Modified watermarked ECG signals by using adaptive normalization factor

In Telemedicine applications, Digital watermarking is a technique to improve the security and authenticity of ECG signals transmitted to the doctor´s end through GSM network. Keeping this in mind, the authors of this paper propose a new watermarking technique which embeds patient´s identification inside the ECG signals that will enhance the security and authenticity of ECG signals. In this paper ECG signals are watermarked with patient identity using Adaptive Normalization Factor (ANF) and Least Significant Bit (LSB) watermarking technique to avoid confusion between the ECG signals and patient´s identity. The entire technique has been found to be useful to a variety of ECG records for all the 12 leads taken from CSE Multi-lead ECG diagnostic record and the maximum 15 character string that is used to implant watermark embodies for patient´s recognition. The novelty of the projected watermarking technique is that the implanted watermark can be completely detached from any altered form of actual signal. It has been observed that the projected method gives a marginal quantity of signal distortion (0.018%), which does not have an effect on any vital features of the ECG signals and it also does not cause any changes in the diagnosis.