Hybrid Non-Blind Watermarking Based on DWT and SVD

Abstract

Watermarking is identified as a major technology to achieve copyright protection and multimedia security. Therefore, recent studies in literature include some evident approaches for embedding data into a multimedia element. Because of its useful frequency component separation, the Discrete Wavelet Transform (DWT) is commonly used in watermarking schemes. In a DWT-based scheme, the DWT coefficients are modified with the data that represents the watermark. In this paper, we present a hybrid non-blind scheme based on DWT and Singular Value Decomposition (SVD). After decomposing the cover image into four sub bands (LL, HL, LH and HH), we apply the SVD to LL band and modify diagonal singular value coefficients with the watermark itself by using a scaling factor. Finally, LL band coefficients are reconstructed with modified singular values and inverse DWT is applied to obtain watermarked image. Experimental results show that the proposed algorithm is considerably robust and reliable. In comparison to the previous literature, peak signal-to-noise ratio (PSNR) values of watermarked images are increased by approximately 20%. In terms of PSNR values before and after attacks and of normalized similarity ratio (NSR); although watermark is embedded into LL sub band; our proposed method gives much more satisfactory results on filtering, scaling, Gaussian, JPEG compression, rotation and cropping than that of previous literature.

A particle swarm optimization and block-SVD-based watermarking for digital images

“…The analysis of PSNR value comparison between the proposed and existing algorithm [27] for the Goldhill watermarked image under different attacks is shown in Table 1, and graphical analysis for watermarked image Pepper is given in Figure 5. The analysis shows that, for the Pepper and Goldhill watermarked images, the proposed algorithm outperforms the original under all attacks except histogram equalization and rotation attacks.…”

“…Therefore, the analysis of the algorithm proposed in [27] is limited to a small set of images. Moreover, the algorithm does not use any technique to get a proper value of a scale factor that can provide better imperceptibility and robustness for a variety of cover images.…”

“…The algorithm proposed in this paper provides a solution to various problems associated with the watermarking technique given in [27]. The proposed algorithm is based on block-SVD and PSO, in which the binary watermark image is directly embedded into a singular matrix obtained from the block-SVD of the LL subband of the cover image.…”

“…In this scheme, PSO is incorporated to get better imperceptibility and robustness. For watermark embedding, the LL subband in wavelet decomposition is robust against different noise attacks, and the small change in singular values of this subband does not significantly affect imperceptibility [27]. The LL subband is therefore selected for watermark embedding in the proposed scheme in this paper.…”

Blind Color Image Watermarking Based on DWT and LU Decomposition

“…In recent years, watermarking algorithms based on the discrete wavelet transform (DWT) [4,5], discrete Fourier transform (DFT) [6], integer wavelet transform (IWT) [7], singular value decomposition (SVD) [8], and other complicated transforms [9,10] have been introduced one after another. In the aforementioned methods, the common feature is that watermark insertion is completed by the modulation of low-frequency components.…”