局部坐标系的嫦娥二号月面影像自动拼接方法

Automatic Mosaic Method for CE-2 Lunar Imagery Based on Local Coordinate System

针对嫦娥二号影像分辨率高、数据量大的特点,提出一种的投影坐标系——局部坐标系。该坐标系建立过程简单,便于数据管理,投影后的影像变形极小。通过转换可将单轨的DOM和DEM进行分解,并生成各局部坐标系对应的分块DOM和DEM。创建了分块数据后,基于重叠影像同名像点,以有理多项式作为校正模型,采用一种全局优化方法来校正重叠影像坐标偏差,使校正后各影像能够很好地配准。校正只在影像子网内进行,各子网间互不影响,有效地控制了误差的传递。试验结果表明,该拼接方法可在微机上有效地对海量月表影像进行拼接处理,并达到很好的拼接效果,最终生成全景三维月球图。

In view of the high resolution and mass quantity of the imagery from CE-2, a new projective coordinate system, named local coordinate system, which can be easily constructed and has a small distortion, was proposed. The DOM and DEM of one orbit could be broken down into a few separate small blocks, every one of which corresponds to its own local coordinate system. After the block data was created, a global optimization method, which is based on the corresponding points of overlapped images and takes the rational polynomial as its model, was implemented to correct the coordinate discrepancies between overlapped images aiming at a good registration. Since the correction was carried out only in every sub net, there was no interference among image block sub nets. As a result, error propagation was effectively controlled. Experimental results indicate the mass lunar imagery can be effectively disposed on PC by applying the proposed mosaic method, and a good effect is achieved. The panoramic 3D lunar map can be produced at last.