Mantis Bug Tracker

View Issue Details Jump to Notes ] Issue History ] Print ]
IDProjectCategoryView StatusDate SubmittedLast Update
0000193openvibebug reportpublic2017-08-10 18:392018-08-24 15:13
Assigned Tojtlindgr 
StatusresolvedResolutionunable to reproduce 
PlatformKDE NeonOSUbuntu LinuxOS Version17.04
Summary0000193: Temporal Filter does not seem to affect signal
DescriptionI have a simple scenario where I run a signal through a Temporal Filter (8-12Hz). When visualizing the raw signal and 'filtered' signal side by side (with signal and power spectrum displays), they are exactly the same. What might I be doing wrong, that the Temporal Filter does not filter the signal?
Additional InformationI have attached the Temporal Filter scenario.
TagsNo tags attached.
Attached Filesxml file icon GDF-temporalFilter.xml [^] (35,728 bytes) 2017-08-10 18:39
png file icon Screenshot_20170810_193612.png [^] (58,837 bytes) 2017-08-10 18:39

- Relationships

-  Notes
brylie (reporter)
2017-08-10 18:39

I also attached a screenshot of the scenario and visualizations.
brylie (reporter)
2017-08-10 18:47

On closer inspection of the screenshot, there does seem to be some difference between the signals. It is just not as pronounced as I was expecting with an 8-12Hz bandpass filter. What can I do to filter the signal so that only 8-12Hz frequencies pass through?
jtlindgr (administrator)
2017-09-06 13:04

I suggest increasing the amount of data the FFT gets (use time based epoching with a large enough epoch) in order to see the spectrum in more detail. The 8-12 should be pronounced with relation to the rest. Note also the typical 1/f decay of the eeg fft. High freqs will naturally have little power.
jtlindgr (administrator)
2018-08-24 15:13

In my experiments Temporal Filter seems to work as intended. If you encounter this problem while giving the FFT a larger signal epoch for a better estimate, please reopen the bug.

- Issue History
Date Modified Username Field Change
2017-08-10 18:39 brylie New Issue
2017-08-10 18:39 brylie File Added: GDF-temporalFilter.xml
2017-08-10 18:39 brylie File Added: Screenshot_20170810_193612.png
2017-08-10 18:39 brylie Note Added: 0001256
2017-08-10 18:47 brylie Note Added: 0001257
2017-09-06 13:04 jtlindgr Note Added: 0001260
2018-08-24 15:13 jtlindgr Note Added: 0001270
2018-08-24 15:13 jtlindgr Status new => resolved
2018-08-24 15:13 jtlindgr Resolution open => unable to reproduce
2018-08-24 15:13 jtlindgr Assigned To => jtlindgr

Copyright © 2000 - 2010 MantisBT Group
Powered by Mantis Bugtracker