US 7,003,461 B2Granted

Method and apparatus for an adaptive codebook search in a speech processing system

AssigneeRenesas Technology Corp.

InventorClifford Tavares

Life of this patent

Estimating the term…

Abstract

An adaptive codebook search (ACS) algorithm is based on a set of matrix operations suitable for data processing engines supporting a single instruction multiple data (SIMD) architecture. The result is a reduction in memory access and increased parallelism to produce an overall improvement in the computational efficiency of ACS processing.

Claims21

Dependent claims

In a computer device for speech synthesis, a method for searching a codebook of excitation vectors to identify a selected excitation vector for CELP (code-excited linear prediction) coding comprising:

receiving an input speech signal;
computing a metric Mi based on the input speech signal and a signal synthesized by an excitation vector vi;
repeating the computing step for each excitation vector in the codebook;
and
identifying a minimum metric (Mmin) from among the computed Mi's, the excitation vector associated with Mmin being the selected excitation vector used to produce synthesized speech,
wherein the computing step includes computing a correlation quantity between a target vector signal and an impulse response comprising:
accessing elements Ri of a first vector (R) stored in a first area of a memory component of the computer device and representative of the target vector signal;
accessing elements Ii of a second vector (I) stored in a second area of the memory component and representative of the impulse response;
computing
⁢
⁢
a
⁢
⁢
vector
⁢
⁢
F
⁢
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1
=
[
0
⋯
⋯
0
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0
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0
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1
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⋱
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0
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0
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1
⋯
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R
(
2
s
-
1
)
]
×
[
I
2
s
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1
⋮
⋮
⋮
I
0
]
;
and
computing
⁢
⁢
a
⁢
⁢
vector
⁢
⁢
F
⁢
2
=
∑
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=
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s
Frm
,
step
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4
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{
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+
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×
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⋮
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}
,
where s>1 and Frm is a framesize,
wherein the vectors F1 and F2 together are representative of the correlation quantity.

257 more elements

A computer program product suitable for execution on a data processing device for use in a speech synthesis system, the data processing device supporting SIMD (single instruction multiple data) instructions comprising:

computer readable media containing a computer program to select an excitation vector from codebook containing a plurality of excitation vectors v,
the computer program comprising:
first computer program code to operate the data processing device to access from a first area of a memory component elements Ri of a vector R representative of a target vector signal;
second computer program code to operate the data processing device to access from a second area of the computer memory component elements Ii of a vector I representative of an impulse response;
third computer program code to operate the data processing device to access the excitation vectors v from the codebook, the codebook stored in a third area of the computer memory component;
fourth computer program code to operate the data processing device to compute a metric Mi based on an input speech signal and a signal synthesized from an excitation vector vi, including computing a vector F2 which is a portion of a correlation vector d representative of a correlation between the target vector signal and the impulse response, where
⁢
vector
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F
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2
=
∑
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2
s
Frm
,
step
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4
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+
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(
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)
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[
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0
]
+
∑
m
=
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+
(
2
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-
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)
l
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step
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4
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⋯
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×
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+
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2
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)
⋮
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l
]
}
,
s>1 and Frm is a framesize;
fifth computer program code to obtain the input speech signal;
and
sixth computer program code to coordinate the first, second, third and fourth computer program codes to compute a metric for each excitation vector in the codebook and to identify a minimum metric therefrom, the excitation vector associated with the minimum metric being the selected excitation vector,
wherein the selected excitation vector can be used to synthesize speech.

192 more elements

A speech codec device comprising:

a input component operable to receive a speech signal to produce an input speech signal;
a processing component supporting one or more single instruction multiple data (SIMD) instructions;
a data storage component coupled to the processing component for transferring data therebetween;
a first portion of the data storage component having stored therein a codebook of excitation vectors v;
a second portion of the data storage component having stored therein a vector R representative of a target vector signal generated based on the input speech signal;
a third portion of the data storage component having stored therein a vector I representative of an impulse response to a synthesis filter;
and
computer program code stored in the data storage component comprising a code portion suitable for execution on the processing component to compute a metric Mi=
(
(
dv
i
)
2
v
i
T
⁢
ϕ
⁢
⁢
v
i
)
for an excitation vector vi, where φ is a covariance matrix of the impulse response and d is a correlation vector representative of a correlation between the target vector signal and the impulse response, the correlation vector d comprising a vector F1 and a vector F2, wherein
vector
⁢
⁢
F1
=
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R
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R
1
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1
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R
(
2
s
-
1
)
]
×
[
I
2
s
-
1
⋮
⋮
⋮
I
0
]
⁢
⁢
and
vector
⁢
⁢
F2
=
∑
n
=
2
s
Frm
,
step
⁢
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4
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+
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+
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2
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=
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,
step
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4
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)
⋯
I
(
m
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(
2
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1
)
)
⋮
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⋮
I
(
m
-
(
2
s
-
1
)
)
⋯
I
m
]
×
[
R
l
+
(
2
s
-
1
)
⋮
⋮
R
l
]
⁢
}
,
where s>1 and Frm is a framesize,
the computer program code further computing a plurality of the metrics Mi and identifying a minimum one of the metrics Mmin, wherein the excitation vector corresponding to Mmin constitutes a selected excitation vector.

256 more elements

Dependencies are inferred from the claim text.

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Abstract