1. INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION Adding the Third Dimension to a Topographic Database Using Airborne Laser Scanner Data Sander Oude Elberink Delft, 1 st September 2006

2. Contents  Introduction  Data properties  Laser data  Map data  Approach  Densifying 2d map  Segmentation  3D reconstruction process (incl. processing rules)  Surface modelling  Results  Conclusions & future work

3. Introduction  Growing demand  3D data  Automated acquisition  Data fusion: laser data + 2d map  Now: focus on infrastructure Research project 3D Modelling 3D Acquisition TU Delft: Oosterom, Verbree, Penninga ITC Enschede: Vosselman, Oude Elberink

4. Data properties Laser scanner data “AHN” Point cloud 1 point / 9 m^2 Topographic database “TOP10NL” Object based 1:10.000 Roads, buildings, land use,… Outlines Classification Semantics

5. Approach - overview  Preprocessing data  Adding height to map points  Reconstruct new 3D polygons  Adding heights to surfaces Segment laser data Densify map data Detect multiple heights Interpolate laser data Multiple levels Add semantics Add laser data or knowledge

6. Preprocessing  Laserdata  Surface growing  Seed surface detection by 3D Hough  Smooth surfaces allowed  Small segments removed  Topographic map  More map points needed in 3D

7. Preprocessing  Laserdata  Surface growing  Seed surface detection by 3D Hough  Smooth surfaces allowed  Small segments removed  Topographic map  More map points needed in 3D Interchange in 2D Interchange in 3D

8. Adding height to map points  Interpolation  Use laser points in nearest dominant segment  For every neighbouring object  Detect multiple heights  Add semantics  Water = horizontal  Average if close  Road = smooth

9. Adding height to map points  Interpolation  Use laser points in nearest dominant segment  For every neighbouring object  Detect multiple heights  Add semantics  Water = horizontal  Average if close  Road = smooth

10. Reconstruct new polygons  Multiple levels Interchange in 3D Hidden polygons New polygons

11. Adding height to surfaces  Laser data  Add to meadow etc.  Perform morphological filtering near edges  Modelling  Roads, buildings, water

12. Results

15. At the moment…  Adding knowledge to program:  Merging road segments correctly  Detect & correct fusion errors automatically  Preparing 4 presentations (feedback) And the next moment…  Building reconstruction  Quality measures for 3D map

16. Conclusions  Complex infrastructural objects can be reconstructed in 3D  New polygons are created where needed  Not yet correctly, or not yet automatically

17. INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION Thank you for your attention. Questions?

18. Extra slides