Posted by
Guy Cox-2 on
URL: http://confocal-microscopy-list.275.s1.nabble.com/averaging-vs-accumulation-for-noise-reduction-is-there-a-difference-tp6483751p6485492.html
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I'm probably risking the wrath of the manufacturers here, but I'd like
to suggest that the difference in these cases could be caused by slight
inaccuracy in the scan. In other words, when you do an averaged image
you are (to a small extent) averaging each pixel with its neighbour, and
hence smoothing the image. Increasing the dwell time in a single scan
will not have this effect. The implication here is that the 710 has a
more precise scan than the 510.
Guy
Optical Imaging Techniques in Cell Biology
by Guy Cox CRC Press / Taylor & Francis
http://www.guycox.com/optical.htm______________________________________________
Associate Professor Guy Cox, MA, DPhil(Oxon)
Australian Centre for Microscopy & Microanalysis,
Madsen Building F09, University of Sydney, NSW 2006
Phone +61 2 9351 3176 Fax +61 2 9351 7682
Mobile 0413 281 861
______________________________________________
http://www.guycox.net
-----Original Message-----
From: Confocal Microscopy List [mailto:
[hidden email]]
On Behalf Of G. Esteban Fernandez
Sent: Friday, 17 June 2011 9:48 AM
To:
[hidden email]
Subject: Re: averaging vs. accumulation for noise reduction - is there a
difference?
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I agree with Julio and Brian about the Zeiss 510 - averaged images were
always less noisy than "dwelled" images. I always taught that point in
training sessions and showed side by side comparisons; newbies could
clearly
see the benefit of averaging over dwelling. However this isn't the case
on
my 710 or 700, I see no difference (just by eye!) between averaging and
dwelling (~800 volt gain comparing 4-8 averages to dwell times 4-8x
slower
than whatever max. is [1~3 us]).
-Esteban
On Thu, Jun 16, 2011 at 2:38 PM, Armstrong, Brian <
[hidden email]>
wrote:
> *****
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>
> I have not done a careful analysis of this either, and I am not quite
sure
how you would, however I share the viewpoint of Julio exactly,
1.6usec/pix
and 2-4 ave.
>
>
>
> Brian Armstrong PhD
> Light Microscopy Core
> Beckman Research Institute
> 1450 East Duarte Rd
> Duarte, CA 91010
> 626-256-4673 x62872
>
http://www.cityofhope.org/SharedResources/LightMicroscopy/LightMicroHome.htm
>
>
> -----Original Message-----
> From: Confocal Microscopy List
[mailto:
[hidden email]]
On Behalf Of Julio Vazquez
> Sent: Thursday, June 16, 2011 2:21 PM
> To:
[hidden email]
> Subject: Re: averaging vs. accumulation for noise reduction - is there
a
difference?
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
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>
> This is what I noticed empirically on our Zeiss LSM 510, where
averaging
tends to give somewhat better noise reduction than increasing dwell
time.
Under "normal" imaging conditions, we typically use a dwell time of
1.6-3.2
microseconds. Increasing the dwell time to greater than 3.2
microseconds
tends to result in more bleaching and somewhat reduced signal.
Typically, we
use 1.6 microseconds dwell time, and 2-4 averages, depending on the
sample.
> --
> Julio Vazquez
> Fred Hutchinson Cancer Research Center
> Seattle, WA
>
>
http://www.fhcrc.org/>
>
> On Jun 16, 2011, at 2:08 PM, Moninger, Thomas wrote:
>
>> Stan,
>>
>> I've been told by Carl Z. engineers that in general averaging (I
usually
use line, not frame) tends to yield better S/N then does increasing
dwell
time. As Lloyd commented this may be model specific. I have not done any
analysis to confirm this however....
>>
>> Tom
>
>
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