利用投影影像精化数字表面模型

随着摄影测量技术的成熟和人们对摄影测量产品应用的要求不断提高，真正射影像在工程与人们生活中扮演越来越重要的角色。生成高质量真正射影像的关键在于如何获取高精度的DSM。目前修正和改善DSM误差的方法普遍存在费力费时、精度缺乏保证及任意性等问题。本文针对DSM精度的修正问题提出了一种新的方法，即基于投影影像的概念，将空间点位在投影影像上的投影轨迹线作为几何约束条件，直接对现有DSM的高程进行修正的方法。通过获取高精度的DSM，进而生成更为精确的真正射影像。本文通过理论推导、单点高程和多点高程修正试验，验证了提出的新方法直观简单，适用性强，具有一定的实际应用价值。

Digital surface model refining using projected images

With the wide use of photogrammetry technology and the increasing demand for photogrammetric products, true orthoimages (orthoimages generated by using digital surface models (DSM)) play an increasingly important role in many engineering applications and lives. How to obtain a highly accurate DSM is the key for true orthoimage generation. The current means of obtaining DSM is mainly through either digital photogrammetry technology or 3D laser scanning technology. For many reasons, the DSM obtained has more or less various error sources. The common methods to correct those DSM errors (DSM obtained through digital photogrammetry technology) are mainly manual editing or reprocessing the troubled images. These methods are time-consuming or/and labor intensive, low-accuracy and random. In this paper, a new method is proposed to correct some DSM errors to improve the quality and accuracy of DSM. The new method is based on the concepts of projected images and the projected loci of a spatial point on the projected images as the geometry constraint, employs some popular image matching techniques to find the correct elevations. The details of the method are given and results from two experiments demonstrate that the proposed method is effective and very promising in correcting and refining DSM, and has certain potentials in practice use.