How do I get the maximum exposure time out of a Grasshopper3 camera?
Answered
Hello everyone,
I am having a hard time maximizing the exposure time available to me on Spinview or through MatLab and their image acquisition toolbox. In both cases it seems like the maximum exposure time is arbitrary, and I do not know how to reach the reported exposure time of 32 seconds mentioned by FLIR in their documentation. Does anything know what I need to do to maximize the exposure time? I do not have a background in optics or the use of cameras like this one so I do not know what settings or interactions between my laptop, the camera, and the ethernet cable will determine the exposure time.
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Official comment
Hi Clinton
Yes, that would be an external trigger signal.
But I think you should be able to reach the 32s by disabling the node AcquisitionFrameRateEnable. An external signal should only be necessary when you want to go beyond that.
Best regards,
Manuel
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Hi Clinton,
You can check in SpinView > Acquisition Control > Exposure Time > right click and select "Display Node Information" to get the Min and Max of the Exposure Time that you can set on your GS3 (units in us).
If you wish to go beyond this Exposure Time Max, you will need to set:
Trigger Mode = On
Trigger Source = Line# that is connected to your external trigger source
Exposure Mode = Trigger Width
and control your Exposure Time by sending a TTL trigger signal that has its pulse width = Exposure Time.
I hope this helps.
Regards,
Kevin
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Thank you very much for taking the time to respond. When you say send a TTL trigger signal, would that be with an external hardware trigger like a function generator? Should I hook one up as described in this note from the following page?
Note: An alternative method of synchronized capture is to have all cameras triggered by an external hardware trigger (for example, a function generator). Any hardware trigger that provides a 3.3 or 5 V square wave TTL signal can trigger the cameras. This application note does not explicitly cover the configuration of an external hardware trigger, but users who want to use an external hardware trigger can act as if the external hardware trigger is the primary camera, and follow the physical layout section mentioned in the article (if a pull-up resistor is implemented, this can be ignored, as external hardware triggers don't need it).
From the following page about configuring synchronized capture with multiple cameras: https://www.flir.com/support-center/iis/machine-vision/application-note/configuring-synchronized-capture-with-multiple-cameras/
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Contrary to our new camera models like BFS, Oryx or Forge, where the exposure time limits the frame rate, on these older models like the GS3, the exposure time is limited by the frame rate.
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Hello Clinton,
I am just following up to make sure you were able to get your 32 second exposure times by disabling AcquistionFrameRate, or by using bulb exposure mode?
Thank you,
Demos
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