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Messages - PIVer

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Chronos User Discussion / frame straddling
« on: July 17, 2019, 10:02:39 AM »
Hello,

I am trying to set up a Chronos 1.4 for particle image velocimetry (PIV) measurements. Many details about PIV are not important in this context, but two are: 1) images are taken in pairs, and 2) you should have control of the time between frames. The latter is, of course limited by the frame rate, i.e. you can't have a 500us inter-frame time if your recording at 1000 kHz.

One trick to decrease the effective inter-frame time is to use frame straddling, that is, use pulsed illumination at the end of the first image and at the beginning of the second image (see attached figure). While this works very well if you don't have no light apart from your pulsed illumination, the image quality is deteriorated when you have a long exposure time and there is significant ambient light.

To minimize the effect of ambient light, I would like to reduce the exposure using Shutter Gating (as also shown in the figure). By limiting the exposure to only a few microseconds before and after the illumination pulse, the ambient light that makes it to the CMOS would be negligible. My question is: can such a timing sequence be achieved?

Thanks for any help.

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