Asymmetric EEG-based coding and decoding method for brain-computer interfaces

Patent metadata

Field	Value
Publication number	US-11221672-B2
Application number	US-201816616834-A
Country	US
Kind code	B2
Filing date	Dec 30, 2018
Priority date	Jan 23, 2018
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

The present invention provides an asymmetric EEG-based coding and decoding methods for BCIs, the BCI system includes an evoked stimulus module, an acquisition module and an EEG signal data set including a training set Xk and a testing sample Y, and an EEG signal decoding module; the evoked stimulus module sends a hybrid coding visual stimulus to subjects to evoke a specific EEG signal as required; the acquisition module obtains data information by amplifying and filtering the EEG signal so as to constitute EEG signal module; the decoding module coverts the data information into an instruction set for outputting the coding method of the present invention uses asymmetric characteristics of brain electrophysiological activity response to stimulus, combines with coding strategies such as SDMA, CDMA, FDMA and phase division multiple access coding.

First claim

What is claimed is:

1. An asymmetric EEG-based coding method for BCIs, comprising the following steps of:
Step 1 : performing hybrid coding comprising the SDMA coding, CDMA coding, FDMA, and phase division multiple access coding, and constructing an evoked stimulus module in a BCI system;
Step 2 : sending, by the evoked stimulus module, a hybrid coding visual stimulus to subjects to evoke a specific EEG signal as required;
Step 3 : amplifying and filtering the EEG signal by an acquisition module so as to obtain data information; and
Step 4 : converting, by a decoding module, the data information into an instruction set for outputting.

2. The coding method of claim 1 , wherein the hybrid coding generated by the evoked stimulus module comprises at least any two combinations of SDMA coding, CDMA coding, FDMA, and phase division multiple access coding.

3. The coding method of claim 2 , wherein the hybrid coding generated by the evoked stimulus module comprises SDMA coding, CDMA coding, FDMA, and phase division multiple access coding.

4. An asymmetric EEG-based decoding method for BCIs, comprising the following steps of:
Step 1 : constructing an EEG signal data set including a training set X k and a testing sample Y based on the BCI system;
Step 2 : performing frequency domain filtering and downsampling data processing to the testing sample Y;
Step 3 : based on Fisher's linear discriminant criterion, calculating the training set X k to obtain a projection matrix W;
Step 4 : performing spatial filtering by using DSP algorithm to the training set X k and the testing sample Y to obtain eigenvector W T {circumflex over (X)} k and W T Y according to the equations (5), (6);

S
w

-
1

⁢

S
B

*
W

=

[

λ
1

⋱

λ

N
c

]

*
W

(
5
)

S
D

=

Σ
11

+

Σ
22

-

Σ
12

-

Σ
21

⁢

⁢

S
w

=

σ
1
2

+

σ
2
2

(
6
)

Step 5 : based on the eigenvector W T {circumflex over (X)} k and W T Y, performing spatial filtering by using CCA algorithm to construct two projection matrixes U k and V k by equation (8);

CCA
⁡

(

W
T

⁢

X
^

k

,

W
T

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Y

)

-

max

U
k

,

V
k

⁢

Assignees

• Univ Tianjin

Inventors

• Xu Minpeng
• Ming Dong
• Xiao Xiaolin

Classifications

• G06F3/015 Primary

  Input arrangements based on nervous system activity detection, e.g. brain waves [EEG] detection, electromyograms [EMG] detection, electrodermal response detection · CPC title

• A61B5/369

  Electroencephalography [EEG] · CPC title