Showing papers on "Watermark published in 1998"

Image-adaptive watermarking using visual models

Abstract: The huge success of the Internet allows for the transmission, wide distribution, and access of electronic data in an effortless manner. Content providers are faced with the challenge of how to protect their electronic data. This problem has generated a flurry of research activity in the area of digital watermarking of electronic content for copyright protection. The challenge here is to introduce a digital watermark that does not alter the perceived quality of the electronic content, while being extremely robust to attack. For instance, in the case of image data, editing the picture or illegal tampering should not destroy or transform the watermark into another valid signature. Equally important, the watermark should not alter the perceived visual quality of the image. From a signal processing perspective, the two basic requirements for an effective watermarking scheme, robustness and transparency, conflict with each other. We propose two watermarking techniques for digital images that are based on utilizing visual models which have been developed in the context of image compression. Specifically, we propose watermarking schemes where visual models are used to determine image dependent upper bounds on watermark insertion. This allows us to provide the maximum strength transparent watermark which, in turn, is extremely robust to common image processing and editing such as JPEG compression, rescaling, and cropping. We propose perceptually based watermarking schemes in two frameworks: the block-based discrete cosine transform and multiresolution wavelet framework and discuss the merits of each one. Our schemes are shown to provide very good results both in terms of image transparency and robustness.

Robust audio watermarking in the time domain

Abstract: The audio watermarking method presented below offers copyright protection to an audio signal by modifying its temporal characteristics. The amount of modification embedded is limited by the necessity that the output signal must not be perceptually different from the original one. The watermarking method presented here does not require the original signal for watermark detection. The watermark key is simply a seed known only by the copyright owner. This seed creates the watermark signal to be embedded. Watermark embedding depends also on the audio signal amplitude in a way that minimizes the audibility of the watermark signal. The embedded watermark is robust to MPEG audio coding, filtering, resampling and requantization.

Digital watermarking using multiresolution wavelet decomposition

Abstract: We present a novel technique for the digital watermarking of still images based on the concept of multiresolution wavelet fusion. The algorithm is robust to a variety of signal distortions. The original unmarked image is not required for watermark extraction. We provide analysis to describe the behaviour of the method for varying system parameter values. We compare our approach with another transform domain watermarking method. Simulation results show the superior performance of the technique and demonstrate its potential for the robust watermarking of photographic imagery.

A public key watermark for image verification and authentication

Abstract: We propose a public key watermarking algorithm for image integrity verification. This watermark is capable of detecting any change made to an image, including changes in pixel values and image size. This watermark is important for several imaging applications, including trusted camera, legal usage of images, medical archiving of images, news reporting, commercial image transaction, and others. In each of these applications, it is important to verify that the image has not been manipulated and that the image was originated by either a specific camera or a specific user. The verification (the watermark extraction) procedure uses a public key as in public key cryptography, and hence it can be performed by any person without the secure exchange of a secret key. This is very important in many applications (e.g., trusted camera, news reporting) where the exchange of a secret key is either not possible or undesirable.

Multiresolution scene-based video watermarking using perceptual models

Abstract: We present a watermarking procedure to embed copyright protection into digital video. Our watermarking procedure is scene-based and video dependent. It directly exploits spatial masking, frequency masking, and temporal properties to embed an invisible and robust watermark. The watermark consists of static and dynamic temporal components that are generated from a temporal wavelet transform of the video scenes. The resulting wavelet coefficient frames are modified by a perceptually shaped pseudorandom sequence representing the author. The noise-like watermark is statistically undetectable to thwart unauthorized removal. Furthermore, the author representation resolves the deadlock problem. The multiresolution watermark may be detected on single frames without knowledge of the location of the frames in the video scene. We demonstrate the robustness of the watermarking procedure to several video degradations and distortions.

Some general methods for tampering with watermarks

Abstract: Watermarks allow embedded signals to be extracted from audio and video content for a variety of purposes. One application is for copyright control, where it is envisaged that digital video recorders will not permit the recording of content that is watermarked as "never copy". In such a scenario, it is important that the watermark survive both normal signal transformations and attempts to remove the watermark so that an illegal copy can be made. We discuss to what extent a watermark can be resistant to tampering and describe a variety of possible attacks.

A new wavelet-based scheme for watermarking images

Abstract: A new method for digital image watermarking which does not require the original image for watermark detection is presented. Assuming that we are using a transform domain spread spectrum watermarking scheme, it is important to add the watermark in select coefficients with significant image energy in the transform domain in order to ensure non-erasability of the watermark. Previous methods, which did not use the original in the detection process, could not selectively add the watermark to the significant coefficients, since the locations of such selected coefficients can change due to image manipulations. Since watermark verification typically consists of a process of correlation which is extremely sensitive to the relative order in which the watermark coefficients are placed within the image, such changes in the location of the watermarked coefficients was unacceptable. We present a scheme which overcomes this problem of "order sensitivity". Advantages of the proposed method include (i) improved resistance to attacks on the watermark, (ii) implicit visual masking utilizing the time-frequency localization property of the wavelet transform and (iii) a robust definition for the threshold which validates the watermark. We present results comparing our method with previous techniques, which clearly validate our claims.

Watermarking for image authentication

Abstract: A data embedding method is proposed for image authentication based on table look-up in frequency domain. A visually meaningful watermark and a set of simple features are embedded invisibly in the marked image, which can be stored in the compressed form. The scheme can detect and localize alterations of the original image, such as the tampering of images exported from a digital camera.

Method for protecting content using watermarking

Abstract: The work to be protected is digitized (10) and a baseline watermark is derived (12). A watermark offset vector is created (16) and then stored (18). The offset vector is added to the baseline watermark vector to generate a modified watermark vector (20). The baseline watermark vector is replaced with the modified watermark in the digitized work (22). And, finally, the watermarked work is returned to the original form (24).

Digital watermarking of color images using amplitude modulation

Abstract: Keywords: LTS1 Reference LTS-ARTICLE-1998-011doi:10.1117/1.482648View record in Web of Science Record created on 2006-06-14, modified on 2016-08-08

Watermarking techniques for intellectual property protection

Abstract: Digital system designs are the product of valuable effort and know-how Their embodiments, from software and HDL 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 (i) nearly invisible to human and machine inspection, (ii) difficult to remove, and (iii) permanently embedded as an integral part of the design We survey related work in cryptography and design methodology, then develop desiderata, metrics and example approaches — centering on constraint-based techniques — for watermarking at various stages of the VLSI design process

Fragile watermarks for detecting tampering in images

Abstract: A watermarking scheme for images which includes techniques for inserting and extracting fragile watermarks in the frequency domain and for determining whether an image so watermarked has been tampered with. Watermark insertion is accomplished by embedding the bits of a digital signature of a hash function of the image in the frequency coefficients of the image. Tamper detection is accomplished generally as follows: the fragile watermark which was embedded during the watermark insertion process is extracted from the image; the hash function of the image is computed as in the insertion process; it is verified using a public key whether the extracted watermark is a valid signature of the hash value. If so, then there is assurance that the image has not been tampered with. Otherwise, there is reason to conclude that the image has been tampered with.

Multiresolution watermarking for digital images

Abstract: In this paper, a multiresolution-based technique for embedding digital "watermarks" into images is proposed. The watermarking technique has been proposed as a method by hiding secret information in the images so as to discourage unauthorized copying or attesting the origin of the images. In our method, we take advantage of multiresolution signal decomposition. Both the watermark and the host image are composed of multiresolution representations with different structures and then the decomposed watermarks of different resolution are embedded into the corresponding resolution of the decomposed images. In case of image quality degradation, the low-resolution rendition of the watermark will still be preserved within the corresponding low-resolution components of the image. The experimental results show that the proposed watermarking technique results in an almost invisible difference between the watermarked image and the original image, and is robust to common image processing operations and JPEG lossy compression.

Method and system for transferring content information and supplemental information relating thereto

Abstract: A method and system for recording and reproducing, such as on a record carrier, content information and supplemental information relating thereto. The content information may be audio and/or video, and the supplemental information may provide author identification and/or copy control status. An encoded signal is generated representing the content information and which includes a watermark pattern representing the supplemental information. The watermark pattern cannot be changed without impairing the quality of the content information during reproduction. The supplemental information also includes a control pattern, the watermark being generated by applying a one-way function to such control pattern. This has the advantage that any alteration of the watermark or the control pattern can be detected easily, because it is not computationally feasible to calculate a new control pattern for an altered watermark. Therefore, the supplemental information is well protected against unauthorized manipulation. An attempt to fully replace the watermark pattern will affect the quality of reproduction of the content information. In a copy control method allowing a first generation copy (“copy-once”), the original control pattern is processed several times by the one-way function for generating the watermark. Each player or recorder processes the control pattern once before outputting/recording it, thus forming a cryptographically protected down-counter.

Image watermarking for tamper detection

Abstract: We propose an oblivious watermarking technique for tamper detection in digital images. By comparing correlation values from different portions of the image, the technique enables us to distinguish malicious changes, such as replacing/adding features from nonmalicious changes resulting from common image processing operations. The technique can be implemented with small memory and computational requirements, which makes it potentially useful for hardware implementation in digital cameras. The technique works by dividing an image into blocks and watermarking each block with a transparent, robust watermark that sensitively depends on a secret key (camera's ID) and continuously on the image. The watermarking method is a frequency based spread spectrum technique. To achieve a continuous dependency on the image, we propose a special bit extraction procedure that extracts bits from each block by thresholding projections onto key-dependent random smooth patterns. Those bits are then used for initializing a PRNG and synthesizing the spread spectrum signal.

A buyer-seller watermarking protocol

Abstract: Digital watermarks have previously been proposed for the purpose of copy protection and copy deterrence for multimedia content. Copy deterrence using digital watermarks is achieved by inserting a unique watermark into each copy of the watermark content sold which could be used to trace unauthorized copies to the erring buyer. One problem with such an approach is the fact that the 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 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 buyers watermark. However, in case the seller finds an unauthorized copy, he/she can identify the buyer from whom this unauthorized copy has originated and furthermore can also prove this fact to a third party by means of a dispute resolution protocol. Hence, the buyer cannot claim that an unauthorized copy may have originated from the seller.

Wavelet transform based watermark for digital images.

Abstract: In this paper, we introduce a new multiresolution watermarking method for digital images. The method is based on the discrete wavelet transform (DWT). Pseudo-random codes are added to the large coefficients at the high and middle frequency bands of the DWT of an image. It is shown that this method is more robust to proposed methods to some common image distortions, such as the wavelet transform based image compression, image rescaling/stretching and image halftoning. Moreover, the method is hierarchical.

Smart images and image bookmarking for an internet browser

Abstract: Web pages which contain images are displayed by a browser. A special visual indicia is placed on any the images which contain a digital watermark so that a user can know that the image contains hidden watermark data. By clicking on the indicia which is placed on the image, the user will be linked to the web page identified by the watermark data hidden in the image. Such a link will be established without the web page designer having to include a tag in the web pages design which displayed the original image. The present invention also opens a separate window which contains a thumbnail of each image in a web page. If a user right clicks on one of the thumbnails in this window the image will be added to a list of images in a special image bookmark file. When a user opens the bookmark web page, thumbnails of all the stored images in the bookmark file are displayed. A user can recall the web page which originally contained the image by clicking on the thumbnail.

Methods and systems for watermark processing of line art images

Abstract: Line art on banknotes and the like is subtly altered to steganographically encode plural-bit digital information. For example, the lines' widths or spacings can be locally changed so as to slightly modulate the apparent luminance of the document. The encoded information can be decoded using suitably-equipped processing equipment and used to identify a document as a banknote. Various anti-counterfeiting actions can then be taken.

Robust watermark method and apparatus for digital signals

Abstract: Watermark data is encoded in a digitized signal by forming a noise threshold spectrum which represents a maximum amount of imperceptible noise, spread-spectrum chipping the noise threshold spectrum with a relatively endless stream of pseudo-random bits to form a basis signal, dividing the basis signal into segments, and filtering the segments to smooth segment boundaries. The data encoded in the watermark signal is precoded to make the watermark data inversion robust and is convolutional encoded to further increase the likelihood that the watermark data will subsequently be retrievable notwithstanding lossy processing of the watermarked signal. To produce the endless pseudo-random bit stream, subsequent bits of the sequence are generated in a pseudo-random manner from previous bits of the sequence. The pseudo-random bits are appended to the stream of pseudo-random bits and, additionally, replace a number of bits of the state. The remaining bits are shifted such that, in effect, the least recently generated bits of the state are discarded. Thus, after production of a number of pseudo-random bits of the stream, the state changes significantly. Accordingly, repeating the above process generates additional pseudo-random bits which are very likely to differ significantly from the previously generated pseudo-random bits. A basis signal is generated by spread-spectrum chipping in accordance with the stream of pseudo-random bits and watermark data is encoded in the basis signal to form a watermark signal which is added to a digitized signal.

Compressed image authentication and verification

Abstract: A watermarking method involves mostly invisible artifacts and is sensitive to any modification of the picture at the level of precision rendered by the compressed version of the image. The image is compressed according to a known compression standard, such as the JPEG standard, and with a fixed quality setting. Using the JPEG standard, the original image is cut into blocks to which the Discrete Cosine Transform (DCT) is applied and the DCT coefficients quantized. The watermark according to the invention is applied to the quantized DCT coefficients. This is done using an encryption function, such as a secret key/public key algorithm. The JPEG compression is then completed using a lossless compression scheme, such as Huffman coding, to produce the compressed and watermarked image. Authentication of the compressed and watermarked image begins with a lossless decompression scheme to obtain the set of quantized DCT coefficients. The coefficients are authenticated, and the DCT output of each block is dequantized. If necessary, an inverse DCT is applied to each block to output the decompressed watermarked image.

Electronic watermark system electronic information distribution system and image filing apparatus

Abstract: Disclosed is an electronic watermark method, used for a network, comprising a plurality of entities, wherein provided weparately are an entity for embedding an electronic watermark in encrypted data that are exchanged by said plurality of entities, and an entity for performing an encryption process and a corresponding decryption process.

A Watermark for Image Integrity and Ownership Verification.

Abstract: We describe in this paper a watermarking scheme ownership verification and image authentication. Th authentication watermark is invisible, and has applic tions in trusted cameras, image transactions, legal ages, medical archiving, and others. This watermark conjunction with an appropriate digital key, can dete and localize any modifications to images. The wate mark inherits the security of a cryptographic hash fun tion, hence it is computationally infeasible for any una thorized user to confuse the image integrity or owners by forgery. We also describe using this invisible authe tication watermark to protect any visible watermarks.