Firefly optimization-based dual watermarking for colour images with improved capacity

This paper discusses the improved capacity of colour image authentication in media applications and proposes an optimization-based robust watermarking algorithm. The algorithm first uses firefly optimization to compute the optimal embedding strength factor, which is useful for maintaining an effective relationship between robustness and quality. The combination of spatial and transformed domain schemes is then adopted to conceal the multiple marks on the different channels of the carrier media through the optimal strength factor. In order to make image marking safer, it is encrypted before being concealed by the media channel. Extensive experiments analyzed the impact of various results on Kodak and USI-SIPI datasets, demonstrating that the suggested algorithm has improved robustness, excellent quality, and high capacity. Superior to other existing schemes, the proposed algorithm achieves robustness of up to 11% with the improved watermark capacity.