敦煌壁画数字图像的三维信息恢复

详细阐述了用数字近景摄影测量和计算机图像处理技术来恢复敦煌壁画三维信息的过程,以达到原样数字保存敦煌壁画的目的.通过建立洞窟的统一坐标系统,对洞窟壁画进行近景摄影测量,并把近景摄影测量获取的底片用高分辨率的扫描仪扫描成数字图像.然后经过坐标变换,建立每个墙面壁画的辅助空间坐标.在此基础上,经过模型定向、核线重采样、影像匹配、数字表面模型的生成,直至最后生成正射影像,恢复壁画的三维信息.从壁画图像处理的结果来看,所有控制点绝对定向的残差都在毫米级,壁画数字表面模型的中误差也在毫米级,也就是说敦煌壁画图像数据的几何纠正达到了毫米级.这表明用近景摄影测量和计算机图像处理技术可以很精确地恢复敦煌壁画的三维空间信息,从而达到保护和永久地数字化存贮敦煌壁画、塑像文物的目的.同时也为我们提供了一种文物保护的新方法和新思路,为古代珍贵文物的保护、复原与研究提供了新的手段.

Three Dimensional Information Restoration of the Digital Images of the Dunhuang Mural Paintings

The processes to restore 3D information of the Dunhuang mural paintings by means of digital close-range photogrammetry and computer-based image processing technology was expounded in this paper in order to digitally preserve the Dunhuang mural paintings in their original style.The uniform coordinate system of the Grottoes was set up,and the mural paintings of the Grottoes were photogrammetried in close-range.Furthermore,the films obtained from the close-range photogrammetry were scanned as digital images by a high resolution scanner.The assistant spatial coordinate of the mural paintings on each wall was then set up by the coordinate transformation.On the basis of this and by means of model orientation,kernel line resampling,image matching and the orthoimages of the mural paintings were created and the 3D information was finally restored.The processing results of the mural paintings showed that the residual errors of the absolute orientation of all control points and the middle errors of the digital surface model of the mural paintings reached millimeter scale.That is the geometric correction of the image data of Dunhuang mural paintings reached millimeter scale.We believe that the 3D information of Dunhuang mural paintings can be accurately restored by the close-range photogrammetry and computer-based image processing technology in order to protect and digitally restore the mural paintings and statues of Dunhuang forever.At the same time,This study provided for us a new method and thought for relics protection,and new measures for ancient valuable relics protection,restoration and research.