AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

History of AFNI updates  

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January 07, 2018 08:23PM
Dear all,

I have a question regarding the TSNR image outputted from the afni_proc.py program. The explanation provided is the following:

By default, a temporal signal to noise (TSNR) dataset is created at
the end of the regress block. The "signal" is the all_runs dataset
(input to 3dDeconvolve), and the "noise" is the errts dataset (the
residuals from 3dDeconvolve). TSNR is computed (per voxel) as the
mean signal divided by the standard deviation of the noise.

TSNR = average(signal) / stdev(noise)

I am a little confused since the errts dataset is as far as I know the dataset we use after all nuisance signals have been regressed out of the data, so why is it referred as the "noise" dataset? From my understanding of the above, SNR is then mean(all_runs)./std(errts) . Is that correct?

Second, what would be considered a good SNR?

Thanks a lot,
George
Subject Author Posted

signal to noise ratio afni_proc

gchahine January 07, 2018 08:23PM

Re: signal to noise ratio afni_proc

rick reynolds January 09, 2018 04:54PM

Re: signal to noise ratio afni_proc

gchahine January 10, 2018 06:18PM

Re: signal to noise ratio afni_proc

RWCox January 10, 2018 08:56PM

Re: signal to noise ratio afni_proc

dlhuynh August 13, 2018 11:25AM

Re: signal to noise ratio afni_proc

rick reynolds August 13, 2018 01:24PM

Re: signal to noise ratio afni_proc

dlhuynh August 13, 2018 04:32PM

Re: signal to noise ratio afni_proc

rick reynolds August 13, 2018 04:45PM

Re: signal to noise ratio afni_proc

dlhuynh August 14, 2018 12:49PM

Re: signal to noise ratio afni_proc

rick reynolds August 14, 2018 01:05PM

Re: signal to noise ratio afni_proc

dlhuynh August 14, 2018 01:18PM

Re: signal to noise ratio afni_proc

rick reynolds August 20, 2018 01:03PM