<s>
The	O
moment	B-General_Concept
distance	I-General_Concept
index	I-General_Concept
(	O
MDI	O
)	O
is	O
a	O
shape-based	O
metric	O
or	O
shape	O
index	O
that	O
can	O
be	O
used	O
to	O
analyze	O
spectral	O
reflectance	O
curves	O
and	O
waveform	O
LiDAR	O
,	O
proposed	O
by	O
Salas	O
and	O
Henebry	O
in	O
2014	O
.	O
</s>
<s>
Vegetation	B-General_Concept
indices	I-General_Concept
(	O
VIs	O
)	O
use	O
the	O
concept	O
of	O
band	O
ratio	O
and	O
differences	O
or	O
weighted	O
linear	O
combinations	O
to	O
take	O
advantage	O
of	O
the	O
visible	O
and	O
NIR	O
bands	O
,	O
two	O
important	O
spectral	O
bands	O
for	O
vegetation	O
studies	O
,	O
in	O
measuring	O
the	O
photosynthetic	O
activity	O
of	O
the	O
plant	O
and	O
explore	O
vegetation	O
dynamics	O
.	O
</s>
<s>
There	O
is	O
an	O
extensive	O
list	O
of	O
such	O
indices	O
,	O
including	O
the	O
normalized	O
difference	O
vegetation	B-General_Concept
index	I-General_Concept
(	O
NDVI	O
)	O
,	O
ratio-based	O
indices	O
such	O
as	O
the	O
modified	O
simplerRatio	O
,	O
soil-distance-based	O
indices	O
such	O
as	O
the	O
modified	O
soil	O
adjusted	O
vegetation	B-General_Concept
index	I-General_Concept
(	O
MSAVI	O
)	O
,	O
and	O
many	O
others	O
.	O
</s>
<s>
MDI	O
departs	O
from	O
the	O
usual	O
Gaussian	B-Application
modeling	I-Application
in	O
detecting	O
peaks	O
(	O
canopy	O
and	O
ground	O
)	O
for	O
example	O
in	O
canopy	O
height	O
estimation	O
and	O
focus	O
more	O
on	O
the	O
full	O
geometry	O
(	O
raw	O
shape	O
)	O
and	O
radiometry	O
(	O
raw	O
power	O
)	O
of	O
the	O
LiDAR	O
waveform	O
to	O
retain	O
richness	O
of	O
the	O
data	O
.	O
</s>
