Month: September 2011

Mobile brain scanners for real-time brain mapping: a smartphone brain scanner

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Mobile neuroimaging has been available for some time. The Danish company Ceretronix has manufactored the Cortexplorer 16 “compact, mobile, 16 detector bedside” brain scanner which seems to have been used since 1992 by researchers. According to the documentation on the Web (on a Web page that hasn’t been updated since 2002) the results are are presented after 15 minutes on a PC. It seems to be a fairly old system (20 years?), but the brain scanner has wheels so it is mobile!

Now my colleagues at the Section for Cognitive Systems at the Technical University of Denmark have constructed a system that employs the Emotive EEG system together with a smartphone for real-time 3D brain mapping. The reasonably priced Emotive EEG system is 14-channel and it has wireless connection to a small USB device. The USB device can be plugged into a smartphone (if you have an adapter between the normal and the small USB stick) and provided you have an appropriate driver for the device you can access the EEG signal from the smartphone. Our Arkadiusz Stopczynski has got a hold on a driver and programmed a Qt application for the Nokia N900 smartphone. It uses OpenGL visualization and touch-based interface so a coarse polygon-based representation of the brain surface can be updated and rotated in real-time smoothly. To colorcode the brain surface based on the EEG signal Stopczynski uses an algorithm by Carsten Stahlhut. Stahlhut studied these kinds of algorithms in his PhD. 

There are earlier computer programs that can read EEG signals and present 3D visualization of the brain activity, e.g., on the Emotiv homepage is a commerical Windows application. What is surprising with the system of my colleagues is that they are able to do the colorcoding algorithm (the inversion) on a smartphone. I wouldn’t immediately have thought that a smartphone would have enough computer power to perform this kind of usually quite computational expensive operation. It helps there are few electrodes and that the representation of the brain surface is coarse: There are only 14 EEG channels and around 1’000 vertices in the brain surface model.

Our Jakob Eg Larsen was interviewed and got the story into New Scientist. From there it spread to Engadget and has now been taken up by, Smartplanet, betanews, psfk,, Simplyzesty and Kurzweil.

In Denmark one of the big newspapers Politiken runs the story today. The news also reached Dutch

A short technical description by Stopczynski and others from our section is available in the conference contribution A smartphone interface for a wireless EEG headset with real-time 3D reconstruction With Michael Kai Petersen as first author another paper describes in more detail an analysis of the EEG data collected with the mobile phone when subjects viewed emotional pictures presented on the mobile phone. A bit more information is available from the Smartphone Brain Scanner homepage.

While you wonder why on earth Jakob Eg Larsen did not put sound on the YouTube video you can take a look on ezgod3’s version with remixed music.


(2011-10-28: Spelling correction in title and body text – mobil to mobile)

Who to vote for in the Danish parliamentary election September 2011

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Now is the city lamp post made glorious by the posters of politicians. The state of Denmark is election and politicians have since election announcement two weeks ago put up posters. On central lamp posts we see up to 8 posters on each. They mostly display the candidate name, the party name and portrait of politicians. They hang on top of each other or back to back.

So how are the posters? Who should you vote for if you had nothing else to judge from than the posters. Having a view to posters on the Kongens Nytorv “Square” (it is actually round) at the beginning of the election period I could see many posters. According the the ruling spin doctor credo politician should say as little as possible about their own politics and in good old American election style you should critize the opponent. Well, on the posters there is not much declamation: Conservative (C) Rasmus Jarlow says “lower tax”. (Dang, there, I was hoping for higher housing tax to cover next year huge deficit in the budget of the state). Radical left (which fiscally is the moderate right) Manu Sareen says “take responsibility”.

What about the physical quality of the posters? Can we determine which candidate to vote for based on the quality of the set up.

Lets take the poster in front of the statue of Danish national poet Adam Ø. On top of one post we have Manu Sareen. The poster does not fully cover the poster board. He has two posters back to back. Unfortunate the direction is wrong. Car traffic and cyclist come from one direction and Sareen posters are turned in an unfortunate angle that does not allow cars and cyclist to get a good view of him. The wire strap used to fix the poster board to the lamp post is the same color (black) as his hair and jacket and blends well. The old fashion masonite-like poster board seems a bit old (is it from last election?). We see part of another poster just slighly below his neck. So he is an experience politician? Lærke Helene Becker from the Danish Peoples Party has economically only hung one poster on the poster and it has a clear sense of direction: Directly towards most of the traffic. The top wire strap is the same color as the background, bottom wire strap not. Her poster board and poster are integrated as if the poster is printed on the carbon board. Nice and handy, but will it hold to the Danish rain? She looks young and perhaps unexperienced. Below Becker we have no-portrait SF poster with the name of party leader Villy Søvndal, Socialistic Peoples Party (SF). The poster has been put on top of an older poster. The poster gluing quality is poor with wrinkles. The lower left has slipped off. It got some dirt on it. Almost as if it has been vandalized. We got a URL on this poster. There are two posters back-to-back. It got a better sense of direction than Manu Sareen, almost as good as Becker.

Below SF we have Social Democrat Irkam Sarwar with a URL and a Cary Grant-like photo. The upper wire strap matches his black hair color, while the lower strap unfortunately covers most of party name. This is a two poster back-to-back setup with an excellent sense of direction. The people that have set up the poster has not bothered to use two wire straps for each poster. This means they are not well-tied and I believe it cannot support itself resting on the protuberance of the lamb post. It also means the the stop mechanism of the wire strap is visible on the front of one of the posters. There are some gluing faults. On another lamb post we have on top Villy Søvndal (back-to-back), on the next level Manu Sareen and Rasmus Jarlov. Then below Becker and fourth from the top Ida Auken, SF and at the bottom Ikram. Yet again we see the same problem of the Ikram’s poster. It is not well-tied, slips down and rests on the ground. Ida Auken’s well-directed poster, though it looks as if it really have been tighten hard, is loose and seems to rest on Ikram’s poster. Becker is well-tied again. Jarlov’s has the complete wrong sense of direction opposite traffic, and the people hanging up the poster has the fixing mechanism on the front side of the poster. Also for Manu Sareen on this lamp post the wire strap fixing mechanism is on the front, but the people have had a plier with them shortened the unused part of the strap. Further along Kongens Nytorv we have another lamp post were it has gone completely wrong. The Villy Søvndal poster has crashed (vandalism?) and taken Per Stig Møller with him as well as covered Jarlov. The only one left is Ikram, again standing on the ground and towering Becker on the top. On a fourth lamp post we see that the only reason the Lotte Wassini poster hangs is due to her straps are actually hanging on the straps of the Villy Søvndal poster. Ikram again is standing on the ground.

The holes in Beckers poster board are well-positioned with respect the diameter of the lamb post. Manu Sareen’s are too narrow, SF and the Social Democrates too far. Judging from these posters the vote should go to Lærke Helene Becker who has a clean sense of direction, holes well-positioned and the board well-tied to support itself.

If we go to the Copenhagen suburb Lyngby we also see many posters. Most of the boards on the Lyngby main street are the integrated Becker-type boards, and generally they are better set up than the Copenhagen ones. It may be because the Copenhagen posters have been exposed to vandalism (we do not engage in vandalism in Lyngby), or it may be that Lyngby politicians are more careful and better skilled. The Lyngby boards have all a clear sense of direction and fairly well-tied, but if we look closer there are some differentiations. Boards by Jakob Engel-Schmidt from Venstre have wire strap holes positioned well in comparison with the diameter of the lamb post. This is not the case with Morten Normann, SF nor Charlotte Dyremose, C. The white background of Jakob Engel-Schmidt’s poster also matches the white wire strap and it does not cover the name. The color match and the separation from material on the posters are not on this level for the other politicians, e.g., Normann’s bottom black wire strap makes it look like part of his name is underlined.

Common for almost all the poster boards of the politicians is that the wire strap is not cut. The people who have setup the poster have simply not bothered to take a plier and shortened the strap. One attempted exception is Jakob Engel-Schmidt, where his surplus part of a few of his
wire straps have been twisted so as not to stick out in the open air. It is interesting to compare the politicians’ poster setup with professional setup. Above Charlotte Dyremose’s poster we have a poster from a circus, Cirkus Dannebrog, announcing shows. These professional circus posters are
well-tied, the wire strap holes supported by metal ri
ngs, the back-to-back posters are tied together with multiple straps, the wire straps are well-shortened, the color of straps matches the background of poster. The only issue is that the poster does not have two holes for each central wire strap which means that the poster is slightly slanting. But on all other accounts we see a quality setup. Compare that with Charlotte Dyremose’s poster (see the photos): wire strap holes too far from each other, the color not quite matched, a unnecessary sticker on the front page (probably the contact details for the person that has setup the poster), the sticker slanted, the wire strap not shortened and only a single board posters, – not back-to-back. When I later came by the Dyremose and the circus posters I saw that Dyremose had sunken and turned in the wrong direction.

In conclusion, given no other information, don’t vote Irkam Sarwar, avoid Charlotte Dyremose, vote for Jakob Engel-Schmidt or alternatively Lærke Helene Becker. That is, if you cannot find Cirkus Dannebrog on the voting list.


(Correction 2011-11-17: removed the word “not” from “…politician should not say as little as possible…”)