Robust Transmission of Watermarked Medical Images over Wireless Channels
In this paper, a robust approach for transmission of medical images with concealed patient information as watermark is evinced. In this approach, spatial domain digital watermarking technique is adapted wherein the patient information is embedded as watermark into the lower order bits of the medical image pixels. The watermark, which comprises of text data, is encrypted to prevent unauthorized access of data. To enhance the robustness of the embedded information, the encrypted watermark is coded by concatenation of Reed Solomon (RS) codes and low density parity check codes (LDPC). However, even under no noise conditions, the extracted watermark accuracy depends on the region of the medical image into which it is embedded. Hence extracted watermark accuracy is evaluated for three different regions of the image with no noise. The bursty wireless channel is simulated by adding impulse noise to the embedded image. Furthermore, turbo channel coding is proposed to correct the transmission errors over impulsive noisy wireless channels. The efficacy of the proposed approach is illustrated with the implementation results on a watermarked medical image.