A watermarking algorithm based on permutation and 2-D barcode

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.

We present a method for digital image watermarking based on the modification of certain subsets of the wavelet packet decomposition. These subsets are determined both from a secret key and an image dependent procedure that chooses a best basis from an energy criterion. The mark is set by imposing a parity constraint at each level of the decomposition. We elaborate on the choice of some of the parameters of the model, showing how they can be tuned so as to obtain good resistance to attacks. Examples are illustrated to assess the validity of our approach.

In this paper a new method for digital image watermarking based on zero assigned filter banks and embedded zero tree wavelet (EZW) algorithm is presented. An image is partitioned into 128 times 128 subblocks and each block is processed in a three stage decomposition structure by a filter bank which is assigned a zero around the stop band. The coefficients to be marked are chosen according to the EZW algorithm. This method not only provides a robust watermarking scheme but may also be used as an effective compression strategy. The algorithm is tested under white Gaussian noise and against JPEG compression and it is observed to be robust even when exposed to high levels of corruption

Most computers and systems are dealing with huge volumes of digital data. Major part of these digital data deals with multimedia, images and videos. The storage and secure transfer of this class of data is a burden for both individuals and organizations. Data authentication, data security and data compression are the primary requisites for any class of digital data in communication systems. Due to widespread and unrestricted use of the internet, multimedia data are available to everyone. For the protection of the author copyrights, image authentication is extremely important in present-day day communication systems. In image processing, authentication is implemented by using watermarking techniques. Nevertheless, whatever be the technique of watermarking, one of the important factors to be considered is robustness. In this chapter, novel methods for digital image watermarking and digital image compression are discussed. A novel method for digital watermarking in spatial domain, called as the (VB)2 (Variance Based Variable Block) Algorithm, will be discussed. The comparison in robustness of the spatial domain algorithm called as the DIMA (Diversified Intensity Matrix Algorithm) with our DCT-based frequency domain algorithm has been presented in [2]. The proposed work compares all watermarking techniques and determines the method with the highest robusteness. Additionally, a compression technique to address the problem of multimedia data storage and management is also proposed. This compression is brought about by a variance based algorithm.

A commutative digital image watermarking and encryption method in the tree structured Haar transform domain

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 often proposed methods to some common image distortions, such as the wavelet transform based image compression, and image halftoning. Moreover, the method is hierarchical. The computation load needed to detect the watermark depends on the noise level in an image.

In this work, a new quaternion-based method for color image watermarking is proposed. In this method, a novel set of quaternion radial substituted Chebyshev moments (QRSCMs) is presented for robust geometrically invariant image watermarking. An efficient computational method is proposed for highly accurate, fast, and numerically stable QRSCMs in polar coordinates. The proposed watermarking method consists of three stages. In the first stage, the Arnold transform is used to improve the security of the watermarking scheme by scrambling the binary watermark. In the second stage, the proposed accurate and stable QRSCMs of the host color image are computed. In the third stage, the encrypted binary watermark is embedded into the host image by employing the quantization technique on selected-magnitude QRSCMs where the watermarked color image is obtained by adding the original host color image to the compensation image. Then, the binary watermark can be extracted directly without using the original image from the magnitudes of QRSCMs. Numerical experiments are performed where the performance of proposed method is compared with the existing quaternion moment-based watermarking methods. The comparison clearly shows that the proposed method is very efficient in terms of the visual imperceptibility capability and the robustness under different attacks compared to the existing quaternion moment-based watermarking algorithms.

A blind dual color images watermarking based on singular value decomposition

For image authentication, the competence of accurately locating tampering and ensuring security is desirable. In this paper, a novel reversible data embedding based on Integer Wavelet Transform for tamper-proof watermarks is proposed. A contentbased watermark generated from host image is embedded into the carrier. The embedded data can be retrieved and the original host image can be recovered without distortion. The difference between the extracted watermark and the watermark generated from specific coefficients representing local features is applied to localize tampers. Experimental results show that the host image can be recovered after extracting the watermark if there are no attacks. Otherwise, the tampered positions can be localized explicitly and directly in the reconstructed host image even if the watermarked image was attacked by an invisible tampering. The proposed algorithm can be used for image authentication and tampering localization without using original image and original watermark.

An algorithm of dynamic watermark based on neural network is presented which is more robust against attack of false authentication and watermark-tampered operations contrasting with one watermark embedded method. (1) Five binary images used as watermarks are coded into a binary array. The total number of 0s and 1s is 5*N, every 0 or 1 is enlarged fivefold by information-enlarged technique. N is the original total number of the watermarks' binary bits. (2) Choose the seed image pixel p_x,y and its 3&times;3 vicinities pixel p _x-1,y-1,p_x-1,y,p_x-1,y+1,p_x,y-1,p_x,y+1,p_x+1,y-1,p_x+1,y,p_x+1,y+1 as one sample space. The p_x,y is used as the neural network target and the other eight pixel values are used as neural network inputs. (3) To make the neural network learn the sample space, 5*N pixel values and their closely relevant pixel values are randomly chosen with a password from a color BMP format image and used to train the neural network.(4) A four-layer neural network is constructed to describe the nonlinear mapped relationship between inputs and outputs. (5) One bit from the array is embedded by adjusting the polarity between a chosen pixel value and the output value of the model. (6) One randomizer generates a number to ascertain the counts of watermarks for retrieving. The randomly ascertained watermarks can be retrieved by using the restored neural network outputs value, the corresponding image pixels value, and the restore function without knowing the original image and watermarks (The restored <i>coded-watermark</i>_bit=1, if <i>ox,y(restored)</i>&gt;p_x,y(<i>reconstructed, else coded-watermark_bit </i>=0). The retrieved watermarks are different when extracting each time. The proposed technique can offer more watermarking proofs than one watermark embedded algorithm. Experimental results show that the proposed technique is very robust against some image processing operations and JPEG lossy compression. Therefore, the algorithm can be used to protect the copyright of one important image.

In order to combine the copyright protection with the content authentication commendably in the digital watermark, this paper proposes an improved error correction coding -based multipurpose method where the authentication watermark and the robust watermark are embedded in the different coefficients of DCT transform domain respectively. In addition, to strengthen the security, the method still utilizes the error correction coding. Through a series of experiment, the invisibility of the method can be proved both from the PSNR value (PSNR=51.2 dB) and the histogram equalization. The similarity between the original watermark and extracted watermark is almost above 95%. The proposed method is effective in image authentication and it's robust against some image processing operations, such as low-pass filtering, Gaussian noise, JPEG lossy compression, cropping and histogram equalization.

This paper presents a singular value decomposition (SVD) based steganalysis technique to determine the watermarking method used to embed a watermark in an image. The detection is carried out in three steps. First, the proposed technique determines whether an image under consideration contains a watermark. If a watermark is detected, the embedding domain is revealed. Finally, the exact watermarking algorithm is named. The idea behind the method is that when the image is watermarked, relative and strict linear dependencies of rows/columns will differ from the original image and this can be modeled by the analysis of SVD. By using SVD, several features for the classification of the original and watermarked images are defined. The classification operation including both a linear and a SVM classifier is performed with a feature selection algorithm, which serves to reduce the number of features and to increase the detection performance. The performance of the proposed technique is promising and simulation results indicate that the chosen features can reliably detect the watermarking domain as well as the watermarking method.

In this paper, an image watermarking scheme is presented, in which Least Significant Bit and discrete cosine transform are used. The discrete cosine transform is performed on the original host image, and the secret watermark image is embedded into the coefficient of discrete cosine transform, which will replace the least significant bit. The embedded secret watermark bit will cause minimal distortion of the original host image, but we cannot find the difference of the original host image and the watermarked image. The experiment based on this algorithm demonstrates that the watermarking is robust to the common signal processing techniques, including noise attack, JPEG Compression attack and so on.

Based on the method of SVD, a novel watermark algorithm is designed in this paper. Firstly, the SVD is performed on each segment of the original host image; Secondly, the watermark bits are formed by chaotic encrypting;Thirdly, the secret bits are embedded into the S component of the matrix by quantization; Lastly, the inverse SVD transformation is performed on each block and the watermarked image is constructed. The original host image is not required in the secret watermark recovery. Experimental results show that the watermarked image has transparent feature, and the quality of the recovered watermark is satisfying. The algorithm is strongly robust to many attacks, such as JPEG compression attack, Noise Interference and so on..

Now high-capacity reversible watermarking has been a popular research topic in image watermarking. Existing algorithms only focus on the control of additional information, but ignore the process of original host image and watermark, so the embedding capacity is not fully utilized. In this paper, a high capacity reversible watermarking algorithm based on image segmentation and difference expansion is proposed, firstly original host image is segmented by image segmentation, secondly watermark is preprocessed using lossless compression in order to increase the number of expansible difference values and improve the compressed ability of the location map. Experiments show the proposed algorithm is better than traditional difference expansion based algorithms in respects of embedding capacity, compressed ability of location map and distortion of watermarked image.