Super Resolution Image Reconstruction for FY-3 MWRI 10.6 GHz Band

To improve the spatial resolution of FY-3 MWRI, super-resolution reconstruction algorithm is used for the first time. Analysis on the working model of FY-3 MWRI indicates that the 10.6 GHz channel data are over-sampled, and the information included in the over-sample data is the key factor for improving the spatial resolution by super-resolution reconstruction algorithm. Based on the super-resolution reconstruction theory, the orbit, attitude and characteristics of MWRI are all used as the physics restriction, the speed of the satellite and the antenna pattern are both used to calculate the over-sample rate along the orbit, the ground sample distance dividing the flying distance in the integral time of one pixel is over-sample rate along the orbit, the speed of scanning mirror and antenna pattern are both used to calculate the over-sample rate across the orbit, and the field of view dividing the scanning angel in the integral time is over-sample rate across the orbit. Based on the over-sample rates of two directions, the super-resolution imaging matrix is estimated, the scale of the matrix is over-sample rate value along the orbit times the over-sample rate value across the orbit, and parameters of the matrix are calculated out from the metrical value of the antenna pattern by integral. The 10.6 GHz image reconstruction is conducted with POCS reconstruction algorithm. Firstly, a high-resolution image is estimated from the low-resolution image by interpolation algorithm, the new observing image is estimated by the high-resolution times the super-resolution imaging matrix, and then the process is repeated over and over based on the error, through which the high-resolution image becomes closer and closer to the factual scene. In the experiment, a real 10.6 GHz image of FY-3 MWRI is processed, the spatial resolution of the high-resolution image is estimated by artificial observation and mathematic statistic. The average grads of one pixel advances from 11.72 to 14.82, the sum of the power spectral increases 5.7%, and reconstruction image is of a higher spatial resolution. The typhoon temperature analysis shows that more details can be found in the reconstruction image, and details are similar as that in the image of 37 GHz, proving the reconstruction is effective and right. The super-resolution reconstruction is useful for FY-3 MWRI image of 10.6 GHz, which can offer more images with higher spatial resolution, accelerating the application of FY-3 MWRI.