Robust and Secure Patch-based Color Image Watermarking Using DWT with Pelican Gradient Descent Optimization for Secure Image Transmission

In the digital age, protecting intellectual property and verifying the authenticity of multimedia content has become increasingly important. Digital watermarking, particularly color image watermarking (CIW), offers a promising solution by embedding hidden information directly into visual media. Despite numerous advancements, CIW techniques face challenges in maintaining a balance between watermark imperceptibility, robustness against attacks and computational efficiency. To protect the issue of watermark security, this paper introduces an effective and robust CIW technique that utilizes RGB components, i.e. red (R), green (G) and blue (B) channels for embedding. In this research, the optimal patches are selected by the developed Pelican gradient descent optimization patch (PGDOpatch), which is modeled by hybridizing the Pelican optimization algorithm (POA) and the gradient descent algorithm (GDA). Moreover, dual phases are followed in CIW, such as the embedding phase and extraction phase. Here, the embedding phase is responsible for inserting a secret message into the cover image, whereas the extraction process is responsible for extracting the watermark image from the watermarked image. Moreover, the embedding process is carried out by merging the selected patches with the binary watermark block of the secret message. Finally, based on experimental results, the PGDOpatch scheme attained a maximal peak signal-to-noise ratio (PSNR) of 34.78[Formula: see text]dB and a minimal normalized correlation (NC) of 0.774.