Copyright Watermark Research Articles

Convolutional neural network and 2D logistic-adjusted-Chebyshev-based zero-watermarking of color images

Robust zero-watermarking is a protection of copyright approach that is both effective and distortion-free, and it has grown into a core of research on the subject of digital watermarking. This paper proposes a revolutionary zero-watermarking approach for color images using convolutional neural networks (CNN) and a 2D logistic-adjusted Chebyshev map (2D-LACM). In this algorithm, we first extracted deep feature maps from an original color image using the pre-trained VGG19. These feature maps were then fused into a featured image, and the owner's watermark sequence was incorporated using an XOR operation. Finally, 2D-LACM encrypts the copyright watermark and scrambles the binary feature matrix to ensure security. The experimental results show that the proposed algorithm performs well in terms of imperceptibility and robustness. The BER values of the extracted watermarks were below 0.0044 and the NCC values were above 0.9929, while the average PSNR values of the attacked images were 33.1537 dB. Also, it is superior to other algorithms in terms of robustness to conventional image processing and geometric attacks.

Zero-Watermarking for Vector Maps Combining Spatial and Frequency Domain Based on Constrained Delaunay Triangulation Network and Discrete Fourier Transform.

With its lossless properties, zero-watermarking has attracted a lot of attention in the field of copyright protection for vector maps. However, the common zero-watermarking algorithm puts too much emphasis on mining for global features, making it vulnerable to cropping attacks, and the robustness is not comprehensive enough. This study provides a vector map zero-watermarking scheme that utilizes spatial statistical information and frequency domain transformation methods in an effort to solve the aforementioned issue. In order to make the scheme more resistant to cropping and compression, it is constructed on the basis of feature point extraction and point constraint blocking of the original vector map. Within each sub-block, feature points are used to build constraint Delaunay triangulation networks (CDTN), and the angular values within the triangle networks are then extracted as spatial statistics. The angle value sequence is further transformed by discrete Fourier transform (DFT), and the binarized phase sequence is used as the final feature information to build a zero watermark by executing an exclusive disjunction operation with the encrypted copyright watermark image, both of which contribute to the scheme's robustness and security. The results of the attack experiments show that the proposed vector map zero-watermarking can restore identifiable copyright images under common geometric attacks, cropping attacks, and coordinate system transformations, demonstrating a high level of robustness. The theoretical basis for the robustness of this watermarking scheme is the stability of CDTN and the geometric invariance of DFT coefficients, and both theory and experiment validate the method's validity.

A Self-Error-Correction-Based Reversible Watermarking Scheme for Vector Maps

The existing digital watermarking schemes for vector maps focus mainly on the process of watermark embedding, while few works have been conducted on the topic of the self-optimization of watermark data in the process of watermark detection. There is thus still much room for accuracy improvement in watermark detection. In this paper, a model of mixed watermark data construction is built first. It constructs the error-correction codes and checking code of the original copyright watermark data and combines them to generate the final watermark data. Additionally, a lossless compression algorithm is designed for watermark data to constrain the total watermark length. Based on the constructed model, a self-error-correction-based reversible watermarking scheme is put forward for vector maps. In this scheme, map vertices are divided into non-intersecting groups first according to stability, and mixed watermark data are then embedded with respective vertex groups. Simulation results demonstrate that the watermark capacity of this scheme is 1.0000, the coordinate error caused by the watermark embedding process can be limited to no more than 0.00001 when the strength of watermark embedding is set to five, and several watermark bits can be effectively detected and corrected after watermark extraction. Experimental results and analysis show that it can strike a good balance among reversibility, invisibility, capacity and robustness. It can provide a novel solution to improve the watermark detection accuracy of digital watermarking schemes for vector maps.

Video Watermarking Algorithm Based on NSCT, Pseudo 3D-DCT and NMF.

Video watermarking is an important means of video and multimedia copyright protection, but the current watermarking algorithm is difficult to ensure high robustness under various attacks. In this paper, a video watermarking algorithm based on NSCT, pseudo 3D-DCT and NMF has been proposed. Combined with NSCT, 3D-DCT and NMF, the algorithm embeds the encrypted QR code copyright watermark into the NMF base matrix to improve the anti-attack ability of the watermark under the condition of invisibility. The experimental results show that the algorithm ensures the invisibility of the watermark with a high signal-to-noise ratio of the video, and meanwhile has high ability and robustness against common single and combined attacks, such as filtering, noise, compression, shear, rotation and so on. The issue that the video watermarking algorithm has poor resistance to various attacks, especially the shearing attack, has been solved in this paper; thus, it can be used for digital multimedia video copyright protection.

Reversible watermarking algorithm of vector maps based on ECC

Robustness of current watermarking schemes of vector maps is mainly dependent on algorithms of watermark embedding and extraction, while few works have been done focusing on error correction algorithms after watermark extraction. In this paper, a reversible watermarking scheme is proposed for vector maps based on error correction codes (ECC). Original copyright information is firstly expressed by a binary array (copyright watermark data), for which ECC are then generated exploiting XOR operation. Then, the copyright watermark data and its corresponding ECC are merged to compose the final watermark data. To enhance the robustness of this scheme under geometric transformation, watermarks are embedded into polar coordinates of map vertices. After watermark extraction, this scheme can not only obtain the original copyright information, but also recover the original map content accurately. Both theoretical analysis and comprehensive experimental results validate the reversibility, invisibility, capacity and robustness of the proposed watermarking scheme.

Digital Image Watermarking in Frequency Domain Using ECC and Dual Encryption Technique

This study presented an algorithm to protect the copyright watermark by providing Hamming codes as error correcting technique. Watermark was embedded in frequency domain using discrete cosine transformation and discrete wavelet transformation, to enhance the susceptibility. Combinations of two techniques are used to target medium frequencies only. Randomness of the watermark is also created before embedding. Instead of embedding in the same place in every block, it is embedded adaptively which depends upon the row and column of that particular block. Results prove the effectiveness of the algorithm against various attacks like jpeg attack, filtering and addition of noises like Gaussian noise, salt and pepper noise and speckle noise. ECC proved to be effective to recover the watermark after certain attacks performed.

A Novel Lossless Robust Watermarking Method for Copyright Protection of Biomedical Image

Nanoscience and Nanotechnology promotes the development of biomedical imaging devices, more and more valuable biomedical images are transmitted through the open network, and their copyright suffers a major challenge. This paper proposes a new lossless robust watermarking method to realize biomedical image's copyright protection. For high-resolution biomedical images, the redundant theory and histogram shifting method based on image block's difference are utilized to repeatedly embed copyright watermark into different color channels. In the extracting procedure, each layer's watermark information can be extracted from watermarked image respectively, and the final watermark is judged by the voting theory. The redundant scheme and voting theory guarantees the watermark can resist against random noise's attack well. Besides, in order to reduce the watermark overhead in embedding procedure, the histogram narrowing down technique is used to tackle with those image blocks would overflows and underflows. Experimental results showed that the proposed method outperformed the existing semi-fragile reversible watermarking scheme and provided a great robustness against moderate JPEG compression and salt-pepper and Gaussian noise.

Reversible medical image watermarking based on wavelet histogram shifting

This paper introduces a reversible and scalable blind watermarking method for medical images based on histogram shifting in wavelet domain. The histogram shifting‐based watermarking especially in spatial domain suffers from the overhead of positions information that has to be embedded. This not only has negative impact on the capacity of the embedded data, but also reduces the quality of the watermarked image. To overcome this problem, a new histogram shifting approach in wavelet domain is introduced which adaptively manages the parts of the required histogram to be shifted. For inserting watermark data, two thresholds, T1 and T2, are determined in the high‐frequency sub‐bands of the histogram based on the size of watermark data. Two zero‐points, Z1 and Z2, are created in the histogram shifting. In the histogram shifting procedure, only small parts of the histogram have been shifted and therefore, introduced distortion has been considerably decreased and the quality of the watermarked image has been increased. Applications of the method were examined for the multiple medical image watermarking. Two sets of data, one as copyright watermark and the other as caption watermark which contains patients’ information, are first encrypted and then inserted in the high‐frequency sub‐bands in the integer wavelet domain. Inserting the data in different sub‐bands besides encryption of it by a private key provides high security for the embedded data. Experimental results obtained for several watermarked medical images indicate imperceptibility of the approach even for high payloads. The proposed approach overcomes other related works introduced in the recent literatures.

Watermarking software in practical applications

In the recent years, several digital watermarking applications have been developed for copyright protection of digital images. In this article we have tested how they perform in practical applications. We have identified the most common operations performed by professional photographers and web developers, and tested the robustness of watermarks embedded using the applications for copyright watermarking. Our aim was to prove that commercially available software does not meet the requirements of photography and web industry. We have also identified areas in which the software should be improved in order to meet current and future requirements of the industry.

Visual-based embedding systems with targeted secret disclosures and applications

In this paper, a VWC-system is proposed. In the system, the embedded information can hold the secret for the encryption key. The system adopts the technique of frequency-domain watermarking and visual cryptography, respectively. Furthermore, the embedded part is only a share, meaning a portion of the watermark generated from a chosen KFI. The remaining shares not used in the embedding procedure are kept until the extraction procedure in order to reveal the targeted secret or copyright watermark shown in the message of the watermark image. Another feature is the key could be easily applied in a symmetric-key cryptosystem for a common key agreement via a public channel.

ElGarnal함수를 사용하는 디지털 이미지 워터마킹 기법

디지털 이미지 워터마킹(digital image watermarking)은 이미지 소유자의 정보를 디지털 이미지 속에 삽입시켜 이미지 소유자의 저작권을 보호하는 것을 목적으로 하는 기법이다. 저작권 보호를 위한 디지털 이미지 워터마킹 기법은 기존의 스테가노그라피(steganography)보다 워터마킹 공격에 대한 견고성과 육안적 비구별성을 동시에 추구해야 하고, 워터마킹 알고리즘의 은닉성 대신 키의 은닉성이 보장되어야 하며, 암호학과 마찬가지로 키의 사용으로 허가받지 않은 사용자의 워터마크 검출을 방지할 수 있어야 한다. 본 논문에서는 암호학 함수인 ElGamal함수를 사용하는 워터마킹 기법을 제안한다. 일방향 해쉬 함수를 구현하기 위해 ElGamal일방향 함수와 모듈라 연산을 사용한다. 제안하는 워터마킹 기법은 LSB(least significant bit)공격과 감마 보정 공격에 대해 견고하며 육안적 비구별성(perceptual invisibility)이 높다. 제안하는 워터마킹 기법의 실제 구현 및 실험을 통한 실험 결과를 분석하여 견고성과 육안적 비구별성의 특징을 확인한다 향후 과제로, 키생성을 위한 의사난수성과 비대칭키의 생성을 동시에 달성시키는 알고리즘 연구가 요구된다. Digital image watermarking is a technique for the purpose of protecting the ownership of the image by embedding proprietary watermarks in a digital image. It is required for the digital image watermarking scheme to pursue the robustness against water marking attacks and the perceptual Invisibility more than usual in steganography area, to guarantee not a hidden watermarking algorithm but the publicity of water-marking algorithm details and hidden use of key, which can protect the unauthorized user access from detection. In this paper we propose a new copyright watermarking scheme, which is barred on one-way hash functions using ElGamal functions and modular operations. ElGamal functions are widely used in cryptographic systems. Our watermarking scheme is robust against LSB(least significant bit) attacks and gamma correction attack, and also perceptually invisible. We demonstrate the characteristics of our proposed watermarking scheme through experiments. It is necessary to proceed as the future work the algorithm of achieving at the same time both the pseudo-randomness for the steno-key generation and the asymmetric-key generation.

A watermarking technique based on one-way hash functions

Digital watermarking techniques have been proposed for the copyright protection of digital images. A digital watermarking technique is a technique for embedding invisible watermarks in a digital image. The watermarks must be designed to be unrecognizable by unauthorized people and to be identified by the legal copyright owner of the image. In this paper, we proposed a new copyright watermarking scheme. Our scheme is based on one-way hash functions, which are widely used in cryptosystems. The main goal of our method is to design a secure watermarking scheme.