A Novel Block-based Watermarking Scheme Using the SVD Transform

In this paper, a block-based watermarking scheme based on the Singular Value Decomposition (SVD) is proposed. Our watermark, a pseudo-random Gaussian sequence, is embedded by modifying the angles formed by the right singular vectors of each block of the original image. The orthogonality property of the right singular vector matrix is preserved during the embedding process. Several experiments have been carried out to test the performance of the proposed scheme against different attack scenarios. We conclude that the proposed scheme is resistant against common signal processing operations and attacks, while it preserves the quality of the original image

Improvement Of Hybrid Digital Image Watermarking Schemes Based On Svd In Wavelet Transform Domain

Digital image watermarking techniques have enabled imperceptible information in images to be hidden to ensure the information can be extracted later from those images. Robustness, imperceptibility, capacity and security are the most important requirements of any watermarking scheme. Recently, hybrid Singular Value Decomposition (SVD)- based watermarking schemes in the wavelet domain have significantly gained a lot of attention. The aim of this study is to develop hybrid digital image watermarking schemes by combining the properties of SVD and the chosen wavelet transforms to achieve high robustness and imperceptibility, as well as maintaining the trade-off between robustness, imperceptibility and capacity. The security issue due to the false positive problem (FPP) that may be occurring in most of SVD-based watermarking schemes, has been covered and addressed. This study proposes five hybrid robust SVD-based image watermarking schemes in the wavelet domain. In the first scheme, a grey image watermark is embedded directly into the singular values (S) of each redundant discrete wavelet transform transform (RDWT) sub-band of the host image. The scheme is named RDWT-SVD. The second proposed scheme, namely IWT-SVD-AT, utilised the integer wavelet transform (IWT) instead of RDWT due to its properties. The watermark is scrambled using Arnold Transform (AT) before being embedded into the S of each IWT sub-band host. Despite the impressive results by the first and the second schemes, they were vulnerable to the FPP. Thus, they have failed to resolve the rightful ownership. In the third scheme, a hybrid IWT-SVD scheme is proposed with a novel Digital Signature (DS)-based authentication mechanism to solve the FPP. The scheme outperforms the previous schemes in terms of robustness, capacity, security, computation time and attains high imperceptibility. In the remaining two proposed schemes; the fourth and fifth schemes, the FPP is totally avoided using new different embedding strategies. In the fourth scheme namely IWT-SVD-MOACO, the singular vector U of the watermark is embedded into the S of IWT LL sub-band. Multi-objective ant colony optimisation (MOACO) is used to find the optimal multiple zooming/scaling factor (MZF) instead of the single scaling factor (SSF) to achieve the optimal trade-off between imperceptibility and robustness. Finally, a hybrid SVD block-based scheme namely DWT-SVD-HVS using discrete wavelet transform (DWT) is developed. A binary watermark is embedded into a number of blocks which is selected based on some human visual system (HVS) criterion. The scheme shows a high imperceptibility and good robustness. Finally, all the proposed schemes are evaluated with different colour images and had been shown a successful applicability with colour images

Secure and Robust Image Watermarking Scheme Using Homomorphic Transform, SVD and Arnold Transform in RDWT Domain

The main objective for a watermarking technique is to attain imperceptibility, robustness and security against various malicious attacks applied by illicit users. To fulfil these basic requirements for a scheme is a big issue of concern. So, in this paper, a new image watermarking method is proposed which utilizes properties of homomorphic transform, Redundant Discrete Wavelet Transform (RDWT), Arnold Transform (AT) along with Singular Value Decomposition (SVD) to attain these required properties. RDWT is performed on host image to achieve LL subband. This LL subband image is further decomposed into illumination and reflectance components by homomorphic transform. In order to strengthen security of proposed scheme, AT is used to scramble watermark. This scrambled watermark is embedded with Singular Values (SVs) of reflectance component which are obtained by applying SVD to it. Since reflectance component contains important features of image, therefore, embedding of watermark in this part provides excellent imperceptibility. Proposed scheme is comprehensively examined against different attacks like scaling, shearing etc. for its robustness. Comparative study with other prevailing algorithms clearly reveals superiority of proposed scheme in terms of robustness and imperceptibility