Comparative Analysis of Wavelet Transform-Based Robust Reversible Watermarking Using Adaptive Spread Spectrum Techniques

In the digital era, data security has become a critical concern due to the increasing prevalence of threats like unauthorized access, modification, and forgery. Watermarking techniques have emerged as an effective means to safeguard digital images by embedding additional information, such as ownership details or authentication codes, within the image. However, ensuring that the image's quality and integrity remain intact while embedding a watermark is particularly challenging, especially in sensitive fields like healthcare and military, where any form of image degradation is unacceptable. This study presents a comparative analysis of robust reversible watermarking techniques based on wavelet transforms, using Adaptive Spread Spectrum (ASS) methods. The approach incorporates both Haar Wavelet Transform (HWT) and Integer Wavelet Transform (IWT) to embed and extract the watermark. During the process, the image is decomposed into four sub-bands, and the watermark is embedded into the low-frequency (LL) sub-band, which typically preserves more image details. Experimental results show that the proposed method significantly improves resistance to various types of attacks, including JPEG compression, noise, and rotation, while maintaining a BER of 0 in the LL sub-band and high PSNR values. The watermarking system effectively safeguards copyright and image integrity using the HWT scheme and LL sub-band, further enhancements are required to improve its robustness against more complex attacks. This makes the approach ideal for applications where both high security and minimal image distortion are required.