<s>
An	O
Implicit	B-Algorithm
Shape	I-Algorithm
Model	I-Algorithm
for	O
a	O
given	O
object	O
category	O
consists	O
of	O
a	O
class-specific	O
alphabet	O
(	O
codebook	B-Algorithm
)	O
of	O
local	O
appearances	O
that	O
are	O
prototypical	O
for	O
the	O
object	O
category	O
,	O
and	O
of	O
a	O
spatial	O
probability	O
distribution	O
which	O
specifies	O
where	O
each	O
codebook	B-Algorithm
entry	O
may	O
be	O
found	O
on	O
the	O
object	O
.	O
</s>
