A Hybrid Domain Color Image Watermarking Based on DWT-SVD

In recent years, digital image watermarking has been emerged as a promising solution for copyright protection and authentication problem of digital images. Among several existing watermarking schemes, very few have been designed for the authenticity and copyright protection problem of color images. To protect the copyright and validate the authenticity of color images, in this paper a hybrid robust image watermarking scheme based on discrete wavelet transform (DWT) and singular value decomposition is proposed and simulated. Initially, RGB color image is switched to YCbCr color space from which only Y achromatic component is considered for watermark data insertion. In the next step, Y component of the YCbCr color model is decomposed into non-overlapping blocks and subsequently DWT are applied to each block. In this work, non-overlapping decomposed gray watermark image blocks are embedded into singular values of DWT-transformed cover image blocks. Proposed technique's simulation result established the robustness by extracting adequate watermark data from the restructured cover image after applying common geometric transformation attacks (like rotation, flip operation, cropping, scaling, shearing and deletion of lines or column operation), common enhancement technique attacks (like lowpass filtering, histogram equalization, sharpening, gamma correction, noise addition), JPEG compression attacks and combinational attacks (like combination of geometric transformation attacks and common enhancement technique attacks, combination of geometric transformation attacks and JPEG compression attacks, combination of common enhancement technique attacks and JPEG compression attacks, and combination of geometric transformation attacks and geometric transformation attacks).