基于混合像元灰度分布的提高点位平面精度方法

Research on improving the planar accuracy of ground point based on mixed pixel gray distribution

随着卫星遥感技术的日趋发展与成熟,利用卫星影像进行测绘生产也越来越重要。由于卫星影像与传统航空影像不同,当运用现有的测图相关技术手段将数字影像放大到像元级别以寻找控制点位时,受传感器随机分割生成的像元以及周围地物的影响,无法在一系列混合像元中准确进行控制点的定位和量测,增加了航测绘图产品的误差。为此,设计了一种用于数字摄影测量且不同于现有航测规范中所涉及的地面标志,并提出了基于该种标志的点位偏移量解算方法。该算法解决了在数字影像上寻找点位困难问题的同时提高了单点的定位精度。最后,通过Geo Eye-1卫星立体像对的定位实验验证了该方法的实用性和准确性。

With the development and matureness of the satellite remote sensing technology, the use of satellite images for mapping production has become more and more important. As satellite images and traditional aerial photographs are different, during the utilization of existing mapping techniques to enlarge the image to the pixel level to seek for control points, the exact pixel points and the point coordinates can’ t be found in a series of mixed pixels because of the division generated randomly by the sensor element and the influence of the surrounding surface features. As a result, the image can’ t be accurately measured at a point, which will cause aerial mapping error. Therefore, a new symbol used in digital photogrammetry is presented in this paper, which is different from the ones in relative standard, and an algorithm is put forward based on the grayness of pixels of this kind of symbol in the digital image, which can find points and simultaneously improve the single point positioning accuracy. Finally, with a GeoEye-1 stereo pair through the actual encryption work, the practicability and the accuracy of the method are verified.