For a 3D scanning project I need to capture a video/snapshots of an object and a projector image that is projected on the object. The projector works (only) with a framerate of 60Hz, the camera supports rates in {3.75,7.5,15,30,60} Hz. I have to work in Matlab, and since it's an IEEE 1394 camera, I can only use the CMU 1394 Camera driver since other drivers are not supported by matlab.
Now, my problem is, that the framerates of the camera (driver) seem to have a tiny non-zero phase-offset that adds up over time such that the captured image gets darker and darker until it reaches some minimum and becomes brighter and brighter again and so on. This is annoying. There are sample applications for 3D scanners that are able to work with different drivers. There, the problem does not exist, so I am pretty sure that it's the driver's fault.
Fortunately, the driver is open source, so putting a little offset somewhere in it and trying to solve the problem by trying out different times, could work. There is, however, one additional idea I had: The camera supports triggering. Is there any way that I can trigger it using the output of the projector? If that would work, that would be much easier and more elegant than fiddling around with that driver. The projector uses VGA. Do you know of any possibility to capture the signal and use it as a trigger? If possible without lot's of additional hardware.