Comparing UAV multispectral and field hyperspectral data collection for vegetation indexes calculation

HV-UAV multispectral compared to
hyperspectral data collection as applied
to vegetation indexes calculation
Prof. Sabino Aurelio Bufo*, Dott. Massimo Bavusi**
DIPARTIMENTO
DI SCIENZE
*Dipartimento di Scienze – Università degli Studi della Basilicata – sabino.bufo@unibas.it
** Terralab S.r.l. – info@terralab.eu – www.terralab.eu
** Tab Consulting S.r.l. – info@tabconsulting.it – www.tabsrl.com
Summer School of Hydrology Applied Course on UAVs for Environmental Monitoring, Matera, July 27-31, 2015
1

Contents
 Assessing the robustness of Vegetation Indices (VIs) to
estimate Durum Wheat grown (precision agriculture).
 Comparing satellite remote sensing (multispectral
reflectance) and hyperspectral measurements (first year)
 Comparing UAV multispectral vs field hyperspectral data
collection (second year)
 Working in progress for environmental applications
2

First Year MAPRE Project
 Regional Project on ‘Advanced Precision Agriculture
Tools to Reduce the Environmental Impact of Wheat
Cropping (Triticum Durum, Desf.)’. Funded by P.S.R.
Basilicata (European Fund for Regional Development)
2007/2013.
Experimental
Field (10 ha)
3

Method
 Remote sensing:
The RapidEye Satellite Constellation
http://blackbridge.com/rapideye/products/ortho.htm
 Summer School of Hydrology Applied Course on UAVs for Environmental Monitoring, Matera, July 27-31, 2015
Multispectral reflectance values, monitored by satellite, were used
to determine specific indices of plant health.
Spectral bands Blue: 440-510 nm (B)
Green: 520-590 nm (G)
Red: 630-685 nm (R)
Red Edge: 690-730 nm (RE)
NIR: 760-850 nm
4

Method
 Mostly used indices:
Normalized Difference Vegetation Index (NDVI), or
structural index (canopy development)
Normalized Difference Red Edge Index (NDRE), or
chlorophyll index
NDVI = NDRE =
NIR – Red
NIR + Red
NIR – Red Edge
NIR + Red Edge
Green: 520-590 nm (G)
Red: 630-685 nm (R)
NIR: 760-850 nm
5

Method
 Other indices:
Green: 520-590 nm (G)
Red: 630-685 nm (R)
NIR: 760-850 nm
• Canopy Chlorophyll Content Index (CCCI) or
Nitrogen uptake index: CCCI = NDRE/NDVI
• Normalized Difference Water Index (NDWI) or water
stress index: (NIR-BLUE)/(NIR+BLUE)
• Meris Terrestrial Chlorophyll Index (MTCI), or
chlorophyll assessment index:
(NIR-RedEdge)/(RedEdge-RED).
6

Method
 Field measurements (walking):
FieldSpec® HandHeld 2:
Hand-held Vis-NIR
Spectroradiometer, working in
the 325 nm – 1075 nm spectral
range, with an accuracy of ±1
nm and a resolution of <3 nm
at 700 nm, equipped with GPS
accessory
7

Results
8Normalized Difference Vegetation
Index (NDVI)
Cultivars
C= Core
T= Tirex
S= Simeto
NDVI, March, 2013
NDVI, March, 2013

Results
Cultivars
C= Core
T= Tirex
S= Simeto
9
NDVI, April, 2013
Normalized Difference Vegetation
Index (NDVI)
NDVI, April, 2013

Results
10Normalized Difference Red Edge Index
(NDRE)
Cultivars
C= Core
T= Tirex
S= Simeto
10
NDRE, March, 2013
NDRE, March, 2013

Results
11Normalized Difference Red Edge Index
(NDRE)
NDRE, April, 2013
NDRE, April, 2013
Cultivars
C= Core
T= Tirex
S= Simeto

Results
12Meris Terrestrial Chlorophyll Index
(MTCI)
MTCI, March, 2013
MTCI, March, 2013
Cultivars
C= Core
T= Tirex
S= Simeto

Results
13Meris Terrestrial Chlorophyll Index
(MTCI)
MTCI, April, 2013
MTCI, April, 2013
Cultivars
C= Core
T= Tirex
S= Simeto

Results
14Normalized Difference Water Index
(NDWI)
MDWI, March, 2013
MDWI, March, 2013
Cultivars
C= Core
T= Tirex
S= Simeto

Results
15Normalized Difference Water Index
(NDWI) MDWI, April, 2013
MDWI, April, 2013
Cultivars
C= Core
T= Tirex
S= Simeto

Results
16Canopy Chlorophyll Content Index
(CCCI) CCCI, March, 2013
CCCI, April, 2013
Cultivars
C= Core
T= Tirex
S= Simeto

Second Year FRUINDEX Project
 Regional Project on ‘Reduction of
environmental impact in the production of
durum wheat by means of fertilization
based on reflectance measurements and
related vegetation indices’.
Also funded by P.S.R. Basilicata (European Fund for
Regional Development) 2007/2013.
17

Instrumentation and techniques
Field Spec HandHeld2
Spectroradiometer
•Spectral range: 325 nm – 1075
nm
•Accuracy :±1 nm
•Resolution: <3 nm at 700 nm
SenseFly Ebee
Resolution: 1.2 Mp x 4
Ground resolution at 100m:10 cm/px
Sensor size: 4.8 x 3.6 mm per
sensor
Pixel pitch: 3.75 um
Image format: RAW
Upward looking irradiance sensor
Multispec 4c
18

UAV
19
UAV: Unmanned Aerial Vehicle
Synonymous and variants: RPA (Remotely Piloted Aircraft), RPAS
(Remotely Piloted Aircraft), SAPR (Sistemi Aerei a Pilotaggio Remoto),
APR (Aeromobile a Pilotaggio Remoto); Autonomous Aircraft

The vector
Hardware
Weight (inc. supplied camera): Approx. 0.69 kg (1.52 lbs)
Wingspan: 96 cm (38 in)
Material: EPP foam, carbon structure & composite parts
Propulsion: Electric pusher propeller, 160 W brushless
DC motor
Battery: 11.1 V, 2150 mAh
Camera (supplied) : WX (18.2 MP)
Cameras (optional), S110 RGB, thermoMAP,
Carry case dimensions,
55 x 45 x 25 cm (21.6 x 17.7 x 9.8 in)
Operation
Maximum flight time: 50 minutes
Nominal cruise speed: 40-90 km/h (11-25 m/s or
25-56 mph)
Radio link range: Up to 3 km (1.86 miles)
Maximum coverage (single flight): 12 km² / 4.6 mi²
(at 974 m / 3,195 ft altitude AGL)
Wind resistance: Up to 45 km/h (12m/s or 28 mph)
Ground Sampling Distance (GSD): Down to 1.5 cm
(0.6 in) per pixel
Relative orthomosaic/3D model accuracy
1-3x GSD
Absolute horizontal/vertical accuracy (w/GCPs)
Down to 3 cm (1.2 in) / 5 cm (2 in)
Absolute horizontal/vertical accuracy (no GCPs)
1-5 m (3.3-16.4 ft)
Multi-drone operation : Yes (inc. mid-air collision
avoidance)
Automatic 3D flight planning: Yes
Linear landing accuracy: Approx. 5 m (16.4 ft)
20

UAV in Agriculture
Index variations
Patterns in canopy height, vigour, colour, density
Developing erosion channels
Damage observations
Plant statistical variations & comparisons to other
data (e.g. planter data)
Patterns in dry soil vs. wet soil
Determine relative location of drainage tile &
whether functioning/broken
Disaster management
21

UAV in Agriculture
Platform
Cost
Time
consumption
Spatial
resolution
Spectral
resolution
Cloud
sensitivity
Coverage
Ondemand
services
Satellite
high
low
2-30
m
4 or
more
bands
high
Square
kilometers
No
UAV low low
3 -20
cm
4 bands low
Up to 10
Km2 Yes
Field low high
Dependingon
thestep
Hyperspectral
ability
low
few
hectares
Yes
22

Fruindex project: location
Location: Genzano di Lucania (Basilicata, Italy)
Coordinates: 40°49'15.35"N, 16° 4'43.96"E
Soc. Coop. Agr. LA GENERALE
23

Fruindex project: test site
N fertilization:
100 or 150 Kg/ha
applied in two rates
April and May
Wheat accessions
Tirex and Core
6 replicates
24

Fruindex project: Flight plan
25

Fruindex project: vegetation indexes
NDVI (Normalized Difference
Vegetation Index)
NDWI (Normalized
Difference Water
Index)
NDVI is directly related to
the photosynthetic capacity
and hence energy
absorption of plant canopies
MTCI (Meris
Terrestrial
Clorophyll Index)
MTCI is sensitive to
chlorophyll content
NDRE (Normalized
Difference RedEdge Index
NDRE is sensitive to
chlorophyll content
CCCI (Canopy
Chlorophyll
Content Index)
(NIR-Red)/(NIR+Red)
(NIR-RE)/(NIR+RE)
NDRE/NDVI
CCCI is sensitive to the
chlorophyll content
NIR-RE/RE-Red
NIR-Blue/NIR+Blue
NDWI is sensitive to
changes in water content of
vegetation canopies
VariGREEN Visible
Atmospherically
Resistant Index
(Green-Red)/
(Green+Red+Blue)
Related to the resistance to
adverse climatic conditions
26

NDVI: (NIR-Red)/(NIR+Red)
FieldSpec - April FieldSpec - May
Multispec4c - April Multispec4c - May
27

NDRE: (NIR-RE)/(NIR+RE)
28

CCCI: NDRE/NDVI
29

MTCI : NIR-RE/RE-Red
30

NDWI: NIR-Blue/NIR+Blue
31

VariGREEN : (Green-Red)/(Green+Red+Blue)
FieldSpec - May
32

NDVI vs production
33

Advantages of UAV multispectral mapping
Control of sprayers based on remote sensing data
can lead to a reduction of 80 % -90 % of the doses
of herbicide.
Full coverage herbicide
Patch-sprying

Other applications
Vegetation and biodiversity monitoring

Other applications
Landslide characterization
Executive planning

Many thanks
for your kind attention

Comparing UAV multispectral and field hyperspectral data collection for vegetation indexes calculation

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