Image Watermarking Robust to Print and Generation Copy

After a watermarked image is printed, copied several times and scanned, the watermark usually cannot be extracted rightly, as well as distorted by noise. In this paper, a spread spectrum technique was introduced to image watermarking which can be applied to print and generation copy. The watermarking message is modulated by the key-dependent pseudo-random sequences to produce a spread spectrum signal. The watermark is embedded into the cover image by modifying the gray value of each pixel. The cover image is not needed when the watermark is detected. The watermark is estimated exploiting the properties of HVS(Human Visual System) and extracted through the same key-dependent 2D sequences. Experimental results show that the scheme can resist print, generation copy and scan process.

An enhanced hybrid image watermarking scheme for security of medical and non-medical images based on DWT and 2-D SVD

Reversible visible watermarking is used to combat the copyright infringement which can perfectly restore the original cover image by removing the embedded visible watermark. This paper proposes an improved reversible visible image watermarking scheme based on human visual system (HVS) and a region of interest selection (ROI-selection) strategy. Firstly, the cover image is partitioned into non-overlapped blocks. Then, a visual effect factor (VEF) based on HVS is adopted to adaptively modify the pixel values, which can provide a better fusion effect for the visible watermark and the cover image. The VEF value is determined by using the estimated watermarked and non-watermarked blocks within the neighborhood of each block. Finally, the visible watermark is embedded into the divided blocks using the traditional difference-expansion method, and a ROI-selection strategy is designed to find the most suitable regions for watermark embedding. Experimental results show the effectiveness and superiority of the proposed scheme compared to some existing works.

Image steganography is the study of embedding sensitive information in images without distorting their visual quality. In this paper, we have proposed an efficient image steganography algorithm to embed the secret image in the cover image. In this scheme, the secret image is encrypted that refers to the transformation of the secret data with Discrete Cosine Transform (DCT) compound with its hash file that is secured by a secret key. By this means, the embedded image is transformed into a noise-like cipher image called random noise in steganography methods with its HMAC file. The randomness property of the resultant image reduces the possibility of its detection by the human visual system (HVS) and steganalysis techniques. Next, LSB substitution method is employed to embed the transformed image in the cover image. To authenticate the image at the receiver side, the HMAC of the secret image is embedded in the cover image using LSB method. Simulation results have verified the effectiveness of the proposed algorithm.

Steganography algorithms used to secure sensitive data on the Internet. It hides the secret data in the cover image and provides imperceptibility to the attacker. The least significant bit (LSB) is the most preferred data hiding technique in the steganography. In this technique, the least significant bit of the cover image pixel replaced with data bits. In the literature, the data hiding achieved without considering the human visual system (HVS) characteristics that degrade the visual quality of the image. In this paper, the optimized data hiding has done while considering the HVS characteristics. The colour image contains three planes known as the red–green–blue plane. The green plane is the most sensitive, and blue is less sensitive to the human eyes. Thus, in the proposed technique, the green plane used as a reference plane for data hiding in the red and blue planes. In the optimized data hiding technique, the secret data bits match with the cover pixel bits. If the bits match, then the corresponding optimal index determines, else data hiding done in the LSB bits of the cover pixel. After that, the optimal indexes hide in the cover image using a 2-bit LSB technique. In the proposed technique, image smooth and edge region characteristics explored before data hiding. There is a high correlation between the consecutive pixels in the smooth region and the minimum correlation on the edges. Thus, we have matched the secret data bits with the cover pixel bits in the smooth region and hide the optimal indexes on the edges. The experimental results performed on the standard dataset images downloaded from the USC-SIPI image database. The experimental results show that the proposed technique provides better visual quality as compared to the existing techniques.

This paper proposes an RGB-based, secure technique to maintain and authenticate the integrity of a document. The novel Steganographic algorithm that we have proposed has its strength greatly enhanced by use of hybrid cryptography on data that is to be hidden in cover image. The secret message is converted into two kinds of plaintexts by subsequent ASCII and binary conversions and suitable bit stuffing. Two cipher texts are obtained using RSA and IDEA algorithms, which make up for a hybrid crypto-system. Both of these cipher texts are hidden in the cover image of the note using our novel, variable-length lSB-based Steganographic technique for data hiding in RGB images. One cipher text is used to determine the position for data hiding and the other cipher text is hidden in the lSBs of the color channel (that have minimum color contribution in the image) of the chosen pixels using variable length lSB based data embedding. Maximum intensity color channel is used to indicate which minimum intensity channel has how many bits of data embedded in it. We define the indicator and data channels from among the RGB color channels and use them for hiding of respective data in the cover image. Choosing such channels for hiding indicator and data bits, causes minimum distortion in the color of the pixels and such changes go undetected by Human Vision System (HVS).

In this paper, we propose an image authentication method based on digital image watermarking approach for paper checks. In the process of watermark embedding, a binary watermark image is added into the blue color component of a white color image. Paper check template is overlaid on the result, and printed out on a piece of paper. In the watermark extraction process, a paper check is first scanned back to obtain an electronic copy. A technique of image registration based on affine transformation is then applied to reduce geometric distortions from the printing and scanning processes, followed by a thresholding step to estimate the embedded bit in each watermarked component. The performance of the proposed method was investigated using different scanning resolutions and printing quality modes. Its extraction performance from the paper checks with written texts and folded marks was also investigated. The promising results demonstrate the effectiveness of the proposed method.

This paper presents a novel approach for Image steganography based on Integer Wavelet Transform. In this method, the cover image is mapped to a specific frequency domain. Then in the obtained frequency domain, edge coefficients are classified based on their MSBs. The suggested method prevents changes in MSB in a way that receiver can extract the information without any mistakes. Considering the preformed classification, secret bits will be embedded in the frequency coefficients and then with the use of inverse transformation, stego image will be obtained. The most important features that our work obtained are good adaptation with human vision system and retrieval of data without error. Simulation results show that our proposed method has a good adaptation with human vision system (HVS) and outperforms in terms of PSPNR factors over recently published works.

Image steganography is a technique used to conceal secret information within digital images in such a way that the existence of the hidden data is not perceptible to the human eye. This method leverages the vast amount of data contained in image files, embedding the secret message by altering certain pixel values in a manner that is undetectable. The primary goal of image steganography is to ensure that the embedded information is secure and invisible, maintaining the original image's appearance and quality. Applications of image steganography include secure communication, digital watermarking, and copyright protection. Advanced methods often employ complex algorithms and machine learning models to enhance the robustness and imperceptibility of the hidden data, making it resistant to detection and manipulation.. The main idea of the proposed work is to utilize features extracted from images to construct a Hash Table, which will be employed for concealing and revealing a secret message. Since the same CNN model and input image (i.e., cover image) produce identical features, even if the cover image is slightly affected by noise, the same features (and consequently the same Hash Table) will be generated. The work demonstrated promising results in regenerating images when the cover image is slightly affected. However, as the noise level increases on the cover image, the regenerated images begin to lose more details.

This paper proposes a two-stage lossless robust watermarking scheme based on deep neural network. In the first stage, the encoder, noise layer and decoder network are combined to design an end-to-end network framework, which is used to train the input watermark information and cover image. In this framework, the encoder outputs a robust watermarked image whose visual quality is similar to the cover image, and the decoder can extract the embedded watermark information to evaluate robustness. In the second stage, by using reversible information hiding algorithm with extended prediction error, the auxiliary information that can recover the cover image is embedded into the robust watermarked image to ensure reversibility. If the watermarked image does not undergo attack processing, the hidden watermark information can not only be extracted, but also the cover image can be completely recovered. Even if the watermarked image does undergo attack processing, the embedded watermark information can also be extracted correctly because of the strong robustness in the first stage. Experimental results demonstrate the robustness of proposed scheme in terms of JPEG compression, gaussian filtering noise, rotation and shearing operations.KeywordsReversible information hidingRobust watermarkingDeep neural networkTwo-stage embeddingNoise simulation

In this paper, a general concept called the n+k/n method is introduced. In the n+k/n method, a special mapping function is defined to map an intermediate set with n+k bits into a n bit information set. In the embedding process, the intermediate set is embedded into a cover image rather than embedding the information set. If the distance between features of the cover image and the bits of the intermediate set is less than that between the features and information bits, the better the cover image quality. According to the idea of the n+k/n method, a special case called the n+1/n method is proposed. In this method, the mapping function is an exclusive-or operation. When an information set is given, two sets which satisfy the mapping function can be obtained. That which has a smaller distance from feature bits is selected as an intermediate set. In the paper, it is proved that the maximum distance between the intermediate set and feature set is less than the average distance between the information set and the feature set. The reduction rate of feature modification for the n+1/n method will reach 25%, and the improving quality in the embedded cover image is more than 2.5 db.

Like the digital watermark, which has been highlighted in previous studies, the quantum watermark aims to protect the copyright of any image and to validate its ownership using visible or invisible logos embedded in the cover image. In this paper, we propose a method to include an image logo in a cover image based on quantum fields, where a certain amount of texture is encapsulated to encode the logo image before it is included in the cover image. The method also involves transforming wavelets such as Haar base transformation and geometric transformation. These combination methods achieve a high degree of security and robustness for watermarking technology. The digital results obtained from the experiment show that the values of Peak Signal Noise Ratio (PSNR) and Mean Squared Error (MSE) that apply to one of the set cover images were 68.74 and 0.093, respectively.

Most schemes exhibit low robustness due to LSB’s (Least Significant Bit) and MSB’s (Most Significant Bit) based information hiding in the cover image. However, most of these IW schemes have low imperceptibility as the cover image distortion reveals to the attacker due to information hiding in MSB’s. In this paper, a hybrid image watermarking scheme is proposed based on integrating Robust Principal Component Analysis (R-PCA), Discrete Tchebichef Transform (DTT), and Singular Value Decomposition (SVD). A grayscale watermark image is twisted/scrambled using a 2D Discrete Hyper-chaotic Encryption System (2D-DHCES) to boost up the robustness/heftiness and security. The original cover image is crumbled into sparse components using R-PCA and using DTT the substantial component is additionally decomposed and the watermark will be embedded in the cover image using SVD processing. In DTT, scarcer coefficients hold the utmost energy, also provide an optimum sparse depiction of the substantial image edges and features that supports proficient retrieval of the watermark image even after unadorned image distortion based channel attacks. The imperceptibility and robustness of the proposed method are corroborated against a variety of signal processing channel attacks (salt and pepper noise, multi-directional shearing, cropping, and frequency filtering, etc.). The visual and quantifiable outcomes reveal that the proposed image watermarking scheme is much effective and delivers high forbearance against several image processing and geometric attacks.

Traditional image watermarking technology focuses on the robustness and imperceptibility of the copyright information embedded in the cover image. However, in addition to copyright theft, the cover images stored and transmitted in the open network environment is facing the threat of being identified and retrieved by deep neural network (DNN) with malicious purpose, which is a new privacy threat. Therefore, it is essential to protect the copyright and the privacy of cover image simultaneously. In this paper, a novel cover-concealed image watermarking (CCIW) is proposed, which combines conditional generative adversarial networks with channel attention mechanisms to generate adversarial examples of the cover image containing invisible copyright information. This method can effectively prevent privacy leakage and copyright infringement simultaneously, since the cover image cannot be collected and processed by DNNs without permission, and the embedded copyright information is hardly to be removed. The experimental results show that the proposed method achieved a success rate of adversarial attack over 98% on the Caltech256 dataset, and the generated adversarial examples have good image quality. The accuracy of copyright information extraction is close to 100%, and it also exhibits good robustness in different noise environments.

The seminal exhibition ‘Parallel of Life and Art’ (PLLA) which took place at the ICA in London in 1953 continues to capture the attention of art historians and curators through exhibition histories and curatorial studies. The exhibition is a key element in defining “discourse through images (Bilddiskurs),” a longstanding practice that nonetheless experienced significant change when it encountered the image-making properties of cameras and the means for their dissemination in the press (Flusser). This change coincided with a developing awareness of iconography and the work of the Warburg circle within the Independent Group, that equally understood this form of visual analysis in relation to emerging cybernetic theories of communication and information theory. Building on research undertaken for the Tate Britain display ‘New Brutalist Image 1949-55’ (24 Nov 2014 – 20 Sep 2015), the article argues that PLLA demonstrates how photography was put to work discursively in post-war Britain, deploying new conditions of ‘seeing’ to define a visual order brought about by the transformation of image-capture and mass reproduction technologies, by the new ubiquity of photography, and by the lure of consumer society. Accompanying unprecedented technological possibilities was a new visual sensibility – in other words, a new contemporary aesthetic - rooted in the camera’s lens and mediated through printing processes. Together, this media combination encoded a manner of communication meant to challenge the cultural and social primacy of the printed word, invoking an “Esperanto” of images. Anticipating Lawrence Alloway’s conceptualisation of a ‘fine art pop art continuum’, the article argues, that the photographic image, through its mediating and remediating qualities became a sophisticated, nuanced tool of communication across the practices of art, architecture and design. It also highlights Peter Smithson’s proposition that understanding the visual motivations behind PLLA revealed contemporary cultural conditions “like a Rosetta Stone.” The collaborative team of Alison & Peter Smithson, Nigel Henderson, Eduardo Paolozzi and Ronald Jenkins behind ‘Parallel of Life and Art’ shared an ambition to release the expanded field of everyday day visual culture into vision and experience across the board, displacing the highly invested and ordered culture of art and architecture, one traditionally governed by elitist ideas of public value and taste. The specificity and importance of photography as both a tool of communication and a medium of visual convergence that synthesised disparate registers, has been neglected in studies of British art, leading to misrecognition and an under-conceptualised reading of the exhibitions produced by IG members, including PLLA. As Reyner Banham, the architecture critic and theorist of New Brutalism noted when reviewing PLLA, “We tend to forget that every photograph is an artifact ... the photograph being an artifact applies its own laws of artefaction to the material it documents, and discovers similarities and parallels between the documentation, even where none exists between the objects and events recorded. Thus photographs make us see connections ...” (Reyner Banham, ‘Photography’ [PLLA review], AR, 1953) For the PLLA team of ‘editors’, a body of photographic images taken by Nigel Henderson (who they mutually identified and awarded the role of photographer to act as their translator, mediator and ‘image-finder’) nonetheless reflects the experiments of the group, documenting their work and recording their visual sensibility. Through our selection and curation of images, the article will demonstrate how photography was exploited as a medium to bring disparate practices, spatial and temporal environments, social and cultural spaces together in the binding matrix of the photographic image.