A Robust watermarking using RDWT and Schur with Firefly optimization* *Note: Sub-titles are not captured in Xplore and should not be used

In this paper, firefly optimization is applied to balance robustness and imperceptibility in image watermarking. First of all, the original image is partitioned into 4 × 4 blocks, and later Redundant Discrete Wavelet Transform (RDWT) and Schur applied for obtaining transform coefficients. The highly correlated pixels in the first column are collected from each 4 × 4 block and are amended by blindly concealing the watermark using quantization index modulation. These quantized values are amended with the randomized matrix and quantization factor randomly selected from the firefly algorithm to obtain the best performance in terms of robustness without compromising the quality of the image. Experimental results show that the proposed scheme maintains improved imperceptibility, and the watermark can still extract from a seriously distorted image.