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Trouble with triggered image acquisition with Basler camera and frame grabber

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Hi,

 

I am in need of synchronized image acquisition via frame grabber PCIE 1433. I have Basler  ACA2000-340km and I am trying to use IMAQ Vision Acquisition Software, version 17.5. I have read manuals of the camera and it seems to me that IMAQ misses some functionality for specifying trigger modes etc...I have connected the triggering signal to my camera's CC1 Line, configured as external (from another device - digital micromirror, Vialux), which generates some spatial patterns that I want to observe. I am using two independent programs to first wait for external trigger and grab a series of pictures and second to program the projection of two patterns to my digital micromirror. First pattern is blank- just clean image, the second shoud be mostly obscured by the square. Instead I sometimes get good image but sometimes I see something in between this two cases. I am sure I have right exposure time. I am sure trigger works well. See programs attached. Does anybody know how to repair this, please?

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The bad image looks the same as good2 image, just darker.  What kind of light are you using?  If you have a fast trigger with an incandescent light, you can get different amounts of light depending on where you are in the 60 Hz power cycle (50 Hz European), because the light actually pulses 120 times a second.  If you try a LED light or high frequency fluorescent light, you might have better results.

 

After looking at your images some more, I see that there is a shape blocking the light in good, and bad looks like a combination of the two (good and good2).  It looks like it is triggering too early, and the shape hasn't moved out of the way yet.  Without knowing the mechanics of your setup, I can't really explain why.  Perhaps the mirror reacts slowly sometimes, and doesn't move to the new position quite as quickly as you expect.  Another possibility is that the triggering is set up wrong, and the camera is free running and you are just grabbing the most recent picture.

 

Bruce

Bruce Ammons
Ammons Engineering
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Hi. I have SLED, which is very stable, so I believe this is the problem of bad triggering or exposure time which I set 10x smaller than the trigger pulse length so I don't understand what is happening. The mirror is superfast (up to tens of kHz, and test it for less than a  kHz) and its control board is actually triggering the camera. I have also a simple photodiode so I know that the trigger and the mirror are synchronous.

 

Thanks for your response,

 

JulIS

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Solution
Accepted by topic author JulIS

Ok, So the case was trigger pulse width. Everything below 1 ms is too short for the camera.

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