HIGH ACCURATE GEOMETRIC CORRECTION FOR NOAA AVHRR DATA CONSIDERING THE IMPACT OF ELEVATION ON ERROR

摘要

NOAA images have been provided very useful environmental information from all over the world. In order to use NOAA images, they need to be transformed from image into map. This paper proposes a method that corrects the errors caused by this transformation. First, elevation errors are calculated and corrected based on elevation values, which are read from GTOPO30 database. These elevation values are also verified to divide data into flat and rough blocks. Next, GCP template matching is used to calculate the residual errors for the blocks that match GCP templates. Reference data is referred in case the number of GCP templates is not enough. Based on the blocks which match GCP templates, the residual errors of other flat and rough blocks are calculated by Affine and Radial Basic Function transformation respectively. According to residual errors, all points in the image are moved to their correct positions. Finally, data is transformed from image into map by bilinear interpolation. With proposed method, because the relationship between the error and the variation of elevation is controlled better, residual errors are corrected more accurately and the errors of bilinear interpolation are smaller. As a result, the error after correction is considerably reduced. This method was applied to correct the errors for NOAA images receiving in Tokyo, Bangkok and Ulaanbaatar. The results proved that this is a high accurate geometric correction method.