Re: !!!help!!! synchronization camera and measurements
- From: Mark _T <x@xxxxxxxx>
- Date: Thu, 29 Mar 2007 14:40:07 -0500 (CDT)
Hello Dan,
If you want to display the live video feed all the time but only write certain
frames to the AVI it's only a matter of programming. You will need an
outer while loop that is constantly reading images and displaying them.
Then you will also need a case structure within the while loop where the AVI
write frame VI will be. The Boolean input to the case structure will then
be determined from your data acquisition device's trigger. You will need
to read the trigger line and when it triggers execute the correct state of the
case structure to save that current frame in the AVI. Please note that
this methodology for saving an image by reading a trigger line on a DAQ device
is going to be very non deterministic. Since you do not have the ability
to trigger the camera the frame you are saving might not be the same frame the
data corresponds too. The trigger and data acquisition will happen in
real time but reading the trigger for purposes of saving images to the AVI file
will happen when ever windows executes that part of the code. So as long
as it does not have to be real accurate this might work.
So I assume that with each frame you are also writing a time stamp with the
image. To then perform a "seek" on the images according to the
timestamp it will just be a matter of iterating through each image, extracting
out the data, then comparing that data to the timestamp you need. As soon
as it finds the correct timestamp then update an IMAQ display with the correct
image. I hope this information helps. Thanks and have a great day.
Regards,
Mark T
Applications Engineer
National Instruments
.
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