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paolo
November 19, 2013, 20:15:52
Hi all!
I'm experiencing a strange behavior of my new DFK23GM021 cameras. If I set the exposure time to a small value (less than 1/250 - my application needs it) the blue channel of the white balance goes up and down continuously from 140 to 220 following a "sine wave" with a period of about 3 seconds. This happens either in my C++ application or in the IC Capture 2.2 program. I've tried to change the gain of the image but nothing happens.
How can I solve it? I have to work at 1024x768x24bit@50Hz with an external trigger, so I need an exposure time of 1-2 ms to have time to process the images (I work with three cameras at the same time connected to an ethernet switch).
Thank you very much,

paolo

paolo
November 20, 2013, 10:19:38
Just a few more information: I've tried also to disable the auto white balance, but the issue isn't solved...

Stefan Geissler
November 20, 2013, 11:02:27
Hi

That means, white balance automatic is disabled and the blue slider moves around on its own? This is not possible.

Which light source do you use? Does the very same happen, if you use natural day light? If not, then I point to your light source. 1/250 second exposure time is short enough to catch only a part of the flicker period of a 50Hz flickering light source.

I assume, your trigger frequency is also nearly 50Hz, so running automatics should not be a problem. The automatics can run into trouble, if the trigger frequency is too low. e.g. 1Hz.

paolo
November 21, 2013, 15:45:27
Hi.
Thank you for your answer. Actually in this moment I cannot reproduce the problem anymore. The only change I made in my setup was setting the frame rate of the trigger to 40Hz.

Anyway, the problem was that if I removed the automatic white balance, the sliders were still, but the effect of the image was the same: the "color" of the image turned from "red" to "blue/green" and viceversa. If I kept the auto white balance enabled and clicked the Refresh button I could see the slider moving up and down.
In this moment I'm working in my laboratory under a common office neon light.