Watermark Pattern Research Articles

Robust high-definition video watermarking based on self-synchronizing signals against composite distortions

This paper proposes a high-definition video watermarking method robust against compound geometrical attacks by camcorder capture as well as common video processing such as frame-rate conver- sion and transcoding. Unlike traditional watermarking systems using the original reference pattern, the proposed method exploits the reference pattern estimated from the watermarked video. Since the reference pat- tern and watermark pattern are embedded in the same spatial position of each frame, the two patterns estimated from the embedded video are always in spatial sync. Thus, the watermark information can be simply detected without an additional synchronizing step, even if geometrical distortions happen to the marked video. Also, the problem of misestima- tion of the reference pattern caused by temporal video clipping is solved using the proposed two-pass detector. Extensive experiments prove that the proposed method is robust against various temporal and spatial distortions. © 2010 Society of Photo-Optical Instrumentation Engineers.

Image watermarking with a directed periodic pattern to embed multibit messages resilient to print-scan and compound attacks

In this paper, we propose a blind method to embed multibit watermarks in images, robust to various attacks on geometry and print-scan process. For carrying the multibit information, a method using directed watermark patterns is proposed. A message sequence is mapped to a directional angle of a periodic pattern, which is then embedded into image blocks. In the detection, using autocorrelation function, filtering, masking, and adaptive line search with Hough transform, the alignment of the autocorrelations peaks are detected from image blocks, and interpreted as a message. The method provides a robust and blind extraction of information after a print-scan attack. Additionally, the experiments with two laser printer and two printout material show that the method is robust to compound attacks, such as Stirmark random bending, shearing, aspect ratio change, cropping, translation, or JPEG combined with print-scan.

Digital Video Watermarking in DWT Domain Using Chaotic Mixtures

This paper presents a public video watermarking algorithm, whose robustness depends on the embedding energy, which must be limited due to the degradation of video sequence caused by the same watermark signal. The proposed algorithm embeds a perceptually recognizable binary pattern, such as owner's logotype. Firstly the video sequences are segmented by each scene, and then the binary watermark pattern is embedded into Discrete Wavelet Transform (DWT) domain of the randomly selected scene blocks. To increase the security of the proposed scheme, the biary watermark pattern is mapped to a noise like binary pattern using a chaotic mixing method, before its embedding. Simulation results show the watermark imperceptibility and robustness against several attacks, such as noise contamination, frame dropping, frame averaging and frame swapping; the evaluation results also show that the extracted watermark pattern is sufficiently clear, although the watermarked video sequence may suffered several attacks.

Audio steganalysis with Hausdorff distance higher order statistics using a rule based decision tree paradigm

The aim of this paper is to construct a practical forensic steganalysis tool for audio signals that can properly analyze the statistics disturbed by stego embedding and classify them to selected current steganographic methods. The objective of this paper is to prove that the choice of effective stego sensitive features and a proficient machine learning paradigm enhances the detection accuracy of the steganalyser. In this paper a rule based approach with a family of six decision tree classifiers viz., Alternating Decision Tree, Decision Stump, J48, Logical Model Tree, Naïve Baye’s Tree and Fast Decision Tree learner, to perform the detection of audio subliminal channel is introduced. In particular the higher order statistics extracted from the Hausdorff distance are investigated for an improvement of the detection performance, as competent audio steganalytic features. The evaluation of the enhanced feature space and the decision tree paradigm, on a database containing 4800 clean and stego audio files is performed for classical steganographic as well as for watermarking algorithms. With this strategy it is shown how general forensic approach can detect information hiding techniques in the field of covert communication as well as for DRM applications. For the latter case, the detection of the presence of a potential watermark in a specific feature space can lead to new attacks or to a better design of the watermarking pattern.

Watermarking of Free-view Video

With the advances in image based rendering (IBR) in recent years, generation of a realistic arbitrary view of a scene from a number of original views has become cheaper and faster. One of the main applications of this progress has emerged as free-view TV(FTV), where TV-viewers select freely the viewing position and angle via IBR on the transmitted multiview video. Noting that the TV-viewer might record a personal video for this arbitrarily selected view and misuse this content, it is apparent that copyright and copy protection problems also exist and should be solved for FTV. In this paper, we focus on this newly emerged problem by proposing a watermarking method for free-view video. The watermark is embedded into every frame of multiple views by exploiting the spatial masking properties of the human visual system. Assuming that the position and rotation of the virtual camera is known, the proposed method extracts the watermark successfully from an arbitrarily generated virtual image. In order to extend the method for the case of an unknown virtual camera position and rotation, the transformations on the watermark pattern due to image based rendering operations are analyzed. Based upon this analysis, camera position and homography estimation methods are proposed for the virtual camera. The encouraging simulation results promise not only a novel method, but also a new direction for watermarking research.

A new video watermarking algorithm based on 1D DFT and Radon transform

In this paper, we propose a new video watermarking algorithm based on the 1D DFT (one-dimensional discrete Fourier transform) and Radon transform. The 1D DFT for a video sequence generates an ideal domain, in which the spatial information is still kept and the temporal information is obtained. With detailed analysis and calculation, we choose the frames with highest temporal frequencies to embed the fence-shaped watermark pattern in the Radon transform domain of the selected frames. The adaptive embedding strength for different locations keeps the fidelity of the watermarked video. The performance of the proposed algorithm is evaluated by video compression standard H.264 with three different bit rates; geometric attacks such as rotation, translation, and aspect-ratio changes; and other attacks like frame drop, frame swap, spatial filtering, noise addition, lighting change, and histogram equalization. The main contributions of this paper are the introduction of the 1D DFT along temporal direction for watermarking that enables the robustness against video compression, and the Radon transform-based watermark embedding and extraction that produces the robustness against geometric transformations. One of the most important advantages of this video watermarking algorithm is its simplicity and practicality.

새로운 도트형 프린트 워터마크 패턴의 생성 및 부호화 기법

본 논문에서는 2차원 인쇄물의 고유정보 즉, 텍스트, 도형 및 기호 등에 대응하는 음성, 영상 및 기타정보를 출력시킬 수 있도록 하기 위한 새로운 방법의 도트형 프린트 워터마크 생성 방법 및 부호화 기법을 제안하였다. 프린트 워터마크는 인쇄물의 고유정보에 대응하여 고유정보위에 다시 인쇄되는 특정마크로서 고유정보의 특성을 훼손하지 않으면서 음성, 또는 영상정보와 연결시키는 중간 매개 역할을 한다. 제안한 도트형 프린트 워터마크 패턴은 <TEX>$0.4mm^2$</TEX>의 면적 내에 <TEX>$16{\times}16$</TEX>의 행렬구조를 가지며, 256개의 원소(element) 중 23개의 위치에 도트가 인쇄된다. 인쇄되는 도트의 크기는 0.02mm고 매우 작아 가시화되지 않는다. 23개의 위치는 2진수 비트 위치와 매핑 되어 800만개 정도의 인쇄물 고유정보를 표현할 수 있으며, 도트가 인쇄되는 위치에 따라 쉽게 2진수로 부호화할 수 있다는 특징을 갖는다. 또한 실험을 통해 제안한 프린트 워터마크 패턴이 자체 제작된 인식장치에 의해 쉽게 인식됨을 보였다. In this paper, the technique for production and encoding of new dot-type print watermark is proposed. The print watermark has characteristics similar to those of the digital watermark and function as link which change various first informations(texts, symbols, figures, etc) on the printed matter to secondary contents (sound, video, character, etc) corresponding each to informations on the printed matter. The proposed dot-type print watermark pattern is represented as <TEX>$16{\times}16$</TEX> matrix in <TEX>$0.4mm^2$</TEX> area and dots are printed on only 23 elements of <TEX>$16{\times}16$</TEX> matrix. The size of each dot is so small(0.02mm)that it can not be seen. Because position of printed dots correspond to the position of each digit in binary notation in this paper, they are encoded easily and there are about 8,000,000 watermark patterns enough to express first information of printed matters. It was showed that the proposed print watermark patterns are recognized without difficulty by the own recognition device.

A Contrast-Sensitive Reversible Visible Image Watermarking Technique

A reversible (also called lossless, distortion-free, or invertible) visible watermarking scheme is proposed to satisfy the applications, in which the visible watermark is expected to combat copyright piracy but can be removed to losslessly recover the original image. We transparently reveal the watermark image by overlapping it on a user-specified region of the host image through adaptively adjusting the pixel values beneath the watermark, depending on the human visual system-based scaling factors. In order to achieve reversibility, a reconstruction/recovery packet, which is utilized to restore the watermarked area, is reversibly inserted into non-visibly-watermarked region. The packet is established according to the difference image between the original image and its approximate version instead of its visibly watermarked version so as to alleviate its overhead. For the generation of the approximation, we develop a simple prediction technique that makes use of the unaltered neighboring pixels as auxiliary information. The recovery packet is uniquely encoded before hiding so that the original watermark pattern can be reconstructed based on the encoded packet. In this way, the image recovery process is carried out without needing the availability of the watermark. In addition, our method adopts data compression for further reduction in the recovery packet size and improvement in embedding capacity. The experimental results demonstrate the superiority of the proposed scheme compared to the existing methods.

Multimodal biometric image watermarking using two-stage integrity verification

In this paper, we propose multimodal biometric image watermarking scheme through a two-stage integrity verification method using the hidden thumbnail feature vectors for safe authentication of multimodal biometrics data, face and fingerprint, respectively. It is basically blind and spread spectrum-based robust watermarking method. The proposed method enables us to detect a tampered region by controlling watermark embedding strength to meet the requirement of predefined watermark extraction threshold. The key idea is that the thumbnail feature vectors of a face image as a watermark pattern are utilized by embedding into a fingerprint image in order to verify the integrity of respective biometric data. The first stage of integrity verification for a fingerprint image is done by deciding the validity of extracted thumbnail patterns. The second stage of integrity verification for a face image is done by one-to-one matching between the thumbnail feature vectors extracted from a face image and the thumbnail one of the received face image. Experimental results showed that the proposed method has a high detection rate of the forged biometric data and guarantees the security assurance.

Improving robustness of visible image watermarks

The visible watermarking is an important intellectual property rights (IPR) protection technique for digital images. In some circumstances such as multimedia contents used in learning websites or digital libraries, digital images have to be released but illegal reproductions of them are prohibited. Digital images embedded with visible watermarks contain perceptible but unobtrusive patterns. The embedded patterns should be difficult to remove unless expensive human labours are involved. Recently, Huang and Wu have proposed an efficient attacking scheme against visible watermarks. Based on the attacking scheme, the watermark patterns can be almost completely eliminated and a perceptually satisfying recovered image can be obtained by means of limited human interventions. In the present article, a novel scheme is proposed to improve the robustness of visible watermarks. For counterattacking the removal of the visible watermark pattern, the significant information of watermark patterns is extracted and embedded in the protected image imperceptibly by the information hiding techniques. In addition, to specify the positions of destroyed areas of watermarks, a fragile watermarking technique is designed and applied in the proposed scheme. Simulation results demonstrate that the proposed scheme is robust to the up to date attacks.

Robust Video Watermarking of H.264/AVC

A robust video watermarking scheme of the state-of-the-art video coding standard H.264/AVC is proposed in this brief. 2-D 8-bit watermarks such as detailed company trademarks or logos can be used as inconvertible watermark for copyright protection. A grayscale watermark pattern is first modified to accommodate the H.264/AVC computational constraints, and then embedded into video data in the compressed domain. With the proposed method, the video watermarking scheme can achieve high robustness and good visual quality without increasing the overall bit-rate. Experimental results show that our algorithm can robustly survive transcoding process and strong common signal processing attacks, such as bit-rate reduction, Gaussian filtering and contrast enhancement

Speech authentication system using digital watermarking and pattern recovery

The objective of this paper is to detect speech forgery using digital audio watermarking and pattern recovery techniques. A digital watermark pattern has been attached with the speech signal to detect three kinds of alterations or forgeries such as substitution, insertion, and removal. The watermark pattern will be modified if some changes have been made to the speech contents. Modification and forgery can be measured and detected by pattern recovery. The proposed method uses the cyclic pattern embedding to overcome synchronizing problems of previous detection techniques. In addition, pattern recovery enhances the robustness to compression. This method has been tested and verified using six recording devices, which was used for collecting verbal data. The speech signals were sampled at the rate of 8 kHz and digitized at 16 bits resolution. Randomly chosen regions were substituted, removed, and compressed in MP3 at the rate of 16 kbps as well as in CELP at the rate of 11.5 kbps. The experiment shows the perfect detection for three kinds of forgeries and it proved the validity of the proposed method.

Watermarking Relying on Cover Signal Content to Hide Synchronization Marks

In watermarking, the exploitation of synchronization marks embedded within the cover signal has been widely used to provide robustness against geometrical distortions. However, in most schemes, synchronization marks are easily detectable which makes them vulnerable to malicious removal or tampering. Relying on embedded signals which exhibit strong reference features to recover synchronization can therefore lead to security flaws in the watermarking system. In this paper, we present and discuss the synchronization recovery process through detection of the periodicity of the embedded signal. We then propose a scheme to hide synchronization marks through the modulation of the embedded signal by a content-based pseudo-random signal. We study the robustness of this pseudo-random masking signal and illustrate the efficiency of this approach on watermark patterns with a periodic structure.

An algorithm for removable visible watermarking

A visible watermark may convey ownership information that identifies the originator of image and video. A potential application scenario for visible watermarks was proposed by IBM where an image is originally embedded with a visible watermark before posting on the web for free observation and download. The watermarked image which serves as a teaser. The watermark can be removed to recreate the unmarked image by request of interested buyers. Before we can design an algorithm for satisfying this application, three basic problems should be solved. First, we need to find a strategy suitable for producing large amount of visually same but numerically different watermarked versions of the image for different users. Second, the algorithm should let the embedding parameters reachable for any legal user to make the embedding process invertible. Third, an unauthorized user should be prevented from removing the embedded watermark pattern. In this letter, we propose a user-key-dependent removable visible watermarking system (RVWS). The user key structure decides both the embedded subset of watermark and the host information adopted for adaptive embedding. The neighbor-dependent embedder adjusts the marking strength to host features and makes unauthorized removal very difficult. With correct user keys, watermark removal can be accomplished in informed detection and the high quality unmarked image can be restored. In contrast, unauthorized operation either overly or insufficiently removes the watermark due to wrong estimation of embedding parameters, and thus, the resulting image has apparent defect.

Maintaining Picture Quality and Improving Robustness of Color Watermarking by Using Human Vision Models

Digital watermarks on pictures are more useful when they are better able to survive image processing operations and when they cause less degradation of picture quality. Random geometric distortion is one of the most difficult kinds of image processing for watermarks to survive because of the difficulty of synchronizing the expected watermark patterns to the watermarks embedded in pictures. This paper proposes three methods to improve a previous method that is not affected by this difficulty but that is insufficient in maintaining picture quality and treating other problems in surviving image processing. The first method determines the watermark strength in L*u*v* space, where human-perceived degradation of picture quality can be measured in terms of Euclidian distance, but embeds and detects watermarks in YUV space, where the detection is more reliable. The second method, based on the knowledge of image quantization, uses the messiness of color planes to hide watermarks. The third method reduces detection noises by preprocessing the watermarked image with orientation-sensitive image filtering, which is especially effective in picture portions where pixel values change drastically. Subjective evaluations have shown that these methods improved the picture quality of the previous method by 0.5 point of the mean evaluation score at the representative example case. On the other hand, the watermark strength of the previous method could be increased by 30% through 60% while keeping the same picture quality. Robustness to image processing has been evaluated for random geometric distortion, JPEG compression, Gaussian noise addition, and median filtering and it was clarified that these methods reduced the detection error ratio to 1/10 through 1/4. These methods can be applied not only to the previous method but also to other types of pixel-domain watermarking such as the Patchwork watermarking method and, with modification, to frequency-domain watermarking.

Use of cryptographic technologies for privacy protection of watermarks in internet retails of digital contents

In this paper, we propose a scheme of secure watermarking protocol using cryptographic technologies for use in real life internet retail market of digital contents, in which trust between customers and digital contents providers may not be assumed. A commutative encryption algorithm is used in our scheme to doubly lock the information by the secret keys of both a contents provider, and its customer, separately. The privacy of watermark pattern is maintained while the digital rights of the contents provider are protected. This is achieved by allowing the customer to choose a secret pattern of watermark combination unknown to the contents provider. Consequently, the quality of the watermarked digital contents can be guaranteed. We show that the protocol is secure against any possible attacks from the customer and the contents provider. Moreover, the disputes resolution process becomes mechanical.

Watermarking schema for digital still images based on geometrical transformation

In real time watermarking applications robustness and computational complexity are playing very important role. In this paper we focus on new algorithm for inserting of watermark in digital still images. This algorithm is based on simple but efficient geometrical transformation of image and has fast embedding and extracting watermark pattern with acceptable robustness. Proposed method is illustrated on one example. It has been shown that it is possible to confirm existing of the watermark also in JPEG compressed image.

Robust optimum detection of transform domain multiplicative watermarks

Digital watermarking is an emerging technique to protect data security and intellectual property right. Identification or verification of watermarking patterns can be achieved by detecting watermarks in received signals. However, one of the biggest challenges in watermarking detection is that the strengths of the watermark signals will change after being distorted by an attacker in a watermarking channel. Meanwhile, the embedding strengths may be adapted to the original signals, which are unknown at the receiver end. Further, the original signals are often highly non-Gaussian. Although some work has been done on optimum detection of watermarks, the uncertainty of watermark signal strengths and real statistical behavior of multimedia contents have not been taken into account simultaneously. Much more study is needed to enhance the performance of watermarking systems. Since multiplicative watermarks are robust and well suited for copyright protection, this paper presents our investigation on robust optimum detection of multiplicative watermarks. For sub-band transformed domains such as the discrete cosine transform (DCT), discrete wavelet transform (DWT), and pyramid transform, a class of generalized correlators is constructed based on the generalized Gaussian distributions. Thresholding methods to achieve a given false alarm rate, and the performance analyses are provided. The square-root detector is designed and demonstrated to have near performance for a large set of natural images and can be employed as a universally optimal detector or decoder for images and video. The locally most powerful detection method is then extended to DFT domain multiplicative watermarking, with the magnitudes of coefficients modeled by the Weibull distributions. Another class of detectors is built based on this statistical modeling. The robust optimum detection of multiplicative watermarks can be applied to copyright notification, enforcement, and broadcast monitoring. We have applied the robust optimum watermarking detection to combined audio and video watermarking.