[Gate-users] Interpreting the uncertainty image obtained by FFDA

[Simon Rit]

Hi,
Please keep using the mailing list. If you look at the code
https://github.com/OpenGATE/Gate/blob/develop/source/digits_hits/include/GateFixedForcedDetectionFunctors.hh#L913
you will see that I followed Gate habits of giving the relative
uncertainty. So it's a fraction, i.e., 5.2e-3 means 0.52% error.
Simon

On Mon, Feb 27, 2017 at 3:06 PM, Triltsch, Nicolas <nicolas.triltsch at tum.de>
wrote:

> Hello Simon,
>
> I tried to understand the uncertainty images for Compton and Rayleigh
> scatter obtained by the Fixed Forced Detection actor (FFDA). I have read
> the paper about history-by-history calculation of the statistical
> uncertainty which is also applied in the FFDA algorithm as you told me.
>
> Let's say I have a Compton scatter image with a maximum value of 4.6e-3
> and a minimum value of 3.9e-3. The uncertainty image gives us a maximum
> value of 5.2e-3 and a minimum value of 5.0e-3. Does that mean that the
> maximum value of the uncertainty image exceeds the maximum value in the
> Compton image (which would mean that we have more than 100% error? That
> would be my interpretation if the values of the uncertainty image are
> "s_mean(x)" (equation 2 in the paper attached).
>
> Can you state on that?
>
> I would appreciate a lot your help,
>
> Nico
>
> --
> B.Sc. Nicolas Triltsch
> Masterand
>
> Technische Universität München
> Physik-Department
> Lehrstuhl für Biomedizinische Physik E17
>
> James-Franck-Straße 1
> 85748 Garching b. München
>
> Tel: +49 89 289 12591
>
> nicolas.triltsch at tum.de
> www.e17.ph.tum.de
>
>
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