Posted by
Neil Anthony on
URL: http://confocal-microscopy-list.275.s1.nabble.com/sCMOS-salt-n-pepper-issues-tp7583323.html
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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=sharinghttps://drive.google.com/file/d/0BzfJAGNfrgieVjViTWNoeExpdDQ/view?usp=sharing