A Robust blind watermarking with integer wavelets and Hadamard transform using Gray Wolf Optimization algorithm

In this work, Gray-Wolf optimization (GWO) is applied to decrease the trade-off between robustness and imperceptibility. Initially, the cover image is applied with integer wavelet transform (IWT) and later the whole image partitioned into $4 \times 4$ blocks. After this, the Hadamard transform (HT) is applied for obtaining transform coefficients. The first three pixel intensities in the first rows of each $4 \times 4$ block HT coefficients are quantized with the watermark coefficients. These three-pixel intensities are randomized with a vector, and the threshold parameters are obtained from GWO. When these optimized parameters applied, and the GWO algorithm improves the transparency. The results show the proposed algorithm has high imperceptibility and robust to attacks than existing works in literature.