<s>
The	O
log-spectral	B-Algorithm
distance	I-Algorithm
(	O
LSD	O
)	O
,	O
also	O
referred	O
to	O
as	O
log-spectral	O
distortion	O
or	O
root	O
mean	O
square	O
log-spectral	B-Algorithm
distance	I-Algorithm
,	O
is	O
a	O
distance	O
measure	O
between	O
two	O
spectra	O
.	O
</s>
<s>
The	O
log-spectral	B-Algorithm
distance	I-Algorithm
between	O
spectra	O
and	O
is	O
defined	O
as	O
p-norm	O
:	O
</s>
<s>
Unlike	O
the	O
Itakura	B-Algorithm
–	I-Algorithm
Saito	I-Algorithm
distance	I-Algorithm
,	O
the	O
log-spectral	B-Algorithm
distance	I-Algorithm
is	O
symmetric	O
.	O
</s>
<s>
Usually	O
the	O
average	O
of	O
spectral	O
distortion	O
over	O
a	O
large	O
number	O
of	O
frames	O
is	O
calculated	O
and	O
that	O
is	O
used	O
as	O
the	O
measure	O
of	O
performance	O
of	O
quantization	B-Algorithm
or	O
interpolation	B-Algorithm
.	O
</s>
<s>
When	O
the	O
signals	O
are	O
transformed	O
into	O
the	O
spectral	O
domain	O
with	O
transformation	O
methods	O
such	O
as	O
Fourier	B-Algorithm
transform	I-Algorithm
and	O
DCT	B-General_Concept
,	O
the	O
spectral	O
distance	O
is	O
the	O
measure	O
to	O
compare	O
the	O
transformed	O
signals	O
.	O
</s>
<s>
Moreover	O
,	O
LSD	O
is	O
equal	O
to	O
the	O
cepstral	B-Algorithm
distance	O
which	O
is	O
the	O
distance	O
between	O
the	O
signals	O
 '	O
cepstrum	B-Algorithm
when	O
the	O
p-numbers	O
are	O
the	O
same	O
by	O
Parseval	O
's	O
theorem	O
.	O
</s>
