TECHNION – Israel Institute of Technology
Department of Electrical Engineering
The Vision Research and Image Science Laboratory
MMI – Man Machine
Interface
By
Ohad Stein
Epel Sefi
Supervised by
Dr. Daniel Langue
May 2003
Introduction
It is known for years that stress, press, fear, happiness and many other
feelings, can be measured by several techniques .
Based on this knowledge, we would like to build an interface, that will
enable people to communicate without using any muscle, and without
making any physical effort.
How can we do it?
There are several ways to “speak” with the machine:
One way, is to measure the resistance of the skin, to the
passage of a very small electric current.
The main disadvantage of this technique is that it is hard to calibrate
the system. The measured values changes between different subjects,
and between different times with the same subject.
Our way was to measure the change in DC potential across neurones
of the autonomic nervous system connected to the sensori-motor strip
of the cortex.
In this way – we will detect a signal only after causing it.
Experimental background
In order to gain some basic knowledge about the MMI abilities we
have done some basic experiments, in several different ways.
We have done 3 different experiments:
The first and second experiments have a strong emotional effect. We
did them in order to have a basic indication about the ability of
building a MMI.
The third experiment do not have any emotional aspect. The subject
should try to control the voltage deflections measured from his arm.
The third experiment is actually the prototype for our project.
Bio-Feedback
Our implementation was based on Bio-Feedback.
In the next line we will shortly describe the basics of the Bio-FeedBack:
The meaning of “Bio-Feedback” is that man can “learn” his reflexes, can
control them, and can use them as a way of therapy.
Every hospital uses, nowadays, biofeedback experts in the pain
clinics, in order to help the people help themselves.
The technique is based on a long training session, led by experts, in order
to learn the “patient emotionalism”, and the special biofeedback way that
can be useful for him.
There could be some differences between patients:
In the recording site.
In the detection way.
In the psychological ways of the training.
In the time of training session which is needed.
In order to improve our biofeedback abilities, and after consulting
with some experts from the academy and from the medicine area, we
have built 3 different train tools for the training.
1.A balloon. The balloon radius is affected by the measured voltage
ratio, of the subject skin. The subject should try to increase the balloon
radius. ( 2 other tools you could find in our book/presentation)
Visual Basic
Real-Time implementation
In this part of the project we have build an real-time user-interface, for
our implementation.
Stage #1 – a matrix is shown to the subject. 5 lines of 5 letters each.
Each line become bold for 5 seconds.
The subject choose one of the 25 letters, therefore he will “like” one
line more than the others (the one that includes the chosen letter…)
After choosing a line, by the changes of the voltage ratio on the
subject arm, we stop bolding lines and start bolding letters on the
chosen line. Now, the subject will be able to choose the wanted letter
and print it in the right place. The screen will look as followed.
In this way, we can write a full word.