Showing papers on "Watermark published in 2001"

Improved wavelet-based watermarking through pixel-wise masking

Abstract: A watermarking algorithm operating in the wavelet domain is presented. Performance improvement with respect to existing algorithms is obtained by means of a new approach to mask the watermark according to the characteristics of the human visual system (HVS). In contrast to conventional methods operating in the wavelet domain, masking is accomplished pixel by pixel by taking into account the texture and the luminance content of all the image subbands. The watermark consists of a pseudorandom sequence which is adaptively added to the largest detail bands. As usual, the watermark is detected by computing the correlation between the watermarked coefficients and the watermarking code, and the detection threshold is chosen in such a way that the knowledge of the watermark energy used in the embedding phase is not needed, thus permitting one to adapt it to the image at hand. Experimental results and comparisons with other techniques operating in the wavelet domain prove the effectiveness of the new algorithm.

Digital watermarking: algorithms and applications

Abstract: Digital watermarking of multimedia content has become a very active research area over the last several years. A general framework for watermark embedding and detection/decoding is presented here along with a review of some of the algorithms for different media types described in the literature. We highlight some of the differences based on application such as copyright protection, authentication, tamper detection, and data hiding as well as differences in technology and system requirements for different media types such as digital images, video, audio and text.

Rotation, scale, and translation resilient watermarking for images

Abstract: Many electronic watermarks for still images and video content are sensitive to geometric distortions. For example, simple rotation, scaling, and/or translation (RST) of an image can prevent blind detection of a public watermark. In this paper, we propose a watermarking algorithm that is robust to RST distortions. The watermark is embedded into a one-dimensional (1-D) signal obtained by taking the Fourier transform of the image, resampling the Fourier magnitudes into log-polar coordinates, and then summing a function of those magnitudes along the log-radius axis. Rotation of the image results in a cyclical shift of the extracted signal. Scaling of the image results in amplification of the extracted signal, and translation of the image has no effect on the extracted signal. We can therefore compensate for rotation with a simple search, and compensate for scaling by using the correlation coefficient as the detection measure. False positive results on a database of 10 000 images are reported. Robustness results on a database of 2000 images are described. It is shown that the watermark is robust to rotation, scale, and translation. In addition, we describe tests examining the watermarks resistance to cropping and JPEG compression.

Secret and public key image watermarking schemes for image authentication and ownership verification

Abstract: We describe a watermarking scheme for ownership verification and authentication. Depending on the desire of the user, the watermark can be either visible or invisible. The scheme can detect any modification made to the image and indicate the specific locations that have been modified. If the correct key is specified in the watermark extraction procedure, then an output image is returned showing a proper watermark, indicating the image is authentic and has not been changed since the insertion of the watermark. Any modification would be reflected in a corresponding error in the watermark. If the key is incorrect, or if the image was not watermarked, or if the watermarked image is cropped, the watermark extraction algorithm will return an image that resembles random noise. Since it requires a user key during both the insertion and the extraction procedures, it is not possible for an unauthorized user to insert a new watermark or alter the existing watermark so that the resulting image will pass the test. We present secret key and public key versions of the technique.

Robust audio watermarking in the time domain

Abstract: The audio watermarking method proposed in this paper offers copyright protection to an audio signal by time domain processing. The strength of audio signal modifications is limited by the necessity to produce an output signal that is perceptually similar to the original one. The watermarking method presented here does not require the use of the original signal for watermark detection. The watermark signal is generated using a key, i.e., a single number known only to the copyright owner. Watermark embedding depends on the audio signal amplitude and frequency in a way that minimizes the audibility of the watermark signal. The embedded watermark is robust to common audio signal manipulations like MPEG audio coding, cropping, time shifting, filtering, resampling, and requantization.

System for controlling the distribution and use of rendered digital works through watermarking

Abstract: A trusted rendering system for use in a system for controlling the distribution and use of digital works. A trusted rendering system facilitates the protection of rendered digital works which have been rendered on a system which controls the distribution and use of digital works through the use of dynamically generated watermark information that is embedded in the rendered output. The watermark data typically provides information relating to the owner of the digital work, the rights associated with the rendered copy of the digital work and when and where the digital work was rendered. This information will typically aid in deterring or preventing unauthorized copying of the rendered work to be made. The system for controlling distribution and use of digital works provides for attaching persistent usage rights to a digital work. Digital works are transferred between repositories which are used to request and grant access to digital works. Such repositories are also coupled to credit servers which provide for payment of any fees incurred as a result of accessing a digital work.

Multipurpose watermarking for image authentication and protection

Abstract: We propose a novel multipurpose watermarking scheme, in which robust and fragile watermarks are simultaneously embedded, for copyright protection and content authentication. By quantizing a host image's wavelet coefficients as masking threshold units (MTUs), two complementary watermarks are embedded using cocktail watermarking and they can be blindly extracted without access to the host image. For the purpose of image protection, the new scheme guarantees that, no matter what kind of attack is encountered, at least one watermark can survive well. On the other hand, for the purpose of image authentication, our approach can locate the part of the image that has been tampered with and tolerate some incidental processes that have been executed. Experimental results show that the performance of our multipurpose watermarking scheme is indeed superb in terms of robustness and fragility.

Hiding digital watermarks using multiresolution wavelet transform

Abstract: In this paper, an image accreditation technique by embedding digital watermarks in images is proposed. The proposed method for the digital watermarking is based on the wavelet transform. This is unlike most previous work, which used a random number of a sequence of bits as a watermark and where the watermark can only be detected by comparing an experimental threshold value to determine whether a sequence of random signals is the watermark. The proposed approach embeds a watermark with visual recognizable patterns, such as binary, gray, or color image in images by modifying the frequency part of the images. In the proposed approach, an original image is decomposed into wavelet coefficients. Then, multi-energy watermarking scheme based on the qualified significant wavelet tree (QSWT) is used to achieve the robustness of the watermarking. Unlike other watermarking techniques that use a single casting energy, QSWT adopts adaptive casting energy in different resolutions. The performance of the proposed watermarking is robust to a variety of signal distortions, such as JPEG, image cropping, sharpening, median filtering, and incorporating attacks.

A buyer-seller watermarking protocol

Abstract: Digital watermarks have previously been proposed for the purposes of copy protection and copy deterrence for multimedia content. In copy deterrence, a content owner (seller) inserts a unique watermark into a copy of the content before it is sold to a buyer. If the buyer sells unauthorized copies of the watermarked content, then these copies can be traced to the unlawful reseller (original buyer) using a watermark detection algorithm. One problem with such an approach is that the original buyer whose watermark has been found on unauthorized copies can claim that the unauthorized copy was created or caused (for example, by a security breach) by the original seller. In this paper, we propose an interactive buyer-seller protocol for invisible watermarking in which the seller does not get to know the exact watermarked copy that the buyer receives. Hence the seller cannot create copies of the original content containing the buyer's watermark. In cases where the seller finds an unauthorized copy, the seller can identify the buyer from a watermark in the unauthorized copy and furthermore the seller can prove this fact to a third party using a dispute resolution protocol. This prevents the buyer from claiming that an unauthorized copy may have originated from the seller.

Attacks on digital watermarks: classification, estimation based attacks, and benchmarks

Abstract: Watermarking is a potential method for protection of ownership rights on digital audio, image, and video data. Benchmarks are used to evaluate the performance of different watermarking algorithms. For image watermarking, the Stirmark package is the most popular benchmark, and the best current algorithms perform well against it. However, results obtained by the Stirmark benchmark have to be handled carefully since Stirmark does not properly model the watermarking process and consequently is limited in its potential for impairing sophisticated image watermarking schemes. In this context, the goal of this article is threefold. First, we give an overview of the current attacking methods. Second, we describe attacks exploiting knowledge about the statistics of the original data and the embedded watermark. We propose a stochastic formulation of estimation-based attacks. Such attacks consist of two main stages: watermark estimation, exploitation of the estimated watermark to trick watermark detection or create ownership ambiguity. The full strength of estimation-based attacks can be achieved by introducing additional noise, where the attacker tries to combine the estimated watermark and the additive noise to impair watermark communication as much as possible while fulfilling a quality constraint on the attacked data. With a sophisticated quality constraint it is also possible to exploit human perception: the human auditory system in case of audio watermarks and the human visual system in case of image and video watermarks. Third, we discuss the current status of image watermarking benchmarks. We present Petitcolas'(see Electronic Imaging '99: Security and Watermarking of Multimedia Content, SPIE Proc., vol.3657, San Jose, CA, 1999) Stirmark benchmarking tool. Next, we consider the benchmark proposed by the University of Geneva Vision Group that contains more deliberate attacks. Finally, we summarize the current work of the European Certimark project, whose goal is to accelerate efforts from a number of research groups and companies in order to produce an improved ensemble of benchmarking tools.

Optimal differential energy watermarking of DCT encoded images and video

Abstract: This paper proposes the differential energy watermarking (DEW) algorithm for JPEG/MPEG streams. The DEW algorithm embeds label bits by selectively discarding high frequency discrete cosine transform (DCT) coefficients in certain image regions. The performance of the proposed watermarking algorithm is evaluated by the robustness of the watermark, the size of the watermark, and the visual degradation the watermark introduces. These performance factors are controlled by three parameters, namely the maximal coarseness of the quantizer used in pre-encoding, the number of DCT blocks used to embed a single watermark bit, and the lowest DCT coefficient that we permit to be discarded. We follow a rigorous approach to optimizing the performance and choosing the correct parameter settings by developing a statistical model for the watermarking algorithm. Using this model, we can derive the probability that a label bit cannot be embedded. The resulting model can be used, for instance, for maximizing the robustness against re-encoding and for selecting adequate error correcting codes for the label bit string.

Authentication watermarks for printed objects and related applications

Abstract: The disclosure describes systems for creating and authenticating printed objects (45, 46) using authentication and copy detection watermarks. For example, one verification system includes a watermark decoder (50) and a verification module (64, 66, 68, 70). The watermark decoder (50) detects a copy detection watermark in a printed object (45, 46) to determine whether the printed object has been reproduced. The verification module (64, 66, 68, 70) processes a message decoded from an authentication watermark on the printed object to authenticate the printed object or bearer of the printed object. The authentication and copy detection watermarks may be implemented as the same or different watermarks. For example, the authentication and copy detection watermarks may be separate watermarks embedded in an image that is printed on the object. The authentication watermark, in some applications, includes an identifier that links the object to a database entry with related information about the object.

Circularly symmetric watermark embedding in 2-D DFT domain

Abstract: In this paper, a method for digital image watermarking is described that is resistant to geometric transformations. A private key, which allows a very large number of watermarks, determines the watermark, which is embedded on a ring in the DFT domain. The watermark possesses circular symmetry. Correlation is used for watermark detection. The original image is not required in detection. The proposed method is resistant to JPEG compression, filtering, noise addition, scaling, translation, cropping, rotation, printing and rescanning. Experimental results prove the robustness of this method against the aforementioned attacks.

Wavelet domain watermarks

Abstract: A wavelet domain watermark encoder and decoder embed and detect auxiliary signals in a media signal, such as a still image, video or audio signal. The watermark encoders and decoders employ techniques that take advantage of processing plural levels of resolution of the signal to embed and detect auxiliary information in the media signal.

A survey of watermarking techniques applied to multimedia

Abstract: In the early days, encryption and control access techniques were used to protect the ownership of media. Recently, the watermark techniques are utilized to keep the copyright of media. Digital watermarking, a concept of embedding a special pattern, uses an algorithm of inserting a watermark to protect the copyright of media. It has recently become important in various application areas. The various of watermark techniques have been proposed by many authors in the last several years. However, there are not enough analysis and comparison on the previous researches. In this paper, for the understanding of the previous works and for the future related research, the authors try to classify and analyze the conventional watermark techniques from the various points of view. Currently watermark techniques based on the transfer domain, are more popular than those of the spatial domain. DCT-based methods have been most widely used among the transform based methods. However, recently wavelet-based watermark techniques are becoming the main research topic. With wide use of the internet, effective audio and video watermarking researches are also required.

Rotation, scale, and translation resilient public watermarking for images

Abstract: A method for detecting a watermark signal in digital image data. The detecting method includes the steps of: computing a log-polar Fourier transform of the image data to obtain a log-polar Fourier spectrum; projecting the log-polar Fourier spectrum down to a lower dimensional space to obtain an extracted signal; comparing the extracted signal to a target watermark signal; and declaring the presence or absence of the target watermark signal in the image data based on the comparison. Also provided is a method for inserting a watermark signal in digital image data to obtain a watermarked image. The inserting method includes the steps of: computing a log-polar Fourier transform of the image data to obtain a log-polar Fourier spectrum; projecting the log-polar Fourier spectrum down to a lower dimensional space to obtain an extracted signal; modifying the extracted signal such that it is similar to a target watermark; performing a one-to-many mapping of the modified signal back to log-polar Fourier transform space to obtain a set of watermarked coefficients; and performing an inverse log-polar Fourier transform on the set of watermarked coefficients to obtain a watermarked image.

Constraint-based watermarking techniques for design IP protection

Abstract: Digital system designs are the product of valuable effort and know-how. Their embodiments, from software and hardware description language program down to device-level netlist and mask data, represent carefully guarded intellectual property (IP). Hence, design methodologies based on IP reuse require new mechanisms to protect the rights of IP producers and owners. This paper establishes principles of watermarking-based IP protection, where a watermark is a mechanism for identification that is: (1) nearly invisible to human and machine inspection; (2) difficult to remove; and (3) permanently embedded as an integral part of the design. Watermarking addresses IP protection by tracing unauthorized reuse and making untraceable unauthorized reuse as difficult as recreating given pieces of IP from scratch. We survey related work in cryptography and design methodology, then develop desiderata, metrics, and concrete protocols for constraint-based watermarking at various stages of the very large scale integration (VLSI) design process. In particular, we propose a new preprocessing approach that embeds watermarks as constraints into the input of a black-box design tool and a new postprocessing approach that embeds watermarks as constraints into the output of a black-box design tool. To demonstrate that our protocols can be transparently integrated into existing design flows, we use a testbed of commercial tools for VLSI physical design and embed watermarks into real-world industrial designs. We show that the implementation overhead is low-both in terms of central processing unit time and such standard physical design metrics as wirelength, layout area, number of vias, and routing congestion. We empirically show that the placement and routing applications considered in our methods achieve strong proofs of authorship and are resistant to tampering and do not adversely influence timing.

Methods and systems using multiple watermarks

Abstract: Two or more digital watermarks, with different characteristics, are embedded in a document. The characteristics are chosen so that the watermarks will be affected in different manners if the document is subsequently copied or reproduced. The detection process or mechanism reads two or more of the watermarks and compares their characteristics. While wear and handling may change the characteristics of the digital watermarks in a document, the relationship between the characteristics of the multiple digital watermarks in a document will nevertheless give an indication as to whether a document is an original or a copy of an original. Document wear can be independently assessed and used as an aid in interpreting the detected watermark characteristics.

Watermarking 3D polygonal meshes in the mesh spectral domain

Abstract: Digital watermarking embeds a structure called watermark into the target data, such as image and 3D polygonal models. The watermark can be used, for example, to enforce copyright and to detect tampering. This paper presents a new robust watermarking method that adds watermark into a 3D polygonal mesh in the mesh's spectral domain. The algorithm computes spectra of the mesh by using eigenvalue decomposition of a Laplacian matrix derived only from connectivity of the mesh. Mesh spectra can be obtained by projecting coordinates of vertices onto the set of eigenvectors. A watermark is embedded by modifying the magnitude of the spectra. Watermarks embedded by using this method are resistant to similarity transformation, random noise added to vertex coordinates, mesh smoothing, and partial resection of the meshes.

Invertible authentication watermark for JPEG images

Abstract: We present two new invertible watermarking methods for authentication of digital images in the JPEG format. While virtually all previous authentication watermarking schemes introduced some small amount of non-invertible distortion in the image, the new methods are invertible in the sense that, if the image is deemed authentic, the distortion due to authentication can be completely removed to obtain the original image data. The first technique is based on lossless compression of biased bit-streams derived from the quantized JPEG coefficients. The second technique modifies the quantization matrix to enable lossless embedding of one bit per DCT coefficient. Both techniques are fast and can be used for general distortion-free (invertible) data embedding. The new methods provide new information assurance tools for integrity protection of sensitive imagery, such as medical images or high-importance military images viewed under non-standard conditions when usual criteria for visibility do not apply.

A new decoder for the optimum recovery of nonadditive watermarks

Abstract: Watermark detection, i.e., the detection of an invisible signal hidden within an image for copyright protection or data authentication, has classically been tackled by means of correlation-based techniques. Nevertheless, when watermark embedding does not obey an additive rule, or when the features the watermark is superimposed on do not follow a Gaussian pdf, correlation-based decoding is not the optimum choice. A new decoding algorithm is presented here which is optimum for nonadditive watermarks embedded in the magnitude of a set of full-frame DFT coefficients of the host image. By relying on statistical decision theory, the structure of the optimum is derived according to the Neyman-Pearson criterion, thus permitting to minimize the missed detection probability subject to a given false detection rate. The validity of the optimum decoder has been tested thoroughly to assess the improvement it permits to achieve from a robustness perspective. The results we obtained confirm the superiority of the novel algorithm with respect to classical correlation-based decoding.

Natural Language Watermarking: Design, Analysis, and a Proof-of-Concept Implementation

Abstract: We describe a scheme for watermarking natural language text by embedding small portions of the watermark bit string in the syntactic structure of a number of selected sentences in the text, with both the selection and embedding keyed (via quadratic residue) to a large prime number. Meaning-preserving transformations of sentences of the text (e.g., translation to another natural language) cannot damage the watermark. Meaning-modifying transformations have a probability, of damaging the watermark, proportional to the watermark length over the number of sentences. Having the key is all that is required for reading the watermark. The approach is best suited for longish meaning-rather than style-oriented "expository" texts (e.g., reports, directives, manuals, etc.), of which governments and industry produce in abundance and which need protection more frequently than fiction or poetry, which are not so tolerant of the small meaning-preserving syntactic changes that the scheme implements.

Steganalysis based on JPEG compatibility

Abstract: In this paper, we introduce a new forensic tool that can reliably detect modifications in digital images, such as distortion due to steganography and watermarking, in images that were originally stored in the JPEG format. The JPEG compression leave unique fingerprints and serves as a fragile watermark enabling us to detect changes as small as modifying the LSB of one randomly chosen pixel. The detection of changes is based on investigating the compatibility of 8x8 blocks of pixels with JPEG compression with a given quantization matrix. The proposed steganalytic method is applicable to virtually all steganongraphic and watermarking algorithms with the exception of those that embed message bits into the quantized JPEG DCT coefficients. The method can also be used to estimate the size of the secret message and identify the pixels that carry message bits. As a consequence of our steganalysis, we strongly recommend avoiding using images that have been originally stored in the JPEG format as cover-images for spatial-domain steganography.

Second Generation Benchmarking and Application Oriented Evaluation

Abstract: Digital image watermarking techniques for copyright protection have become increasingly robust. The best algorithms perform well against the now standard benchmark tests included in the Stirmark package. However the stirmark tests are limited since in general they do not properly model the watermarking process and consequently are limited in their potential to removing the best watermarks. Here we propose a second generation benchmark for image watermarking which includes attacks which take into account powerful prior information about the watermark and the watermarking algorithms. We follow the model of the Stirmark benchmark and propose several new categories of tests including: denoising (ML and MAP), wavelet compression, watermark copy attack, active desynchronization, denoising, geometrical attacks, and denoising followed by perceptual remodulation. In addition, we take the important step of presenting results as a function of application. This is an important contribution since it is unlikely that one technology will be suitable for all applications.

Robust spread-spectrum audio watermarking

Abstract: We present several mechanisms that enable effective spread-spectrum audio watermarking systems: prevention against detection desynchronization, cepstrum filtering, and chess watermarks. We have incorporated these techniques into a system capable of reliably detecting a watermark in an audio clip that has been modified using a composition of attacks that degrade the original audio characteristics well beyond the limit of acceptable quality. Such attacks include: fluctuating scaling in the time and frequency domain, compression, addition and multiplication of noise, resampling, requantization, normalization, filtering, and random cutting and pasting of signal samples.

User control and activation of watermark enabled objects

Abstract: Methods and systems for associating watermark enabled objects with machine behaviors. Machine behaviors refer to actions by devices or systems in response to a triggering event. Examples of these behaviors include fetching a web page, opening an email client to send an email to a specific person, initiating a phone or video conference call, etc. A registration system (104) enables users to associate machine behaviors with objects through a watermark embedded in the objects. The decoding (104) of the watermark initiates a process for triggering the machine behaviors associated with the watermarked object. While the disclosure describes an implementation for stickers (116) as a class of watermark enabled objects, the system and related methods apply to other forms of watermark enabled objects, including both electronic and physical objects.

Watermarking in the time-frequency domain

Abstract: Methods and systems for time-frequency domain watermarking of media signals, such as audio and video signals. An encoding method divides the media signal into segments (Fig.4A, element 401), transforms each segment into a time-frequency representation (Fig.4A, element 403), and computes a time-frequency domain watermark signal based on the time frequency representation (Fig.4A, element 404). It then combines the time-frequency domain watermark signal with the media signal to produce a watermarked media signal (Fig.4A, element 405).

Low visibility watermarks using an out-of-phase color

Abstract: The present invention relates to digital watermarks. In a preferred embodiment, a media signal is embedded with a digital watermark component. The media signal includes a cyan color plane, a magenta color plane, a yellow color plane, and a black plane. The digital watermark component is embedded in the cyan, magenta, and yellow color planes. The digital watermark component is inverted, and embedded in the black color plane. The resulting watermark is fragile, since signal processing techniques that combine the color planes with the black color plane effectively cancels the watermark signal in local areas. The inventive watermark also includes low-visibility properties, by canceling perceived luminance change in local areas throughout the media signal. In another embodiment, a watermark signal is embedded in a first color scheme to be out-of-color gamut in a second color scheme.

MPEG2 moving picture encoding/decoding system

Abstract: An MPEG2 moving picture and encoding/decoding system to provide digital copy protection of digital moving picture data. The MPEG2 moving picture encoder discrete cosine transforms a video input signal and uses a digital watermark inserter to embed digital watermark information on a frequency domain of the discrete cosine transformed video input signal. The MPEG2 moving picture decoder receives the encoded video output signal from the MPEG2 moving picture encoder and removes the embedded visual watermark information to locally decode the encoded video signal.