Electronic – Industrial flash (LED?) for rolling shutter

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I am developing industrial monitoring system, at this moment with Raspberry Pi and its camera (this might change if it is not satisfactory). The camera will take still pictures of the scene once in a few seconds. Since the objects are moving, it has shutter time max 1/1000s. After some experiments, I determined I need around 10kLux light source which is either turned on all the time (though without producing excessive heat), which is turned on and off programatically, bracketing the camera action, or one which can be synced with the camera shutter using the camera's chip flash sync.

The camera unfortunately has rolling shutter, so xenon flash tubes are out, AFAIK — their light interval is probably too short, there would be partial exposure — but that's just what I understand from readings sources, so I will be glad to be corrected here).

What other flash options do I have? I will be glad to use LED-based flash, but need reliable circuitry around it as well. Ready-made industrial cameras systems costing over $4000 are something I would like to avoid, if possible.

I would like to ask for pointer in which way to go, keywords to search for, or even marketed products which would be suitable. I am personally only moderately skilled in low-level electronics, but have colleagues who know that stuff.

Best Answer

Rolling shutter with fast moving objects is just not a good mix. You don't mention some key elements of your requirements (like imager format, frame rate etc.) so it will be hard to recommend a solution. It's likely you will need to go to a ILT (Inter Line Transfer) CCD for a global shutter.

You also don't say what control you have over the the rolling rest and the rolling read so again it will be hard to give any recommendations.

The one fall back that you do have is to do the following. - Set you exposure time to be longer than a frame time (or as long as possible) - Figure out how to determine when the Imager has finished the rolling reset - Keep everything in the dark - Fire your flash once the imager has finished the reset but has not started to read out the imager. - Read out the imager

Note: - this will adversely affect your frame rate.