A Color Image Watermarking Scheme Resistant against Geometrical Attacks

The geometrical attacks are still a problem for many digital watermarking algorithms at present. In this paper, we propose a watermarking algorithm for color images resistant to geometrical distortions (rotation and scaling). The singular value decomposition is used for watermark embedding and extraction. The log-polar map- ping (LPM) and phase correlation method are used to register the position of geometrical distortion suffered by the watermarked image. Experiments with different kinds of color images and watermarks demonstrate that the watermarking algorithm is robust to common image processing attacks, especially geometrical attacks

Построение цифрового водяного знака, устойчивого к потере синхронизации

Описана проблема потери синхронизации, возникающая при внедрении цифровых водяных знаков в изображение. Рассмотрен один из новых подходов к решению этой проблемы, основанный на вычислении локальных характеристик изображения. Предложены улучшения в процессе построения и выбора характеристик. Попутно получен фильтр адаптивного размытия изображения, позволяющий сохранить тонкие детали

Robustness of a Blind Image Watermark Detector Designed by Orthogonal Projection

Blind digital watermarking, which can detect watermark without using the original image, is a key technique practical intellectual property protecting systems and concealment correspondence systems. In this paper, we discussed a blind detection method for the digital image watermark. The theories research show that the orthogonal projection sequence of a digital image is one-to-one correspondence with this digital image. To make use of this conclusion, we designed and realized a kind of blind watermark detector with the good performance. To calculate the correlation value between the image and watermark, the intensity information of digital image is not adopted, but the orthogonal projection sequence of this image is adopted. Experiment results show that this watermark detector not only to have very strong resistant ability to translation and rotation attacks, but also to have the good robustness to Gaussian noise. Performance of this watermark detector is better than general detector designed by making use of the intensity information directly. The conclusions obtained by experiments are useful to the research in the future

A novel perceptually adaptive image watermarking scheme by selecting adaptive threshold in dht domain

This paper proposed a novel image watermarking technique by applying the characteristics of the human visual system, in Hadamard transform domain. Statistical information measures were used to select proper blocks for data embedding. Watermark was embedded by the modification of Discrete Hadamard transform (DHT) coefficients of selected blocks. Threshold and modification value were selected adaptively for each image block, which improved robustness and transparency. The proposed algorithm was able to withstand a variety of attacks and image processing operations like rotation, cropping, noise addition, resizing, lossy compression and etc. The experimental results showed good performance of the proposed scheme in comparison with some of the recently reported watermarking techniques.Keywords: Digital image watermarking, Hadamard transform, Entropy, Lossy compression, Adaptive Threshol

DIGITAL IMAGE WATERMARKING (DIW) ROBUST TO GEOMETRIC TRANSFORMATIONS

Digital images can be easily copied and distributed illegally using widely available software tools. Watermarking methods that embed side information into images with the aim of protecting copyright have been proposed. So far, these methods have been defeated by simple attacks such as rotation, translation and scaling. In this research, a novel digital image watermarking system that takes advantage of the Wavelet Transform properties to embed a spread spectrum circular symmetric watermark in an image is proposed. Watermark robustness against translation, rotation and scaling attacks is achieved by the proposed method. Successful experiments showing the performance of the method to geometric. Key words: watermarking, mark, wavelet, spread spectrum circular symmetri

Toward a content-based watermarking scheme

Image watermarking consists in embedding an unnoticeable and indelible mark inside a digital image. Watermarking technologies aims at solving copyright and integrity problems. Nevertheless classical geometrical transforms generally induce a loss of synchronization that prevent the detection of the mark. We propose in this paper a content-based watermarking scheme that uses a feature point detector to link the mark with the content of the image. In this scheme, feature point detection is followed by a triangular tessellation and the signature is embedded in each triangle of the partition. Our results show that the presented scheme is robust to local geometrical transforms and attacks such as Stirmark.Le tatouage d'images consiste à insérer une signature invisible et indélébile dans une image. Il permet de répondre à des problèmes de droit d'auteur ou d'intégrité. Les transformations géométriques peuvent cependant provoquer une perte de synchronisation et ainsi empêcher la détection de la signature. Nous proposons une méthode de tatouage fondée sur le contenu qui utilise un détecteur de points d'intérêts pour lier la signature au contenu de l'image. La détection de point d'intérêts permet de créer une partition triangulaire et la signature est ensuite insérée dans chacun des triangles. Nos résultats montrent que la méthode présentée est robuste aux déformations géométriques tels que Stirmark

Influence of a Large Image Watermarking Scheme Parallelization on Possible Attacks

Digital data representation provides an efficient and fast way to access to information and to exchange it. In many situations though ownership or copyright protection mechanisms are desired. For still images and video, one possible way to achieve this is through watermarking. Watermarking consists of an imperceptible information embedded within a given media. Parallel ProcessingWatermarking Embedding Schemes have demonstrated to be efficient from a computational and memory usage point of view for very large images. These schemes consist in dividing the image into tiles and watermarking each independently. The processing allows the use of a parallel computation scheme. The watermarking method used in the scope of this work is a parallel variant of an approach known as self-referenced Spread Spectrum signature pattern. Since the watermarking scheme has been modified through tiling, the extra references due to signature replication can be used in the retrieval. This work describes the above mentioned approach to watermark images and provides an analysis of its performance