Setting up an experiment environment – Part 2

Well, I think the article about Setting up an experiment environment with OpenViBE was quite appreciated…

I can now write about an application Laurent quickly made for the Cité des sciences demo. We expect many people to test the application in the next 6 months so it was important not to mess things up with the recorded data. Laurent took advantage of the configuration manager for this… The idea is basically for each subject to generate a configuration file that is parsed by the configuration manager at runtime…

Just to remind you, the standard provided configuration file includes a custom configuration file where you can override some of the standard settings or add your own. This custom configuration file is $HOME/.openviberc on Linux and %USERPROFILE%/openvibe.conf on Windows. The inclusion of a subfile is performed thanks to the special token name Include. So at the end of his custom configuration file, Laurent added the following lines :

# added for the “cite-demo”

Include = c:/cite-demo/config.cfg

This c:/cite-demo/config.cfg configuration file is automatically generated each time the demo is launched by a small application he created. In fact, it simply includes a per-user configuration file such as e.g. :

# root “cite-demo” configuration file
# simply includes the current user configuration file

Include = c:/cite-demo/data/20100426/subject-5/config.cfg

At last, the per-user configuration can contain all the needed information for the scenarios to be run :

# child “cite-demo” configuration file
# contains the current user configuration

CiteDemo_DataPath = c:/cite-demo/data/20100426/subject-5
CiteDemo_SubjectAge = 30
CiteDemo_SubjectSex = M
CiteDemo_SubjectHandedness = Right

Given such configuration, it becomes easy to have a generic scenario that preserves all the data… The file recorders for the baseline record to ${CiteDemo_DataPath}/baseline.gdf, the mean / variance trainers generate setting overrides to ${CiteDemo_DataPath}/simple-dsp-config.xml and ${CiteDemo_DataPath}/crop-config.xml, etc…

Back in 2008 when we showed the first version of “Use the Force” demo with Fabien, we had to backup every single file between trials. Damn that was dangerous. As far as I remember, we lost 1 trial over 22/23 persons who tried the demo… Almost 5% ! As shown here, you won’t have to care about this anymore if you take the time to have a clean set-up first…

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