DICOM medical image watermarking of ECG signals using EZW algorithm
A. Kannammal, Shweta Rani · International Journal of Medical Engineering and Informatics · 2013
A novel blind watermarking method with secret key is proposed by embedding ECG signals in medical images combined with the EZW-based wavelet coder. At first, the host image and the mark signal are decomposed using discrete wavelet transform. The image starts to be encoded using EZW algorithm for its maximum threshold. Then threshold is halved and encoding process is repeated. Watermark insertion begins when the signal threshold is reached. After entropy coding of the bits to be transmitted, the watermarked image is progressively encoded. At the receiver both the inverse EZW algorithm is applied and both the image and the signal are reconstructed. The watermarking is done for 128 to 8,192 bytes of the mark signal. The peak signal to noise ratio (PSNR) between the original and watermarked image is found to be as high as 80 dB and increases as the size of the watermark decreases.