Qibin Sun

Blind detection of photomontage using higher order statistics

We investigate the prospect of using bicoherence features for blind image splicing detection. Image splicing is an essential operation for digital photomontaging, which in turn is a technique for creating image forgery. We examine the properties of bicoherence features on a data set, which contains image blocks of diverse image properties. We then demonstrate the limitation of the baseline bicoherence features for image splicing detection. Our investigation has led to two suggestions for improving the performance of bicoherence features, i.e., estimating the bicoherence features of the authentic counterpart and incorporating features that characterize the variance of the feature performance. The features derived from the suggestions are evaluated with support vector machine (SVM) classification and is shown to improve the image splicing detection accuracy from 62% to about 70%.

Robust Lossless Image Data Hiding Designed for Semi-Fragile Image Authentication

Recently, among various data hiding techniques, a new subset, lossless data hiding, has received increasing interest. Most of the existing lossless data hiding algorithms are, however, fragile in the sense that the hidden data cannot be extracted out correctly after compression or other incidental alteration has been applied to the stego-image. The only existing semi-fragile (referred to as robust in this paper) lossless data hiding technique, which is robust against high-quality JPEG compression, is based on modulo-256 addition to achieve losslessness. In this paper, we first point out that this technique has suffered from the annoying salt-and-pepper noise caused by using modulo-256 addition to prevent overflow/underflow. We then propose a novel robust lossless data hiding technique, which does not generate salt-and-pepper noise. By identifying a robust statistical quantity based on the patchwork theory and employing it to embed data, differentiating the bit-embedding process based on the pixel groups distribution characteristics, and using error correction codes and permutation scheme, this technique has achieved both losslessness and robustness. It has been successfully applied to many images, thus demonstrating its generality. The experimental results show that the high visual quality of stego-images, the data embedding capacity, and the robustness of the proposed lossless data hiding scheme against compression are acceptable for many applications, including semi-fragile image authentication. Specifically, it has been successfully applied to authenticate losslessly compressed JPEG2000 images, followed by possible transcoding. It is expected that this new robust lossless data hiding algorithm can be readily applied in the medical field, law enforcement, remote sensing and other areas, where the recovery of original images is desired.

New semi-fragile image authentication watermarking techniques using random bias and nonuniform quantization

Semi-fragile watermarking techniques aim at detecting malicious manipulations on an image, while allowing acceptable manipulations such as lossy compression. Although both of these manipulations are considered to be pixel value changes, semi-fragile watermarks should be sensitive to malicious manipulations but robust to the degradation introduced by lossy compression and other defined acceptable manipulations. In this paper, after studying the characteristics of both natural images and malicious manipulations, we propose two new semi-fragile authentication techniques robust against lossy compression, using random bias and nonuniform quantization, to improve the performance of the methods proposed by Lin and Chang.

A hybrid watermarking scheme for H.264/AVC video

A novel H.264/AVC watermarking method is proposed in this paper. By embedding the robust watermark into DCT domain and the fragile watermark into motion vectors respectively, the proposed method can jointly achieve both copyright protection and authentication. Our scheme outperforms other video watermarking schemes on higher watermarking capacity especially in lower compression bit-rates. Furthermore, being well aligned with Lagrangian optimization for mode choice featured in H.264/AVC, the proposed scheme only introduces small distortions into the video content. Experimental results also demonstrate that the proposed solution is very computationally efficient during watermark extraction.

Robust Hash for Detecting and Localizing Image Tampering

An image hash should be (1) robust to allowable operations and (2) sensitive to illegal manipulations and distinct queries. Some applications also require the hash to be able to localize image tampering. This requires the hash to contain both robust content and alignment information to meet the above criterion. Fulfilling this is difficult because of two contradictory requirements. First, the hash should be small and second, to verify authenticity and then localize tampering, the amount of information in the hash about the original required would be large. Hence a tradeoff between these requirements needs to be found. This paper presents an image hashing method that addresses this concern, to not only detect but also localize tampering using a small signature (< 1kB). Illustrative experiments bring out the efficacy of the proposed method compared to existing methods.

Passive-blind Image Forensics

Publisher Summary This chapter discusses passive-blind image forensics (PBIF). PBIF is concerned with two problems: image forgery detection and image source identification. Most of the image forgery detection techniques are associated to the specific image forgery creation techniques. Forgery detectors uncover act of fabrication by assessing the authenticity of a given image. There are two approaches for image forgery detection: detecting the authentic characteristics of images and detecting the telltale characteristics specific to the image forgery creation techniques. The goal of the passive-blind image source identification is to identify the type of image source. Identification of the image source helps in deciding whether an image is acceptable for a specific application. One problem of concern in image source identification is the classification of photographic images (PIMs) and photorealistic computer graphics (PRCGs), so the chapter summarizes the differences between PIMs and PRCGs––namely, object model difference, light transport difference, and acquisition difference. The chapter gives a reference of data set by enlisting the category of images in it and concludes with a review of the automatic or the semi-automatic computer techniques for image forgery creation.

A robust and secure media signature scheme for JPEG images

We have introduced a robust and secure digital signature solution for multimedia content authentication, by integrating content feature extraction, error correction coding (ECC), watermarking, and cryptographic hashing into a unified framework. We have successfully applied it to JPEG2000 as well as generic wavelet transform based applications. In this paper, we shall introduce a new JPEG-compliant solution under our proposed framework but with different ECC and watermarking methods. System security analysis as well as system robustness evaluation will also be given to further demonstrate the practicability of our method.

Robust lossless image data hiding

Recently, among various data hiding techniques, a new subset, lossless data hiding, has drawn tremendous interest. Most existing lossless data hiding algorithms are, however, fragile in the sense that they can be defeated when compression or other small alteration is applied to the marked image. The method of C. De Vleeschouwer et al. (see IEEE Trans. Multimedia, vol.5, p.97-105, 2003) is the only existing semi-fragile lossless data hiding technique (also referred to as robust lossless data hiding), which is robust against high quality JPEG compression. We first point out that this technique has a fatal problem: salt-and-pepper noise caused by using modulo 256 addition. We then propose a novel robust lossless data hiding technique, which does not generate salt-and-pepper noise. This technique has been successfully applied to many commonly used images (including medical images, more than 1000 images in the CorelDRAW database, and JPEG2000 test images), thus demonstrating its generality. The experimental results show that the visual quality, payload and robustness are acceptable. In addition to medical and law enforcement fields, it has been applied to authenticate losslessly compressed JPEG2000 images.

A secure and robust digital signature scheme for JPEG2000 image authentication

In this paper, we present a secure and robust content-based digital signature scheme for verifying the authenticity of JPEG2000 images quantitatively, in terms of a unique concept named lowest authenticable bit rates (LABR). Given a LABR, the authenticity of the watermarked JPEG2000 image will be protected as long as its final transcoded bit rate is not less than the LABR. The whole scheme, which is extended from the crypto data-based digital signature scheme, mainly comprises signature generation/verification, error correction coding (ECC) and watermark embedding/extracting. The invariant features, which are generated from fractionalized bit planes during the procedure of embedded block coding with optimized truncation in JPEG2000, are coded and signed by the senders private key to generate one crypto signature (hundreds of bits only) per image, regardless of the image size. ECC is employed to tame the perturbations of extracted features caused by processes such as transcoding. Watermarking only serves to store the check information of ECC. The proposed solution can be efficiently incorporated into the JPEG2000 codec (Part 1) and is also compatible with Public Key Infrastructure. After detailing the proposed solution, system performance on security as well as robustness will be evaluated.

A new semi-fragile image authentication framework combining ECC and PKI infrastructures

Presents a new semi-fragile framework aiming at extending public key signature scheme from message level to content level. The content signing procedure includes signature generation and watermark embedding while the content authentication procedure includes watermark extraction and signature verification. One main unique contribution is the novel use of error correction coding (ECC) to address the incidental distortions caused by some acceptable manipulations such as lossy compression. Another unique feature is integration of PKI security infrastructure and the hashing mechanism to achieve security and short signatures/watermarks. In the signing procedure, block-based invariant features are extracted from the image content and then encoded by ECC to obtain their corresponding parity check bits (PCB). All PCBs are then embedded back into image as watermarks for the purpose of authentication and locating content alteration. In addition, codewords are concatenated, hashed and finally signed by content owners private key to generate a global cryptographic signature. The authentication procedure is the inverse procedure of signing except using content owners public key for signature verification.