Rapid Forest Triage by
Sub-canopy MAV
S u k Yu n g L e e
A d a m Wo l f, Ke l l y Cay l o r, Ro l a nd Bro c kers
Oc to b e r 3 , 2 0 1 4
Overview
• Project objective: Fly a quadcopter through a
forest and survey trees autonomously
• Rationale:
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Microclimate and local competition
Determine biomass and carbon sink potential
Cost and time effective method
Branch applications (surveillance, etc)
• Combines fields such as computer vision,
controls, and data processing*
Fig 1 – Concept of a forest survey conducted by an MAV
Manual Surveying
• Formulate a ground truth with a manual
survey
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Rectangular survey grid
Diameter at breast height
Tree locations
Tree heights
Canopy radius and area
y2
a2
x2
b1
a1
DBH
x1
• Metadata
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Number of trees
Grid size
Survey date & location
GPS coordinates of four grid corners (w/ error
margins
h
o
y1
β
Origin
y
Fig 2 – Measuring of tree location, diameter, and height
GPS Error
• Polaris Navigation, GPS
Status Android apps
• Averaged an error margin of
±3.048 meters, but varied
• Navcom Technology –
satpredictor
• Number of satellites
available
• Dilution of precision
• Target specific times of day
for best accuracy and
precision
Fig 3 – Satellite Availability and DOP (Navcom)
Fig 4 – Geometric Error
Ecology Maps
• Neighborhood Basal Area Density
• Nearest Tree
• DBH of Nearest Tree
• Neighborhood Height
• Standard Deviation of Neighborhood Height
• Average Distance within Neighborhood
Fig 5 – Nearest Tree Map (m)
Biomass
• 𝐴𝐺𝐵 = 𝐹 ∗ 𝜌 ∗
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𝜋𝐷2
4
∗ 𝐻
Chave et al 2005
F = 0.06, broadleaf
𝜌 = 0.59, Quercus agrifolia
19,895.54 kg
• Lower limit
• Cone geometry
• 11,053.08 kg
• Upper limit
• Cylinder geometry
• 33,159.23 kg
Environmental Sensor board
• Sensor board, operating in ROS using the
asctec_mav_framework
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Time stamp
Relative humidity
IR thermometer
Thermistor
Short-wave radiation
Normalized difference vegetation index1
Fig 5 – Environmental Sensor Board Readings
Website
• Demonstration
Future Considerations
• Above canopy survey
• Autonomous height and canopy measurements
• More effective biomass estimate2
• Leaf area index
• Density of plant canopies
• Primary photosynthetic production
• Evapotranspiration
• Image processing upward-facing hemispherical photos
Fig 7 – Upward facing hemispherical shot of canopy
Acknowledgments
• Adam Wolf
• Kelly Caylor
• Roland Brockers
• Jet Propulsion Laboratory
• Princeton Environmental Institute
Citations
References
1 - http://en.wikipedia.org/wiki/Normalized_Difference_Vegetation_Index
2 - Chave et al. 2005
Images
Fig 1 - http://www-robotics.jpl.nasa.gov/
Fig 2 - http://oregonstate.edu/
Fig 4 – Richard Langley, http://www.iastate.edu/
Fig 7 - Stuart B Weiss