Showing papers on "Watermark published in 2003"

Integrating digital watermarks in multimedia content

Abstract: A method for decoding auxiliary data from media signals in multimedia content decodes watermarks from different media signals and uses the watermarks to control processing of the multimedia content. A copy control method decodes a watermark from one of the media signals in multimedia content, and uses the watermark to control processing of the multimedia content. Another method uses a watermark decoded from a first media signal to decode a second media signal. Yet another method uses a watermark decoded from a media signal to decode metadata associated with the media signal. Finally, another method forms a key for decoding data from at least first and second watermarks extracted from first and second media signals.

Spread-spectrum watermarking of audio signals

Abstract: Watermarking has become a technology of choice for a broad range of multimedia copyright protection applications. Watermarks have also been used to embed format-independent metadata in audio/video signals in a way that is robust to common editing. In this paper, we present several novel mechanisms for effective encoding and detection of direct-sequence spread-spectrum watermarks in audio signals. The developed techniques aim at (i) improving detection convergence and robustness, (ii) improving watermark imperceptiveness, (iii) preventing desynchronization attacks, (iv) alleviating estimation/removal attacks, and finally, (v) establishing covert communication over a public audio channel. We explore the security implications of the developed mechanisms and review watermark robustness on a benchmark suite that includes a combination of audio processing primitives including: time- and frequency-scaling with wow-and-flutter, additive and multiplicative noise, resampling, requantization, noise reduction, and filtering.

A DWT-DFT composite watermarking scheme robust to both affine transform and JPEG compression

Abstract: Robustness is a crucially important issue in watermarking. Robustness against geometric distortion and JPEG compression at the same time with blind extraction remains especially challenging. A blind discrete wavelet transform-discrete Fourier transform (DWT-DFT) composite image watermarking algorithm that is robust against both affine transformation and JPEG compression is proposed. The algorithm improves robustness by using a new embedding strategy, watermark structure, 2D interleaving, and synchronization technique. A spread-spectrum-based informative watermark with a training sequence is embedded in the coefficients of the LL subband in the DWT domain while a template is embedded in the middle frequency components in the DFT domain. In watermark extraction, we first detect the template in a possibly corrupted watermarked image to obtain the parameters of an affine transform and convert the image back to its original shape. Then, we perform translation registration using the training sequence embedded in the DWT domain, and, finally, extract the informative watermark. Experimental work demonstrates that the proposed algorithm generates a more robust watermark than other reported watermarking algorithms. Specifically it is robust simultaneously against almost all affine transform related testing functions in StirMark 3.1 and JPEG compression with quality factor as low as 10. While the approach is presented for gray-level images, it can also be applied to color images and video sequences.

A feature-based robust digital image watermarking scheme

Abstract: A robust digital image watermarking scheme that combines image feature extraction and image normalization is proposed. The goal is to resist both geometric distortion and signal processing attacks. We adopt a feature extraction method called Mexican hat wavelet scale interaction. The extracted feature points can survive a variety of attacks and be used as reference points for both watermark embedding and detection. The normalized image of an image (object) is nearly invariant with respect to rotations. As a result, the watermark detection task can be much simplified when it is applied to the normalized image. However, because image normalization is sensitive to image local variation, we apply image normalization to nonoverlapped image disks separately. The disks are centered at the extracted feature points. Several copies of a 16-bit watermark sequence are embedded in the original image to improve the robustness of watermarks. Simulation results show that our scheme can survive low-quality JPEG compression, color reduction, sharpening, Gaussian filtering, median filtering, row or column removal, shearing, rotation, local warping, cropping, and linear geometric transformations.

Identification document and related methods

Abstract: The present invention provides methods and systems for authenticating identification documents (100). We also teach an identification document (100) including two or more digital watermarks (27, 60). The watermarks correspond with each other or with indicia carried by the identification document (100). The correspondence can be verified to determine authenticity. We also provide digital watermark detection methods and systems to identify the different watermarks (100) through embedded orientation components. We then focus watermark message-decoding efforts on areas identified as likely including watermark orientation components (27, 60). In one implementation we provide a watermark detection trigger to identify so-called legacy documents. The trigger may indicate the presence or expected absence of a digital watermark. In other implementations we provide a versatile document authenticator to toggle between watermarking and non-watermarking authentication processes depending on a detection trigger (100).

Invariant image watermark using Zernike moments

Abstract: The paper introduces a robust image watermark based on an invariant image feature vector. Normalized Zernike moments of an image are used as the vector. The watermark is generated by modifying the vector. The watermark signal is designed with Zernike moments. The signal is added to the cover image in the spatial domain after the reconstruction process. We extract the feature vector from the modified image and use it as the watermark. The watermark is detected by comparing the computed Zernike moments of the test image and the given watermark vector. Rotation invariance is achieved by taking the magnitude of the Zernike moments. An image normalization method is used for scale and translation invariance. The robustness of the proposed method is demonstrated and tested using Stirmark 3.1. The test results show that our watermark is robust with respect to geometrical distortions and compression.

DCT-based image watermarking using subsampling

Abstract: A DCT-based image watermarking algorithm is described, where the original image is not required for watermark recovery, and is achieved by inserting the watermark in subimages obtained through subsampling.

Techniques and Applications of Digital Watermarking and Content Protection

Abstract: Digital watermarking applications of digital watermarking digital watermarking for still images digital watermarking for audio data digital watermarking for other media attacks, benchmarks and standardization other content protection mechanisms integrated content protection solutions conclusion.

Watermarking relational data: framework, algorithms and analysis

Abstract: .We enunciate the need for watermarking database relations to deter data piracy, identify the characteristics of relational data that pose unique challenges for watermarking, and delineate desirable properties of a watermarking system for relational data. We then present an effective watermarking technique geared for relational data. This technique ensures that some bit positions of some of the attributes of some of the tuples contain specific values. The specific bit locations and values are algorithmically determined under the control of a secret key known only to the owner of the data. This bit pattern constitutes the watermark. Only if one has access to the secret key can the watermark be detected with high probability. Detecting the watermark requires access neither to the original data nor the watermark, and the watermark can be easily and efficiently maintained in the presence of insertions, updates, and deletions. Our analysis shows that the proposed technique is robust against various forms of malicious attacks as well as benign updates to the data. Using an implementation running on DB2, we also show that the algorithms perform well enough to be used in real-world applications.

Color adaptive watermarking

Abstract: A color mapping process enhances a watermark by computing a change in colors that is less visible for a given watermark strength. The mapping process provides smooth transitions from one color region to another, and may be implemented efficiently with a 3D look up table. A user interface scheme enables the user to control encoding of the watermark in desired color regions.

Digital watermarking and fingerprinting including symchronization, layering, version control, and compressed embedding

Abstract: This disclosure describes several video watermarking and fingerprinting enhancements. These enhancements include synchronizing watermark detectors with one-dimensional calibration signals, layering digital watermarks, watermarks for version control, compressed domain watermarking, watermarking of video object layers, key channel watermark embedding for video, robust fingerprinting of video and watermarking of scalable video.

Rights protection for relational data

Abstract: Protecting rights over relational data is of ever increasing interest, especially considering areas where sensitive, valuable content is to be outsourced. A good example is a data mining application, where data is sold in pieces to parties specialized in mining it.Different avenues for rights protection are available, each with its own advantages and drawbacks. Enforcement by legal means is usually ineffective in preventing theft of copyrighted works, unless augmented by a digital counter-part, for example watermarking.Recent research of the authors introduces the issue of digital watermarking for generic number sets. In the present paper we expand on this foundation and introduce a solution for relational database content rights protection through watermarking.Our solution addresses important attacks, such as data re-sorting, subset selection, linear data changes (applying a linear transformation on arbitrary subsets of the data). Our watermark also survives up to 50% and above data loss.Finally we present wmdb.*, a proof-of-concept implementation of our algorithm and its application to real life data, namely in watermarking the outsourced Wal-Mart sales data that we have available at our institute.

Robust optimum detection of transform domain multiplicative watermarks

Abstract: 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 optimal 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.

RST-invariant digital image watermarking based on log-polar mapping and phase correlation

Abstract: Based on log-polar mapping (LPM) and phase correlation, the paper presents a novel digital image watermarking scheme that is invariant to rotation, scaling, and translation (RST). We embed a watermark in the LPMs of the Fourier magnitude spectrum of an original image, and use the phase correlation between the LPM of the original image and the LPM of the watermarked image to calculate the displacement of watermark positions in the LPM domain. The scheme preserves the image quality by avoiding computing the inverse log-polar mapping (ILPM), and produces smaller correlation coefficients for unwatermarked images by using phase correlation to avoid exhaustive search. The evaluations demonstrate that the scheme is invariant to rotation and translation, invariant to scaling when the scale is in a reasonable range, and very robust to JPEG compression.

Digital watermarking-based DCT and JPEG model

Abstract: In recent years, digital watermarking techniques have been proposed to protect the copyright of multimedia data. Different watermarking schemes have been suggested for images. The goal of this paper is to develop a watermarking algorithm based on the discrete cosine transform (DCT) and image segmentation. The image is first segmented in different portions based on the Voronoi diagram and features extraction points. Then, a pseudorandom sequence of real numbers is embedded in the DCT domain of each image segment. Different experiments are conducted to show the performance of the scheme under different types of attacks. The results show that our proposed watermark scheme is robust to common signal distortions, including geometric manipulations. The robustness against Joint Photographic Experts Group (JPEG) compression is achieved for a compression ratio of up to 45, and robustness against average, median, and Wiener filters is shown for the 3/spl times/3 up to 9/spl times/9 pixel neighborhood. It is observed that robustness against scaling was achieved when the watermarked image size is scaled down to 0.4% of its original size.

Discrete wavelet transform based multiple watermarking scheme

Abstract: The low-frequency embedding of the watermark increases the robustness with respect to image distortions that have low pass characteristics like filtering, lossy compression, geometrical distortions. On the other hand, oblivious schemes with low-frequency watermarks are more sensitive to modifications of the histogram, such as contrast/brightness adjustment, gamma correction, histogram equalization, and cropping. Watermarks inserted into middle and high frequencies are typically less robust to low-pass filtering lossy compression and small geometric deformations of the image, but are extremely robust with respect to noise adding, nonlinear deformations of the gray scale. It is understandable that the advantages and disadvantages of low and middle-to-high frequency watermarks are complementary. It appears that by embedding both watermarks into one image, one could achieve extremely high robustness properties with respect to a large spectrum of image processing operations. The above reasoning leads to proposed technique of embedding multiple watermarks into the low frequency and high frequency bands of discrete wavelet transform.

Natural language watermarking and tamperproofing

Abstract: Two main results in the area of information hiding in natural language text are presented. A semantically-based scheme dramatically improves the information-hiding capacity of any text through two techniques: (i) modifying the granularity of meaning of individual sentences, whereas our own previous scheme kept the granularity fixed, and (ii) halving the number of sentences affected by the watermark. No longer a long text, short watermark approach, it now makes it possible to watermark short texts, like wire agency reports. Using both the above-mentioned semantic marking scheme and our previous syntactically-based method hides information in a way that reveals any non-trivial tampering with the text (while re-formatting is not considered to be tampering-the problem would be solved trivially otherwise by hiding a hash of the text) with a probability 1-2 -β(n+1) , n being its number of sentences and β a small positive integer based on the extent of co-referencing.

Layered security in digital watermarking

Abstract: A media object authentication system uses layers of security features based on digital watermarks embedded in media objects. The system generates a first digital watermark with a message payload carrying data about the object, such as a hash of text data printed on the object. The first digital watermark is combined with a content signature derived from features of the media object, such as frequency domain attributes, edge attributes, or other filtered version of the media signal (e.g., image photo on a secure document) on the media object. This combination forms a new digital watermark signal that is embedded in the host media object. To verify the object, the digital watermark payload is extracted and compared with the data about the object. The combined digital watermark and content signature is also evaluated to authenticate the media signal on the media object.

Novel blind multiple watermarking technique for images

Abstract: Three novel blind watermarking techniques are proposed to embed watermarks into digital images for different purposes. The watermarks are designed to be decoded or detected without the original images. The first one, called single watermark embedding (SWE), is used to embed a watermark bit sequence into digital images using two secret keys. The second technique, called multiple watermark embedding (MWE), extends SWE to embed multiple watermarks simultaneously in the same watermark space while minimizing the watermark (distortion) energy. The third technique, called iterative watermark embedding (IWE), embeds watermarks into JPEG-compressed images. The iterative approach of IWE can prevent the potential removal of a watermark in the JPEG recompression process. Experimental results show that embedded watermarks using the proposed techniques can give good image quality and are robust in varying degree to JPEG compression, low-pass filtering, noise contamination, and print-and-scan.

Reversible watermark using difference expansion of triplets

Abstract: A new reversible watermarking algorithm based on the difference expansion of colored images has been developed. Since the watermark is completely reversible, the original image can be recovered exactly. The algorithm uses spatial and spectral triplets of pixels to hide pairs of bits, which allows the algorithm to hide a large amount of data. A spatial triplet is any three pixel values selected from the same spectral component, while a spectral triplet is any three pixel values selected from different spectral components. The algorithm is recursively applied to the rows and columns of the spectral components of the image and across all spectral components to maximize the hiding capacity. Simulation results show that the hiding capacity of the algorithm is very high and the resulting distortion is low.

Watermarks carrying content dependent signal metrics for detecting and characterizing signal alteration

Abstract: The invention provides methods and systems for detecting and characterizing alterations of media content, such as images, video and audio signals, using watermark messages to carry signal metrics. By comparing signal metrics extracted from the watermark to signal metrics calculated from a suspect signal, a watermark decoder can detect and even classify types of alterations to the watermarked signal.

Optimum decoding and detection of multiplicative watermarks

Abstract: This work addresses the problem of optimum decoding and detection of a multibit, multiplicative watermark hosted by Weibull-distributed features: a situation which is classically encountered for image watermarking in the magnitude-of-DFT domain. As such, this work can be seen as an extension of the system described in a previous paper, where the same problem is addressed for the case of 1-bit watermarking. The theoretical analysis is validated through Monte Carlo simulations. Although the structure of the optimum decoder/detector is derived in the absence of attacks, some experimental results are also presented, giving a measure of the overall robustness of the watermark when attacks are present.

Concept and Application of Zero-Watermark

Abstract: In the existing method of digital watermark,for embedding watermark information,authors modify more or less original image data through various methods to limit its robustness and security.Zero watermark is a new digital watermarking technology without modifying the data of original image.In this paper,we construct zero watermark using high order cumulants.The result of experiment shows that this zero watermark constructed by this method has good performance.

A novel echo-hiding scheme with backward and forward kernels

Abstract: The paper presents a novel echo-hiding method for audio watermarking. The method is quite different from previous echo-hiding methods since it presents a new echo kernel which introduces a forward kernel as well as a backward kernel. The new kernel, a combination of the backward and forward kernels, can enhance considerably the watermark detection rate. Thus, it is possible to reduce echo amplitude. The paper proves mathematically that the combination of kernels improves watermark performance. Experimental results show that the proposed watermarking scheme is much better than previous echo-hiding schemes in terms of detection rate and imperceptibility.

Audio watermarking with dual watermarks

Abstract: A watermark encoding system encodes an audio signal with both a strong and a weak watermark. The strong watermark identifies the content producer and is designed to survive all typical kinds of processing and malicious attacks. The weak watermark identifies the content as an original and is designed to be significantly removed as a result of most normal signal processing (other than A/D and D/A). The watermark encoding system has a converter to convert an audio signal into frequency and phase components and a mask processor to determine a hearing threshold for corresponding frequency components. The watermark encoding system also has a pattern generator to generate both the strong and weak watermarks and a watermark insertion unit to selectively insert either the strong or weak watermark into the audio signal. The watermark insertion unit adds the strong watermark to the audio signal when the signal exceeds the hearing threshold by a buffer value (e.g., 1-8 dB) and adds the weak watermark insertion unit when the signal falls below the hearing threshold by the buffer value. When the signal falls within the buffer area about the hearing threshold, the insertion unit takes no action. A watermark detecting system is equipped with a watermark detector that determines which block interval of the watermarked audio signal contains a watermark pattern and if the strong or weak watermark is present in that block interval of the signal.

Fragile watermarking scheme for image authentication

Abstract: A simple fragile watermarking scheme for image authentication is proposed. The insertion of a binary watermark is accomplished by replacing the least significant bit of the host image with a random binary image obtained by random permutations and suitable XOR operations among bitplanes. The proposed scheme is secure, fast, and capable of detecting and localising modification, and is immune of the well-known quantisation attack.

Digital watermarking for identification documents

Abstract: A watermark-based age verification system is provided in one implementation. The verification system may also verify a biometric template against a biometric sample. Shelf-life identification documents are provided in another implementation. Another aspect of the present invention analyzes image data to identify a face region or silhouette associated with a human subject depicted in the image data. The image data is adjusted, e.g., to center or align a face region within an image frame. A digital watermark is embedded after realignment. Another aspect authenticates or handles digital images that are captured at a first location and transferred to a second location via watermarking. In another implementation, first machine-readable code on an identification document layer is cross-correlated with second machine-readable code on the identification document. The first and second machine-readable codes are preferably sensed though different means, but can be cross-correlated to determine authenticity of an identification document.

Digital authentication with digital and analog documents

Abstract: A watermark embedder transforms a media signal from its perceptual domain to frequency domain regions and embeds a hash of data from one frequency domain region into a watermark in another frequency domain region. Alternatively, it encodes instances of the same message into the frequency domain regions. To detect alteration of the media signal, a watermark decoder transforms a suspect signal into the frequency domain regions, extracts the watermark message from a first frequency domain region and compares it with a reference derived from another frequency domain region. The reference signal is either a hash computed from the other frequency domain region of the watermarked signal, or another instance of the same message embedded into the other frequency domain region. The decoder can be used to detect alteration of the signal, such as alteration that occurs with reproduction (printing, scanning, copying, D/A-A/D conversion, etc.), compression, cropping or swapping of media signal content, etc.