摘要:
高分一号(GF-1)卫星是我国高空间分辨率对地观测系统重大专项中的首颗卫星,目前已正常运行4 a多,为全国中、高空间分辨率影像镶嵌提供了丰富的数据源.针对GF-1多光谱宽幅覆盖(wide field of view,WFV)影像特点,制定了影像处理的技术流程,主要包括数据选取、几何纠正、匀色镶嵌和制图4项关键技术,重点解决大幅宽影像高精度几何定位问题;在选取高质量数据基础上,自动采集控制点,控制点均方根误差(root mean square er-ror,RMSE)不大于1个像元,平均每景影像中控制点数量为54个;应用有理函数模型(rational function model,RFM)对影像进行正射纠正,然后进行色调调整和镶嵌处理,制作全国1:500万比例尺陆地卫星影像专题地图.镶嵌结果具有空间精度高、地物色彩丰富和时效性强等特点.所采用的技术流程和方法可为高分系列卫星全国镶嵌制图提供参考,同时也将促进国产高分卫星在全国重大资源环境调查中的应用推广.
Abstract:
GF-1 is the first satellite in the major projects of high resolution observation system in China. It has provided abundant data for high and moderate spatial resolution image mosaicking for more than four years since its launching. The process of image mosaicking was based on the characteristics of the wide field of view ( WFV ) images of GF -1,including four key techniques i. e. , data selection, geometric rectification, color adjustment, image mosaicking and mapping. The high precision geometric positioning of wide image is the key technology. After high quality data selection, ground control points ( GCPs) were collected automatically. The root mean square error (RMSE) of each image should be less than 1 pixel with the average number of GCPs being 54. Then rational function model( RFM) was applied to the images for ortho-rectification. The 1:5000000 national land image map was completed after color adjustment and mosaicking. This map has high spatial accuracy, colored pixels and temporal resolution. The method proposed in this paper could provide an important reference for the series of GF satellites image mosaicking and mapping, and would promote the domestic satellites to play a greater role in investigation of major resources and environment in China.
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