This document provides an overview of different types of LiDAR acquisition methods. Aerial LiDAR is used to capture large areas and generates 2.5D data by scanning from aircraft. Terrestrial LiDAR captures smaller areas in full 3D using static or mobile ground-based units. Bathymetric LiDAR maps shallow underwater areas using dual lasers. Atmospheric LiDAR surveys air properties by transmitting laser pulses and analyzing backscatter. Common to all is using a laser transmitter and detector to measure discrete points or full waveforms, with variations depending on the objective and environment.

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. Introduction
• LiDAR = Light Detection and Ranging
• Laser-based scanning
– terrain
– bathymetry
– atmospheric properties
• Collection of point set („point cloud“) data

3. Introduction
• Common setup to all scanners: transmitter
and detector
• Detectors varies between
scanners

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. Aerial LiDAR
• Objective:
– earth observation of large areas (municipalities or
bigger)
– 2.5D data

6. Aerial LiDAR
• Scanning process
plane pos. F
α
Δz
s(t)
p Δy
β

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. 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. 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. 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. 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. 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. 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. 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. 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. Atmospheric LiDAR
Image courtesy of: Xinzhao Chu, CU-Boulder, Lecture “Fundamentals of LiDAR
Remote Sensing”, 2011