Post on 01-Jan-2016
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Effects of distance to Effects of distance to target, time of the day, target, time of the day,
wetness of the leaves, and wetness of the leaves, and sensor position on active sensor position on active
sensor readingssensor readings
Fernando Solari, Paul Hodgen, Fernando Solari, Paul Hodgen, John Shanahan, and Jim John Shanahan, and Jim
SchepersSchepers
ObjectivesObjectives
To determine howTo determine how Sensors distance to the target Sensors distance to the target Time of the day Time of the day Wetness of the leaves Wetness of the leaves Shifts from on row positionShifts from on row position
Affects sensor readings outputs Affects sensor readings outputs
Distance to targetDistance to targetCrop Circle -IR upwelling radiance
0
1
2
3
4
5
6
7
8
9
40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210
Distance to the target (cm)
IR u
p-r
ad
grass NIR
Bare soil IR
Corn V4 IR
Corn V10 IR
Distance to targetDistance to targetCrop Circle-Amber upwelling radiance
0
0.2
0.4
0.6
0.8
1
1.2
40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210
Distance to the target (cm)
Am
be
r u
p-r
ad grass Amber
Bare soil Amber
Corn V4 Amber
Corn V10 V4
Distance to targetDistance to targetCrop circle-ANDVI
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210
Distance to the target (cm)
AN
DV
I
grass ANDVI
Bare soil ANDVI
Corn V4 ANDVI
Corn V10 ANDVI
cv2% 2% 4%
Crop circle-ANDVI-cvCrop circle-ANDVI-cvDistancDistancee
GrassGrass Bare Bare SoilSoil
Corn V4Corn V4 Corn Corn V10V10
40-100 40-100 cmcm
1%1% 1%1% 3%3% 2%2%
101-101-140140
cmcm
1%1% 5%5% 4%4% 2%2%
40-14040-140
cmcm1%1% 4%4% 8%8% 4%4%
VI=(VI=(ρρ-1 -1 VIS- VIS- ρρ-1 -1 IRIR) * ) * ρρ IRIR (IR/Amber)-1
0
1
2
3
4
5
6
7
40 60 80 100 120 140
Distance to the target (cm)
VI
grass
bare soil
corn v4
cornv10
1%
1%
6%
3%
Distance to targetDistance to targetGNDVI Green Seeker
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210
Distance to the target (cm)
GN
DV
I
Grass
Corn V10
Corn V4
Bare soil
36in+-14in
CV 7%
35+-7
CV 4%
GreenSeeker-GNDVI-cvGreenSeeker-GNDVI-cv
GrassGrass Bare Bare soilsoil
Corn V4Corn V4 Corn Corn V10V10
55-125 55-125 cmcm
4%4% 14%14% 5%5% 7%7%
70-105 70-105 cmcm
9%9% 9%9% 5%5% 4%4%
Distance to targetDistance to targetConclusionsConclusions
Crop Circle: 40 to 100 cm lowest CV Crop Circle: 40 to 100 cm lowest CV for NDVI and Gitelson VIfor NDVI and Gitelson VI
GreenSeeker: 70-105 cm lower CV GreenSeeker: 70-105 cm lower CV than 55-125cmthan 55-125cm
Crop circle - 8:00Crop circle - 8:00Corn V12. Crop circle. 8am
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 10 20 30 40 50 60 70 80
distance (cm)
AN
DV
I
rep 1
rep2
rep3
rep4
rep5
rep6
GreenSeeker – 8:00GreenSeeker – 8:00Corn V12 Green Seeker
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 10 20 30 40 50 60 70 80 90
distance (cm)
GN
DV
I
rep1
rep 2
rep3
rep4
rep5
rep6
Crop circle – 12:00Crop circle – 12:00Corn V12. Crop Circle 12hs
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 10 20 30 40 50 60 70
distance (cm)
AN
DV
I
rep1
rep2
rep3
rep4
rep6
GreenSeeker – 12:00GreenSeeker – 12:00Corn V12. Green Seeker
12hs
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 10 20 30 40 50 60 70 80
distance (cm)
GN
DV
I
rep 1
rep 2
rep 3
rep 4
rep 5
rep 6
Crop circle – 17:00Crop circle – 17:00Corn V12. Crop circle 17hs
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 20 40 60 80 100 120
distance (cm)
AN
DV
I
rep1
rep2
rep3
rep4
rep5
rep6
GreenSeeker – 17:00GreenSeeker – 17:00Corn V12. Green Seeker. 17hs
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 20 40 60 80 100 120 140 160
Distance (cm)
GN
DV
I
rep1
rep2
rep3
rep4
rep5
rep6
Crop CircleCrop CircleCorn V12. Crop circle
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 10 20 30 40 50 60 70 80
distance (cm)
AN
DV
I average ANDVI 8
average ANDVI 12
average ANDVI 17
GreenSeekerGreenSeekerCorn V12. Green Seeker
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 20 40 60 80 100
Distance (cm)
GN
DV
I average GNDVI 8 am
average GNDVI 12 am
average GNDVI 17
Table 1: NDVI valuesTable 1: NDVI values
Time of Time of the daythe day
CCCC
V10V10CCCC
V12V12GSGS
V10V10GSGS
V12V12
8:008:00 0.62c0.62c 0.73a0.73a 0.67b0.67b
12:0012:00 0.55a0.55a 0.69a0.69a 0.44b0.44b 0.64a0.64a
17:0017:00 0.58b0.58b 0.67a0.67a 0.42a0.42a 0.68c0.68c
Different letters are significant differences within column (sensor and stage)
Time of the day effect studyTime of the day effect studyConclusionsConclusions
Time of the day can affect sensor Time of the day can affect sensor readings readings
(Growth?, Wind?, Power supply,?)(Growth?, Wind?, Power supply,?)
Across rowsAcross rowsGNDVI Head parallel to the row
Corn V7, 76cm wide
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Distance across the rows (cm)
GN
DV
I
Across rowsAcross rowsGreenSeeker(red). Head parallel to the row
Corn V12
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160
distance across row (cm)
NDVI
Across rowsAcross rowsCrop Circle. Across the row.
Corn V7, 76cm wide
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Distance across the rows (cm)
AN
DV
I
Across rowsAcross rowsCrop circle. Head parallel to the row. Corn V12
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Distance across the row (cm)
ANDV
I
91 cm
ROWROW
6 in=15cm
Corn V10-KansasCorn V10-KansasANDVIANDVI
Crop circle (Kansas data Corn V10)
y = 1.3552x - 0.1925
R2 = 0.5575
0.4
0.45
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8
ANDVI (NADIR position 4 inch left)
AN
DV
I (N
AD
IR p
osi
tio
n)
Corn V10 KansasCorn V10 KansasWDRVIWDRVI
Crop Circle (Kansas data Corn V10)
y = 1.0178x + 0.0404
R2 = 0.6914
-0.05
0
0.05
0.1
0.15
0.2
0.25
-0.05 0 0.05 0.1 0.15 0.2 0.25
WDRVI (NADIR position 4 inch left)
WD
RV
I (N
AD
IR p
osi
tio
n)
Corn V9-ArgentinaCorn V9-ArgentinaGreenSeekerGreenSeeker
GreenSeeker (Argentina data Corn V9)
y = 1.3706x + 0.009
R2 = 0.7842
0
0.05
0.1
0.15
0.2
0.25
0 0.05 0.1 0.15 0.2 0.25
GNDVI (NADIR position 6 inch left)
GN
DV
I (N
AD
IR p
osi
tio
n )
On the row studyOn the row studyConclusionConclusion
The principal effect of to be off the The principal effect of to be off the row is underestimation. row is underestimation.
The effect is much more important at The effect is much more important at early stages. early stages.
wetness of the leavesrep1
0.6
0.65
0.7
0.75
0.8
0 20 40 60 80 100 120
distance (cm)
AN
DV
I andvi before
andvi watering
andvi after
How important is dew presence or sprinkle?
Wetness of the leavesWetness of the leavesWetness of the leaves-(Crop Circle)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
before watering after
Treatment
AN
DV
I
aa a
ConclusionsConclusions
Distance:Distance: GreenSeeeker: 80-110cm cm to targetGreenSeeeker: 80-110cm cm to target Crop Circle: 40-100 cm to targetCrop Circle: 40-100 cm to target
Time of the dayTime of the day Time of the day can affect sensor readings Time of the day can affect sensor readings
(Growth?, Wind?, Power supply,?)(Growth?, Wind?, Power supply,?) PositionPosition
Important to be on row (If not, underestimation)Important to be on row (If not, underestimation) WateringWatering
Does not affect Does not affect