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August 2012

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From:
Andrew York <[log in to unmask]>
Reply To:
Confocal Microscopy List <[log in to unmask]>
Date:
Mon, 13 Aug 2012 18:55:50 -0400
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*****
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*****

 We've some experience using the pco.edge in both global shutter and
rolling-with-strobe mode. We generally don't use the pco in rolling shutter
without strobe, because of the artifacts you mention. Compared to global
shutter, we get higher framerates in rolling-with-strobe mode, and seem to
get lower noise, although I've done nothing truly rigorous to show this.

 You can calculate how long you have to wait 'til global exposure with the
pco.edge: ~4.577 microseconds for each horizontal line in your region of
interest. It's really twice this much per line, but the camera
simultaneously deals with one line from the top and bottom of the chip, so
effectively it's 4.577. If you're willing to work with the company's
engineers, you can also get the pco.edge to indicate when all lines are
exposing, vs if any lines are not exposing.

 We often use python to control our hardware, and I've written some code to
talk to the pco.edge:
http://code.google.com/p/msim/source/browse/hardware_control/pco.py
 MY CODE IS NOT ROBUST CODE, IT CONTAINS KNOWN BUGS, so there isn't much
here of value to the non-programmer. However, it's also the code we've used
for several of our papers, so it's not worthless, either. For other python
nerds, it might have some useful clues how to get the camera to perform at
high frame rates. The code is open-source (GPL), so feel free to use, copy,
and modify, as long as you keep it open-source.

 Overall we're extremely happy with the pco.edge, but to be clear, this is
currently a camera that rewards the careful user, and can punish the casual
user. A few things we learned are described in Note 3 of this document:
http://www.nature.com/nmeth/journal/v9/n7/extref/nmeth.2025-S1.pdf
I suspect the company has since addressed some of these issues, so check
with them if any of these points sound like dealbreakers.

 Hope someone finds this useful.

On Sun, Aug 12, 2012 at 3:44 PM, Shalin Mehta <[log in to unmask]>wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Hi Michael,
> We have demoed sCMOS cameras from Hamamatsu, Andor, and PCO.  I found
> that Flash 4 has better sensitivity as compared to Andor or PCO's
> cameras. I have been told by Hamamatsu's representative that the
> Micro-manager driver is very useable, but it does not handle the top
> frame-rate of Flash 4.
>
> We are still undecided and I need to understand a couple of issues
> before we make the decision.
>
> For our target application (quantitative imaging and analysis of fast
> moving specimens) the rolling shutter-only operation of Flash 4 is an
> issue. To investigate the performance of global vs. rolling exposure,
> we used Andor's Neo with the same settings in either mode. Here is a
> dark-field image of an intact sea urchin sperm beating at about 30
> waveforms per second:
> http://www.mshalin.com/interesting-data/GlobalvsRollingShutter.png
>
> From the images and intensity profiles we see that rolling shutter
> introduces motion artifacts such as skew in the shape of head and
> flagellum waveform in vertical direction. But, rolling exposure has
> visibly better sensitivity and SNR.
>
> I still don't understand the following completely. All inputs from
> community and manufacturers will be appreciated.
>
> a) How does global exposure work in Andor and PCO cameras? What
> sources of noise have increased contribution when doing global
> exposure?
>
>  b) For any camera in rolling shutter mode, we can achieve global
> exposure by strobing the light-source (such as LED or laser) so that
> * the specimen is illuminated right after all the pixels have been
> rolled active
> * the source is turned-off right before the pixels are read out in
> rolling fashion
>
> The cameras take about 10 ms 'to roll the full chip'. So if we set the
> exposure to desired global exposure + 20ms and strobe as above, it
> seems we again have global exposure. Will noise be any better with
> this custom arrangement?
>
> Thanks,
> Shalin
> website: http://mshalin.com
> (office) Lillie 110, (ph) 508-289-7374.
>
> HFSP Postdoctoral Fellow,
> Marine Biological Laboratory,
> 7 MBL Street, Woods Hole MA 02543, USA
>
>
> On Sun, Aug 12, 2012 at 1:37 PM, Cammer, Michael
> <[log in to unmask]> wrote:
> > We demoed an Andor Neo camera a few weeks ago and was very impressed
> with it.  We couldnt quite get the sensitivity needed for single molecule
> imaging but were very impressed by its other features.  We'd like to get a
> camera with these capabilities that we may use both with Nikon Elements on
> one microscope and with MicroManager on another (currently one microscope
> has a DU897 and we want ta bigger field and wider dynamic range of view for
> some applications and the other has decade old Orca ER).
> >
> > Two part question.
> >
> > 1.  Is anyone developing a driver for MicroManager that will take
> advantage of this camera's many many features?
> >
> > 2.  While we really liked the Andor Neo, does anybody have data or
> feelings that other sCMOS cameras out there are better-- keeping in mind
> that drivers for both software packages is also important.
> >
> > Thank you!!
> >
> > _________________________________________
> > Michael Cammer, Assistant Research Scientist
> > Skirball Institute of Biomolecular Medicine
> > Lab: (212) 263-3208  Cell: (914) 309-3270
> >
> >
> >
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