Embed Size (px)
Citation preview
Dr. Ahmed Shaker, Department of Civil Engineering
Potential Use of LiDAR Technology in Forestry Applications
Dr. Ahmed Shaker
by
Dr. Ahmed Shaker, Department of Civil Engineering
Research
• Use of mobile and airborne LiDAR technology in engineering applications with a particular interest on land cover classification and object extraction.
• Develop algorithms to improve the LiDAR data quality: – Radiometric Correction
– Radiometric Normalization
• Demonstrate the use of single/multi-wavelength LiDAR for: – Land Cover Classification
– Land/Water Delineation
– Other Applications
May 4th, 2016 S2
Dr. Ahmed Shaker, Department of Civil Engineering
Radiometric Correction
𝑐𝑣 =𝜎
𝜇
May 4th, 2016 S3
Dr. Ahmed Shaker, Department of Civil Engineering
Radiometric Normalization
• Radiometric Normalization
– To reduce the radiometric misalignment found in overla
May 4th, 2016 S4
0
.
Laser
Footprint
Laser
Pulse
1st Scan
2nd Scan
Flying
Height
Overlapping
Region
Combined intensity data with
line striping noise
Dr. Ahmed Shaker, Department of Civil Engineering
Radiometric Normalization
• Two radiometrically corrected intensity dataset XA and XB with partial overlap
– Locate all possible pairwise closest points within a certain threshold
– Plot the joint intensity-histogram using the pairwise dataset
– Perform weighted least-squares polynomial fitting
– Normalize the XB with reference to XA using the fitted function
May 4th, 2016 S5
Pairwise Closest Points K Intensity bin of XB
0
J
Inte
ns
ity b
in o
f X
A
Intensity normalization of
XB with reference to XA Generate Joint-histogram
LiDAR data strip XA
LiDAR data strip XB
Overlap
Polynomial
Fitting
Dr. Ahmed Shaker, Department of Civil Engineering
Examples of Radiometric Correction and Normalization
• Orion (1500 nm) LiDAR Intensity Data
May 4th, 2016 S6
Original Intensity Data Corrected and Normalized Intensity Data
Dr. Ahmed Shaker, Department of Civil Engineering
• Gemini (1064 nm) LiDAR Intensity Data
May 4th, 2016 S7
Original Intensity Data Corrected and Normalized Intensity Data
Examples of Radiometric Correction and Normalization
Dr. Ahmed Shaker, Department of Civil Engineering
• Gemini (1064 nm) LiDAR Intensity Data
May 4th, 2016 S8
Original Intensity Data Corrected and Normalized Intensity Data
Examples of Radiometric Correction and Normalization
Dr. Ahmed Shaker, Department of Civil Engineering
LiDAR Single-Wavelength Classification
Dataset 3-classes 4-classes 5-classes
OI 60.50% 51.78% 30.50%
GCI 60.59% 53.17% 32.08%
RCI 68.52% 62.08% 42.08%
GC & RCI 69.90% 63.47% 43.27%
OI
Misclassified as grass
RCI
Tree
Misclassified as tree
OI
Building
RCI
Accuracy Improvement • Geometric Calibration (GC): 0.1 to 1.6% • Radiometric Correction (RC): 8.0 to 11.6% • GC & RC: 9.4% to 12.8%
May 4th, 2016 S9
Dr. Ahmed Shaker, Department of Civil Engineering
Multispectral LiDAR – Teledyne Optech
May 4th, 2016 S10
Parameter Specification
Wavelengths Channel 1 = 1550 nm,
Channel 2 = 1064 nm,
Channel 3 = 532 nm
Altitudes Topographic: 300-2000 m AGL, all channels
Bathymetric: 300-600 m AGL, channel 3
Scan Angle (FOV) Programmable; 0 - 60° max
Beam Divergence Channel 1 & 2 = 0.35 mrad ,
Channel 3 = 0.7 mrad
Pulse Repetition Frequency (PRF) 50 - 300 kHz/channel; 900 kHz total
Scan Frequency Programmable; 0 - 210 Hz
Swath width Up to 115% of AGL
Point Density Bathymetric: >15 pts/m2
Topographic: >45 pts/m2
Dr. Ahmed Shaker, Department of Civil Engineering
Multispectral LiDAR Data Classification
May 4th, 2016 S11
532 nm 1064 nm 1550 nm
Digital Surface Model (DSM)
Dr. Ahmed Shaker, Department of Civil Engineering
Multispectral LiDAR Data Classification
• Optech Titan LiDAR data (three wavelengths)
May 4th, 2016 S12
Combined intensity images with DSM; DSM in Red, C3 in Green,
and C2 in Blue
Combined intensity images; C1 in red,
C2 in green, and C3 in blue
Dr. Ahmed Shaker, Department of Civil Engineering
Multispectral LiDAR Data Classification
May 4th, 2016 S13
• Classified Points
• Classification accuracy of 93%
Dr. Ahmed Shaker, Department of Civil Engineering
Land/Water Delineation - Coastal Area
May 4th, 2016 S14
Aerial Photo Channel 3: 1550 nm Channel 2: 1064 nm Channel 1: 532 nm
Land Water 2D View
3D View
Whitby, ON
Dr. Ahmed Shaker, Department of Civil Engineering
Thank You
