Single-Input Multiple-Output(SIMO)-model-based signals

Blind Source Separation using
SIMO-model-based ICA with
Self-Generator for Initial Filter

Generally speaking, human being do not hear the source signal itself.
Because the signals we hear involve not only the information aboutsource signal but also the information about spatial qualities.
SourceTomoya TAKATANI
Speech and Acoustics Processing Laboratory
Graduate School of Information Science
Nara Institute of Science and Technology
The multiple signals from single source are defined as Single-Input
Multiple-Output (SIMO)-model-based signals.

Transmission of acoustic signals

Mixing process (1/2)

SourceSource1
Source2

Right ear

Left ear

The SIMO-model-based signals in both ears include theinformation about the directivity, localization, or spatial
qualities of each sound source.

Mixing process (2/2)
s1 (t )

Source 1

Right ear

Source 2

Left ear

Binaural sound reproduction system

A11(z )s1 (t )JammerA21 (z )s1 (t )A11(z )s1 (t )s1 (t )SIMO model 1

A12 (z )s2 (t )s2 (t )

Head and Torso
Simulator(HATS)

Female and maleare talking to me

TargetA21(z )s1 (t )A22 (z )s2 (t )A12 (z )s2 (t )s2 (t )SIMO model 2

Mixed signals (primary field)
A22 (z )s2 (t )Right ear A11 (z )s1 (t ) + A12 (z )s2 (t )Left ear

A21 (z )s1 (t ) + A22 (z )s2 (t )Primary sound field

Secondary sound field

Binaural sound reproduction system can copy the primary sound field.
⇒ This system can not reproduce only the target sound.

The mixed signals are sum of the SIMO-model-based signals.

•1Research goal

Application
Tele-existence system using vision and audio modality

FemaleFemale andis talking
maleare talking
to meto me

JammerTargetSystemSystem
Primary field

Secondary field

Realization of audio augmented reality system
which can enhance and reproduce the target soundConventional method 1:
Independent Component Analysis (ICA) withProjection Back (ICA-PB) [Murata et al., 1998]

Approachs1 (t )
A11(z )s1 (t )s1 (t )A12 (z )s2 (t )s2 (t )

A21(z )s1 (t )A22 (z )s2 (t )BlindDecomposing
Process ※rescue personnel (operator)

robot

In order to represent only target sound to an operator,
the followings are required.
① High-fidelity sound (Sound reproduction)② Noise suppression (Enhancement of the target sound)A11(z )s1 (t )A11 (z )s1 (t )+A12 (z )s2 (t )A21 (z )s1 (t )A21 (z )s1 (t )A11 (z )s1 (t )+A22 (z )s2 (t )

PB

ICA

SIMO model 1s2 (t )A22 (z )s2 (t )SIMO model 2
We should decompose the mixed signals into the SIMO-model-based

A12 (z )s2 (t )A22 (z )s2 (t )ICA-PBA12 (z )s2 (t )Primary field

A21 (z )s1 (t )Features:
Unsupervised algorithm

signals without a priori information.

Conventional method 2:
Multi-stage SIMO-model-based ICA(MS-SIMO-ICA) [Ukai, Takatani, et al., 2004]
A11 (z )s1 (t )+A12 (z )s2 (t )A21 (z )s1 (t )A11 (z )s1 (t )+A22 (z )s2 (t )ICAPB

SIMOICAA21 (z )s1 (t )A12 (z )s2 (t )A22 (z )s2 (t )Experiment 1
In order to evaluate there effectiveness, the decomposition
experiments of the binaural mixed signals are carried outfor the different directions of sources.
 Conventional ICA-PB
 Conventional MS-SIMO-ICA

ICA-PB

Features:
Unsupervised algorithm
The performance of this method is superior to that ofICA-PB.

Sound source

2 male and 2 female (12 combination)

Sampling frequency

8000 Hz

Length of filter

1024 [taps]

Initial value of filter

Inverse filter of HRTF whose directions of sources are ±60[deg]

Evaluation score

SIMO-model Accuracy [dB]•2Experimental conditions+A22 (z )s2 (t )BlindDecomposing
Processs1(t): fixedθOutput 2
Output 3Reverberation
Time: 200 ms

SA = 10log10

Real SIMO - model - based signal

Reverberation
Time: 200 ms

0.74 m2.04 m
HATS

1-(a)

1-(b)

s1(t): -60°(fixed)
s2(t): 0°, 15°, 30°, 45°, 60°, 75°, 90°

s1(t): 0°(fixed)
s2(t): 0°, 15°, 30°, 45°, 60°, 75°, 90°tReal SIMO - model - based signal − Output signal

2

Experimental results 1-(a)Experimental results 1-(b)2520s2(t)s1(t)(fixed)15-60 ° θ101.50 m
5FDICA-PB
MS-SIMO-ICA

0015 30 45 60 75
Direction of s 2 : θ [deg]90SIMO-Model Accuracy [dB]25
SIMO-Model Accuracy [dB]

HATS

2ts1(t)(fixed)20151.50 m

105015 30 45 60 75
Direction of s 2 : θ [deg]A11 (z )s1 (t )s1(t)(fixed)15

1.50 m105

FDICA-PB
MS-SIMO-ICA

0015 30 45 60 75
Direction of s 2 : θ [deg]

90

1-(b)

θ90

1-(b)

Proposed method:
SIMO-ICA with Self-Generator for Initial Filter25
20s2(t)

FDICA-PB
MS-SIMO-ICA01-(a)Experimental results 1-(b)SIMO-Model Accuracy [dB]θMicrophones(Height:1.17 m)

2.04 mOutput 4

s1(t): fixeds2(t)1.50 m-60 °1.50 mMicrophones(Height:1.17 m)

0.58 m

4.25 m

A12 (z )s2 (t )Output 1

Loudspeakers(Height:1.17 m)s2(t)4.25 m+Loudspeakers(Height:1.17 m)

A21 (z )s1 (t )2.02 m

A11 (z )s1 (t )4.25 m

0.58 m0.74 m

4.25 mSimilarity between the output signals of the ICA and real
SIMO-model-based signals

2.02 m

Evaluation Score: SIMO-Model Accuracy (SA)θ+

A12 (z )s2 (t )s2(t)A21 (z )s1 (t )+A22 (z )s2 (t )SelfGenerator
for InitialFilter

A11 (z )s1 (t )SIMOICAA21 (z )s1 (t )A12 (z )s2 (t )A22 (z )s2 (t )Features:
Unsupervised algorithm
Self-Generator consists of ICA-PB, single talk detection ,and DOA estimation.

•3

Experiment 2Experimental results 2-(a)Sound source

2 male and 2 female (12 combination)

Sampling frequency

8000 Hz

Length of filter

1024 [taps]

Initial value of filter

Inverse filter of HRTF whose directions of sources are ±60[deg]Evaluation score

SIMO-model Accuracy [dB]25
SIMO-Model Accuracy [dB]

In order to evaluate its effectiveness, the decomposition
experiments of the binaural mixed signals are carried out
for the different directions of sources.
 Conventional ICA-PB
 Conventional MS-SIMO-ICA
 Proposed SIMO-ICA with Self-Generator for Initial Filter

2015SIMO-Model Accuracy [dB]

FDICA-PB
MS-SIMO-ICA
Propsoed Method

50015 30 45 60 75
Direction of s 2 : θ [deg]901.50 m

1-(a)Conclusion25s1(t)(fixed)20-60 ° θ

10Experimental results 2-(b)

s2(t)

s1(t)
(fixed)s2(t)We propose a new blind decomposition using single-input
multiple-output-model-based independent component
analysis (SIMO-ICA) with Self-Generator for Initial Filter.
The self-generator consists of ICA-PB, single talk detection, andDOA estimation.
 Using the estimated DOA of sources, the self-generator generate
the valid initial filter automatically.
15

1.50 m10



FDICA-PB
MS-SIMO-ICA
Propsoed Method

50015 30 45 60 75
Direction of s 2 : θ [deg]90θIn order to evaluate its effectiveness, decomposition
experiments are carried out.
1-(b)The experimental results reveal that the performance of theproposed method is superior to those of conventional methods.

•4