INTEGRATION OF FULL-WAVEFORM INFORMATION INTO THE AIRBORNE LASER SCANNING DATA FILTERING PROCESS

Terrain classification of current discrete airborne laser scanning data requires filtering algorithms ba ed on the spatial relationship between neighbouring three-dimensional points. Howe ver, difficulties commonly occur with low vegetatio n on steep slopes and when abrupt changes take place in the terrain. This paper reports on the integration of additional inf ormation from latest generation full-waveform data into a filtering algorithm in or der to achieve improved digital terrain model (DTM) creation. Prior to a filtering procedure, each point was given an attribute based on pulse width information. A novel routine was the n used to integrate pulse width information into the progressive densificatio n filter developed by Axelsson. The performance was investigated in two areas that were found to be problematic when applying typ ical filtering algorithms. The derived DTM was foun d to be up to 0.7 m more accurate than the conventional filtering approach. Moreover, compared to typical filtering algorithms, dense low vegetation points could be removed more effectively. Overall, it is r ecommended that integrating waveform information ca provide a solution for areas where typical filtering algorithms cannot per form well. Full-waveform systems are relatively cos t-effective in terms of providing additional information without the need t o fuse data from other sensors. * Corresponding author.