[Homer-users] Error while running Homer2_UI

[Yucel, Meryem A.]

Hi Karthik,

You have some negative values in your raw signal (d), which -when converted to optical density (dod) by taking the logarithm- results in Inf values. That is why you receive that error. I do not know how you get the negative values in the first place -it is probably system related, but they belong to the noisiest channels, so I suggest you remove them from your analysis. One way to do that is:

load  xxx.nirs -mat    (load nirs file in matlab)
d(:, find(any(d<0 ))) = 1; (find all the channels that have any negative d value and equate the whole channel to an arbitrary constant (here I put 1), so at the end you won't have any HRF from that channel, but the code will work for the rest of the good signal.)
save xxx.nirs  (save the new d)

You may want to keep a copy of your original .nirs files before doing this.
Hope this helps and please let me know if you have further questions.

Meryem



From: homer-users-bounces at nmr.mgh.harvard.edu [mailto:homer-users-bounces at nmr.mgh.harvard.edu] On Behalf Of KRISHNAMURTHY, KARTHIK [Alumni]
Sent: Friday, June 16, 2017 5:04 AM
To: homer-users at nmr.mgh.harvard.edu
Subject: [Homer-users] Error while running Homer2_UI


Dear Homer users,



I have attempted conducting analysis with Homer2_UI for my fNIRS data with the aim of removing artifacts and calculating HRF. I used 3 x 11 probe consisting of 52 channels which target on the frontal lobe for the data retrieved from children aged between 9 and 12 years. Before the Homer2 analysis, the data had been converted from .csv format to .nirs format using Hitachi2Homer program. The converted file has successfully been recognized by the Homer2_UI program. However, when I defined values in the "ProcessOpt functions" and ran the analysis, I obtained an error message that was popped up as below,



"Error: Function hmrMotionArtifact generated error at line 72: fs must either be "sample frequency or a time vector with same length as d"



I looked at various options and changing the values in Homer2_UI to sort out this issue but they were unsuccessful. I even tried out various MATLAB versions but the error still reminded the same. I do not how to rectify this problem and conduct the analysis further. So, it would be highly thankful if you could provide a feasible solution to overcome this issue and help me to move on further.



Looking forward your assistance.



Thank you

Best regards,

Karthik.

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