BLOCK ORTHORECTIFICATION AND MOSAIC OF 1960s DISP IMAGES IN QUJING, YUNNAN
Keywords: DISP, Orthorectification, Mosaic, Color balance, Rocky desertification, Karst
Abstract. Remote sensing digital image mosaic refers to the splicing of two or more remote sensing images into a panoramic image to meet the application requirements of wide images. It is becoming more and more important to cover large areas of mosaic images. The data pre-processing and mosaic process are different for different images. In this paper, the declassified intelligence satellite photography (DISP) in the 1960s was used as experimental data, taking Qujing in Yunnan Province as an example, a total of 92 scene images were used for DISP image processing and seamless mosaic. Firstly, In order to make full use of the image, it is necessary to perform orthorectification on the KH-4B images covering Qujing. Considering that the satellite orbit parameters and other parameters are unknown, several models for orthorectification of satellite images are proposed. After experiments and analysis, it is concluded that the third order polynomial is the optimal. Secondly, given the problem of radiation imbalance caused by the difference of time phase, the histogram equalization method is used for color balance, the image of the seam line is eliminated. Finally, the seamless mosaic is achieved. The map of the 1960s DISP in Qujing is obtained. The map can provide material basis for future research and other fields. The processing methods of historical images can be used for reference by others.