AIRWiki - User contributions [en]

IIT-Lab

2009-12-18T11:19:08Z

StefanoMorciano: /* Booking */

== What is the IIT-Lab ==

AIRLab-IITLab is dedicated to activities founded by the Italian Institute of Technology.
The lab hosts activities related to Brain-Computer Interfaces (BCI) and Affective Computing.

=== Location ===
It is located in the Rimembranze di Lambrate building of the Department of Electronics and Information, [http://www.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=101039811798485926206.00045c07a77c0f575377f&ll=45.481957,9.238375&spn=0.005363,0.008433&z=17 Via Rimembranze di Lambrate, 14, Milan].

'''The Lab has moved. It is now located at the first floor just over the Airlab, always in the Rimembranze di Lambrate building.'''

=== Access Rules ===
The access to AIRLab-IITLab is reserved to registered users. If you are student and want to register, you have to fill the AIRLab registration form (to be signed by your tutor) and the security form. The key of the lab is provided to registered users by the doorkeeper at the main entrance of the Lambrate building.

=== Booking ===

Please book the instrument you want to use by adding an entry to the table; the booking of an instrument implies the booking of the room. If you want to use a different instrument at the same time of an existing booking, please contact the other person involved and check that you can share the room; alternatively, you can ask the doorkeeper for an empty room in the building.


{| border="1"
! Day !! Time !! Person !! Instrument
|-
| friday 11 December || 12:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
| friday 18 December || 12:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
|}

== Links ==

* [[Brain-Computer Interface]] page on this Wiki
* [[Affective Computing]] page on this Wiki
* [http://www.airlab.elet.polimi.it/index.php/airlab/visitor_info/airlab_iitlab AIRLab - IITLab]

IIT-Lab

2009-12-11T11:16:35Z

StefanoMorciano: /* Booking */

== What is the IIT-Lab ==

AIRLab-IITLab is dedicated to activities founded by the Italian Institute of Technology.
The lab hosts activities related to Brain-Computer Interfaces (BCI) and Affective Computing.

=== Location ===
It is located in the Rimembranze di Lambrate building of the Department of Electronics and Information, [http://www.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=101039811798485926206.00045c07a77c0f575377f&ll=45.481957,9.238375&spn=0.005363,0.008433&z=17 Via Rimembranze di Lambrate, 14, Milan].

'''The Lab has moved. It is now located at the first floor just over the Airlab, always in the Rimembranze di Lambrate building.'''

=== Access Rules ===
The access to AIRLab-IITLab is reserved to registered users. If you are student and want to register, you have to fill the AIRLab registration form (to be signed by your tutor) and the security form. The key of the lab is provided to registered users by the doorkeeper at the main entrance of the Lambrate building.

=== Booking ===

Please book the instrument you want to use by adding an entry to the table; the booking of an instrument implies the booking of the room. If you want to use a different instrument at the same time of an existing booking, please contact the other person involved and check that you can share the room; alternatively, you can ask the doorkeeper for an empty room in the building.


{| border="1"
! Day !! Time !! Person !! Instrument
|-
| thursday 10 December || 12:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
| friday 11 December || 12:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
|}

== Links ==

* [[Brain-Computer Interface]] page on this Wiki
* [[Affective Computing]] page on this Wiki
* [http://www.airlab.elet.polimi.it/index.php/airlab/visitor_info/airlab_iitlab AIRLab - IITLab]

IIT-Lab

2009-12-10T10:38:10Z

StefanoMorciano: /* Booking */

== What is the IIT-Lab ==

AIRLab-IITLab is dedicated to activities founded by the Italian Institute of Technology.
The lab hosts activities related to Brain-Computer Interfaces (BCI) and Affective Computing.

=== Location ===
It is located in the Rimembranze di Lambrate building of the Department of Electronics and Information, [http://www.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=101039811798485926206.00045c07a77c0f575377f&ll=45.481957,9.238375&spn=0.005363,0.008433&z=17 Via Rimembranze di Lambrate, 14, Milan].

'''The Lab has moved. It is now located at the first floor just over the Airlab, always in the Rimembranze di Lambrate building.'''

=== Access Rules ===
The access to AIRLab-IITLab is reserved to registered users. If you are student and want to register, you have to fill the AIRLab registration form (to be signed by your tutor) and the security form. The key of the lab is provided to registered users by the doorkeeper at the main entrance of the Lambrate building.

=== Booking ===

Please book the instrument you want to use by adding an entry to the table; the booking of an instrument implies the booking of the room. If you want to use a different instrument at the same time of an existing booking, please contact the other person involved and check that you can share the room; alternatively, you can ask the doorkeeper for an empty room in the building.


{| border="1"
! Day !! Time !! Person !! Instrument
|-
| friday 27 November || 08:00-19:00 || [[User:SiegfriedCattaneo]] || EEG + Laptop
|-
| tuesday 09 December || 12:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
| wednesday 10 December || 12:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
|}

== Links ==

* [[Brain-Computer Interface]] page on this Wiki
* [[Affective Computing]] page on this Wiki
* [http://www.airlab.elet.polimi.it/index.php/airlab/visitor_info/airlab_iitlab AIRLab - IITLab]

IIT-Lab

2009-12-08T09:54:35Z

StefanoMorciano: /* Booking */

== What is the IIT-Lab ==

AIRLab-IITLab is dedicated to activities founded by the Italian Institute of Technology.
The lab hosts activities related to Brain-Computer Interfaces (BCI) and Affective Computing.

=== Location ===
It is located in the Rimembranze di Lambrate building of the Department of Electronics and Information, [http://www.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=101039811798485926206.00045c07a77c0f575377f&ll=45.481957,9.238375&spn=0.005363,0.008433&z=17 Via Rimembranze di Lambrate, 14, Milan].

'''The Lab has moved. It is now located at the first floor just over the Airlab, always in the Rimembranze di Lambrate building.'''

=== Access Rules ===
The access to AIRLab-IITLab is reserved to registered users. If you are student and want to register, you have to fill the AIRLab registration form (to be signed by your tutor) and the security form. The key of the lab is provided to registered users by the doorkeeper at the main entrance of the Lambrate building.

=== Booking ===

Please book the instrument you want to use by adding an entry to the table; the booking of an instrument implies the booking of the room. If you want to use a different instrument at the same time of an existing booking, please contact the other person involved and check that you can share the room; alternatively, you can ask the doorkeeper for an empty room in the building.


{| border="1"
! Day !! Time !! Person !! Instrument
|-
| friday 27 November || 08:00-19:00 || [[User:SiegfriedCattaneo]] || EEG + Laptop
|-
| tuesday 09 December || 12:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
|}

== Links ==

* [[Brain-Computer Interface]] page on this Wiki
* [[Affective Computing]] page on this Wiki
* [http://www.airlab.elet.polimi.it/index.php/airlab/visitor_info/airlab_iitlab AIRLab - IITLab]

IIT-Lab

2009-12-08T09:49:56Z

StefanoMorciano: /* Booking */

== What is the IIT-Lab ==

AIRLab-IITLab is dedicated to activities founded by the Italian Institute of Technology.
The lab hosts activities related to Brain-Computer Interfaces (BCI) and Affective Computing.

=== Location ===
It is located in the Rimembranze di Lambrate building of the Department of Electronics and Information, [http://www.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=101039811798485926206.00045c07a77c0f575377f&ll=45.481957,9.238375&spn=0.005363,0.008433&z=17 Via Rimembranze di Lambrate, 14, Milan].

'''The Lab has moved. It is now located at the first floor just over the Airlab, always in the Rimembranze di Lambrate building.'''

=== Access Rules ===
The access to AIRLab-IITLab is reserved to registered users. If you are student and want to register, you have to fill the AIRLab registration form (to be signed by your tutor) and the security form. The key of the lab is provided to registered users by the doorkeeper at the main entrance of the Lambrate building.

=== Booking ===

Please book the instrument you want to use by adding an entry to the table; the booking of an instrument implies the booking of the room. If you want to use a different instrument at the same time of an existing booking, please contact the other person involved and check that you can share the room; alternatively, you can ask the doorkeeper for an empty room in the building.


{| border="1"
! Day !! Time !! Person !! Instrument
|-
| friday 27 November || 08:00-19:00 || [[User:SiegfriedCattaneo]] || EEG + Laptop
|-
| tuesday 08 December || 12:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
|}

== Links ==

* [[Brain-Computer Interface]] page on this Wiki
* [[Affective Computing]] page on this Wiki
* [http://www.airlab.elet.polimi.it/index.php/airlab/visitor_info/airlab_iitlab AIRLab - IITLab]

IIT-Lab

2009-11-13T11:26:00Z

StefanoMorciano: /* Booking */

== What is the IIT-Lab ==

AIRLab-IITLab is dedicated to activities founded by the Italian Institute of Technology.
The lab hosts activities related to Brain-Computer Interfaces (BCI) and Affective Computing.

=== Location ===
It is located in the Rimembranze di Lambrate building of the Department of Electronics and Information, [http://www.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=101039811798485926206.00045c07a77c0f575377f&ll=45.481957,9.238375&spn=0.005363,0.008433&z=17 Via Rimembranze di Lambrate, 14, Milan].

'''The Lab has moved. It is now located at the first floor just over the Airlab, always in the Rimembranze di Lambrate building.'''

=== Access Rules ===
The access to AIRLab-IITLab is reserved to registered users. If you are student and want to register, you have to fill the AIRLab registration form (to be signed by your tutor) and the security form. The key of the lab is provided to registered users by the doorkeeper at the main entrance of the Lambrate building.

=== Booking ===

Please book the instrument you want to use by adding an entry to the table; the booking of an instrument implies the booking of the room. If you want to use a different instrument at the same time of an existing booking, please contact the other person involved and check that you can share the room; alternatively, you can ask the doorkeeper for an empty room in the building.


{| border="1"
! Day !! Time !! Person !! Instrument
|-
| wednesday 11 November|| 08:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
| friday 13 November|| 12:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
|}

== Links ==

* [[Brain-Computer Interface]] page on this Wiki
* [[Affective Computing]] page on this Wiki
* [http://www.airlab.elet.polimi.it/index.php/airlab/visitor_info/airlab_iitlab AIRLab - IITLab]

IIT-Lab

2009-11-09T12:08:17Z

StefanoMorciano: /* Booking */

== What is the IIT-Lab ==

AIRLab-IITLab is dedicated to activities founded by the Italian Institute of Technology.
The lab hosts activities related to Brain-Computer Interfaces (BCI) and Affective Computing.

=== Location ===
It is located in the Rimembranze di Lambrate building of the Department of Electronics and Information, [http://www.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=101039811798485926206.00045c07a77c0f575377f&ll=45.481957,9.238375&spn=0.005363,0.008433&z=17 Via Rimembranze di Lambrate, 14, Milan].

'''The Lab has moved. It is now located at the first floor just over the Airlab, always in the Rimembranze di Lambrate building.'''

=== Access Rules ===
The access to AIRLab-IITLab is reserved to registered users. If you are student and want to register, you have to fill the AIRLab registration form (to be signed by your tutor) and the security form. The key of the lab is provided to registered users by the doorkeeper at the main entrance of the Lambrate building.

=== Booking ===

Please book the instrument you want to use by adding an entry to the table; the booking of an instrument implies the booking of the room. If you want to use a different instrument at the same time of an existing booking, please contact the other person involved and check that you can share the room; alternatively, you can ask the doorkeeper for an empty room in the building.


{| border="1"
! Day !! Time !! Person !! Instrument
|-
| tuesday 10 November|| 08:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
| wednesday 11 November|| 08:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
|}

== Links ==

* [[Brain-Computer Interface]] page on this Wiki
* [[Affective Computing]] page on this Wiki
* [http://www.airlab.elet.polimi.it/index.php/airlab/visitor_info/airlab_iitlab AIRLab - IITLab]

IIT-Lab

2009-11-06T19:06:47Z

StefanoMorciano: /* Booking */

== What is the IIT-Lab ==

AIRLab-IITLab is dedicated to activities founded by the Italian Institute of Technology.
The lab hosts activities related to Brain-Computer Interfaces (BCI) and Affective Computing.

=== Location ===
It is located in the Rimembranze di Lambrate building of the Department of Electronics and Information, [http://www.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=101039811798485926206.00045c07a77c0f575377f&ll=45.481957,9.238375&spn=0.005363,0.008433&z=17 Via Rimembranze di Lambrate, 14, Milan].

'''The Lab has moved. It is now located at the first floor just over the Airlab, always in the Rimembranze di Lambrate building.'''

=== Access Rules ===
The access to AIRLab-IITLab is reserved to registered users. If you are student and want to register, you have to fill the AIRLab registration form (to be signed by your tutor) and the security form. The key of the lab is provided to registered users by the doorkeeper at the main entrance of the Lambrate building.

=== Booking ===

Please book the instrument you want to use by adding an entry to the table; the booking of an instrument implies the booking of the room. If you want to use a different instrument at the same time of an existing booking, please contact the other person involved and check that you can share the room; alternatively, you can ask the doorkeeper for an empty room in the building.


{| border="1"
! Day !! Time !! Person !! Instrument
|-
| thursday 29 October|| 08:00-19:00 || [[User:SiegfriedCattaneo]] || EEG + Laptop
|-
| tuesday 10 November|| 08:00-19:00 || [[User:StefanoMorciano]] || EEG + Laptop
|-
|}

== Links ==

* [[Brain-Computer Interface]] page on this Wiki
* [[Affective Computing]] page on this Wiki
* [http://www.airlab.elet.polimi.it/index.php/airlab/visitor_info/airlab_iitlab AIRLab - IITLab]

Mu and beta rhythm-based BCI

2009-11-06T19:01:48Z

StefanoMorciano:

== '''Part 1: project profile''' ==

=== Project name ===
Control of a two-dimensional movement signal by a noninvasive BCI

=== Project short description ===
The aim of this project is to design and develop a Brain-Computer Interface in order to control a two-dimensional movement signal, as done at the Wadsworth Center (Wolpaw and McFarland, 2004). A non-invasive approach will be adopted, using EEG as a signal source and Mu and Beta rhythms over sensorimotor cortex as information carriers.

=== Dates ===
Start date: 2008/04/01

End date:

=== People involved ===

===== Project head(s) =====

[[User:MatteoMatteucci|Matteo Matteucci]]

===== Other Politecnico di Milano people =====

[[User:RossellaBlatt|Rossella Blatt]]

===== Students currently working on the project =====

[[User:StefanoMorciano|Stefano Morciano]]

=== Laboratory work and risk analysis ===

Laboratory work for this project will be mainly performed at AIRLab/Lambrate. The main laboratory activity will be the EEG data acquisition. Though apparently safe, the contact between the subject's body and the EEG instrumentation makes this activity potentially harmful. For safety's sake any electronic device connected to the system should be isolated from the power line.
In addition to this, more general risks are present in the laboratory. Standard safety measures described in [http://airlab.elet.polimi.it/index.php/airlab/content/download/461/4110/file/documento_valutazione_rischi_AIRLab.pdf Safety norms] will be followed.

== '''Part 2: project description''' ==

The main purpose of this project is to implement the BCI algorithms used at the Wadsworth Center and proposed by J.R.Wolpaw and D.J.McFarland in their 2004 paper. In that experiment, subjects were able to control the position of a cursor on the screen by appropriately modifying the amplitude of their Mu and Beta rhythms.

=== The Wadsworth BCI ===

==== The study protocol ====

[[Image:wadsworth_trial_structure.jpg]]

While the subject sat in front of the screen, EEG data from 64 electrodes on the scalp were recorded, bandpass filtered (0.1Hz - 60Hz) and digitized at 160Hz. At the beginning of a trial, a target appeared at one of eight possible locations along the edges of the screen, in a block-randomized fashion. One second later, the cursor appeared in the center of the screen and began to move around according to the EEG activity. The movement lasted for 10 seconds (or less if the cursor reached the target before), then there was one second of blank screen and another trial began.

A session is composed of eight 3-minutes runs, separated by 1 minute breaks.

==== Control of cursor movement ====

[[Image:wadsworth_control.jpg]]

The position of the cursor was updated every 50ms. The movement amount depended from Mu and Beta amplitudes in the right and left emispheres (the selection of precise Mu and Beta bands was based on previous experiments on the subjects).

Last 400ms of signal data from electrodes C3 and C4 went through autoregressive frequency analysis to determine the spectral features; movement in vertical and horizontal directions was calculated as:

Mv = av (wrv*Rv + wlv*Lv + bv)

Mh = ah (wrh*Rh + wlh*Lh + bh)

where Rv, Lv, Rh, Lh are right and left Mu and Beta amplitudes, wij are weight factors adaptively selected (see below), and av, bv, ah, bh are normalizing factors.

==== Adaptation algorithm ====

Initially, the weights in the linear equations above were set as:

wrv = wlv = 1

wrh = 1

wlh = -1

so that the vertical movement was controlled by the sum of right and left spectral amplitudes in one of the two bands, while the horizontal one was controlled by the difference between right and left amplitudes in the other.

The weights were adapted automatically at each trial in order to optimize the transformation of EEG signals in cursor movement signals. First of all, each target was expressed as a couple of values (or coordinates) representing one of the four horizontal or vertical possible positions. Then, at each trial, Least-Mean-Square algorithm was used to minimize for past trials the difference between the actual target position and the position predicted by the two linear equations.

=== Implementation ===

==== BCI2000 ====

This project's Brain-Computer Interface is realized with [http://www.bci2000.org BCI2000]. BCI2000 is a multi-purpose EEG software toolbox, developed by the Wadsworth Center and the University of Tubingen, designed to facilitate research and application development in the BCI area.

(More detailed information about BCI2000 can be found at the [http://www.bci2000.org application website] or at the [http://www.bci2000.org BCI2000 wiki]).

BCI2000 is structured in blocks called modules: the Source, Filtering and Application modules are independent on each other and allow easy modification and insertion of new code.

In our case, we need to write a new filter. The filtering section of a BCI2000-developed interface is represented by a filter chain: the input signal from the Source module passes through a series of filters in order to be translated in a control signal. For example, a simplified Wadsworth BCI could have a spatial (laplacian) filter, an autoregressive filter for frequency analysis, a linear classifier and a normalizer.

In such a situation, all we need is a filter between the autoregressive filter and the linear classifier, applying an iterative version of the LMS algorithm on the classifier weights and updating them at the end of each trial.

==== Delta Rule Adapter ====

The new filter is called DeltaRuleAdapter. It implements the [http://www.willamette.edu/~gorr/classes/cs449/Classification/delta.html Delta Rule], a gradient descent learning rule, in order to minimize the error.

The filter takes the current weights from the classifier at the beginning of each trial, and then updates them iteratively in his buffer according to the Delta Rule along the trial duration. At the end of the trial, it updates the classifier's weights.
There are currently two different types of adaptation.

The first is based on positional error at each sample block. At each iteration, the new predicted position is computed, and the error is the distance from the target position:

<pre>
// compute new position
predicted[0] *= Parameter("NormalizerGains")(0);
predicted[1] *= Parameter("NormalizerGains")(1);
pos[0] += predicted[0] * 0.0125;
pos[1] += predicted[1] * 0.0125;

//compute x and y error
err[0]= xTarget - pos[0];
err[1]= yTarget - pos[1];
</pre>

where "predicted" represents the output of the linear classifier with the current weights.
This kind of adaptation is more intuitive, but since the cursor starts each trial at the center of the screen, large errors are always present, leading to unnecessary weights adaptations. The filter offers another possibility: adaptation on directional error

<pre>
// compute movement direction (y=mx+q)
m = predicted[1] / predicted[0];
q = pos[1] - m*pos[0];

// compute the coordinates of the intersection between the
// movement direction and the edges of the screen
if (m>=0) {
if (predicted[0]>0) {
fpos[0] = min(1.0, (1.0-q)/m);
fpos[1] = min(1.0, m+q);
}
if (predicted[0]<0) {
fpos[0] = max(-1.0, (-1.0-q)/m);
fpos[1] = max(-1.0, -1.0+q);
}
}
if (m<0) {
if (predicted[0]>0) {
//...
}
if (predicted[0]<0) {
//...
}
}

// compute x and y error
err[0] = xTarget - fpos[0];
err[1] = yTarget - fpos[1];
</pre>
=== Laboratory activity ===

(coming soon)

Mu and beta rhythm-based BCI

2009-10-06T17:02:00Z

StefanoMorciano:

== '''Part 1: project profile''' ==

=== Project name ===
Control of a two-dimensional movement signal by a noninvasive BCI

=== Project short description ===
The aim of this project is to design and develop a Brain-Computer Interface in order to control a two-dimensional movement signal, as done at the Wadsworth Center (Wolpaw and McFarland, 2004). A non-invasive approach will be adopted, using EEG as a signal source and Mu and Beta rhythms over sensorimotor cortex as information carriers.

=== Dates ===
Start date: 2008/04/01

End date:

=== People involved ===

===== Project head(s) =====

[[User:MatteoMatteucci|Matteo Matteucci]]

===== Other Politecnico di Milano people =====

[[User:RossellaBlatt|Rossella Blatt]]

===== Students currently working on the project =====

[[User:StefanoMorciano|Stefano Morciano]]

=== Laboratory work and risk analysis ===

Laboratory work for this project will be mainly performed at AIRLab/Lambrate. The main laboratory activity will be the EEG data acquisition. Though apparently safe, the contact between the subject's body and the EEG instrumentation makes this activity potentially harmful. For safety's sake any electronic device connected to the system should be isolated from the power line.
In addition to this, more general risks are present in the laboratory. Standard safety measures described in [http://airlab.elet.polimi.it/index.php/airlab/content/download/461/4110/file/documento_valutazione_rischi_AIRLab.pdf Safety norms] will be followed.

== '''Part 2: project description''' ==

The main purpose of this project is to implement the BCI algorithms used at the Wadsworth Center and proposed by J.R.Wolpaw and D.J.McFarland in their 2004 paper. In that experiment, subjects were able to control the position of a cursor on the screen by appropriately modifying the amplitude of their Mu and Beta rhythms.

=== The Wadsworth BCI ===

==== The study protocol ====

[[Image:wadsworth_trial_structure.jpg]]

While the subject sat in front of the screen, EEG data from 64 electrodes on the scalp were recorded, bandpass filtered (0.1Hz - 60Hz) and digitized at 160Hz. At the beginning of a trial, a target appeared at one of eight possible locations along the edges of the screen, in a block-randomized fashion. One second later, the cursor appeared in the center of the screen and began to move around according to the EEG activity. The movement lasted for 10 seconds (or less if the cursor reached the target before), then there was one second of blank screen and another trial began.

A session is composed of eight 3-minutes runs, separated by 1 minute breaks.

==== Control of cursor movement ====

[[Image:wadsworth_control.jpg]]

The position of the cursor was updated every 50ms. The movement amount depended from Mu and Beta amplitudes in the right and left emispheres (the selection of precise Mu and Beta bands was based on previous experiments on the subjects).

Last 400ms of signal data from electrodes C3 and C4 went through autoregressive frequency analysis to determine the spectral features; movement in vertical and horizontal directions was calculated as:

Mv = av (wrv*Rv + wlv*Lv + bv)

Mh = ah (wrh*Rh + wlh*Lh + bh)

where Rv, Lv, Rh, Lh are right and left Mu and Beta amplitudes, wij are weight factors adaptively selected (see below), and av, bv, ah, bh are normalizing factors.

==== Adaptation algorithm ====

Initially, the weights in the linear equations above were set as:

wrv = wlv = 1

wrh = 1

wlh = -1

so that the vertical movement was controlled by the sum of right and left spectral amplitudes in one of the two bands, while the horizontal one was controlled by the difference between right and left amplitudes in the other.

The weights were adapted automatically at each trial in order to optimize the transformation of EEG signals in cursor movement signals. First of all, each target was expressed as a couple of values (or coordinates) representing one of the four horizontal or vertical possible positions. Then, at each trial, Least-Mean-Square algorithm was used to minimize for past trials the difference between the actual target position and the position predicted by the two linear equations.

=== Implementation ===

==== BCI2000 ====

This project's Brain-Computer Interface is realized with [http://www.bci2000.org BCI2000]. BCI2000 is a multi-purpose EEG software toolbox, developed by the Wadsworth Center and the University of Tubingen, designed to facilitate research and application development in the BCI area.

(More detailed information about BCI2000 can be found at the [http://www.bci2000.org application website] or at the [http://www.bci2000.org BCI2000 wiki]).

BCI2000 is structured in blocks called modules: the Source, Filtering and Application modules are independent on each other and allow easy modification and insertion of new code.

In our case, we need to write a new filter. The filtering section of a BCI2000-developed interface is represented by a filter chain: the input signal from the Source module passes through a series of filters in order to be translated in a control signal. For example, a simplified Wadsworth BCI could have a spatial (laplacian) filter, an autoregressive filter for frequency analysis, a linear classifier and a normalizer.

In such a situation, all we need is a filter between the autoregressive filter and the linear classifier, applying an iterative version of the LMS algorithm on the classifier weights and updating them at the end of each trial.

==== Delta Rule Adapter ====

The new filter is called DeltaRuleAdapter. It implements the [http://www.willamette.edu/~gorr/classes/cs449/Classification/delta.html Delta Rule], a gradient descent learning rule.

The filter takes the current weights from the classifier at the beginning of each trial, and then updates them iteratively in his buffer according to the Delta Rule along the trial duration. At the end of the trial, it updates the classifier's weights.

<pre>
if ((feedback == 1) && (WtControl==2)) // during trial
{
predicted[0]= 0; // predicted x and y speed
predicted[1]= 0;
pos[0] = State("CursorPosX") / 4095; // current position of the cursor
pos[1] = State("CursorPosY") / 4095;

for( size_t i = 0; i < mWeights.size(); ++i )
predicted[mOutputChannels[i]] += Input(mInputChannels[i], mInputElements[i]) * mWeights[i]; // compute predicted speed

predicted[0]-= Parameter("NormalizerOffsets")(0); // include mean in model
predicted[1]-= Parameter("NormalizerOffsets")(1);

predicted[0]*= Parameter("NormalizerGains")(0); // normalize predicted speed
predicted[1]*= Parameter("NormalizerGains")(1);

pos[0] += predicted[0] * 0.0125; // compute new predicted position
pos[1] += predicted[1] * 0.0125;

err[0]= xTarget - pos[0]; // error
err[1]= yTarget - pos[1];

for( size_t i = 0; i < mWeights.size(); ++i ) // update weights
{
mWeights[i] += Input(mInputChannels[i], mInputElements[i]) * err[mOutputChannels[i]] * WtRate;
}
}
</pre>

=== Laboratory activity ===

(coming soon)

Mu and beta rhythm-based BCI

2009-10-06T16:28:15Z

StefanoMorciano:

== '''Part 1: project profile''' ==

=== Project name ===
Control of a two-dimensional movement signal by a noninvasive BCI

=== Project short description ===
The aim of this project is to design and develop a Brain-Computer Interface in order to control a two-dimensional movement signal, as done at the Wadsworth Center (Wolpaw and McFarland, 2004). A non-invasive approach will be adopted, using EEG as a signal source and Mu and Beta rhythms over sensorimotor cortex as information carriers.

=== Dates ===
Start date: 2008/04/01

End date:

=== People involved ===

===== Project head(s) =====

[[User:MatteoMatteucci|Matteo Matteucci]]

===== Other Politecnico di Milano people =====

[[User:RossellaBlatt|Rossella Blatt]]

===== Students currently working on the project =====

[[User:StefanoMorciano|Stefano Morciano]]

=== Laboratory work and risk analysis ===

Laboratory work for this project will be mainly performed at AIRLab/Lambrate. The main laboratory activity will be the EEG data acquisition. Though apparently safe, the contact between the subject's body and the EEG instrumentation makes this activity potentially harmful. For safety's sake any electronic device connected to the system should be isolated from the power line.
In addition to this, more general risks are present in the laboratory. Standard safety measures described in [http://airlab.elet.polimi.it/index.php/airlab/content/download/461/4110/file/documento_valutazione_rischi_AIRLab.pdf Safety norms] will be followed.

== '''Part 2: project description''' ==

The main purpose of this project is to implement the BCI algorithms used at the Wadsworth Center and proposed by J.R.Wolpaw and D.J.McFarland in their 2004 paper. In that experiment, subjects were able to control the position of a cursor on the screen by appropriately modifying the amplitude of their Mu and Beta rhythms.

=== The Wadsworth BCI ===

==== The study protocol ====

[[Image:wadsworth_trial_structure.jpg]]

While the subject sat in front of the screen, EEG data from 64 electrodes on the scalp were recorded, bandpass filtered (0.1Hz - 60Hz) and digitized at 160Hz. At the beginning of a trial, a target appeared at one of eight possible locations along the edges of the screen, in a block-randomized fashion. One second later, the cursor appeared in the center of the screen and began to move around according to the EEG activity. The movement lasted for 10 seconds (or less if the cursor reached the target before), then there was one second of blank screen and another trial began.

A session is composed of eight 3-minutes runs, separated by 1 minute breaks.

==== Control of cursor movement ====

[[Image:wadsworth_control.jpg]]

The position of the cursor was updated every 50ms. The movement amount depended from Mu and Beta amplitudes in the right and left emispheres (the selection of precise Mu and Beta bands was based on previous experiments on the subjects).

Last 400ms of signal data from electrodes C3 and C4 went through autoregressive frequency analysis to determine the spectral features; movement in vertical and horizontal directions was calculated as:

Mv = av (wrv*Rv + wlv*Lv + bv)

Mh = ah (wrh*Rh + wlh*Lh + bh)

where Rv, Lv, Rh, Lh are right and left Mu and Beta amplitudes, wij are weight factors adaptively selected (see below), and av, bv, ah, bh are normalizing factors.

==== Adaptation algorithm ====

Initially, the weights in the linear equations above were set as:

wrv = wlv = 1

wrh = 1

wlh = -1

so that the vertical movement was controlled by the sum of right and left spectral amplitudes in one of the two bands, while the horizontal one was controlled by the difference between right and left amplitudes in the other.

The weights were adapted automatically at each trial in order to optimize the transformation of EEG signals in cursor movement signals. First of all, each target was expressed as a couple of values (or coordinates) representing one of the four horizontal or vertical possible positions. Then, at each trial, Least-Mean-Square algorithm was used to minimize for past trials the difference between the actual target position and the position predicted by the two linear equations.

=== Implementation ===

==== BCI2000 ====

This project's Brain-Computer Interface is realized with [http://www.bci2000.org BCI2000]. BCI2000 is a multi-purpose EEG software toolbox, developed by the Wadsworth Center and the University of Tubingen, designed to facilitate research and application development in the BCI area.

(More detailed information about BCI2000 can be found at the [http://www.bci2000.org application website] or at the [http://www.bci2000.org BCI2000 wiki]).

BCI2000 is structured in blocks called modules: the Source, Filtering and Application modules are independent on each other and allow easy modification and insertion of new code.

In our case, we need to write a new filter. The filtering section of a BCI2000-developed interface is represented by a filter chain: the input signal from the Source module passes through a series of filters in order to be translated in a control signal. For example, a simplified Wadsworth BCI could have a spatial (laplacian) filter, an autoregressive filter for frequency analysis, a linear classifier and a normalizer.

In such a situation, all we need is a filter between the autoregressive filter and the linear classifier, applying an iterative version of the LMS algorithm on the classifier weights and updating them at the end of each trial.

==== Delta Rule Adapter ====

The new filter is called DeltaRuleAdapter. It implements the [http://www.willamette.edu/~gorr/classes/cs449/Classification/delta.html Delta Rule], a gradient descent learning rule.

The filter takes the current weights from the classifier at the beginning of each trial, and then updates them iteratively in his buffer according to the Delta Rule along the trial duration. At the end of the trial, it updates the classifier's weights.

<pre>here goes a code snippet</pre>

=== Laboratory activity ===

(coming soon)

Mu and beta rhythm-based BCI

2009-10-06T15:37:33Z

StefanoMorciano:

Mu and beta rhythm-based BCI

2009-10-06T12:56:50Z

StefanoMorciano:

File:Wadsworth control.jpg

2009-10-06T12:56:13Z

StefanoMorciano: uploaded a new version of "Image:Wadsworth control.jpg"

File:Wadsworth control.jpg

2009-10-06T12:54:26Z

StefanoMorciano:

File:Wadsworth trial structure.jpg

2009-10-06T12:16:35Z

StefanoMorciano:

Mu and beta rhythm-based BCI

2009-10-06T12:06:18Z

StefanoMorciano:

User:StefanoMorciano

2008-05-30T18:09:59Z

StefanoMorciano:

{{User
|firstname=Stefano
|lastname=Morciano
|email=aioros83@gmail.com
|advisor=Matteo Matteucci
|projectpage=Mu and beta rhythm-based BCI
|photo=Morciano.jpg
}}

File:Morciano.jpg

2008-05-30T18:09:33Z

StefanoMorciano:

Mu and beta rhythm-based BCI

2008-05-30T17:45:03Z

StefanoMorciano:

== '''Part 1: project profile''' ==

=== Project name ===
Mu and beta rhythm-based BCI

=== Project short description ===
The aim of this project is to design and develop a Brain-Computer Interface in order to control a two-dimensional movement signal. A non-invasive approach will be adopted, using EEG as a signal source and Mu and Beta rhythms over sensorimotor cortex as information carriers.

=== Dates ===
Start date: 2008/04/01

End date:

=== People involved ===

===== Project head(s) =====

[[User:MatteoMatteucci|Matteo Matteucci]]

===== Other Politecnico di Milano people =====

[[User:RossellaBlatt|Rossella Blatt]]

===== Students currently working on the project =====

[[User:StefanoMorciano|Stefano Morciano]]

=== Laboratory work and risk analysis ===

Laboratory work for this project will be mainly performed at AIRLab/Lambrate. The main laboratory activity will be the EEG data acquisition. Though apparently safe, the contact between the subject's body and the EEG instrumentation makes this activity potentially harmful. For safety's sake any electronic device connected to the system should be isolated from the power line.
In addition to this, more general risks are present in the laboratory. Standard safety measures described in [http://airlab.elet.polimi.it/index.php/airlab/content/download/461/4110/file/documento_valutazione_rischi_AIRLab.pdf Safety norms] will be followed.

== '''Part 2: project description''' ==

(coming soon)

Projects

2008-05-30T17:42:54Z

StefanoMorciano: /* Brain-Computer Interface */

''This page is a repository of links to the pages describing the '''projects''' we are currently working on at AIRLab.
See the list of our finished projects on the [[Finished Projects]] page.''

== Ongoing projects ==
''by research area (areas are defined in the [[Main Page]]); for each project a name and a link to its AIRWiki page is given''

==== [[Agents, Multiagent Systems, Agencies]] ====
----

* [[Multiagent cooperation|Multiagent cooperating system]]

* [[Planning in Ambient Intelligence scenarios| Planning in Ambient Intelligence scenarios]]

==== [[BioSignal Analysis]] ====
----
====== [[Affective Computing]] ======

* [[Relatioship between Cognition and Emotion in Rehabilitation Robotics]]
* [[Driving companions]]
* [[Emotion from Interaction]]
* [[Affective Devices]]

====== [[Brain-Computer Interface]] ======

* [[Online P300 and ErrP recognition with BCI2000]]
* [[BCI based on Motor Imagery]]
* [[Graphical user interface for an autonomous wheelchair]]
* [[Mu and beta rhythm-based BCI]]

====== [[Automatic Detection Of Sleep Stages]] ======

* [[Sleep Staging with HMM]]

====== [[Analysis of the Olfactory Signal]] ======

* [[Lung Cancer Detection by an Electronic Nose]]
* [[HE-KNOWS - An electronic nose]]

==== [[Computer Vision and Image Analysis]] ====
----

* [[Automated extraction of laser streaks and range profiles]]

* [[Data collection for mutual calibration|Data collection for laser-rangefinder and camera calibration]]

* [[Image retargeting by k-seam removal]]

* [[Particle filter for object tracking]]

* [[Wii Remote headtracking and active projector]]

==== [[Machine Learning]] ====
----
* [[Adaptive Reinforcement Learning Multiagent Coordination in Real-Time Computer Games|Adaptive Reinforcement Learning Multiagent Coordination in Real-Time Computer Games]]

==== [[Ontologies and Semantic Web]] ====
----
* [[JOFS|JOFS, Java Owl File Storage]]
* [[FolksOnt|FolksOnt]]
* [[Extending a wiki with semantic templates]]
* [[GeoOntology|Geographic ontology for a semantic wiki]]

==== [[Philosophy of Artificial Intelligence]] ====
----
==== [[Robotics]] ====
----
* [[LURCH - The autonomous wheelchair]]

* [[Rawseeds|RAWSEEDS]]

* [[Balancing robots: Tilty, TiltOne]]

* [[ROBOWII ]]

* [[PoliManus]]

* [[ZOIDBERG - An autonomous bio-inspired RoboFish]]

* [[Styx The 6 Whegs Robot]]

* [[PolyGlove: a body-based haptic interface]]

==== [[Soft Computing]] ====
----

== Note for students ==

If you are a student and there isn't a '''page describing your project''', this is because YOU have the task of creating it and populating it with (meaningful) content. If you are a student and there IS a page describing your project, you have the task to complete that page with (useful and comprehensive) information about your own contribution to the project. Be aware that the quality of your work (or lack of it) on the AIRWiki will be evaluated by the Teachers and will influence your grades.

Instructions to add a new project or to add content to an existing project page are available at [[Projects - HOWTO]].