Remote Sensing to Estimate
Chlorophyll Concentration
Using Multi-Spectral Plant
Reflectance
P. R. Weckler
M. L. Stone
N. Maness
R. Jayasekara
C. Jones
Asst. Professor
Regents Professor
Professor
Research Engineer
Research Engineer
Objective
• Estimate Chlorophyll concentration
using chlorophyll content and biomass
Chlorophyll Yield  Chlorophyll Concentration * Biomass
Sensors
• Passive Sensor
- OSU Plant Reflectance sensor
• Active Sensor
- Patchen Weedseeker™ PHD 600 Sensor
- Ntech Greenseeker™ Sensor
• Multi-Spectral Camera
Sensing Equipment
Spring, 1999 and 2000
OSU Reflectance
Sensor
Fall, 2000 and Spring,
2001
OSU Reflectance Sensor
Patchen Weedseeker™
PHD 600 Sensor
Fall, 2002
OSU Reflectance
Sensor
Ntech Greenseeker™
Sensor
No camera used
Olympus D-360L digital
camera
DuncanTech MS3100
multispectral camera
Sensors
Experimental Plots
Spinach Plot with
Reflectance Targets
Vegetation Through
Multi-spectral Camera
Results
Chlorophyll Content vs. NDVI
Fall, 2002
y = 0.4738e4.1817x
r 2 = 0.9187
10
5
0
20000.0
Biomass, kg/ha
Chl. Cont, kg/ha
15
Biomass vs. NDVI
Fall, 2002
y = 462.52e4.4826x
R2 = 0.9395
15000.0
10000.0
5000.0
0.0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
NDVI
0
0.1 0.2
0.3
0.4
0.5 0.6
NDVI
0.7 0.8
0.9
Results
NDVI/%VC vs. Chlorophyll Concentration
Fall, 2002
NDVI/%VC vs. Chlorophyll Concentration
Fall, 2002
0.018
0.016
2
0.018
r = 0.0263
0.014
NDVI/%VC
NDVI/%VC
0.016
0.014
0.012
0.01
0.008
0.01
0.008
0.006
0.004
0.004
700
750
800
850
900
950
Chlorophyll Concentration, mg/kg
2
r = 0.6629
Week 8
0.012
0.006
0.002
2
r = 0.9508
Week 4
2
r = 0.6762
Week 5
0.002
700
r 2 = 0.9845
Week 7
750
2
r = 0.5473
Week 6
800
850
900
Chlorophyll Concentration, mg/kg
950
Results
Study
NDVI vs
Biomss
NDVI vs.
Chlorophyll
Yield
%Vegatative
Coverage vs.
Biomass
NDVI/%VC vs.
Chlorophyll
Concentration
Spring,1999
0.80
0.80
No camera
data
-----------
Spring, 2000
0.81
0.77
No camera
data
-----------
Fall, 2000
0.93
0.73
0.73
0.02
Spring, 2001
0.93
0.87
0.98
0.38
Fall, 2002
0.94
0.92
0.85
0.03
Conclusions
• The NDVI readings gathered by the handheld sensors and the
multispectral camera were sensitive to changes in plant biomass
and plant chlorophyll content in spinach .
• This study reaffirmed the correlation between %VC and dry
biomass found by Lukina et al. (1999, 2000) and Ter-Mikaelian
and Parker (2000).
• High correlation was observed between the %VC of the spinach
as measured with digital imagery and the spinach biomass as
measured in the laboratory (r2 = 0.73 to 0.98).
Conclusions
• The findings of Lukina et al. (1999, 2000) and Sembiring (1998)
were also supported regarding NDVI readings producing a
stronger estimate of chlorophyll content then of chlorophyll
concentration.
• NDVI derived from processing images from a multispectral
camera correlated well with handheld sensor NDVI.
• The multispectral camera provided accurate %VC information
that correlated well with biomass results.
Further Studies
• Low correlations when predicting chlorophyll concentration from
estimates of biomass and NDVI may suggest further
investigation in following areas:
- canopy stacking
- background interference with sensors
QUESTIONS?
Acknowledgments
Dr. Jerry Brusewitz
Ted Kersten
D. Chrz
Bruce Bostian
Oklahoma Vegetable Research
Station,Bixby,Oklahoma