The Transmission Of The Aurora Image Based On The Fountain Codes In Erasure Channel

The image is one of the most principal information carriers, and the communications of image is so important that it has received close attention in recent years. In the arctic Yellow River station of our country, the aurora image which acquired each year has great research value, but the quality of aurora image over channel transmission declines as noise interference and the limitless of channel capacity, therefore the study of aurora image transmission with the use of channel coding has very important theoretical and realistic significance.This paper focus on the rateless fountain codes. At first, this paper has studied the performance of LT codes and Raptor codes over the erasure channel. Then, on the basis of this study, an aurora image transmission solution based on the fountain codes is presented.In this paper, we make use of LT codes and system Raptor codes to protect the bit stream generated by SPECK algorithm. Compared with traditional RS codes, this new solution can obtain better image restoration effect, in addition, by this method aurora image can be safely transmitted in the wireless channel. Specifically, the details of this paper are as follows:1. This article has realized the coding and decoding process of the aurora image based on the LT codes and has determined two important parameters of the Robust solution distribution. In addition, using success rate of decoding and bit error rate as the standards,this paper has studied the performance of LT codes in three ways, including the degree distribution, the decoding methods and the length of the source codes.2. This paper has studied the performance of the LT codes and then we have realized the Raptor codes which can adjust the code rate automatically. The Raptor codes in this paper is based on the communication standard 802.16 e, using LDPC codes as the precoding.Then the article has realized a coding and decoding process of aurora image based on the Raptor codes and this solution get better transmission quality than LT codes.3. An aurora image transmission solution based on the fountain code is presented. Firstly the wavelet transform is performed on image, in source coding stages, the SPECK codes is used for low complexity and gradual transmission. After that, the rateless LT codes and system Raptor codes is taken as channel coding method. It protects the output stream of SPECK from noise. Compared with traditional RS codes this new solution can obtain better image restoration effect. Moreover, as the improvement measure of the Raptor codes,the aurora image transmission solution based on the system Raptor codes get better performance compared with the transmission solution based on the LT codes.