| Our sensory systems are sensitive to sound than many of the image, when image transmission through wireless channel by a different noise, the image reconstruction at the receiving end, the small error so that we are not comfortable, important errors will result in image can not rebuild, can not meet our needs. To solve this problem, so that the information transmission interference can effectively be protected, to achieve good transmission quality, channel coding technology is one of the technologies used.To improve the image in the validity and reliability of wireless channel, in this article, using irregular LDPC codes to protect their own properties at the time and frequency domain for EEP and UEP, and comparative analysis, that is not as LDPC codes Rules characteristics make them more sensitive and important information to give more protection, the overall transmission is divided into different levels of protection for processing. Simulation results show that the program improved the PSNR on the objective and subjective visual effect than other protective measures are significantly improved.1 Describes the application of techniques ranging from protection, and then introduced today's popular LDPC channel coding, LDPC codes from said check matrix structure, coding method, and the bit flipping decoding algorithm of the hard decision algorithm and confidence spread soft-decision algorithm and the simplification and improvement of areas to be combined with simulation experiments for performance analysis.2 Describes the image format and image transformation, focusing on BMP format. Introduction transform domain of research, and given the principle of discrete cosine transform, definition and application characteristics.3 LDPC channel coding based on the BMP file image studies ranging from protection of transmission, the first under the BMP file data streaming, in the time domain to choose their own characteristics with unequal protection of irregular LDPC codes for Unequal Protection Code; Next in the frequency domain, according to low-frequency, high frequency characteristics of non-uniform energy distribution on the basis of irregular codes using different modulation methods to further enhance protection, improve the image of the transmission quality. |
PDF Full Text Request