<s>
In	O
computer	B-Application
vision	I-Application
,	O
the	O
inverse	B-General_Concept
depth	I-General_Concept
parametrization	I-General_Concept
is	O
a	O
parametrization	O
used	O
in	O
methods	O
for	O
3D	B-Algorithm
reconstruction	I-Algorithm
from	I-Algorithm
multiple	I-Algorithm
images	I-Algorithm
such	O
as	O
simultaneous	B-Application
localization	I-Application
and	I-Application
mapping	I-Application
(	O
SLAM	O
)	O
.	O
</s>
<s>
Given	O
a	O
point	O
in	O
3D	O
space	O
observed	O
by	O
a	O
monocular	O
pinhole	B-Algorithm
camera	I-Algorithm
from	O
multiple	O
views	O
,	O
the	O
inverse	B-General_Concept
depth	I-General_Concept
parametrization	I-General_Concept
of	O
the	O
point	O
's	O
position	O
is	O
a	O
6D	O
vector	O
that	O
encodes	O
the	O
optical	O
centre	O
of	O
the	O
camera	O
when	O
in	O
first	O
observed	O
the	O
point	O
,	O
and	O
the	O
position	O
of	O
the	O
point	O
along	O
the	O
ray	O
passing	O
through	O
and	O
.	O
</s>
<s>
Inverse	B-General_Concept
depth	I-General_Concept
parametrization	I-General_Concept
generally	O
improves	O
numerical	B-Algorithm
stability	I-Algorithm
and	O
allows	O
to	O
represent	O
points	O
with	O
zero	O
parallax	B-Device
.	O
</s>
<s>
Given	O
3D	O
point	O
with	O
world	O
coordinates	O
in	O
a	O
reference	O
frame	O
,	O
observed	O
from	O
different	O
views	O
,	O
the	O
inverse	B-General_Concept
depth	I-General_Concept
parametrization	I-General_Concept
of	O
is	O
given	O
by	O
:	O
</s>
