Securing medical images using multi-stepwatermarking model
摘要
The security of medical images is a growing concern in digital healthcare, especially with the increasing risks of unauthorized access and tampering. This paper proposes a robust multi-step watermarking model designed to ensure the integrity and confidentiality of medical image data. The model begins by converting patient metadata into binary format using ASCII encoding and enhances robustness through forward error correction with Hamming and BCH codes. A Convolutional Neural Network (CNN) is employed to detect the Region of Non-Interest (RONI), ensuring that the watermark is embedded only in diagnostically safe areas. The watermark is then embedded within the LL sub-band of a one-level Discrete Wavelet Transform (DWT), followed by Discrete Cosine Transform (DCT) and Singular Value Decomposition (SVD), achieving imperceptibility and resilience. Experimental evaluation on medical images demonstrated strong performance with PSNR values ranging from 35.2 dB to 38.4 dB, SSIM between 0.92 and 0.96, and Normalized Correlation (NC) values close to 1 under various image processing and malicious attacks. The proposed method ensures robustness against geometric and signal-based distortions while maintaining high image fidelity, making it highly applicable for secure telemedicine and electronic health record systems.