The Principle, Motivation , Limitations and Future of BCI ( PPT )

8/12/2019 The Principle, Motivation , Limitations and Future of BCI ( PPT )

1/22

BRAIN COMPUTER INTERFACE

The Principle, Motivation , Limitations and

Future of BCI


2/22

INTRODUCTION

A brain-computer interface (BCI) is intended to

enable its user to communicate with a

computer by mere thoughts

The main motivation behind BCI is to enable aperson with severe physical disability to

control devices by their thoughts

For a normal human this will be leap fromjoystick to thoughts


3/22

HUMAN BRAIN

The brain controlsall human activitiesin some form or the

other Human brain has a

network of billions ofneurons which make

this controllingpossible

A neuron consists ofseveral dendrites, a

cell body and an


4/22

STRUCTURE OF NEURON


5/22

WORKING OF THE NEURON

Neuron is equivalent to a single binary

processing unit

DendritesInput channel

Axoncarries binary information

If the input exceeds a certain threshold voltage

the neuron is said to be firing

The output is either a 1 or nothing.

Generation of electric field.


6/22

OUTLINE OF BCI

Signal Acquisition

Pre-processing

Feature Extraction

Classification


7/22

SIGNAL ACQUISITION-

ELECTROENCEPHALOGRAPHY

The most commonly used method of signal

acquisition is Electroencephalography or EEG.

Provides continuous recording of the brains

electrical processes

It is a non-invasive technique

Currently in used in clinics for detection of

epileptic seizures


8/22

ELECTROENCEPHALOGRAP

HY

When the neurons

are active, they

produce an

electrical potential. Electrodes -

measurement of

electric potential

Array of electrodes-

more precision

Quantify thoughts


9/22

ELECTROENCEPHALOGRAP

HY

Fig: EEG of a typical human in different

stages


10/22

PRE-PROCESSING AND NOISE

REJECTION

Preprocessing is a step to process raw EEG

signals to re-construct the original brain

activity

It is achieved by:

Referencing

FilteringArtifact subtraction


11/22

FEATURE EXTRACTION

Features arecharacteristics of asignal that are able todistinguish betweendifferent emotions

The method used forfeature extraction isShort-time Fouriertransform

Feature extractionrequirements Reduce the size of the

data

Minimum redundancy

Preserve all information


12/22

CLASSIFICATION

After Feature Extraction we have data, but

we still have to identify the thought

In classification we decode this data and

equate different signal patterns with different

human emotions

Now the output of classifier is given to an

external device according to the application


13/22

APPLICATIONS


14/22

BCI FOR DISABLED

How is a physically disabled person different

from a normal person?

Normal personBody reacts according to the

signals from the brain. Disabled personA particular part of the body is

dead. Hence it cant react to the brain signals. But

the brain is working.

A mobile mind in an immobile body


15/22

PROSTHETIC ARMS AND

LEGS

Brain signals are detected

by the EEG and are

externally given as input

to the prosthetic arms andlegs

The damaged part is

bypassed in this process

The prosthetic partsrespond to the stimulus

from the brain and

perform the desired action


16/22

SENSORY INPUT

Cochlear implant is a common application of

BCI, which is helpful for people with hearing

disability

Sound Waves ---> Several organs in the ear ---> Auditory Nerves

Damaged organs cause hearing disability

In BCI, brain signals are directly given to theauditory nerves which makes a deaf person

listen to sound


17/22

SMART DEVICES

BCI analyses the brain signal of the person

and gives real-time feedback, thus helping the

person train his brain to reduce anxiety,

improve concentration and be relaxed Devices can adjust themselves according to

the users mood and make the machine-

human interaction smoother and smarter

Gaming will become a lot more intuitive


18/22

LIMITATIONS

Timing issues- Speed of the brain is much

greater than the processing speed of

computers

Voltage from each neuron is small and cannotbe detected. Hence we cannot really read

thoughts or understand the words we are

thinking

Interference- External source of noise might

interfere and give inaccurate readings

Need of a very diverse panel of expertise


19/22

COMMERCIAL PRODUCTS

Mind Wave

Developed by Neurosky.

Measures brain waves and

use them to controldevices

The MindWave won the

Guinness Book of World

Records award forHeaviest machine moved

using a brain control

interface


20/22

COMMERCIAL PRODUCTS

Muse

Developed by IntraXon

Four sensor headband

Measures the brain wavesin run time

Can be used to play

games

Made for every day use

Currently on display at

CES 2013


21/22

CONCLUSION

With advancement in our understanding of the

brain and various other engineering disciplines

likes signal processing, etc, the technology of

brain computer interface is bound to benefit Not only is it a fascinating technology for every

human, but also an absolute necessity to a

severely disabled person


22/22

Y U

Documents

The Principle, Motivation , Limitations and Future of BCI ( PPT )