基于航片建立数字高程模型及林分信息提取

Establishment of Digital Elevation Model and Information Extraction for Forest Stands Based on Aerial Images

以东北林业大学帽儿山实验林场2004年航片和同年森林经理调查数据为基础,在V irtuoZo软件平台上应用数字摄影测量方法与技术,完成了帽儿山航片的空三加密过程,在试验区生成立体像对、建立数字高程模型(DEM)及制作数字正射影像图(DOM)。通过等高线回放目视检查法及检查点法验证了DEM的精度,并在数字测图模块(V irtuoZo IGS)下进行了林分平均高及郁闭度两种林分信息提取的研究,结果显示:林分平均高的精度为83.3%,郁闭度的精度为76.6%。将提取的结果与地面实测数据结合,建立了回归模型,通过计算验证,林分平均高、郁闭度精度都有相应的提高,其值分别为86.5%,87.4%。

VirtuoZo software and digital photogrammetric method were applied to complete the process of aerotriangu]ation by means of the data collected from aerial images of Maoershan Experimental Forest Farm of Northeast Forestry University and forest survey in 2004. Then the stereo pairs, the Digital Elevation Model （DEM） and the Digital Orthophoto Map （DOM） were made in the experimental zone. The accuracy of DEM was verified by the methods of contour line replacement and check-points. Extraction of forest stand mean height and canopy closure based on the IGS module showed that the accuracy for forest stand mean height was 83.3% , and that for the canopy closure was 76.6%. The regression equation between the data extracted from aerial photos and the actual measured data was also set up. Result indicated that the prediction accuracy increased, namely 86.5% and 87.4% for mean height and canopy closure, respectively.