Unequal Error Protection For Medical Image Transmission Based On PD-LDPC Codes

With the development of electronic medical, medical images can help doctors diagnose the condition accurately, so how to transmit the medical images effectively and reliably, has become an increasingly important topic.As everyone knows, in image transmission system, the importance of different parts is not the same and different parts have different sensitivity to error. Unequal error protection (UEP) schemes give different protection measures according to the different importance. Therefore, under the same conditions, compare to the equal error protection (EEP) schemes, UEP schemes can allocate resources reasonably, and get better results. Thus, the UEP schemes can improve the performance of the whole transmission system effectively.As of today, there are lots of achievements of the image transmission with UEP strategy. At first, according to the separation of design theory proposed by Shannon, the design of source coding and channel coding are separate in the image transmission with UEP, and then, the joint source-channel coding (JSCC) design was proposed, and the scheme had been proven to have better performance in the overall efficiency compare with the separation design. Some researchers apply this theory to perform image transmission with UEP gradually.The image transmission with UEP scheme based on JSCC design mostly use Turbo codes or RCPC codes as channel codes, and SPIHT or JPEG2000is used for source coding. After the LDPC code was proposed, which was proved to have the performance of near Shannon limit over AWGN channel, researchers began to apply the LDPC code in image transmission with UEP based on JSCC design. However, in these schemes, the researchers were still using the SPIHT or JPEG2000as source codes.In2010, researchers first proposed a JSCC scheme, which used LDPC codes as both source codes and channel codes, named as double LDPC scheme (D-LDPC). The scheme optimized the cascade of the system. In2012, researchers further reduced the system error floor and complexity by employing the protograph LDPC codes in the D-LDPC system, named as PD-LDPC scheme.In view of the above, I apply the PD-LDPC codes in the medical image transmission with UEP, and propose two different solutions of UEP in this paper. The simulation results show that, under the same SNR, two schemes get higher PSNR performance than the existing cases. What’s more, one of my solutions reduces the complexity of image transmission system.