Posted by
Nico Stuurman-3 on
URL: http://confocal-microscopy-list.275.s1.nabble.com/DIY-solution-to-spinning-disc-banding-artifact-tp7586155p7586157.html
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Hi Garyand others,
Not sure about the BNC connector on the CSU21, but the one on the CSU10
was designed to adjustthe disk speed to a video synchronization signal.
The CSU10 manual suggests that the speed of the disk can be changed
slightly by providing synchronization pulses at around 30 Hz (the CSU10
spins at 1800 rpm= 30 rps). I have never used that input.
However, it does help to set the exposure time to exactly n times the
time it takes for the disk to scan the field of view . The CSU10 covers
the field of view in 30 degrees, or 12 times per full rotation. So, if
the disk spins at 30 rps, it will cover the field of view 360 times and
it takes 1/360 = 2.78 ms to cover the field of view once. Since the
disk speed may be slightly different, it is best to play with the exact
exposure time (either using a slide that is fluorescent throughout, or
using trans-illumination) to find out exactly how long to expose the
camera to cover one field of view. Once you have that number, simply
multiply by an integer to go to longer exposures. I do not know about
Elements, but exposure time on the Flash 4 and Zyla can certainly be set
with sub-millisecond accuracy. I wrote a script for our
Micro-Manager-based system to round the exposure time to the nearest
good value just by pressing a key on the keyboard.
With the Flash4.0 you then have the additional issue of dealing with the
rolling shutter. You can work around that by setting up emulated
globalshutter (or whatever the term is for that approach these days):
use the ttl output that fires when the complete chip is exposing and
build an AND gate to your laser illumination. That will of course add
10.0 ms to the exposure time you have to set.
Best,
Nico
On 12/20/16 3:00 AM, Gary Laevsky wrote:
> ***** To join, leave or search the confocal microscopy listserv, go
> to:
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> on
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> Hi All,
>
> Well known artifact result of mismatched exposure and disc field
> acquisitions.
>
> Perking Elmer used to have a "solution" using the ProSynch box (or
> something like that).
>
> We're using a CSU21 that has the synch BNC cable output.
>
> We have triggerable cameras (sCMOS (both Flash and Zyla)).
>
> We're using Elements, so we can't exactly fine tune the exposures per
> acqusition (can any software?).
> We're using a macro to spin up the disc to 5K. We can change the speed of
> the disc, but momentum happens, so we can't do it instantaneously.
>
> We need a way to synch the camera with the disc. Acquisitions are sub 30
> ms.
>
> I imaging we will take a signal off the disc and use this to trigger
> the camera.
>
> Can someone please point me to a solution?
>
> Thanks so much.
>
> --
> Best,
>
> Gary Laevsky, Ph.D.
> Director, Confocal Imaging Facility
> Nikon Center of Excellence
> Dept. of Molecular Biology
> Washington Rd.
> Princeton University
> Princeton, New Jersey, 08544-1014
> (O) 609 258 5432
> (C) 508 507 1310