Watermark Data Research Articles

A Video Watermark Method Based on Chaotic Encryption

An effective and integrated video watermark scheme mainly includes watermark generation, watermark embedding, watermark detecting, and watermark attack. The watermark data come from a meaningful binary image encrypted by two-dimensional chaotic stream encryption to improve watermark security. In the procedure of watermark embedding, watermarks are embedded into the random selected video frames through modifying the DCT coefficients. After robust and frame processes, watermarks can be mainly extracted and identified through watermark extracting algorithm. The experimental results show that the proposed video watermark method has some performances of security, imperceptibility and robustness.

A Blind Video Watermarking Scheme Robust To Frame Attacks Combined With MPEG2 Compression

In this paper, we propose a robust digital video watermarking scheme with completely blind extraction process where the original video data, original watermark or any other information derivative of them are not required in order to retrieve the embedded watermark. The proposed algorithm embeds 2D binary visually recognizable patterns such as company trademarks and owner’s logotype, etc., in the DWT domain of the video frames for copyright protection.Before the embedding process, only two numerical keys are required to transform the watermark data into a noise-like pattern using the chaotic mixing method which helps to increase the security. The main advantages of the proposed scheme are its completely blind detection scheme, robustness against common video attacks, combined attacks andits low complexity implementation. The combined attacks consist of MPEG-2 compression and common video attacks such as noise contamination, collusion attacks, frame dropping and swapping. Extensive simulation results also show that the watermark imperceptibility and robustness outperform other previously reported methods. The extractedwatermark data from the watermarked video sequences is clear enough even after the watermarked video hadsuffered from several attacks.

Watermarking geographical data on spatial topological relations

Geographical data is of great value for data producers. How to protect copyright of geographical data effectively using digital watermarking is a hot research issue. In this paper, spatial topological relation existing between polygons is chosen as cover data, and watermark is embedded by slightly modifying the metric measure of spatial topological relation, and some geographical objects are scaled to derive the watermarked data. Global Main Scaling Distance is introduced to measure the distortions caused by watermark embedding. Experimental results show that the proposed algorithm has a good robustness against geometrical attacks, simplification, interpolation and noise addition attacks, and preserves shape of the watermarked geographical objects. Furthermore, a good tradeoff between robustness and fidelity is acquired in the proposed algorithm.

Reversible fragile watermarking for locating tampered blocks in JPEG images

This paper proposes a novel fragile watermarking scheme for JPEG image authentication. The watermark is generated by folding the hash results of quantized coefficients, and each block is used to carry two watermark bits using a reversible data-hiding method. Because modification to the cover is small, the visual quality of watermarked image is satisfactory. On the receiver side, one may attempt to extract the watermark and recover the original content. By measuring mismatch between the watermark data extracted from the received image and derived from the recovered content, the blocks containing fake content can be located accurately, while the original information in the other blocks is retrieved without any error as long as the tampered area is not extensive.

Reversible Watermarking Using Statistical Information

In most reversible watermarking methods, a compressed location map is exploited in order to ensure reversibility. Besides, in some methods, a header containing critical information is appended to the payload for the extraction and recovery process. Such schemes have a highly fragile nature; that is, changing a single bit in watermarked data may prohibit recovery of the original host as well as the embedded watermark. In this paper, we propose a new scheme in which utilizing a compressed location map is completely removed. In addition, the amount of auxiliary data is decreased by employing the adjacent pixels information. Therefore, in addition to quality improvement, independent authentication of different regions of a watermarked image is possible.

An audio watermarking scheme using singular value decomposition and dither-modulation quantization

Quantization index modulation is one of the best methods for performing blind watermarking, due to its simplicity and good rate-distortion-robustness trade-offs. In this paper, a new audio watermarking algorithm based on singular value decomposition and dither-modulation quantization is presented. The watermark is embedded using dither-modulation quantization of the singular values of the blocks of the host audio signal. The watermark can be blindly extracted without the knowledge of the original audio signal. Subjective and objective tests confirm high imperceptibility achieved by the proposed scheme. Moreover, the scheme is quite robust against attacks including additive white Gaussian noise, MP3 compression, resampling, low-pass filtering, requantization, cropping, echo addition and denoising. The watermark data payload of the algorithm is 196 bps. Performance analysis of the proposed scheme shows low error probability rates.

Chaos-based secure dual self-recovery watermark algorithm for image authentication

To improve the security of dual self-recovery watermark,a chaos-based dual self-recovery watermark scheme for image authentication was proposed in this paper.In the proposed scheme,the chaotic map was first adopted to encrypt the dual watermark data,and then the data were embedded into the image block of less significant bits.And then the authentication data of each block was randomly generated with reference to its content and the recovery watermark embedded according to the chaotic mapping.Theoretical analysis and simulation results show that the proposed scheme can not only maintain the good tamper recovery quality and invisibility of dual self-recovery watermark,but also improve the security against the only-content tampering attack and the dictionary searching attack.

A Robust Image Watermarking in the Ridgelet Domain Using Universally Optimum Decoder

A robust image watermarking scheme in the ridgelet transform domain is proposed in this paper. Due to the use of the ridgelet domain, sparse representation of an image which deals with line singularities is obtained. In order to achieve more robustness and transparency, the watermark data is embedded in selected blocks of the host image by modifying the amplitude of the ridgelet coefficients which represent the most energetic direction. Since the probability distribution function of the ridgelet coefficients is not known, we propose a universally optimum decoder to perform the watermark extraction in a distribution-independent fashion. Decoder extracts the watermark data using the variance of the ridgelet coefficients of the most energetic direction in each block. Furthermore, since the decoder needs the noise variance to perform decoding, a robust noise estimation scheme is proposed. Moreover, the implementation of error correction codes on the proposed method is investigated. Analytical derivation of bit error probability is also carried out and experimental results prove its accuracy. Simulation also shows outstanding robustness of the proposed scheme against common attacks, especially additive white noise and JPEG compression.

An adaptive audio watermarking based on the singular value decomposition in the wavelet domain

This paper presents a secure, robust, and blind adaptive audio watermarking algorithm based on singular value decomposition (SVD) in the discrete wavelet transform domain using synchronization code. In our algorithm, a watermark is embedded by applying a quantization-index-modulation process on the singular values in the SVD of the wavelet domain blocks. The watermarked signal is perceptually similar to the original audio signal and gives high quality output. Experimental results show that the hidden watermark data is robust to additive noise, resampling, low-pass filtering, requantization, MP3 compression, cropping, echo addition, and denoising. Performance analysis of the proposed scheme shows low error probability rates. The data embedding rate of the proposed scheme is 45.9 bps. The proposed scheme has high payload and superior performance against MP3 compression compared to the earlier audio watermarking schemes.

A practical design of content protection for H.264/AVC compressed videos by selective encryption and fingerprinting

Digital Rights Management (DRM) of videos is an important issue nowadays. Considering that H.264/AVC videos will be widely used in various applications, we propose a practical design, which combines the methodologies of selective encryption and fingerprinting, for effective DRM of H.264/AVC streaming videos. A selective encryption scheme is first presented to scramble the video content by encrypting a small amount of data in the compressed bit-stream. The scrambled video is H.264-compliant to reduce the complexity of decoder since it can still be played without triggering errors in the decoding process. A fingerprinting scheme is then introduced to provide further protection. We extract a reasonable amount of data from the video and embed the watermark acting as the fingerprint of the video recipient. To acquire the high-quality video for viewing, the user has to decrypt the video obtained from a video server and then combine it with the watermarked data provided from a user information server. The resulting viewable video is thus fingerprinted to deter the user from illegally redistributing the content. Experimental results will demonstrate the feasibility of the proposed approach.

The problems in digital watermarking into intra-frames of H.264/AVC

Differently from other image/video compression techniques, it is not easy to find a successful watermarking scheme for H.264/AVC. Thus we, as the researchers on digital watermarking, intend to find the reason(s) of the hardness in this paper. Among the various techniques in H.264/AVC we only concern the intra-prediction in this paper, which is the main technique to form an intra picture. We closely examine the properties of intra-prediction in the aspect of digital watermarking. We consider three watermarking schemes: (1) a blind scheme by fixing the watermark positions without using any information from encoding process, (2) a semi-blind scheme which selects watermark positions with a threshold value of the cost function to determine the prediction mode, and (3) a blind scheme selecting only the blocks predicted by 16 × 16 mode as the one to be watermarked. These three schemes are getting more restricted in selecting the watermarking positions. The experiments showed that none of the three schemes were satisfactory. Even the error rates of the extracted watermark data were getting lower. After examining the data, we found the followings. The intra-prediction of H.264/AVC itself is not reversible. That is, the re-engineering of the intra pictures, which is necessary to extract the embedded watermark, does not guarantee the same results as before re-engineering. The intra-prediction modes in many blocks and the coefficient values are changed in re-engineering. In addition, watermarking and attacks further change the prediction modes and coefficient values, which make the watermarking useless. The reason of changing the prediction modes and the coefficient values, we concluded, is heuristics of the technique. That means the intra-prediction includes many heuristic schemes that cannot recover the data exactly. Consequently a new watermarking method rather than the conventional ones is necessary to find.

Contourlet-Based Image Watermarking Using Optimum Detector in a Noisy Environment

In this paper, an improved multiplicative image watermarking system is presented. Since human visual system is less sensitive to the image edges, watermarking is applied in the contourlet domain, which represents image edges sparsely. In the presented scheme, watermark data is embedded in directional subband with the highest energy. By modeling the contourlet coefficients with General Gaussian Distribution (GGD), the distribution of watermarked noisy coefficients is analytically calculated. The tradeoff between the transparency and robustness of the watermark data is solved in a novel fashion. At the receiver, based on the Maximum Likelihood (ML) decision rule, an optimal detector by the aid of channel side information is proposed. In the next step, a blind extension of the suggested algorithm is presented using the patchwork idea. Experimental results confirm the superiority of the proposed method against common attacks, such as Additive White Gaussian Noise (AWGN), JPEG compression, and rotation attacks, in comparison with the recently proposed techniques.

Speech Watermarking for Analog Flat-Fading Bandpass Channels

We present a blind speech watermarking algorithm that embeds the watermark data in the phase of non-voiced speech by replacing the excitation signal of an autoregressive speech signal representation. The watermark signal is embedded in a frequency subband, which facilitates robustness against bandpass filtering channels. We derive several sets of pulse shapes that prevent intersymbol interference and that allow the passband watermark signal to be created by simple filtering. A marker-based synchronization scheme robustly detects the location of the embedded watermark data without the occurrence of insertions or deletions. In light of a potential application to analog aeronautical voice radio communication, we present experimental results for embedding a watermark in narrowband speech at a bit-rate of 450 bit/s. The recursive least-squares (RLS) equalization-based watermark detector not only compensates for the vocal tract filtering, but also recovers the watermark data in the presence of nonlinear phase and bandpass filtering, amplitude modulation, and additive white Gaussian noise (AWGN), making the watermarking scheme highly robust.

Joint Watermarking and Encryption of Color Images in the Fibonacci-Haar Domain

A novel method for watermarking and ciphering color images, based on the joint use of a key-dependent wavelet transform with a secure cryptographic scheme, is presented. The system allows to watermark encrypted data without requiring the knowledge of the original data and also to cipher watermarked data without damaging the embedded signal. Since different areas of the proposed transform domain are used for encryption and watermarking, the extraction of the hidden information can be performed without deciphering the cover data and it is also possible to decipher watermarked data without removing the watermark. Experimental results show the effectiveness of the proposed scheme.

Robust Multiplicative Patchwork Method for Audio Watermarking

This paper presents a Multiplicative Patchwork Method (MPM) for audio watermarking. The watermark signal is embedded by selecting two subsets of the host signal features and modifying one subset multiplicatively regarding the watermark data, whereas another subset is left unchanged. The method is implemented in wavelet domain and approximation coefficients are used to embed data. In order to have an error-free detection, the watermark data is inserted only in the frames where the ratio of the energy of subsets is between two predefined values. Also in order to control the inaudibility of watermark insertion, we use an iterative algorithm to reach a desired quality for the watermarked audio signal. The quality of watermarked signal is evaluated in each iteration using Perceptual Evaluation of Audio Quality (PEAQ) method. The probability of error is also derived for the watermarking scheme and simulation results prove the validity of the analytical derivations. Simulation results show that MPM is robust against various common attacks such as noise addition, filtering, echo, MP3 compression, etc. In comparison to the original patchwork method and its modified versions, and some recent methods, MPM provides more robustness and inaudibility of the watermark insertion.

Robust Scaling-Based Image Watermarking Using Maximum-Likelihood Decoder With Optimum Strength Factor

In this paper, a new scaling-based image-adaptive watermarking system has been presented, which exploits human visual model for adapting the watermark data to local properties of the host image. Its improved robustness is due to embedding in the low-frequency wavelet coefficients and optimal control of its strength factor from HVS point of view. Maximum likelihood (ML) decoder is used aided by the channel side information. The performance of the proposed scheme is analytically calculated and verified by simulation. Experimental results confirm the imperceptibility of the proposed method and its higher robustness against attacks compared to alternative watermarking methods in the literature.

An Image Authentication Based on Discrete Fourier Transform

The advances of network technologies and digital devices facilitate users to exchange multimedia data over the public networks. However, this also raises significant concerns about how to protect sensitive multimedia data from being illegally copied and unauthorized modifications. Thus, this paper proposes a fragile watermarking method to detect illegitimate alterations of the watermarked data. The proposed method embeds a grayscale watermark image into a grayscale cover image in a block-by-block manner by using discrete Fourier transform. Experimental results show that the proposedmethod can successfully and exactly detect and localize any tampered regions of the watermarked image.

Fragile Watermarking With Error-Free Restoration Capability

This paper proposes a novel fragile watermarking scheme capable of perfectly recovering the original image from its tampered version. In the scheme, a tailor-made watermark consisting of reference-bits and check-bits is embedded into the host image using a lossless data hiding method. On the receiver side, by comparing the extracted and calculated check-bits, one can identify the tampered image-blocks. Then, the reliable reference-bits extracted from other blocks are used to exactly reconstruct the original image. Although content replacement may destroy a portion of the embedded watermark data, as long as the tampered area is not too extensive, the original image information can be restored without any error.

A secure radio communication system based on an efficient speech watermarking approach

AbstractThis paper deals with an efficient secure communication system based on a speech watermarking approach. The main goal of the system is to efficiently support air traffic control (ATC) communications by improving safety and security of the existing ATC equipment embedding digital side information into speech signals in order to allow an automatic identification of the talker. An implementation based on the use of the well known LPC (linear predictive coding) principle is discussed. The LPC residual is split up into voiced and unvoiced segments; while the voiced segments cross the system unmodified, the watermarking data are embedded into the unvoiced segments, spectrally similar to a white noise. The watermark signal is decoded by a very similar scheme. We provide also a statistical analysis on the unvoiced parts of the ATC communications that demonstrates the system feasibility. In addition to this, an optimization of the entire system has been also performed to increase performance. The obtained results highlight that the watermark data are nearly imperceptible and provide a data channel with rate from 2000 to 5000 kbits/s, with high robustness to channel noise; the system requires only modular, low‐cost and easy‐to‐install encoders and decoders, maintaining compatibility with legacy RF DSB‐AM transceivers. Moreover, it is well suited both for the actual 25 kHz RF channels and for the new 8.33 kHz European RF channels. Copyright © 2008 John Wiley & Sons, Ltd.

Fragile watermarking scheme using a hierarchical mechanism

This paper proposes a novel fragile watermarking scheme with a hierarchical mechanism, in which pixel-derived and block-derived watermark data are carried by the least significant bits of all pixels. On the receiver side, after identifying the blocks containing tampered content, the watermark data hidden in the rest blocks are exploited to exactly locate the tampered pixels. Moreover, using exhaustive attempts, the proposed scheme is capable of recovering the original watermarked version without any error.