Block-based Tchebichef image watermarking scheme using psychovisual threshold

Author(s):  
Ferda Ernawan ◽  
Muhammad Nomani Kabir ◽  
Mohamad Fadli ◽  
Zuriani Mustaffa

Digital image watermarking has been proposed to protect the digital multimedia content. The main objectives of watermarking scheme are robustness, reliability, security against numerous attacks. To improve the imperceptibility, robustness and capacity of the watermarked image, this paper presents a transform domain watermarking method using spatial frequency and block SVD. The spatial frequency is used to select the appropriate blocks for embedding the watermark image by transforming the SVD coefficients of these blocks of the cover image. In this paper first we scramble the cover image by ZIG-ZAG sequencing and then rearranged. After that Shift Invariant Discrete Wavelet Transformed (SIDWT) cover image is partioned in to non-overlapping blocks. Then find out the spatial frequency of these blocks, those blocks which spatial frequency value greater than threshold value are selected for embedding process. Now the watermark image directly embedded by modifying the SVD coefficient of these blocks and get watermarked image. Then inverse process is applied for extracting for watermark image form noisy image. Experimental outcomes show that the proposed scheme is higher imperceptible, robust against various image processing attacks and produce improved results as compared to previous presented schemes


Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1428
Author(s):  
Musrrat Ali ◽  
Chang Wook Ahn ◽  
Millie Pant ◽  
Sanoj Kumar ◽  
Manoj Singh ◽  
...  

Digital watermarking has become an essential and important tool for copyright protection, authentication, and security of multimedia contents. It is the process of embedding a watermark in the multimedia content and its extraction. Block-based discrete cosine transform (DCT) is a widely used method in digital watermarking. This paper proposes a novel blind image watermarking scheme developed in the spatial domain by quantization of invariant direct current (DC) coefficients. The cover image is redistributed and divided into non-overlapped square blocks and then the DC coefficients invariant to rotation, row and column flip operations, without utilization of the DCT transform, are directly calculated in the spatial domain. Utilizing the quantization parameter and watermark information, the modified DC coefficients and the difference between DC and modified DC coefficients are calculated to directly modify the pixel values to embed watermark bits in the spatial domain instead of the DCT domain. Optimal values of the quantization parameter, which plays a significant role in controlling the tradeoff between robustness and invisibility, are calculated through differential evolution (DE), the optimization algorithm. Experimental results, compared with the latest similar schemes, demonstrate the advantages of the proposed scheme.


Entropy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 255
Author(s):  
Mario Gonzalez-Lee ◽  
Hector Vazquez-Leal ◽  
Luis J. Morales-Mendoza ◽  
Mariko Nakano-Miyatake ◽  
Hector Perez-Meana ◽  
...  

In this paper, we explore the advantages of a fractional calculus based watermarking system for detecting Gaussian watermarks. To reach this goal, we selected a typical watermarking scheme and replaced the detection equation set by another set of equations derived from fractional calculus principles; then, we carried out a statistical assessment of the performance of both schemes by analyzing the Receiver Operating Characteristic (ROC) curve and the False Positive Percentage (FPP) when they are used to detect Gaussian watermarks. The results show that the ROC of a fractional equation based scheme has 48.3% more Area Under the Curve (AUC) and a False Positives Percentage median of 0.2% whilst the selected typical watermarking scheme has 3%. In addition, the experimental results suggest that the target applications of fractional schemes for detecting Gaussian watermarks are as a semi-fragile image watermarking systems robust to Gaussian noise.


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