Showing papers on "Watermark published in 2008"

International Conference on Intelligent Information Hiding and Multimedia Signal Processing

Abstract: This study presents a robust and semi-blind watermarking by embedding information into low frequency AC coefficients of Discrete Cosine Transform (DCT). Since the imperceptibility is the most significant issue in watermarking, the DC value is maintained unchanged. The proposed methods utilize the DC values of the neighboring blocks to predict the AC coefficients of the center block. The low frequency AC coefficients are modified to carry watermark information. The Least Mean Squares (LMS) is employed to yield the intermediate filters, cooperating with the neighboring DC coefficients to precisely predict the original AC coefficients. Two watermarking methods, namely Watermark Embedding in the Predicted AC Coefficient (WEPAC) and Watermark Embedding in the Original AC coefficient (WEOAC), are presented in this study. Moreover, many attacks are addressed to show the robustness of the proposed methods.

Color Image Watermarking Using Multidimensional Fourier Transforms

Abstract: This paper presents two vector watermarking schemes that are based on the use of complex and quaternion Fourier transforms and demonstrates, for the first time, how to embed watermarks into the frequency domain that is consistent with our human visual system. Watermark casting is performed by estimating the just-noticeable distortion of the images, to ensure watermark invisibility. The first method encodes the chromatic content of a color image into the CIE chromaticity coordinates while the achromatic content is encoded as CIE tristimulus value. Color watermarks (yellow and blue) are embedded in the frequency domain of the chromatic channels by using the spatiochromatic discrete Fourier transform. It first encodes and as complex values, followed by a single discrete Fourier transform. The most interesting characteristic of the scheme is the possibility of performing watermarking in the frequency domain of chromatic components. The second method encodes the components of color images and watermarks are embedded as vectors in the frequency domain of the channels by using the quaternion Fourier transform. Robustness is achieved by embedding a watermark in the coefficient with positive frequency, which spreads it to all color components in the spatial domain and invisibility is satisfied by modifying the coefficient with negative frequency, such that the combined effects of the two are insensitive to human eyes. Experimental results demonstrate that the two proposed algorithms perform better than two existing algorithms - ac- and discrete cosine transform-based schemes.

An Efficient Watermarking Method Based on Significant Difference of Wavelet Coefficient Quantization

Abstract: This paper proposes a blind watermarking algorithm based on the significant difference of wavelet coefficient quantization for copyright protection. Every seven nonoverlap wavelet coefficients of the host image are grouped into a block. The largest two coefficients in a block are called significant coefficients in this paper and their difference is called significant difference. We quantized the local maximum wavelet coefficient in a block by comparing the significant difference value in a block with the average significant difference value in all blocks. The maximum wavelet coefficients are so quantized that their significant difference between watermark bit 0 and watermark bit 1 exhibits a large energy difference which can be used for watermark extraction. During the extraction, an adaptive threshold value is designed to extract the watermark from the watermarked image under different attacks. We compare the adaptive threshold value to the significant difference which was quantized in a block to determine the watermark bit. The experimental results show that the proposed method is quite effective against JPEG compression, low-pass filtering, and Gaussian noise; the PSNR value of a watermarked image is greater than 40 dB.

Reversible Watermarking Based on Invariability and Adjustment on Pixel Pairs

Abstract: A novel reversible data hiding scheme based on invariability of the sum of pixel pairs and pairwise difference adjustment (PDA) is presented in this letter. For each pixel pair, if a certain value is added to one pixel while the same value is subtracted from the other, then the sum of these two pixels will remain unchanged. How to properly select this value is the key issue for the balance between reversibility and distortion. In this letter, half the difference of a pixel pair plus 1-bit watermark has been elaborately selected to satisfy this purpose. In addition, PDA is proposed to significantly reduce the capacity consumed by overhead information. A series of experiments is conducted to verify the effectiveness and advantages of the proposed approach.

Interval centroid based watermark

Abstract: An interval centroid-based watermark encoder encodes a watermark into a packet flow. Intervals are defined for the packet flow. Some of the intervals are selected as group A intervals while other intervals are selected as group B intervals. Group A and group B intervals are paired and assigned to watermark bits. A first or second value may be encoded by increasing the relative packet time between packets in either the group A (for the first bit value) or group B (for the second bit value) interval(s) of the interval pair(s) assigned to the watermark bits that are to represent the first or second bit value and the beginning of the same group interval(s). The relative packet times may be measured by a decoder and used to calculate a centroid difference for each interval pair. The centroid differences may be used to reconstruct the watermark.

Invariant Image Watermarking Based on Statistical Features in the Low-Frequency Domain

Abstract: Watermark resistance to geometric attacks is an important issue in the image watermarking community. Most countermeasures proposed in the literature usually focus on the problem of global affine transforms such as rotation, scaling and translation (RST), but few are resistant to challenging cropping and random bending attacks (RBAs). The main reason is that in the existing watermarking algorithms, those exploited robust features are more or less related to the pixel position. In this paper, we present an image watermarking scheme by the use of two statistical features (the histogram shape and the mean) in the Gaussian filtered low-frequency component of images. The two features are: 1) mathematically invariant to scaling the size of images; 2) independent of the pixel position in the image plane; 3)statistically resistant to cropping; and 4) robust to interpolation errors during geometric transformations, and common image processing operations. As a result, the watermarking system provides a satisfactory performance for those content-preserving geometric deformations and image processing operations, including JPEG compression, lowpass filtering, cropping and RBAs.

Fragile Watermarking With Error-Free Restoration Capability

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

Watermarking Relational Databases Using Optimization-Based Techniques

Abstract: Proving ownership rights on outsourced relational databases is a crucial issue in today's internet-based application environments and in many content distribution applications In this paper, we present a mechanism for proof of ownership based on the secure embedding of a robust imperceptible watermark in relational data We formulate the watermarking of relational databases as a constrained optimization problem and discuss efficient techniques to solve the optimization problem and to handle the constraints Our watermarking technique is resilient to watermark synchronization errors because it uses a partitioning approach that does not require marker tuples Our approach overcomes a major weakness in previously proposed watermarking techniques Watermark decoding is based on a threshold-based technique characterized by an optimal threshold that minimizes the probability of decoding errors We implemented a proof of concept implementation of our watermarking technique and showed by experimental results that our technique is resilient to tuple deletion, alteration, and insertion attacks

A singular-value decomposition-based image watermarking using genetic algorithm

Abstract: In this paper, a novel optimal watermarking scheme based on singular-value decomposition (SVD) using genetic algorithm (GA) is presented. The singular values (SVs) of the host image are modified by multiple scaling factors to embed the watermark image. Modifications are optimised using GA to obtain the highest possible robustness without losing the transparency. Experimental results show both the significant improvement in transparency and the robustness under attacks.

Digital Video Watermarking in P-Frames With Controlled Video Bit-Rate Increase

Abstract: Most video watermarking algorithms embed the watermark in I-frames, but refrain from embedding in P- and B-frames, which are highly compressed by motion compensation. However, P-frames appear more frequently in the compressed video and their watermarking capacity should be exploited, despite the fact that embedding the watermark in P-frames can increase the video bit rate significantly. This paper gives a detailed overview of a common approach for embedding the watermark in I-frames. This common approach is adopted to use P-frames for video watermarking. We show that by limiting the watermark to nonzero-quantized AC residuals in P-frames, the video bit-rate increase can be held to reasonable values. Since the nonzero-quantized AC residuals in P-frames correspond to nonflat areas that are in motion, temporal and texture masking are exploited at the same time. We also propose embedding the watermark in nonzero quantized AC residuals with spatial masking capacity in I-frames. Since the locations of the nonzero-quantized AC residuals is lost after decoding, we develop a watermark detection algorithm that does not depend on this knowledge. Our video watermark detection algorithm has controllable performance. We demonstrate the robustness of our proposed algorithm to several different attacks.

Out of phase digital watermarking in two chrominance directions

Abstract: The present invention relate generally to digital watermarking. One claim recites a method including: obtaining first data representing a first chrominance channel of a color image or video, where the first data comprises a watermark signal embedded therein; obtaining second data representing a second chrominance channel of the color image or video, the second data comprising the watermark signal embedded therein but with a signal polarity that is inversely related to the polarity of the watermark signal in the first data; combining the second data with the first data in a manner that reduces image or video interference relative to the watermark signal, said act of combining yielding third data; using at least a processor or electronic processing circuitry, processing the third data to obtain the watermark signal; and once obtained, providing information associated with the watermark signal. Of course, additional combinations and claims are provided as well.

A Robust Image Watermarking Scheme using Singular Value Decomposition

Abstract: This paper presents a robust image watermarking scheme for multimedia copyright protection. In this work, host image is partitioned into four sub images. Watermark image such as ‘logo’ is embedded in the two of these sub images, in both D (singular and diagonal matrix) and U (left singular and orthogonal matrix) components of Singular Value Decomposition (SVD) of two sub images. Watermark image is embedded in the D component using Dither quantization. A copy of the watermark is embedded in the columns of U matrix using comparison of the coefficients of U matrix with respect to the watermark image. If extraction of watermark from D matrix is not complete, there is a fair amount of probability that it can be extracted from U matrix. The proposed algorithm is more secure and robust to various attacks, viz., JPEG2000 compression, JPEG compression, rotation, scaling, cropping, row-column blanking, row-column copying, salt and pepper noise, filtering and gamma correction. Superior experimental results are observed with the proposed algorithm over a recent scheme proposed by Chung et al. in terms of Bit Error Rate (BER), Normalized Cross correlation (NC) and Peak Signal to Noise Ratio (PSNR).

DWT-DCT-SVD based watermarking

Abstract: Some works are reported in the frequency domain watermarking using Single Value Decomposition (SVD). The two most commonly used methods are based on DCT-SVD and DWT-SVD. The commonly present disadvantages in traditional watermarking techniques such as inability to withstand attacks are absent in SVD based algorithms. They offer a robust method of watermarking with minimum or no distortion. DCT based watermarking techniques offer compression while DWT based compression offer scalability. Thus all the three desirable properties can be utilized to create a new robust watermarking technique. In this paper, we propose a method of non-blind transform domain watermarking based on DWT-DCT-SVD. The DCT coefficients of the DWT coefficients are used to embed the watermarking information. This method of watermarking is found to be robust and the visual watermark is recoverable without only reasonable amount of distortion even in the case of attacks. Thus the method can be used to embed copyright information in the form of a visual watermark or simple text.

Digital watermarking with variable orientation and protocols

Abstract: A method of digital watermarking selects a mapping of a digital watermark to audio or video content and an embedding gain to produce uniquely watermarked copies for distribution. The embedding method is implemented at points of distribution, including content servers or receivers. By applying varying mapping protocols and random gain, the digital watermark uniquely serializes copies. It also has a structure and embedding configuration that minimizes the effectiveness of collusion, averaging and over-embedding attacks.

Oblivious Spatio-Temporal Watermarking of Digital Video by Exploiting the Human Visual System

Abstract: Imperceptibility requirement in video watermarking is more challenging compared with its image counterpart due to the additional dimension existing in video. The embedding system should not only yield spatially invisible watermarks for each frame of the video, but it should also take the temporal dimension into account in order to avoid any flicker distortion between frames. While some of the methods in the literature approach this problem by only allowing arbitrarily small modifications within frames in different transform domains, some others simply use implicit spatial properties of the human visual system (HVS), such as luminance masking, spatial masking, and contrast masking. In addition, some approaches exploit explicitly the spatial thresholds of HVS to determine the location and strength of the watermark. However, none of the former approaches have focused on guaranteeing temporal invisibility and achieving maximum watermark strength along the temporal direction. In this paper, temporal dimension is exploited for video watermarking by means of utilizing temporal sensitivity of the HVS. The proposed method utilizes the temporal contrast thresholds of HVS to determine the maximum strength of watermark, which still gives imperceptible distortion after watermark insertion. Compared with some recognized methods in the literature, the proposed method avoids the typical visual degradations in the watermarked video, while still giving much better robustness against common video distortions, such as additive Gaussian noise, video coding, frame rate conversions, and temporal shifts, in terms of bit error rate.

Multi-flow attacks against network flow watermarking schemes

Abstract: We analyze several recent schemes for watermarking network flows based on splitting the flow into intervals. We show that this approach creates time dependent correlations that enable an attack that combines multiple watermarked flows. Such an attack can easily be mounted in nearly all applications of network flow watermarking, both in anonymous communication and stepping stone detection. The attack can be used to detect the presence of a watermark, recover the secret parameters, and remove the watermark from a flow. The attack can be effective even if different the watermarks in different flows carry different messages. We analyze the efficacy of our attack using a probabilistic model and a Markov-modulated Poisson process (MMPP) model of interactive traffic. We also implement our attack and test it using both synthetic and real-world traces, showing that our attack is effective with as few as 10 watermarked flows. Finally, we propose a countermeasure that defeats the attack by using multiple watermark positions.

Power Signature Watermarking of IP Cores for FPGAs

Abstract: In this paper, we introduce a new method for watermarking of IP cores for FPGA architectures where the signature (watermark) is detected at the power supply pins of the FPGA. This is the first watermarking method where the signature is extracted in this way. We are able to sign IP cores at the netlist as well as the bitfile level, so a wide spectrum of cores can be protected. In principle, the proposed power watermarking method works for all kinds of FPGAs. For Xilinx FPGAs, we demonstrate in detail that we can integrate the watermarking algorithms and the signature into the functionality of the watermarked core. So it is very hard to remove the watermark without destroying the core. Furthermore, we introduce a detection algorithm which can decode the signature from a voltage trace with high reliability. Additionally, two enhanced robustness algorithms are introduced which improve the detection probability in case of considerable noise sources. Using these techniques, it is possible to decode the signature even if other cores operate on the same device at the same time.

A Buyer–Seller Watermarking Protocol Based on Secure Embedding

Abstract: In a forensic watermarking architecture, a buyer-seller protocol protects the watermark secrets from the buyer and prevents false infringement accusations by the seller. Existing protocols encrypt the watermark and the content with a homomorphic public-key cipher and perform embedding under encryption. When used for multimedia data, these protocols create a large computation and bandwidth overhead. In this correspondence, we show that the same functionality can be achieved efficiently using recently proposed secure watermark embedding algorithms.

DWT-SVD based image watermarking using Particle Swarm Optimizer

Abstract: Several watermarking schemes have been proposed with the purpose of copyright protection and access control for multimedia objects. In this paper, an optimal discrete wavelet transform-singular value decomposition (DWT-SVD) based image watermarking scheme using particle swarm optimizer (PSO) is presented. Proposed DWT-SVD based watermarking algorithm initially decomposes the host image into subbands, afterwards the singular values of each subband of the host image are modified by different scaling factors to embed the watermark image. Modifications are optimized using PSO to obtain the highest possible robustness without losing the transparency. Experimental results show improvement both in transparency and robustness under certain attacks.

A Video Watermarking Scheme Based on the Dual-Tree Complex Wavelet Transform

Abstract: A watermarking scheme that discourages theater camcorder piracy through the enforcement of playback control is presented. In this method, the video is watermarked so that its display is not permitted if a compliant video player detects the watermark. A watermark that is robust to geometric distortions (rotation, scaling, cropping) and lossy compression is required in order to block access to media content that has been re-recorded with a camera inside a movie theater. We introduce a new video watermarking algorithm for playback control that takes advantage of the properties of the dual-tree complex wavelet transform. This transform offers the advantages of the regular and the complex wavelets (perfect reconstruction, shift invariance, and good directional selectivity). Our method relies on these characteristics to create a watermark that is robust to geometric distortions and lossy compression. The proposed scheme is simple to implement and outperforms comparable methods when tested against geometric distortions.

Invisible watermarking based on creation and robust insertion-extraction of image adaptive watermarks

Abstract: This article presents a novel invisible robust watermarking scheme for embedding and extracting a digital watermark in an image. The novelty lies in determining a perceptually important subimage in the host image. Invisible insertion of the watermark is performed in the most significant region of the host image such that tampering of that portion with an intention to remove or destroy will degrade the esthetic quality and value of the image. One feature of the algorithm is that this subimage is used as a region of interest for the watermarking process and eliminates the chance of watermark removal. Another feature of the algorithm is the creation of a compound watermark using the input user watermark (logo) and attributes of the host image. This facilitates the homogeneous fusion of a watermark with the cover image, preserves the quality of the host image, and allows robust insertion-extraction. Watermark creation consists of two distinct phases. During the first phase, a statistical image is synthesized from a perceptually important subimage of the image. A compound watermark is created by embedding a watermark (logo) into the statistical synthetic image by using a visible watermarking technique. This compound watermark is invisibly embedded into the important block of the host image. The authentication process involves extraction of the perceptive logo as well statistical testing for two-layer evidence. Results of the experimentation using standard benchmarks demonstrates the robustness and efficacy of the proposed watermarking approach. Ownership proof could be established under various hostile attacks.

A New Robust Digital Image Watermarking Technique Based on Joint DWT-DCT Transformation

Abstract: In this paper, a new robust digital image watermarking algorithm based on Joint DWT-DCT Transformation is proposed. The imperceptibility is provided as well as higher robustness against common signal processing attacks. A binary watermarked image is embedded in certain sub-bands of a 3-level DWT transformed of a host image. Then, DCT transform of each selected DWT sub-band is computed and the PN-sequences of the watermark bits are embedded in the coefficients of the corresponding DCT middle frequencies. In extraction stages, the watermarked image, which maybe attacked, is first preprocessed by sharpening and Laplassian of Gaussian filters. Then, the same approach as the embedding process is used to extract the DCT middle frequencies of each sub-band. Finally, correlation between mid-band coefficients and PN-sequences is calculated to determine watermarked bits. Experimental results show that the proposed method improved the performance of the watermarking algorithms which are based on the joint of DWT-DCT.

A Watermarking Algorithm for Digital Image Based on DCT and SVD

Abstract: In this paper, we propose a watermarking algorithm for digital image based on DCT and SVD. The algorithm can satisfy the transparence and robustness of the watermarking system very well. The experiment based on this algorithm demonstrates that the watermarking is robust to the common signal processing techniques including JEPG compressing,noise, low pass filter, median filter, contrast enhance.Experimental results show that the new watermarking scheme is more robust than the SVD methods.