http://confocal-microscopy-list.275.s1.nabble.com/averaging-vs-accumulation-for-noise-reduction-is-there-a-difference-tp6483751p6483805.html
It also depends on how the readout bandwidth is controlled for different scan speeds...
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> Hallo,
> this is a very basic question, but I cannot figure this out from what I have
> been reading, so a simple explanation for a non-physicist would be much
> appreciated:
>
> Is there a real difference in the improvement of the signal to noise ratio
> between frame averaging (or accumulation) and longer dwell times (slower
> scan) for a point-scanning confocal witrh a PMT detector?
>
> For instance, using single point scanning confocal, 12-bit acquisition.
>
> a) averaging (or accumulating) 5 frames, 4 microseconds per pixel
> b) acquiring a single frame, 20 microseconds per pixel
>
> Assumptions:
> no saturation of the detector;
> stable environmental conditions, no focus drift, etc
>
> Would it matter (for the dfference between the two scenarios) if it was analog
> detection or photon counting detection?
>
> I will run this little test later, but I am curious what you think.
>
> I thought that at least for the photon counting mode, the two important
> factors would be the dark counts and the total number of counts detected, so
> whether it is acquired in one scan or in 5 scans, it should be the same. My
> camera expert here insists that the averaging scheme will give better noise
> suppression.
>
> Thanks!
>
>
> Stan Vitha
>
> Microscopy and Imaging Center
> Texas A&M University