averaging vs. accumulation for noise reduction - is there a difference?

Posted by Stanislav Vitha on
URL: http://confocal-microscopy-list.275.s1.nabble.com/averaging-vs-accumulation-for-noise-reduction-is-there-a-difference-tp6483751.html

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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