http://confocal-microscopy-list.275.s1.nabble.com/sCMOS-salt-n-pepper-issues-tp7583323p7583330.html
pixel. The former will show increasingly brighter pixels the longer
the exposure. The latter will not.
>*****
>To join, leave or search the confocal microscopy listserv, go to:
>
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>*****
>
>Maybe I am missing the point here but won't the characterization
>paper that has been cited in this discussion- (but not yet read by
>me) produce at least a Dark Current image and hopefully a an image
>of the dark pixels on a lighter background. These two images could
>be used with some combination of multiplication and division to at
>least give a better looking image. I would have to spend more time
>than I have at the moment to consider the implications for
>quantitation, but whether you are trying to measure light intensity
>or count objects, background correction operation rarely cause
>problems, and usually help.
>
>If you can send me the two images cited and a sample image I woul be
>happy to play around with them and post my results back to you
>and/or the list.
>
>Chris
>
>Chris Tully
>Principal Consultant
>Image Incyte, LLC
>240-475-9753
>Image Incyte, LLC
>
[hidden email]
>
>
>
>-----Original Message-----
>From: Confocal Microscopy List
>[mailto:
[hidden email]] On Behalf Of Andrew York
>Sent: Wednesday, January 21, 2015 8:00 AM
>To:
[hidden email]
>Subject: Re: sCMOS salt'n'pepper issues
>
>*****
>To join, leave or search the confocal microscopy listserv, go to:
>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>Post images on
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>*****
>
>Can you share raw data? Also, how are you doing your illumination?
>On Jan 20, 2015 11:19 PM, "Neil Anthony" <
[hidden email]> wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy>> Post images on
http://www.imgur.com and include the link in your posting.
>> *****
>>
>> Hi all, I hope the
>> science/optics/hardware/software/students/post-docs/
>> reviewers/managers/next-door-neighbors and FedEx are treating you well.
>>
>> We have a couple of issues with a recently installed Hamamatsu Flash
>> 4.0 sCMOS camera and I was wondering if anybody has had any similar
>> experiences, both in terms of feedback on what is expected from sCMOS
>> hardware and what can be done to rectify any issues.
>>
>> Here's what we're seeing:
>> Using a Hamamatsu Flash 4.0 camera link sCMOS (firmware v3.00A) on a
>> spinning disk and acquiring data using Perkin Elmer Volocity 6.3 we're
>> having three issues regarding hot and cold pixels. So far we have
>> tried 4 different sCMOS cameras (kindly supplied/tested by Hamamatsu
>> and Perkin Elmer), to double check the subtleties, but the results are
>> quite similar
>>
>> On the first camera we saw a bright cluster of 4 pixels that are
>> between 2 and 10x greater than the surrounding pixels across nearly
>> all imaging conditions (not seen in the other three cameras). Are
>> these bright pixel clusters something that others have seen much? This
>> issue is seen in both Volocity and ExCap/HDImage, but was not seen on
>> the test sCMOS camera used to cross check. I also see 'ghost'
>> clusters that look similar but only seem to last for one frame...
>> Again, is that something seen in sCMOS cameras in general?
>>
>> Salt:
>> In images with low signal and longer exposure times we see speckled
> > bight pixels using both Volocity and ExCap/HDImage, with an intensity
>> approx twice that of the background signal. Exposure times ~secs; low
>> signal <1000 counts per pixel. These speckled hot spots were seen
>> with all sCMOS cameras to some degree.
>> Pepper:
>> In almost the inverse situation, where we have higher signals with
>> lower exposure times were also seen on all sCMOS cameras (the first
>> camera with the clear hotspot had very bad 'peppering' compared to
>>the others).
>>
>> I know that the pco cameras used on the Deltavision OMX have reference
>> images applied to reduce the affects of these artifacts, and I was
>> wondering if that's something that can be applied post-acquisition.
>> Any thoughts and/or feedback on what's normal for an sCMOS, and how to
>> get the best out of these cameras would be much appreciated. sCMOS
>> cameras certainly are fast and have a great signal to noise, so am I
>> expecting too much from this generation of hardware?
>>
>> Thanks
>> Neil
>>
>>
>> A couple of images to compare salt'n'pepper pixels seen on three
>> cameras are here:
>>
https://drive.google.com/file/d/0BzfJAGNfrgieQ21abmVPbFBqY0k/>> view?usp=sharing
>>
https://drive.google.com/file/d/0BzfJAGNfrgieVjViTWNoeExpdDQ/>> view?usp=sharing
>>
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