Watermark Signal Research Articles

Robust and hybrid SVD-based image watermarking schemes:

These days, researchers have used many techniques in e-multimedia data for intellectual property protection. One of these important techniques is watermarking which is superior to Digital Signature because it does not rise overhead and it can prevent unauthorized users from misusing digital information. However, the number of attacks with aim of distorting watermark signal or disturbing watermarks detecting are exploding. Consequently, the watermark techniques have became more complicated, but still they are not fully robust against some geometric distortions. To overcome this issue and to be enough robust against the malicious attacks, and provide a high level of imperceptibility,the watermark schemes have discovered and developed the advantages by means of Singular-value decomposition. Therefore, in recent decades there has been a significant increasing in using of SVD domain in many new image watermarking schemes, which show high robustness and imperceptibility. This discussion of SVD in image watermarking schemes included: a concise overview on watermarking systems, a brief review on SVD properties in image processing and its weaknesses, the concept of SVD components, the main classification of different SVD based image-watermarking schemes; a brief summary of various secure SVD-based watermarking techniques and all major SVD coefficients modifying strategies are presented. In addition, potential issues and some existing solutions and guidelines are provided. Furthermore, the performance comparisons of the discussed techniques are presented in tabular format. This article contribution provides essential and potential information for the researchers to design, develop and implement efficient robust and hybrid SVD-based image watermarking systems.

Fusing PDTDFB magnitude and relative phase modeling for geometrical correction-based image watermarking

Robustness, which refers to the ability that watermark signal survives various attacks, like additive noise, compression, rotation, etc., has played extremely important role in the multiple applications of digital watermarking. As one of the most difficult kinds of signal processing operations for a digital watermark to survive, geometric distortions have become a central problem in image watermarking research. Therefore, developing a greatly robust digital image watermarking approach, which can withstand geometrical distortions, remains a quite challenging work. In this paper, a new geometrical correction-based image watermarking approach using PDTDFB magnitude and relative phase modeling is proposed. This approach consists of digital watermark embedding, geometric distortions correction, and digital watermark extraction. In the watermark embedding process, PDTDFB (Pyramidal dual-tree directional filter bank) decomposition is performed on the original host image, followed by the low-pass subband partitioning. Watermark bit is inserted into low-pass subband block by modifying (quantization index modulation, QIM) the set of low-pass PDTDFB coefficients. In the geometric correction, the PDTDFB magnitude and relative phase are modeled by using Weibull distribution and Vonn distribution, respectively. Utilizing the compact statistical model parameters, the LS-SVR (Least squares support vector regression) correction is performed to estimate the geometrical distortions parameters. After LS-SVR geometrical correction, the watermark bits are extracted from the watermarked low-pass subband by employing the inverse QIM. Experimental results confirm that, under various well-known practical attacks, including common signal processing operations and geometrical distortions, the proposed approach performs well compared to conventional image watermarking methods.

Audio steganography applications using auditory features watermarking

Watermarking is a technique for hiding data or information on a digital multimedia (image, sound and video) and is not visible to the ordinary eye and is resistant to digitization (editing media, noising, blurring, etc.). While audio watermark is defined as a technique of hiding data or confidential information into an audio data for “boarding” (audio host), people do not aware of the existence of additional data on the data host. Coding phase is hiding data by exchanging the original phase of the initial segment of the sound signal with the absolute phase of the watermark signal, while maintaining the relative phase between the signal segments using different phase segments of the original signal. When the phase difference between the original signal and the modified signal is small, the difference in sound produced is not detected by human hearing. To recognize ownership of multimedia content, testing is done first by combining the cover and watermark files. Experiment result on audio files shows that audio files successfully compressed on 50% efficiency without reducing the duration of the audio. After compression process, One of our audio sample which size is 3.37MB can be reduce to 1.68MB without reducing the duration of the audio.

A reversible and multipurpose ECG data hiding technique for telemedicine applications

Biomedical signals serves as a backbone of telemedicine industry and its analysis help the remote diagnosis possible. Security of biomedical data is one of the critical issues during its transmission from one storage device to another storage device. In this work, a completely reversible data hiding method is proposed for the ECG (Electrocardiogram) data. The proposed scheme is designed in such a way that it can find out false ownership claims as well as detect the tampered region of ECG data. In addition, original ECG signal is perfectly reconstructed from watermarked signal. The reversibility is tested for a large set of 460 different ECG signals generated from MIT-BIH arrhythmia database and complete reversibility (100%) is obtained each time. In proposed approach, deep neural network is used for an improved error prediction and prediction error expansion (PEE) is combined with it to ensure reversibility. Proposed method is a high capacity method and data hiding of 0.99 bps (bits per sample) is achieved with very little distortion in watermarked signal. The performance of proposed work is evaluated through percentage residual difference (PRD), signal to noise ratio (SNR) and normalized cross correlation (NCC). The most important contribution of proposed work is its multipurpose nature: ownership detection, tamper localization and 100% reversibility. Tamper detection and localization performance of the proposed method is also tested against different attacks and it is found to be quite good.

An optimized hierarchical encryption technique for tamper recognition

Digital images contain sensitive information that needs to be watermarked for ownership authentication and copyright verification. It is crucial to have a method to detect and recognize tampering when images are sent over insecure channels. The watermarking scenario becomes more complicated when an intruder is precluded from obtaining a watermark signal from a watermarked image since it can expose future point-to-point correspondences. The proposed scheme utilizes a hierarchical strategy for improving the security of the semi-fragile watermarking scheme that requires fewer data to be exchanged before each transaction. Consequently, the proposed watermarking method obtains a trade-off between robustness and imperceptibility by using a meta-heuristic approach, namely, the Sine Cosine Algorithm (SCA). Furthermore, an Artificial Neural Network (ANN) is built using the Softmax classifier to recognize possible attacks that might be performed by an intruder. The whole scheme is presented in the form of a GUI with the attack recognition triggered from the receiver’s side. Experimental results show improved image quality metrics like PSNR, correlation coefficient, and structural similarity when the scaling factor used in the watermarking algorithm is optimized using SCA.

Dual Video Watermarking Algorithm Based on SIFT and HVS in the Contourlet Domain

We propose dual un-compressed video watermarking algorithms based on human visual system and scale invariant feature transform (SIFT) in the contourlet domain. First, every frame is decomposed by contourlet transform to obtain the low-frequency band and several high-frequency sub-bands in different directions. The energy value of every high-frequency sub-band is calculated. The low-frequency sub-band and the high-frequency sub-bands of the largest energy values are chosen to be embedded into watermarking signals. Second, the first watermarking algorithm is realized to embed watermarking signals by adjusting the size ratio between the coefficient histograms of low-frequency sub-band because the coefficient histogram of low-frequency sub-band possesses invariance to conventional geometric transform. Third, to the second watermarking algorithm, the human visual masking threshold based on contourlet domain is calculated as the maximum embedding tolerance, which is embedded in the largest energy value of the high-frequency sub-band as watermarking signals to guarantee the imperceptibility. Finally, when the watermarked video frame suffered from geometrically attacks, the SIFT and fine corrections are combined to effectively correct and restore the synchronization between geometrically attacked video frames and watermarking signals. The experimental results indicate that: 1) the visual masking based on video motion information in the contourlet domain can effectively improve the transparency and 2) combining the histogram mapping in low-frequency sub-band coefficients with SIFT and fine corrections can resist common geometric attacks and therefore improve the robustness of the watermarking algorithm.

Robust authentication for paper-based text documents based on text watermarking technology.

Aiming at the problem of easy tampering and difficult integrity authentication of paper text documents, this paper proposes a robust content authentication method for printed documents based on text watermarking scheme resisting print-and-scan attack. Firstly, an authentication watermark signal sequence related to content of text document is generated based on the Logistic chaotic map model; then, the authentication watermark signal sequence is embedded into printed paper document by using a robust text watermarking scheme; finally, the watermark information is extracted from scanned image of paper document, and compared with the authentication watermark information calculated in real time by the text document content obtained by OCR technology, thereby performing content integrity authentication of the paper text documents. Experimental results show that our method can achieve the robust content integrity authentication of paper text documents, and can also accurately locate the tampering position. In addition, the document after embedding the watermark information has a good visual effect, and the text watermarking scheme has a large information capacity.

A Logarithmic Quantization-Based Image Watermarking Using Information Entropy in the Wavelet Domain.

Conventional quantization-based watermarking may be easily estimated by averaging on a set of watermarked signals via uniform quantization approach. Moreover, the conventional quantization-based method neglects the visual perceptual characteristics of the host signal; thus, the perceptible distortions would be introduced in some parts of host signal. In this paper, inspired by the Watson’s entropy masking model and logarithmic quantization index modulation (LQIM), a logarithmic quantization-based image watermarking method is developed by using the wavelet transform. Furthermore, the novel method improves the robustness of watermarking based on a logarithmic quantization strategy, which embeds the watermark data into the image blocks with high entropy value. The main significance of this work is that the trade-off between invisibility and robustness is simply addressed by using the logarithmic quantizaiton approach, which applies the entropy masking model and distortion-compensated scheme to develop a watermark embedding method. In this manner, the optimal quantization parameter obtained by minimizing the quantization distortion function effectively controls the watermark strength. In terms of watermark decoding, we model the wavelet coefficients of image by the generalized Gaussian distribution (GGD) and calculate the bit error probability of proposed method. Performance of the proposed method is analyzed and verified by simulation on real images. Experimental results demonstrate that the proposed method has the advantages of imperceptibility and strong robustness against attacks covering JPEG compression, additive white Gaussian noise (AWGN), Gaussian filtering, Salt&Peppers noise, scaling and rotation attack, etc.

A robust image watermarking scheme in DCT domain based on adaptive texture direction quantization

This paper proposes a novel robust image watermarking scheme in Discrete Cosine Transform (DCT) domain for active forensics. We investigate the relation between the positions and the modification magnitudes of DCT coefficients and directions of texture blocks. By exploring such relation, a direction-coefficient mapping is designed. First, the texture direction of each image block is estimated by Gabor filter. And then, according to the direction-coefficient mapping, one watermark bit is embedded into each block along its texture direction. Compared with existing schemes, the proposed method utilizes the direction features of texture blocks better . Therefore, the improvements in watermarked image quality and the robustness of watermark signal against image processing attacks are both achieved.

Watermarking Based on Compressive Sensing for Digital Speech Detection and Recovery †.

In this paper, a novel imperceptible, fragile and blind watermark scheme is proposed for speech tampering detection and self-recovery. The embedded watermark data for content recovery is calculated from the original discrete cosine transform (DCT) coefficients of host speech. The watermark information is shared in a frames-group instead of stored in one frame. The scheme trades off between the data waste problem and the tampering coincidence problem. When a part of a watermarked speech signal is tampered with, one can accurately localize the tampered area, the watermark data in the area without any modification still can be extracted. Then, a compressive sensing technique is employed to retrieve the coefficients by exploiting the sparseness in the DCT domain. The smaller the tampered the area, the better quality of the recovered signal is. Experimental results show that the watermarked signal is imperceptible, and the recovered signal is intelligible for high tampering rates of up to 47.6%. A deep learning-based enhancement method is also proposed and implemented to increase the SNR of recovered speech signal.

Effect of different attacks on image watermarking using dual tree complex wavelet transform (DTCWT) and principle component analysis (PCA)

Perceptibility and robustness are two incongruous requirements demanded by digital image watermarking for digital right management and other applications. A realistic way to concurrently satisfy the two contradictory requirements is to use robust watermark algorithm. The developed algorithm uses DTCWT and PCA techniques to embed watermark signal in host signal. To prove the algorithm robustness without much affecting perceptibility several attacks like noises, cropping, blurring, rotation are applied and tested by varying attack parameters. Parameters like Peak signal noise ratio and Correlation Coefficient are calculated for each attack. Attack percentage is varied and performance parameters are calculated to prove the robustness of the developed algorithm.

A novel CNN based security guaranteed image watermarking generation scenario for smart city applications

The rise of machine learning increases the current computing capabilities and paves the way to novel disruptive applications. In the current era of big data, the application of image retrieval technology for large-scale data is a popular research area. To ensure the robustness and security of digital image watermarking, we propose a novel algorithm using synergetic neural networks. The algorithm first processes a meaningful gray watermark image, then embeds it as a watermark signal into the block Discrete Cosine Transform (DCT) component. The companion algorithm for detection and extraction of the watermark uses a cooperative neural network, where the suspected watermark signal is used as the input while the output consists in the result of the recognition process. The simulation experiments show that the algorithm can complete certain image processing operations with improved performance, not only simultaneously completing watermark detection and extraction, but also efficiently determining the watermark attribution. Compared with other state-of-the-art models, the proposed model obtains an optimal Peak Signal-to-noise ratio (PSNR).

Watermarking Algorithm for PDF Document Based on Comment Objects

As PDF documents used extensively, security issues become increasingly more prominent. This paper presents an object-oriented PDF document page watermarking algorithm, in which a watermark signal is embedded as a legitimate PDF document page object. The object is not a pseudo-page to access the document reader, thus ensuring the regular PDF display function. The simulation results demonstrate the simpleness and robustness, security and invisibility, also with the capacity of watermarking algorithm guaranteed.

Dual-Tree Complex Wavelet Transform Based Audio Watermarking Using Distortion-Compensated Dither Modulation

This paper presents a local audio watermarking method based on the dual-tree complex wavelet transform (DT CWT) and distortion-compensated dither modulation (DC-DM). Specifically, we perform DT CWT on extracted audio segment, and embed the watermark signal in the decomposed low-pass coefficients. During the embedding process, the selected coefficients are block-divided into multiple host vectors, and the watermark signal is embedded into the selected set of host vectors by the dither modulation process. During the extraction process, the DC-DM is applied to generate the statistical differences, and the minimum distance decoding is employed to extract the watermark signal. Experimental results show that the proposed method is robust against common signal processing attacks and de-synchronization attacks, such as re-quantization, resampling, MP3 compression, cropping, and so on. Comparisons with the existing methods also show the superiority of our proposed method.

Distributed watermarking for secure control of microgrids under replay attacks

Abstract The problem of replay attacks in the communication network between Distributed Generation Units (DGUs) of a DC microgrid is examined. The DGUs are regulated through a hierarchical control architecture, and are networked to achieve secondary control objectives. Following analysis of the detectability of replay attacks by a distributed monitoring scheme previously proposed, the need for a watermarking signal is identified. Hence, conditions are given on the watermark in order to guarantee detection of replay attacks, and such a signal is designed. Simulations are then presented to demonstrate the effectiveness of the technique.

Embedding and Extracting Digital Watermark Based on DCT Algorithm

The principle of digital watermark is the method of adding digital watermark in the frequency domain. The digital watermark hides the watermark in digital media, such as image, voice, video, etc., so as to realize the functions of copyright protection, and identity recognition. DCT for Discrete Cosine Transform is used to transform the image pixel value and the frequency domain coefficient matrix to realize the embedding and extracting of the blind watermark in the paper. After success, the image is attacked by white noise and Gaussian low-pass filtering. The result shows that the watermark signal embedded based on the DCT algorithm is relatively robust, and can effectively resist some attack methods that use signal distortion to destroy the watermark, and has good robustness and imperceptibility.

Robust enhancement and centroid-based concealment of fingerprint biometric data into audio signals

Numerous issues are raised through the enhancement, transmission and storage of biometric data due to its high sensitivity and extremely crucial purpose. However, it might be impossible to recover if corrupted, counterfeited or hacked, thereby ruining the general aim of enhancing and securing it. In this paper, an 8-layered feature enhancement algorithm is proposed. The fingerprint image was enhanced and extracted using minutiae-based recognition system with the aim of eliminating all anomalies that comes with the image. The EQF (Effectiveness Quality Factor) and matching accuracy of the system all signifies efficiency and robustness of the enhancement scheme. In the other hand, a centroid-based audio watermarking is used to conceal the enhanced fingerprint biometric data into audio signals. The embedding algorithm starts by encrypting our enhanced image using chaotic logistic map prior to watermarking. It then proceeds with computing the centroid of the audio signal. DWT and DCT are performed on the sub-band which carries the centroid of each audio frame, thereby embedding the encrypted watermark bits into their domain. Achieved results from the performance evaluation of both contributions signify the efficiency of our proposed schemes. Moreover, some signal processing operations are also carried out on the watermarked signal and the outcome was intriguing as they were all counteracted.

Computationally Efficient Robust Color Image Watermarking Using Fast Walsh Hadamard Transform

Watermark is the copy deterrence mechanism used in the multimedia signal that is to be protected from hacking and piracy such a way that it can later be extracted from the watermarked signal by the decoder. Watermarking can be used in various applications such as authentication, video indexing, copyright protection and access control. In this paper a new CDMA (Code Division Multiple Access) based robust watermarking algorithm using customized 8 × 8 Walsh Hadamard Transform, is proposed for the color images and detailed performance and robustness analysis have been performed. The paper studies in detail the effect of spreading code length, number of spreading codes and type of spreading codes on the performance of the watermarking system. Compared to the existing techniques the proposed scheme is computationally more efficient and consumes much less time for execution. Furthermore, the proposed scheme is robust and survives most of the common signal processing and geometric attacks.

A Study on the Security Levels of Spread-Spectrum Embedding Schemes in the WOA Framework.

Security analysis is a very important issue for digital watermarking. Several years ago, according to Kerckhoffs' principle, the famous four security levels, namely insecurity, key security, subspace security, and stego-security, were defined for spread-spectrum (SS) embedding schemes in the framework of watermarked-only attack. However, up to now there has been little application of the definition of these security levels to the theoretical analysis of the security of SS embedding schemes, due to the difficulty of the theoretical analysis. In this paper, based on the security definition, we present a theoretical analysis to evaluate the security levels of five typical SS embedding schemes, which are the classical SS, the improved SS (ISS), the circular extension of ISS, the nonrobust and robust natural watermarking, respectively. The theoretical analysis of these typical SS schemes are successfully performed by taking advantage of the convolution of probability distributions to derive the probabilistic models of watermarked signals. Moreover, simulations are conducted to illustrate and validate our theoretical analysis. We believe that the theoretical and practical analysis presented in this paper can bridge the gap between the definition of the four security levels and its application to the theoretical analysis of SS embedding schemes.

A novel hybrid of DCT and SVD in DWT domain for robust and invisible blind image watermarking with optimal embedding strength

To optimize the tradeoff between imperceptibility and robustness properties, this paper proposes a robust and invisible blind image watermarking scheme based on a new combination of discrete cosine transform (DCT) and singular value decomposition (SVD) in discrete wavelet transform (DWT) domain using least-square curve fitting and logistic chaotic map. Firstly cover image is decomposed into four subbands using DWT and the low frequency subband LL is partitioned into non-overlapping blocks. Then DCT is applied to each block and several particular middle frequency DCT coefficients are extracted to form a modulation matrix, which is used to embed watermark signal by modifying its largest singular values in SVD domain. Optimal embedding strength for a specific cover image is obtained from an estimation based on least-square curve fitting and provides a good compromise between transparency and robustness of watermarking scheme. The security of the watermarking scheme is ensured by logistic chaotic map. Experimental results demonstrate the better effectiveness of the proposed watermarking scheme in the perceptual quality and the ability of resisting to conventional signal processing and geometric attacks, in comparison with the related existing methods.