9KRAUS K, PFEIFER N. Determination of terrain models in wooded areas with airborne laser scanner data [ J]. ISPRS Journal of Photogrametry& Remote Sensing, 1998, 53 : 193 - 203.
10FISCHER A. Multi -Level of Detail Models for Reverse Engineering in Remote CAD Systems [ J]. Engineering with Computers, 2002, 18:50 -58.