189
Table 2 Overview of all image parameters extracted for crown polygons
Image parameter
Short
Data
Formular
References
Normalized
Difference
Vegetation Index
NDVI
NIR
(NIR-RED)/
(NIR+RED)
Tucker (1979)
Thiam’s
Transformed
Vegetation Index
TTVI
NIR
sqrt(ABS(NDVI + 0.5)) Thiam (1998)
Transformed Soil
Adjusted
Vegetation Index
TSAVI
NIR
a(NIR-a) (R-b) /
R + aNIR -ab
Baret et al. (1989)
Perpendicular
Vegetation Index 1
PVI84
NIR
(bNIR-R) + a /
(sqrt(b
2 +1))
Perry and
Lautenschlager (1984)
Perpendicular
Vegetation Index 3
PVI94
NIR
aNIR-bRED
Qi et al. (1994)
Normalized
Green- Red
Difference Index
NGRDI
NIR
(G- R) / (G + R)
Rasmussen et al. (2016)
excessive Redness
exR
RGB
1.4*chrR-chrG
Meyer and Neto (2008)
excessive Greeness exG
RGB
2*chrG-chrR- chrB
Meyer and Neto (2008)
exG-exR
exG-exR RGB
exG-exR
Meyer and Neto (2008)
excessive Greeness 2 exG2
RGB
(2*G-R-B) / (G+R+B)
Rasmussen et al. (2016)
chromatic
coordinate R
chrR
RGB
R* / R* + G* + B*
Meyer and Neto (2008)
chromatic
coordinate G
chrG
RGB
G* / R* + G* + B*
Meyer and Neto (2008)
chromatic
coordinate B
chrB
RGB
B* / R* + G* + B*
Meyer and Neto (2008)
Energy
Energy
Texture ∑ i,j g(i,j)
2
Haralick et al. (1973)
Entropy
Entropy
Texture −∑ i,j g(i,j)log 2 g(i,j)
Haralick et al. (1973)
Correlation
CorrL
Texture ∑
−
( ) −
(
) ( )
i j
,
,
i
j
g i j
µ
µ
σ
2
Haralick et al. (1973)
Inverse Distance
Moment
IDM
Texture ∑ + −
( )
( )
i j
g i,j
,
1
1
2
i j
Haralick et al. (1973)
Inertia
Inertia
Texture ∑ i,j (i−j)
2 g(i,j)
Haralick et al. (1973)
Cluster Shade
ClusSha Texture ∑ i,j ((i−μ)+(j−μ))
3
g(i,j)
Haralick et al. (1973)
Cluster Prominence ClustPro Texture ∑ i,j ((i−μ)+(j−μ))
4
g(i,j)
Haralick et al. (1973)
Haralick‘s
Correlation
HarrCorr Texture
∑ ( ) ( )−
i j i j g i j
i
t
, ,
,
µ
σ
2
2
McInerney and
Kempeneers (2015)
a=intercept, b=slope of soil line, R* = normalized Red channel. μ = window average, σ = window
variance, g(i,j) = function for pixel pair i and j
The Potential of UAV Derived Image Features for Discriminating Savannah Tree Species