Securing patient-specific ECG data in telemedicine through adaptive wavelet-based watermarking

Watermarking proves to be an effective technique for safeguarding crucial medical information. In this research, we propose a robust and imperceptible watermarking method designed to enhance the security of telemedicine-transmitted medical electrocardiogram (ECG) data. Embedding a mark in medical ECGs enables precise patient identification, reduces the risk of confusion during scans, and helps prevent diagnostic errors that could have adverse consequences. To ensure the security of ECG signals exchanged in telemedicine, our approach involves a frequency-domain watermarking method that conceals electronic patient records within the corresponding ECG signals. In this methodology, the signal undergoes a conversion into a 2D image, followed by a three-layer transform to extract the frequency content of the medical image. The low-frequency subbands undergo Schur decomposition, and the watermark bits are subsequently incorporated into the values of the upper triangular matrix. According to experimental results, these proposed techniques maintain a significant level of watermarked ECG quality while demonstrating high resistance to standard attacks. Experimental results show that the proposed SWT–Schur-based watermarking scheme achieves an average PSNR of 44.56 dB and an NCC higher than 0.95 under most common signal processing attacks. The average embedding capacity is 0.27 bits per pixel (BPP), while preserving the diagnostic quality of the ECG signals.