The Study Of Hemispherical Image Geometric Correction Based On Deep Air-to-ground Observation

The global changes and macro-geoscience phenomena of the earth's long-term natural evolution and human activities are becoming one of the increasing concerns of countries and the science and technology circles.The traditional satellite-machine-earth remote sensing for earth observation technology has shortcomings,such as long observation period,small observation angle,etc.,making it difficult to meet the demands of global-scale scientific observation.Then researchers are looking at new areas of deep space-to-earth observation.The United States deep space observatory(DSCOVR)makes global observations at the Lagrange point 1 to better understand the effects of the changes in the earth's radiation budget due to human activities and natural phenomena;Guo huadong,academician of China,put forward the moon-based platform of earth observation technology.The moon has become the ideal platform for monitoring global change,which can realize large scale,the instantaneous global change monitoring,making it advantageous to the macroscopic phenomenon of earth science research.The geometric correction of the planetary scale remote sensing image is one of the important problems to be studied in the deep space-to-earth observation.The planetary scale remote sensing image obtained by deep space observation is affected by various factors such as remote distance,curvature of the earth and relief of topography,causing serious geometric distortion of remote sensing image.In addition,most of earth observation hemisphere image is covered by sea,cloud,these features make traditional satellite remote sensing image geometric correction method can't meet the need of deep observation of space-to-earth hemisphere image geometric correction.Our study aiming at the problem,takes moon-based observation as an example,to carry out study of the method of remote sensing image geometric correction for earth observation hemisphere with less and sparse ground control points.First of all,the influencing factors and image characteristics of the geometrical distortion of hemispherical images is analyzed.Then,a hemisphere polar coordinate system suitable for moon-based observation is established.Finally,a new projection polar geometric correction model is put forward to do geometric correction.Two sets of experiments are completed to study the dependence of the number of control points and the distribution of control points with the new model and the traditional model respectively.The results show that:1)the proposed hemisphere polar coordinate system can effectively express the hemispherical image and can preserve the original information of the moon-based platform earth observation image better;2)our work has solved the problem of geometric distortion caused by the earth model and the curvature of the earth in the hemisphere image of moon-based earth observation;3)based on the proposed hemisphere polar coordinates,a small amount of non-uniform control points can be used for more accurate geocoding,then improving the geometric accuracy of moon-based earth observation planetary scale remote sensing images.This research can push moon-based remote sensing progress of the scientific research work and provide technical support for the subsequent moon-based remote sensing image information recognition,interpretation and analysis.