<s>
In	O
image	B-General_Concept
analysis	I-General_Concept
,	O
a	O
resel	B-Algorithm
(	O
from	O
resolution	O
element	O
)	O
represents	O
the	O
actual	O
spatial	O
resolution	O
in	O
an	O
image	O
or	O
a	O
volumetric	O
dataset	O
.	O
</s>
<s>
The	O
number	O
of	O
resels	B-Algorithm
in	O
the	O
image	O
may	O
be	O
lower	O
or	O
equal	O
to	O
the	O
number	O
of	O
pixel/voxels	O
in	O
the	O
image	O
.	O
</s>
<s>
In	O
an	O
actual	O
image	O
the	O
resels	B-Algorithm
can	O
vary	O
across	O
the	O
image	O
and	O
indeed	O
the	O
local	O
resolution	O
can	O
be	O
expressed	O
as	O
"	O
resels	B-Algorithm
per	O
pixel	B-Algorithm
"	O
(	O
or	O
"	O
resels	B-Algorithm
per	O
voxel	B-Algorithm
"	O
)	O
.	O
</s>
<s>
In	O
functional	B-Algorithm
neuroimaging	I-Algorithm
analysis	O
,	O
an	O
estimate	O
of	O
the	O
number	O
of	O
resels	B-Algorithm
together	O
with	O
random	O
field	O
theory	O
is	O
used	O
in	O
statistical	O
inference	O
.	O
</s>
<s>
Keith	O
Worsley	O
has	O
proposed	O
an	O
estimate	O
for	O
the	O
number	O
of	O
resels/roughness	O
.	O
</s>
<s>
The	O
word	O
"	O
resel	B-Algorithm
"	O
is	O
related	O
to	O
the	O
words	O
"	O
pixel	B-Algorithm
"	O
,	O
"	O
texel	O
"	O
,	O
and	O
"	O
voxel	B-Algorithm
"	O
,	O
and	O
Waldo	O
R	O
.	O
Tobler	O
is	O
probably	O
among	O
the	O
first	O
to	O
use	O
the	O
word	O
.	O
</s>
