Synchronizing USB Camera with Analog Input/Output

[ashenoy]

My lab setup consists of a NI cDAQ 9174 + NI 9205  + NI 9264 connected to pressure regulators and a USB3 Point Grey Camera connected to a microscope.

My experiment requires me to capture a single frame from the camera, do some image processing, output some pressure to the pressure regulators, and then read back the pressure applied using analog input (because some times the pressure input is not the one applied). 

Currently I have a while loop, with the iteration time decided by the vision assistant frame rate. But this causes issues, since the time required for processing a single frame might exceed the desired interval between acquisition.

I wanted to know if there was a way to synchronize the timing of the image acquired from the camera, and the signal written to and acquired from the regulators, and if it was possible to deterministically set the iteration time of a single loop.

[Frankay · Accepted solution]

Hi Ashenoy,

A cDAQ is not going to give you the determinism you are looking for, but a cRIO might because it has a Real-Time OS.

I'm not sure if it is what you are looking for but there is a Triggered Grab example that is shipped with LabVIEW. In LabVIEW navigate to Help>> Find Examples.

Hardware Input and Output>> Vision Acquisition>> NI-IMAQdx>> Signal Input and Output>> Triggered Grab.vi

The other forum I found where they discussed something similar is here: http://forums.ni.com/t5/LabVIEW/camera-synchronize-with-daq-outputs/td-p/3193098

-

Aaron F.

National Instruments