪造.对前者的认定不是依据德国著作权法,而是依据其他法律；对后者的认定则是依据德国著作权法,同时德国刑法有关规定对此亦可适用.与我国法相比,德国著作权法更强调以作品存在为前提来保护作者的著作权.另外,对与被署名人作品有关的艺术伪造的规制,德国法律严于我国.     

Authentication of Surveillance Videos: Detecting Frame Duplication Based on Residual Frame

Nowadays, surveillance systems are used to control crimes. Therefore, the authenticity of digital video increases the accuracy of deciding to admit the digital video as legal evidence or not. Inter‐frame duplication forgery is the most common type of video forgery methods. However, many existing methods have been proposed for detecting this type of forgery and these methods require high computational time and impractical. In this study, we propose an efficient inter‐frame duplication detection algorithm based on standard deviation of residual frames. Standard deviation of residual frame is applied to select some frames and ignore others, which represent a static scene. Then, the entropy of discrete cosine transform coefficients is calculated for each selected residual frame to represent its discriminating feature. Duplicated frames are then detected exactly using subsequence feature analysis. The experimental results demonstrated that the proposed method is effective to identify inter‐frame duplication forgery with localization and acceptable running time.     

案后样本局部再现性伪装笔迹的检验

在实际办案中,笔者发现局部再现性伪装笔迹这种伪装的新特点.在越来越多的经济纠纷案件中,案后样本字迹中也出现了局部再现性伪装.本文就一起案后样本局部再现性伪装笔迹的检验,进行一些讨论.     

A passive approach for effective detection and localization of region-level video forgery with spatio-temporal coherence analysis

In this paper, we present a passive approach for effective detection and localization of region-level forgery from video sequences possibly with camera motion. As most digital image/video capture devices do not have modules for embedding watermark or signature, passive forgery detection which aims to detect the traces of tampering without embedded information has become the major focus of recent research. However, most of current passive approaches either work only for frame-level detection and cannot localize region-level forgery, or suffer from high false detection rates for localization of tampered regions. In this paper, we investigate two common region-level inpainting methods for object removal, temporal copy-and-paste and exemplar-based texture synthesis, and propose a new approach based on spatio-temporal coherence analysis for detection and localization of tampered regions. Our approach can handle camera motion and multiple object removal. Experiments show that our approach outperforms previous approaches, and can effectively detect and localize regions tampered by temporal copy-and-paste and texture synthesis.     

Fingerprint forgery--a survey

The article describes and analyzes the international survey of fingerprint and laboratory personnel about fingerprint forgery, conducted in four countries during the years 1998 through 1999. The awareness and the attitude of the professionals to the problem of fingerprint forgery was tested.     

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.     

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.     

一起練习记忆摹仿签名笔迹的鉴定与启示

本文通过对一起检验鉴定案例的分析,提出练习记忆摹仿的概念,并对该类案件的检验鉴定,总结出十点启示。     

伪装签名检验初探

伪装签名是一种签名造假手段,其目的是通过否认签名是自己所写,非法占有他人财物或逃避责任。伪装签名笔迹貌似正常,但受不同伪装手段的影响,笔迹会发生各种变化,因而检验难度较大。检验伪装签名时,鉴定人要解放思想,客观看待笔迹发生的变化,选用正确的检验方法,客观全面地选择笔迹特征,适时补充笔迹样本,条件具备时还应充分利用案情。     

利用激光、光敏印章机伪造印章印文的鉴定

利用激光刻章机雕刻、光敏印章机制印伪造印章印文是近年来出现的一种新的、仿真程度较高的伪造印章印文的方法。鉴定实践表明,这类伪造印章印文趋于专业化、技术化,且伪造的印章印文与真实印章印文的相似度较高。依据传统的鉴定依据和方法难以鉴别真伪,因此从该类伪造方法对其特点和鉴定依据、方法要点进行研究,尤其是对伪造形成方式及特点的研究,有助于科学的鉴定其真伪。     

Differentiating synthetic and optical zooming for passive video forgery detection: An anti-forensic perspective

A video can be manipulated using synthetic zooming without using the state-of-the-art video forgeries. Synthetic zooming is performed by upscaling individual frames of a video with varying scale factors followed by cropping them to the original frame size. These manipulated frames resemble genuine natural (optical) camera zoomed frames and hence may be misclassified as a pristine video by video forgery detection algorithms. Even if such a video is classified as forged, forensic investigators may ignore the results, believing it as part of an optical camera zooming activity. Hence, this can be used as an anti-forensic method which eliminates digital evidence. In this paper, we propose a method for differentiating optical camera zooming from synthetic zooming for video tampering detection. The features used for this method are pixel variance correlation and sensor pattern noise. Experimental results on a dataset containing 3200 videos show the effectiveness of the proposed method.     

练习摹仿笔迹的检验

在笔迹检验所受理的案件中,采取练习摹仿手法进行作案的呈上升趋势。练习摹仿笔迹酷似被摹仿人笔迹,仿真度高。如何准确识别摹仿,认定摹仿人,已成为当前文检工作者研究的重点课题之一。本文作者总结实践经验,参考有关文献,探讨了练习摹仿笔迹的形成机理、特点、变化规律、相关因素及检验对策。     

“克隆”票据犯罪案件侦查研究

“克隆”票据犯罪案件是指犯罪嫌疑人以真实票据为基础伪造出与其要素相同或基本相同的票据,进行骗诈的犯罪案件。此类案件有两种情况:一是以真实票据为基础,伪造出与其要素相同或基本相同的票据,使用伪造的票据,在票据有效期内向银行或其他金融机构提示付款、申请贴现、质押贷款或背书转让的犯罪案件;二是以真票据为基础,伪造出与其要素相同或基本相同的票据,并不是直接用伪造的票据,而是通过与真实票据接触,伺机偷换票据,使用真实票据向银行或其池金融机构提示付款、申请贴现。“克隆”票据诈骗案件侦查除采用普通诈骗案件侦查的方法外,还可利用票据(包括伪造的票据)为线索,通过调查票据的原因关系、票据兑付、背书等环节进行侦查。