Somayeh Sadeghi

A novel forged blurred region detection system for image forensic applications

As new technologies and devices are introduced in the market, the crime rate also increases in developing and developed countries. One such crime is image forgery which can be detected by forensic applications. In this paper, we propose a novel idea for identifying forgery attack done by blur artifact unlike existing forgery attack done by geometrical distortion such as rotation and scaling. The proposed method segment region of interest from the input forgery image based on the combination of statistical analysis with color texture analysis which includes blur artifact region. For each region of interest, we propose a new method for estimating degree of blur to separate forged blur artifact and normal blur artifact. In order to validate the identified forged blur artifact, we explore Fourier and Gabor texture features to study the structure of the forged blur artifact which eliminates false blur forged blur artifact. To evaluate the proposed forged blurred region detection method, we use two standard databases namely, Image data manipulation, and MICC-F220 for experimentation. Experimental results of the proposed method with existing methods show that the proposed method outperforms the existing methods in terms of forged blur artifact region detection.

Image Region Duplication Forgery Detection Based on Angular Radial Partitioning and Harris Key-Points

Region duplication forgery where a part of the image itself is copied and pasted onto a different part of the same image grid is becoming more popular in image manipulation. The forgers often apply geometric transformations such as rotation and scaling operations to make the forgery imperceptible. In this study, an image region duplication forgery detection algorithm is proposed based on the angular radial partitioning and Harris key-points. Two standard databases have been used: image data manipulation and MICC-F220 (Media Integration and Communication Center– of the University of Florence) for experimentation. Experiment results demonstrate that the proposed technique can detect rotated regions in multiples of 30 degrees and can detect region duplication with different scaling factors from 0.8, to 1.2. More experimental results are presented to confirm the effectiveness of detecting region duplication that has undergone other changes, such as Gaussian noise, and JPEG compression.

Electromagnetismlike Mechanism Descriptor with Fourier Transform for a Passive Copy-move Forgery Detection in Digital Image Forensics.

Copy-move forgery is a special type of forgery that involves duplicating one region of an image by covering it with a copy of another region from the same image. This study develops a simple and powerful descriptor called Electromagnetismlike mechanism descriptor (EMag), for locating tampered areas in copy-move forgery on the basis of Fourier transform within a reasonable amount of time. EMag is based on the collective attraction-repulsion mechanism, which considers each images pixel as an electrical charge. The main component of EMag is the degree of the attraction-repulsion force between the current pixel and its neighbours. In the proposed algorithm, the image is divided into similar non-overlapping blocks, and then the final force for each block is evaluated and used to construct the tampered image features vector. The experimental results demonstrate the efficiency of the proposed algorithm in terms of detection time and detection accuracy. The detection rate of the proposed algorithm is improved by reduction of false positive rate (FPR) and increment of true positive rate (TPR).

Efficient Image Authentication and Tamper Localization Algorithm Using Active Watermarking

Due to the increasing number of forged images and possibilities of effortless digital manipulations, certain organizations have started to focus on approaches that help preserve their digital data integrity. Image authentication systems try to accurately verify the integrity of digital images, of which digital watermarking is known to be one of the most precise techniques in authenticating the originality of digital images. This chapter has presented a novel image authentication system with accurate tamper localization ability. In the proposed algorithm a 16-bit watermark key has been created from each block of pixels in a host image. The generated 16-bit watermark key will be embedded into the host image by utilizing a fragile watermarking algorithm. The security of the watermarking algorithm will be ensured by using the proposed block cipher algorithm, which encrypts the user key and watermarking algorithm. The proposed tamper detection algorithm conducts two comprehensive comparisons, to ensure the accuracy of the results. The high quality watermarks and powerful tamper detection approaches, along with less computational complexity are the main advantages of the proposed image authentication system, which makes it suitable for real-time application. Several tampering experiments have been conducted to examine the proposed algorithm. The experiment results have clearly proved that, the proposed method is not only efficient, but also very accurate in detecting different types of digital image manipulations, such as, small region tampering, cropping tampering and bit tampering.

State of the art in passive digital image forgery detection: copy-move image forgery

Authenticating digital images is increasingly becoming important because digital images carry important information and due to their use in different areas such as courts of law as essential pieces of evidence. Nowadays, authenticating digital images is difficult because manipulating them has become easy as a result of powerful image processing software and human knowledge. The importance and relevance of digital image forensics has attracted various researchers to establish different techniques for detection in image forensics. The core category of image forensics is passive image forgery detection. One of the most important passive forgeries that affect the originality of the image is copy-move digital image forgery, which involves copying one part of the image onto another area of the same image. Various methods have been proposed to detect copy-move forgery that uses different types of transformations. The goal of this paper is to determine which copy-move forgery detection methods are best for different image attributes such as JPEG compression, scaling, rotation. The advantages and drawbacks of each method are also highlighted. Thus, the current state-of-the-art image forgery detection techniques are discussed along with their advantages and drawbacks.

An Efficient Image Self-recovery and Tamper Detection Using Fragile Watermarking

Fragile watermarking is one of the most effective approaches to insure the integrity of digital images. In this paper, an efficient self-recovery and tamper localization scheme using fragile watermarking is proposed. The proposed method generates 12-bit tamper detection data and 20-bit self-recovery data for each 4 \(\times \) 4 block. The generated tamper detection and self-recovery features are encrypted by utilizing user secrete key. A random block mapping scheme is used to embed the encrypted block features into its mapping block. The proposed two-level tamper detection creates high capacity for tamper detection data which improves the security and tamper localization. The performance of the proposed scheme and its robustness against famous security attacks is analyzed. The experimental results demonstrate the high efficiency of the proposed scheme in terms of tamper detection rate, tamper localization and self-recovery. This method is robust against security attacks such as collage attack and constant average attack.