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Robust Imperceptible Gray Image Watermarking with LWT, SVD and QR Decomposition

—This work suggests a unique watermarking technique based on QR decomposition and singular value decomposition (SVD) in the lifting wavelet transform (LWT) domain. It's a hybrid watermarking method working on LWT's energy compaction property with a combination of QR and SVD to enhance watermarking performance. The image is decomposed with three levels of LWT, then QR factorization on CH3 subband and finally SVD is applied to R matrix. Watermark is scrambled using Arnold transform (AT) to improve security aspect. Singular values are modified with scaling factor and watermark bit. Robustness and imperceptibility are important parameters in image watermarking. Proposed technique combats trade-off between robustness and imperceptibility for varying watermark embedding strength. It also withstands attacks like image processing, noising, filtering, compression, geometric. Performance is evaluated with PSNR, SSIM, BER and NCC.