仅用虚拟控制点的超大区域无控制区域网平差

利用光学卫星影像进行无控制测图是摄影测量追求的目标。针对超大区域无控制测图的需求,本文提出了一种以单景影像为平差单元,基于虚拟控制点的光学卫星影像超大规模无控制区域网平差方法。该方法利用待平差影像的初始RPC模型生成虚拟控制点,并将其作为带权观测值引入平差模型中以改善平差模型的状态,克服了在无控制点条件下平差精度不稳定、误差过度累积引起的网的扭曲变形等问题。为了验证本方法的有效性和精度,利用资源三号卫星获取的覆盖全国的26 406景影像进行区域网平差试验,并利用全国范围内分布的约8000个高精度控制点对平差后自动生产的DOM和DSM产品的几何精度进行验证。试验结果表明,平面和高程中误差均达到了4m以内,同时,区域网内部相邻影像之间的几何拼接精度优于1个像素,满足无缝拼接的要求。

Block-adjustment without GCPs for Large-scale Regions only Based on the Virtual Control Points

Mapping from optical satellite images without ground control points (GCPs) is one of the goals of photogrammetry.Aiming at the mapping without GCPs, a large-scale block adjustment method based on the virtual control points is proposed in this paper, in which the single image is regarded as an adjustment unit to be organized.To overcome the block distortion caused by unstable adjustment without GCPs and the excessive accumulation of errors, the virtual control points created by the initial RPC model of the images are regarded as the weighted observations and introduced into the adjustment model to refine the adjustment.To verify the availability and the accuracy of the presented method, 26406 three-linear-array images of ZY-3 covering China are used as the basic data and 8000 uniformly distributed high precision check points are applied to evaluate the geometric accuracy of the DOM (digital ortho model) and DSM (digital surface model) production.The experimental results indicate that the standard deviations of plane and elevation are both better than 4m and the mosaic accuracy of neighboring DOM is within better than 1pixel, which could meet the demand of seamless mosaic.