LiDAR acquisition

3,453 views

Published on

pinciples, techniques, differences and usage of LiDAR-acquired data

Published in: Technology, Business
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
3,453
On SlideShare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
155
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

LiDAR acquisition

  1. 1. LiDAR Acquisition 1. Introduction 1. 2. 2. Aerial LiDAR 1. 2. 3. 3. Objective and general setup static vs. mobile Registration Bathymetric/Hydrographic LiDAR 1. 2. 5. Objective and general setup Scanning process Characteristic properties – further information Terrestrial LiDAR 1. 2. 3. 4. Laser capturing unit Signals Objectives and general setup Characteristics – further information Atmospheric LiDAR
  2. 2. Introduction • LiDAR = Light Detection and Ranging • Laser-based scanning – terrain – bathymetry – atmospheric properties • Collection of point set („point cloud“) data
  3. 3. Introduction • Common setup to all scanners: transmitter and detector • Detectors varies between scanners
  4. 4. Introduction • signals: pulse-ranging or continuous wave • Both create discrete measurements • Final data: single/multi-return range measurements or (full) waveform Images taken from: Conservation Applications of LiDAR Data, Joel Nelson, University of Minesota; Further information on signals: Airbone laser scanning – an introduction and overview, A. Wehr and U. Lohr, ISPRS Journal of Photogrammetry and Remote Sensing, Volume 54, Number 2, July 1999, pp. 68-82(15) Single-return Mutli-return Waveform return
  5. 5. Aerial LiDAR • Objective: – earth observation of large areas (municipalities or bigger) – 2.5D data
  6. 6. Aerial LiDAR • Scanning process plane pos. F α Δz s(t) p Δy β
  7. 7. Aerial LiDAR • Swath scanning -> line scan pattern Image from: A guide to LiDAR data acquisition and processing for the forest of the Pacific Northwest, D. Gatziolis and H.-E. Andersen, Gen. Tech. Rep. PNW-GTR-768. Portland, Oregon, U.S. Department of Agriculture, 2008
  8. 8. Aerial LiDAR • Characteristics and Properties: – – – – – Scanning angle Scanning frequency Pulse length -> vertical resolution Footprint diameter Footprint spacing (non-uniformal horizontal resolution) – Returns per pulse • Beam frequency for topographic scan: 1040 – 1064 nm
  9. 9. Aerial LiDAR • further information – continuous wave: “Introduction to continuous-wave Doppler lidar”, C. Slinger and M. Harris, TechReport – full-waveform lidar: “From single-pulse to fullwaveform airborne laser scanners: Potential and Practical Challenges”, W. Wagner et al., Int. Archives of Photogrammertry and Remote Sensing, Vol. 35, No. Part B, 2004, pp. 201-206 – full-waveform lidar: “Empirical Comparison of FullWaveform Lidar Algorithms: Range Extraction and Discrimination Performance”, C.E. Parrish et al., Photogrammetric Engineering & Remote Sensing, Vol. 77, No. 8, August 2011, pp. 825-838
  10. 10. Terrestrial LiDAR • capture smaller-scale landscape phenomena in full 3D (steep coast segments, yardrangs) • Time-series captures • 360° capture Image courtesy: Using Terrestrial Light Detection and Ranging (Lidar) Technology for Land-surface Analysis in the Southwest, Soulard, C.E. and Bogle, R.C. and Western Geographic Science Center and Geological Survey (U.S.), Fact Sheet, 2011
  11. 11. Terrestrial LiDAR • static LiDAR: fixed position; semi-automatic registration; standard in geological field survey • mobile LiDAR: vehicle-mounted; easier largescale survey; restricted to drivable (urban) regions
  12. 12. Terrestrial LiDAR • reference of scans: – aerial & mobile terrestrial LiDAR: semi-automatic – static terrestrial LiDAR demands registration Computer Vision: – control points in view – inertia sensors – shape fitting – image-guided registration Image: Terrestrial laser scanning in geology: data acquisition, processing and accuracy considerations, Buckley, S.J. et al., Journal of the Geological Society, May 2008, Volume 165, pp. 625-
  13. 13. Bathymetric LiDAR • Objective: scan shallow water areas (harbor, rivers and deltas) • setup very similar to aerial LiDAR • 2 lasers: 532 nm and 1064 nm Image source: Meeting the Accuracy Challenge in Airborne LiDAR Bathymetry, Guenther, G.C et al., Proceedings of EARSeL-SIG-Workshop LIDAR, 2000
  14. 14. Bathymetric LiDAR • further literature: – Meeting the Accuracy Challenge in Airborne LiDAR Bathymetry, Guenther, G.C et al., Proceedings of EARSeL-SIG-Workshop LIDAR, 2000 – Green, waveform lidar in topo-bathy mapping – Principles and Applications, Nayegandhi, A., USGS St. Petersburg/Florida
  15. 15. Atmospheric LiDAR • surveying atmospheric properties (temperature, aerosols, etc.) • usually telescope at detector • observable particles and properties depend on beam wavelength (1064 nm or 532 nm) and backscatter type
  16. 16. Atmospheric LiDAR Image courtesy of: Xinzhao Chu, CU-Boulder, Lecture “Fundamentals of LiDAR Remote Sensing”, 2011

×