Özet:

The exponential increase of multimedia technologies usage has made connectivity simpler, more convenient and quicker, but has also contributed to a number of infringements of digital content. Digital watermarking has been known to offer a solution to compliance issues related to copyright infringements in multimedia technology. This paper proposes a robust approach to image watermarking by integrating the benefits of all four algorithms. The proposed method is based on discrete wavelet transform (DWT), chirp z-transform (CZT), lower and upper (LU) decomposition and singular decomposition value (SVD). In this method, using 1-level DWT, the image is broken down into its frequency sub-bands. The LL sub-band is then converted into a z domain using CZT. LU decomposition was then used to further decompose the image into two matrixes, each of which was used to insert the watermark. SVD has been applied to each of the matrixes and the unique value of the watermark is inserted to the matrixes of the decomposed image. The robustness and imperceptibility of the proposed solution was tested by checking the watermarked image for various image processing operations. Experimental findings show that the proposed technique has high imperceptibility capability and it shows a reasonable level of robustness against signal processing operations such as filtering, scaling, JPEG, rotating, gamma correction, blurring, cropping, gaussian noise, contrast enhancement, histogram equalization, and salt & pepper noise.

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