Showing papers on "Digital watermarking published in 2012"

Low distortion transform for reversible watermarking

Abstract: This paper proposes a low-distortion transform for prediction-error expansion reversible watermarking. The transform is derived by taking a simple linear predictor and by embedding the expanded prediction error not only into the current pixel but also into its prediction context. The embedding ensures the minimization of the square error introduced by the watermarking. The proposed transform introduces less distortion than the classical prediction-error expansion for complex predictors such as the median edge detector or the gradient-adjusted predictor. Reversible watermarking algorithms based on the proposed transform are analyzed. Experimental results are provided.

An improved SVD-based watermarking technique for copyright protection

Abstract: The drawbacks of SVD-based image watermarking are false positive, robust and transparency. The former can be overcome by embedding the principal components of the watermark into the host image, the latter is dependent on how much the quantity (i.e., scaling factor) of the principal components is embedded. For the existing methods, the scaling factor is a fixed value; actually, it is image-dependent. Different watermarks need the different scaling factors, although they are embedded in the same host image. In this paper, two methods are proposed to improve the reliability and robustness. To improve the reliability, for the first method, the principal components of the watermark are embedded into the host image in discrete cosine transform (DCT); and for the second method, those are embedded into the host image in discrete wavelets transform (DWT). To improve the robustness, the particle swarm optimization (PSO) is used for finding the suitable scaling factors. The experimental results demonstrate that the performance of the proposed methods outperforms than those of the existing methods.

Robust Reversible Watermarking via Clustering and Enhanced Pixel-Wise Masking

Abstract: Robust reversible watermarking (RRW) methods are popular in multimedia for protecting copyright, while preserving intactness of host images and providing robustness against unintentional attacks. However, conventional RRW methods are not readily applicable in practice. That is mainly because: 1) they fail to offer satisfactory reversibility on large-scale image datasets; 2) they have limited robustness in extracting watermarks from the watermarked images destroyed by different unintentional attacks; and 3) some of them suffer from extremely poor invisibility for watermarked images. Therefore, it is necessary to have a framework to address these three problems, and further improve its performance. This paper presents a novel pragmatic framework, wavelet-domain statistical quantity histogram shifting and clustering (WSQH-SC). Compared with conventional methods, WSQH-SC ingeniously constructs new watermark embedding and extraction procedures by histogram shifting and clustering, which are important for improving robustness and reducing run-time complexity. Additionally, WSQH-SC includes the property-inspired pixel adjustment to effectively handle overflow and underflow of pixels. This results in satisfactory reversibility and invisibility. Furthermore, to increase its practical applicability, WSQH-SC designs an enhanced pixel-wise masking to balance robustness and invisibility. We perform extensive experiments over natural, medical, and synthetic aperture radar images to show the effectiveness of WSQH-SC by comparing with the histogram rotation-based and histogram distribution constrained methods.

A feature-based robust digital image watermarking scheme

Abstract: The effectiveness of a digital watermarking algorithm is indicated by the robustness of embedded watermarks against various attacks. Improving the robustness of a watermark so as to withstand attacks has been one of the main research objectives in digital image watermarking. The two issues of existing feature-based schemes that have to be addressed are: one is avoiding repeated selection of robust regions for watermarking to resist similar attacks, and the other is the difficulty of selecting the most robust and smallest feature region set to be watermarked. In order to achieve robustness, an overall architecture for a feature-based robust digital image watermarking scheme is designed. A simulated attacking procedure is performed using predefined attacks to evaluate the robustness of every candidate feature region selected. Comparing with some well-known feature-based methods, the proposed method exhibits better performance in robust digital watermarking.

A Joint Encryption/Watermarking System for Verifying the Reliability of Medical Images

Abstract: In this paper, we propose a joint encryption/water-marking system for the purpose of protecting medical images. This system is based on an approach which combines a substitutive watermarking algorithm, the quantization index modulation, with an encryption algorithm: a stream cipher algorithm (e.g., the RC4) or a block cipher algorithm (e.g., the AES in cipher block chaining (CBC) mode of operation). Our objective is to give access to the outcomes of the image integrity and of its origin even though the image is stored encrypted. If watermarking and encryption are conducted jointly at the protection stage, watermark extraction and decryption can be applied independently. The security analysis of our scheme and experimental results achieved on 8-bit depth ultrasound images as well as on 16-bit encoded positron emission tomography images demonstrate the capability of our system to securely make available security attributes in both spatial and encrypted domains while minimizing image distortion. Furthermore, by making use of the AES block cipher in CBC mode, the proposed system is compliant with or transparent to the DICOM standard.

Robust Watermarking of Compressed and Encrypted JPEG2000 Images

Abstract: Digital asset management systems (DAMS) generally handle media data in a compressed and encrypted form. It is sometimes necessary to watermark these compressed encrypted media items in the compressed-encrypted domain itself for tamper detection or ownership declaration or copyright management purposes. It is a challenge to watermark these compressed encrypted streams as the compression process would have packed the information of raw media into a low number of bits and encryption would have randomized the compressed bit stream. Attempting to watermark such a randomized bit stream can cause a dramatic degradation of the media quality. Thus it is necessary to choose an encryption scheme that is both secure and will allow watermarking in a predictable manner in the compressed encrypted domain. In this paper, we propose a robust watermarking algorithm to watermark JPEG2000 compressed and encrypted images. The encryption algorithm we propose to use is a stream cipher. While the proposed technique embeds watermark in the compressed-encrypted domain, the extraction of watermark can be done in the decrypted domain. We investigate in detail the embedding capacity, robustness, perceptual quality and security of the proposed algorithm, using these watermarking schemes: Spread Spectrum (SS), Scalar Costa Scheme Quantization Index Modulation (SCS-QIM), and Rational Dither Modulation (RDM).

Image Watermarking Using 3-Level Discrete Wavelet Transform (DWT)

Abstract: We have implemented a robust image watermarking technique for the copyright protection based on 3-level discrete wavelet transform (DWT). In this technique a multi-bit watermark is embedded into the low frequency sub-band of a cover image by using alpha blending technique. The insertion and extraction of the watermark in the grayscale cover image is found to be simpler than other transform techniques. The proposed method is compared with the 1-level and 2-level DWT based image watermarking methods by using statistical parameters such as peak-signal-to-noise-ratio (PSNR) and mean square error (MSE). The experimental results demonstrate that the watermarks generated with the proposed algorithm are invisible and the quality of watermarked image and the recovered image are improved.

A robust and secure watermarking scheme based on singular values replacement

Abstract: Digital watermarking is an application associated with copyright protection. Any digital object can be used as a carrier to carry information. If the information is related to object then it is known as a watermark which can be visible or invisible. In the era of digital information, there are multiple danger zones like copyright and integrity violations, of digital object. In case of any dispute during rights violation, content creator can prove ownership by recovering the watermark. Two most important prerequisites for an efficient watermarking scheme are robustness and security. Watermark must be robust and recoverable even if a part of content is altered by one or more attacks like compression, filtering, geometric distortions, resizing, etc. In this work, we propose a blind watermarking scheme based on the discrete wavelet transform (DWT) and singular value decomposition (SVD). Singular values (SV’s) of high frequency (HH) band are used to optimize perceptual transparency and robustness constraints. Although most of the SVD-based schemes prove to be robust, little attention has been paid to their security aspect. Therefore, we introduce a signature-based authentication mechanism at the decoder to improve security. Resulting blind watermarking scheme is secure and robust.

A Dual-Channel Time-Spread Echo Method for Audio Watermarking

Abstract: This work proposes a novel dual-channel time-spread echo method for audio watermarking, aiming to improve robustness and perceptual quality. At the embedding stage, the host audio signal is divided into two subsignals, which are considered to be signals obtained from two virtual audio channels. The watermarks are implanted into the two subsignals simultaneously. Then the subsignals embedded with watermarks are combined to form the watermarked signal. At the decoding stage, the watermarked signal is split up into two watermarked subsignals. The similarity of the cepstra corresponding to the watermarked subsignals is exploited to extract the embedded watermarks. Moreover, if a properly designed colored pseudonoise sequence is used, the large peaks of its auto-correlation function can be utilized to further enhance the performance of watermark extraction. Compared with the existing time-spread echo-based schemes, the proposed method is more robust to attacks and has higher imperceptibility. The effectiveness of our method is demonstrated by simulation results.

Robust DT-CWT Watermarking for DIBR 3D Images

Abstract: The popularity of 3D content is on the rise since it provides an immersive experience to viewers. In this situation, depth-image-based rendering (DIBR) has taken on an important role in 3D technology due to its low bandwidth cost and ease of depth configuration. Noting that the viewer could record provided center view or synthesized views for illegal distribution, it is clear that copyright protection must be taken into account for the DIBR 3D content, including the possibility that one single view could be illegally distributed as 2D content. In this paper, we propose a robust watermarking scheme for DIBR 3D images by quantization on dual-tree complex wavelet transform (DT-CWT) coefficients with consideration of imperceptibility. To make the proposed scheme robust to DIBR process, two characteristics of DT-CWT are employed: approximate shift invariance and directional selectivity. We select certain coefficient sub-blocks and group the coefficient rows based on the properties of DIBR. On the extraction side, the threshold is carefully chosen with a low false positive rate. The simulation results show that the embedded watermark is stably extracted from the center view and the synthesized left and right views. In addition, even if the synthesized left and right views are distorted by general attacks, the watermark is successfully extracted. Furthermore, the proposed scheme is robust to pre-processing of the depth image and baseline adjusting, which are common processing on the DIBR system for better quality of 3D views.

Copyright Protection for E-Government Document Images

Abstract: The proposed copyright protection scheme combines the discrete cosine transform (DCT) and singular value decomposition (SVD) using a control parameter to avoid the false-positive problem. In this article, we propose an efficient copyright protection scheme for e-government document images. First, we apply the discrete cosine transform (DCT) to the host image and use the zigzag space-filling curve (SFC) for the DCT coefficients. The DCT coefficients in the zigzag manner are then mapped into four areas with different frequencies in a rectangular shape. Then, we apply the singular value decomposition (SVD) operation to each area, and the host image is modified by the left singular vectors and the singular values of the DCT-transformed watermark to embed the watermark image. The left singular vectors and singular values are used as a control parameter to avoid the false-positive problem. Each area decides the scaling factor's optimal value using a genetic algorithm (GA) with the mean of the watermark's SVs. A scaling factor is simulated by chromosomes, and several optimization GA operators are used. After remapping each modified coefficient DCT back to the original position, the proposed inverse DCT produces the watermarked image. Our experimental results show that we can improve the image quality GA-based evolution and that this approach is robust under several kinds of attacks.

An Introduction to Image Steganography Techniques

Abstract: Steganography is a form of security technique through obscurity, the science and art of hiding the existence of a message between sender and intended recipient. Steganography has been used to hide secret messages in various types of files, including digital images, audio and video. The three most important parameters for audio steganography are imperceptibility, payload, and robustness. Different applications have different requirements of the steganography technique used. This paper intends to give an overview of image steganography, its uses and techniques.

An SVD-based image watermarking in wavelet domain using SVR and PSO

Abstract: The paper presents a novel blind watermarking scheme for image copyright protection, which is developed in the discrete wavelet transform (DWT) and is based on the singular value decomposition (SVD) and the support vector regression (SVR). Its embedding algorithm hides a watermark bit in the low-low (LL) subband of a target non-overlap block of the host image by modifying a coefficient of U component on SVD version of the block. A blind watermark-extraction is designed using a trained SVR to estimate original coefficients. Subsequently, the watermark bit can be computed using the watermarked coefficient and its corresponding estimate coefficient. Additionally, the particle swarm optimization (PSO) is further utilized to optimize the proposed scheme. Experimental results show the proposed scheme possesses significant improvements in both transparency and robustness, and is superior to existing methods under consideration here.

A wavelet-based particle swarm optimization algorithm for digital image watermarking

Abstract: Digital watermarking techniques have been proposed for copyright protection and multimedia data authentication. The achieved tradeoffs from these techniques between imperceptibility and robustness are always controversial. This paper proposes the application of Discrete Wavelet Transform DWT into image watermarking by using Particle Swarm Optimization PSO which is an evolutionary technique with the stochastic, population-based algorithm for solving this problem. To protect copyright information of digital images, the original image is decomposed according to two-dimensional discrete wavelet transform. Subsequently the preprocessed watermark with an affined scrambling transform is optimal embedded into the vertical subband HL_{m} coefficients in wavelet domain without compromising the quality of the image. In the optimal process, the scaling factors are trained with the assistance of PSO. Furthermore, a novel algorithmic framework is proposed via a forecasted feasibility of the approach to parameters evaluation of hypothesized watermarked images in DWT domain. Simulation results show that the proposed watermarking procedure has better performances in imperceptibility and robustness under various distortions in the comparison of the previous scheme.

Analysis of P-QRS-T Components Modified by Blind Watermarking Technique Within the Electrocardiogram Signal for Authentication in Wireless Telecardiology Using DWT

Abstract: Presently considerable amount of work has been done in tele-monitoring which involves the transmission of bio-signals and medical images in the wireless media. Intelligent exchange of bio-signals amongst hospitals needs efficient and reliable transmission. Watermarking adds ―ownership‖ information in multimedia contents to prove the authenticity, to verify signal integrity, or to achieve control over the copy process. This paper proposes a novel session based blind watermarking method with secret key by embedding binary watermark image into (Electrocardiogram) ECG signal. The ECG signal is a sensitive diagnostic tool that is used to detect various cardio-vascular diseases by measuring and recording the electrical activity of the heart in exquisite detail. The first part of this paper proposes a multi-resolution wavelet transform based system for detection ‗P',‗Q',‗R',‗S',‗T' peaks complex from original ECG signal of human being. ‗R-R' time lapse is an important component of the ECG signal that corresponds to the heartbeat of the concerned person. Abrupt increase in height of the ‗R' wave or changes in the measurement of the ‗R-R' interval denote various disorders of human heart. Similarly ‗P-P', ‗Q-Q', ‗S-S', ‗T-T' intervals also correspond to different disorders of heart and their peak amplitude envisages other cardiac diseases. In this proposed method the ‗P Q R S T'-peaks are marked and stored over the entire signal and the time interval between two consecutive ‗R'-peaks and other peaks interval are measured to detect anomalies in behavior of heart, if any. The peaks are achieved by the composition of Daubechies sub-bands wavelet of original ECG signal. The accuracy of the P, QRS and T components detection and interval measurement is achieved with high accuracy by processing and thresholding the original ECG signal. The second part of the paper proposes a Discrete Wavelet Transformation (DWT) and Spread Spectrum based watermarking technique. In this approach, the generated watermarked signal having an acceptable level of imperceptibility and distortion is compared to the Original ECG signal. Finally, a comparative study is done for the intervals of two consecutive ‗R-R' peaks, ‗P-R', ‗Q-T', ‗QTc', QRS duration, cardiac output between original P, QRS and T components detected ECG signal and the watermarked P,QRS and T components detected ECG signal.

Performance Analysis of a Block-Neighborhood-Based Self-Recovery Fragile Watermarking Scheme

Abstract: In this paper, we present the performance analysis of a self-recovery fragile watermarking scheme using block-neighbor- hood tamper characterization. This method uses a pseudorandom sequence to generate the nonlinear block-mapping and employs an optimized neighborhood characterization method to detect the tampering. Performance of the proposed method and its resistance to malicious attacks are analyzed. We also investigate three optimization strategies that will further improve the quality of tamper localization and recovery. Simulation results demonstrate that the proposed method allows image recovery with an acceptable visual quality (peak signal-to-noise ratio (PSNR) as 25 dB) up to 60% tampering.

Robust Image Alignment for Tampering Detection

Abstract: The widespread use of classic and newest technologies available on Internet (e.g., emails, social networks, digital repositories) has induced a growing interest on systems able to protect the visual content against malicious manipulations that could be performed during their transmission. One of the main problems addressed in this context is the authentication of the image received in a communication. This task is usually performed by localizing the regions of the image which have been tampered. To this aim the aligned image should be first registered with the one at the sender by exploiting the information provided by a specific component of the forensic hash associated to the image. In this paper we propose a robust alignment method which makes use of an image hash component based on the Bag of Features paradigm. The proposed signature is attached to the image before transmission and then analyzed at destination to recover the geometric transformations which have been applied to the received image. The estimator is based on a voting procedure in the parameter space of the model used to recover the geometric transformation occurred into the manipulated image. The proposed image hash encodes the spatial distribution of the image features to deal with highly textured and contrasted tampering patterns. A block-wise tampering detection which exploits an histograms of oriented gradients representation is also proposed. A non-uniform quantization of the histogram of oriented gradient space is used to build the signature of each image block for tampering purposes. Experiments show that the proposed approach obtains good margin of performances with respect to state-of-the art methods.

A blind reversible method for watermarking relational databases based on a time-stamping protocol

Abstract: Highlights? An authentication protocol is designed for a reversible watermarking using time-stamp protocol. ? The prediction-error expansion on integers technique is used to achieve reversibility. ? The watermark is detected successfully even most of watermarked relation tuples are deleted. Digital watermarking technology has been adopted lately as an effective solution to protecting the copyright of digital assets from illicit copying. Reversible watermark, which is also called invertible watermark, or erasable watermark, helps to recover back the original data after the content has been authenticated. Such reversibility is highly desired in some sensitive database applications, e.g. in military and medical data. Permanent distortion is one of the main drawbacks of the entire irreversible relational database watermarking schemes. In this paper, we design an authentication protocol based on an efficient time-stamp protocol, and we propose a blind reversible watermarking method that ensures ownership protection in the field of relational database watermarking. Whereas previous techniques have been mainly concerned with introducing permanent errors into the original data, our approach ensures one hundred percent recovery of the original database relation after the owner-specific watermark has been detected and authenticated. In the proposed watermarking method, we utilize a reversible data-embedding technique called prediction-error expansion on integers to achieve reversibility. The detection of the watermark can be completed successfully even when 95% of a watermarked relation tuples are deleted. Our extensive analysis shows that the proposed scheme is robust against various forms of database attacks, including adding, deleting, shuffling or modifying tuples or attributes.

Location based robust audio watermarking algorithm for social TV system

Abstract: There is a big gap between TV and social network in conventional Social Networking Services. The mobile terminals cannot get the interactive URL from TV broadcasting automatically and the social network cannot get the location information of TV customers at the same time. To bridge the two kind of media, the information of value-added services hiding in the real-time audio stream of TV programs is transmitted. In this paper, the robust audio watermarking algorithm for social TV system is proposed, which analyze the character of background noise in the air channel, modify the energy coefficients of adjacent frequency bands in DCT domain of original audio carrier, and realize the recycling embedding of synchronization signal and watermarking information into original audio carrier. The experimental results indicate that, the proposed algorithm has a good hidden effect, and it is robust to air-channel background noise attack in transmitting process, AD/DA conversion, common signal processing, etc. In a conclusion, the proposed algorithm could put together TV and social network, which are separated before, and provide new idea for social TV system in its true sense.