A Robust Digital Watermarking Scheme and Its Application in Certificate Verification

A digital image watermark algorithm based on Human Visual System (HVS) and chaotic system is presented. The positions and grey values of the watermark image pixels are shuffled by Arnold Cat Map in the spatial domain first. Then the shuffled image is encrypted by Chen's chaotic system continuously before embedding in the host image. Exploiting the excellent properties of the wavelet transform and some characteristics of HVS, watermark is embedded into the wavelet domain to ensure the robustness and invisibility of watermark. The experiment results show that the algorithm proposed in this paper is effective and robust to common signal processing operations such as JPEG compression, resizing, median filtering, adding noise etc.

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.

A blind robust digital image watermarking scheme using chaotic encryption and HVS in DWT domain is presented. Firstly, the original image is transformed into some sub-band coefficients using discrete wavelet transformation (DWT), and then the binary image watermark signal is encrypted using logistic chaos map before it is embedded. Taking into account the characteristics of human visual system (HVS), the watermark is embedded into the important sub-band coefficients. Because of the multi-resolution decomposition for DWT and meaningful HVS, the proposed scheme can achieve good robustness, which is demonstrated in the following experiments.

The human visual system is very complicate and able to handle a voluminous amount of visual information. It is composed of a receiver with a pre-processing stage, the eye and the retina, a transmission channel, the optic nerve, and a processing engine, the visual cortex. Though one has attempted to understand and model the human visual system process a stimulus is progressed through its huge neural network has not well known because of our lack of knowledge about brain behavior. As well known, the discrete wavelet transform is widely used in signal processing applications such as signal analysis, de-noising, compression etc. It has also played a key role in the field of digital image and/or audio watermarking. A general metric to measure perceptible transparency is peak signal to signal ratio which is the ratio between the maximum possible power of a signal and the power of error that affects the fidelity of its representation. But peak signal to noise ratio does not consider the characteristics of human visual system. In this paper we proposed new metric to measure the invisibility of discrete wavelet transform domain watermarked image based on human visual system using 2- dimensional contrast sensitivity function. The proposed metric was applied to a spread spectrum image watermarking scheme in discrete wavelet transform domain and evaluated by the Minkowski pooling. The experimental results were compared with peak signal to noise ratio.KeywordsImperceptibility metricDigital image watermarkingDWT domainHuman visual systemContrast sensitivity function

The transition from analog technologies to digital technologies has increased the ever-growing concern for protection and authentication of digital content and data. Owners of digital content of any type are seeking and exploring new technologies for the protection of copyrighted multimedia content. Multimedia protection has become an issue in recent years, and to deal with this issue, researchers are continuously searching for and exploring new effective and efficient technologies. This thesis study has been prepared in order to increase the invisibility and durability of invisible watermarking by using the multilayer Discrete Wavelet Transform (DWT) in the frequency plane and embedding two marks into an image for the purpose of authentication and copyright when digital content travels through an unsecured channel. A novel watermarking algorithm has been proposed based on five active positions and on using two marks. In addition to the extraction process, watermarking images will be subjected to a set of attack tests. The evaluation criteria have been the bases of assessing the value of SNR, PNSR, MAE and RMSE for both the watermarking images and the watermarking images after attacks, followed by the invisibility of the watermarking being measured before and after the attacks. Our lab results show high robustness and high quality images obtaining value for both SNR and PNSR.

In this paper, an efficiently DWT-based watermarking technique is proposed to embed gray-scale logos as watermark in images to attest the owner identification and discourage the unauthorized copying. The method transforms both the host image and watermark into the discrete wavelet domain where their coefficients are fused adaptively based on Human Visual System (HVS) model to hide a higher energy hidden watermark in salient image components. The method repeatedly merges the watermark coefficients at the various resolution levels of the host image which provides simultaneous spatial localization and frequency spread of the watermark to provide robustness against different attacks. From the simulation results it can be observed that proposed method is robust to wide variety of attacks, such as image compression, linear or non-linear filtering, noise addition, image resizing, cropping, and image enhancement, etc. Keywords—Digital watermark, discrete wavelet transform, HVS characteristics,

The Digital Image and Communication On Medicine (DICOM) images are now subjected for transmission over the internet which bring about concerns regarding data security. The security of the medical images over the DICOM network currently relies on encryption techniques such as Advanced Encryption Standard (AES) and Triple Data Encryption Standard (3DES). These techniques however consume substantial processing time for the medical images. A new lossless encryption technique using quaternions can be adopted which reduces the processing time enormously. The quaternion technique is implemented using counter mode of encryption and modular arithmetic operations. The security of the medical image transmission can even be enhanced by incorporating digital watermarking which serves as an authentication of the sender and also reduces the difficulty in maintenance of multiple documents. The signature of the patient and the patient data are used as the watermark images and they are embedded in the DICOM image using DWT-SVD (Digital Wavelet Transform- Singular Value Decomposition).

Now a day's large amount of digital information such as video, audio or image is spread over the internet. So it should be a great challenge for all researchers to provide security to such a type of digital data. Also the piracy and copyright is emerging issue when digital information in the form of video, audio & image is transmitted over the transmission media. So to prevent the problem of piracy and security of digital data such as video, video watermarking techniques has been introduced. There are various watermarking schemes to give the security to videos but they were unable to provide the quality in terms of robustness and security. In this paper optimized and hybrid based robust digital video watermarking scheme has been proposed. The optimization is performed in the proposed system with the help of genetic algorithm. The quality of the proposed watermarking scheme is measured in terms of PSNR and NC values. The PSNR calculated using our approach is off 50.48 db which is far better than existing approaches.

Digital watermarking consists of hiding subliminal information into digital media content, also called host data. It can be the basis of many applications, including security and media asset management. In this paper, we focus on the imperceptibility requirement for image watermarking. We present the main features of the human visual system (HVS) to be translated into watermarking technology. This paper highlights the need for dedicated inputs from the human vision community. The human visual system (HVS) is very complex and able to deal with a huge amount of information. Roughly speaking, it is composed of a receiver with a pre-processing stage, the eye and the retina, a transmission channel, the optic nerve, and a processing engine, the visual cortex. Mainly because of our lack of knowledge about brain behavior, i.e. about the way a stimulus is processed through its huge neural network, the large effort to understand and model the HVS behavior has partly remained fruitless. The aim of this paper is not to provide a thorough description of the HVS. For complete HVS models and more specific details, the reader is referred to existing literature. Here, we only try to understand, in a synthetic way and from an engineering perspective, the HVS features on which the designer of a watermarking algorithm can rely, i.e. its sensitivity and masking capabilities.

A novel DCT domain color digital watermarking scheme based on chaotic maps is proposed, and the host image is color RGB image. The color space of the color host image is first converted from RGB to YIQ. In order to resist JPEG compression, all three watermark RGB channel signals are buried to Y component of the YIQ color space host images. In the proposed method, the image watermark is embedded into low-band DCT coefficients with different strength according to the characteristics of human vision system. The watermark signal and the embedding position of the host image are encrypted respectively by the unified chaotic map and multilayer Arnold cat map, and compared with the general Arnold cat map, the key space is highly increased. The simulation results show that the proposed scheme possesses the invisibility and the robustness to common image processing attacks, such as noise addition, JPEG compression, image rotation, cutting and so on.

Palmprint recognition is one of the most popular biometric technologies. Recent researches mainly focus on the recognition performance, while pay less attention to the data protection issues. In this paper, we propose an active biometric data protection model for securing palmprint images in transmission or storage scenarios, called Dynamic Random Invisible Watermark Embedding (DRIWE) model. The DRIWE model implicitly embeds a watermark in each original palmprint ROI image, and then separates the embedded watermark from the watermarked image before identification. If the separated watermark is consistent with the original watermark, it indicates that the image is trustworthy and can be used in the subsequent recognition process. Otherwise, it proves that the image has been illegally tampered with. Furthermore, a two-dimensional image information entropy loss is proposed to enhance the generalization of the model to different watermarks. It ensures that the model can always assign enough information to the host image (i.e., original palmprint image) when different watermarks are applied. Thus, it enables the separator to extract the complete watermark from the watermarked image. This greatly enhances the dynamics and randomness of the watermark embedding process and further improves the ability to secure the data. Adequate experiments are conducted on two benchmark palmprint databases. The results show that the proposed DRIWE model has satisfactory attack resistance and strong generalization ability: even if only one watermark is used in training stage, it can be generalized to a dozen of other new watermark images in the testing stage. In addition, the optimal accuracy of the watermarked data is only reduced by 0.07% compared with the original data.

In this article, a blind image watermarking scheme, which is a robust against common image processing and geometric attacks is proposed by adopting the concept of histogram-based embedding. The average filter is employed to low-pass pre-filter the host image. The watermark bits are embedded into the histogram of the low-frequency component and the template bits are embedded in the high-frequency residual. The embedding is performed by adjusting the value of two consecutive histogram bins. Furthermore, a post-quantization is employed after the embedding round to improve robustness. All pixel modifications incurred are based on the human visual system (HVS) characteristics. As a result, a good tradeoff between robustness and imperceptibility is achieved. Experimental results reported the satisfactory performance of the proposed scheme with respect to both common image processing and geometric attacks.

The paper presents a robust digital image watermarking scheme that uses both the characteristics of the human visual system (HVS) and statistical information measure. Spread transform approach is used where data is embedded through transform coefficients of both the cover and the watermark data. The spread transform watermarking technique yields better results in terms of imperceptibility, resiliency, capacity and cost compared to widely used spread spectrum watermarking schemes. Hadamard transformation is used not only for simpler implementation but also for its higher data hiding capacity (M. Ramkumar and AN Akansu, 2001). Experimental results show that the visual quality of the extracted watermark is good in spite of several external attacks. The fact is also supported by mutual information values used as objective measure.

This paper proposes a watermarking algorithm based on curvelet transform. Considering the characteristics of Human Visual System (HVS), the algorithm extract the embedding field of one image using curvelet transforms. Then the watermark is embedded the embedding field. A scheme for detect and recovering rotation attacks is applied before watermark detection. Experimental results show that our algorithm is quite robust under attacks like rotation cropping noise adding etc.

Digital watermark has been proposed as an effective method to protect the copyright of multimedia data. An adaptive watermark system of still image in discrete cosine transform (DCT) domain is proposed. By exploiting the luminance and texture characteristics of human visual system (HVS) and considering properties of DCT block coefficient, a soft computing framework is designed. adopts the feature vectors composed the luminance and texture information of each DCT block, the fuzzy clustering (FC) for more reliable classifying to DCT blocks, and neural network (NN) for determining adaptively the best watermark embedding strength of each DCT block are used. The experimental results show that the proposed system are robust against attacks most commonly used image processing algorithms and provides very good results in term of image imperceptibility.