Triangle mesh compression

摘要

The present invention is concerned with a computer implemented method of processing elevation mesh data defining a polygon mesh surface to determine an alternative representation of the surface using fewer polygons than in the original representation. The method comprises sub-sampling original elevation mesh data defining a polygon mesh surface where vertices of polygons correspond to points on an X-Y grid with a variable Z value at each grid point to generate low resolution elevation mesh data for a low resolution representation of the polygon mesh surface where vertices of polygons correspond to points on a coarser X-Y grid than the original elevation mesh data; determining error values indicative of the extent that portions of the surface defined by the low resolution elevation mesh data differ from corresponding portions of the surface defined by the original elevation mesh data; and generating an alternative representation of the polygon mesh surface comprising: low resolution elevation mesh data for the portions of the polygon mesh surface associated with error values less than a threshold value; transition mesh data defining a polygon mesh surface immediately adjacent the perimeter of portions of the surface represented by the low resolution elevation mesh data; and higher resolution elevation mesh data for the remaining portions of the polygon mesh surface wherein the higher resolution elevation mesh data comprises data defining a polygon mesh surface where vertices of polygons correspond to points on finer regular X-Y grid than the low resolution elevation mesh data. 2:Fit A. 6