NI-ImaqDX slow to connect to USB 2.0 cameras?

[Gort000]

Hi all,

I'm having very long image acquistion times (~3 sec.), and from the searching I have done, I think that ImaqDX takes a long time to go out and acquire in a three-camera usb 2.0 system I am running.  I can't change to USB3 or GiGe right now.  I am taking two sets of three images, it's taking approx 3 sec per acquisition.  In trying to speed things up,  I have tried to have ImaqDx open the cameras in an initialization state, pass the data using a shift register, then use ImaqDx snap.vi to get my images.  I get an error "1074360317, Imaqdx Get Image2.vi", possibile reason invalid pointer.  Not sure how else to do this, any help would be appreciated, I'm somewhat new with LabView.  Images attached.  Image 4 is the current long acquistion using vision express.

[Gregory]

I have no idea what you're doing since you only posted screenshots, but I think it's a problem with your program, not the hardware. Try setting up for grabbing images rather than snapping them. Label your wires so you know what is what, even better make your own typedef cluster so that each session and image has a name tacked on to it.

[Gort000]

The code is just to big, with to many dependencies to include, so I included screenshots.  There is no issue with the hardware. What I am trying to find out is how to start an Imaqdx session, connect to a camera, then in another part of my state machine, acquire the image.  I am assuming that this would be faster than connecting to the cameras every time.  Hopefully someone here on the forum will have experience with this type of acquistion in imaqdx.

[Gregory]

Yes, many people have experience working with the IMAQdx functions, but it is still hard to remotely debug an application that we cannot even see. Try to make a stripped down version of your program that you can upload.

[Bob_Schor]

The general idea that you open or initialize a resource (DAQ device, file, camera), use it in a loop (take analog samples, read/write data, acquire video images), then close/finalize the resource.  I know when I started learning about IMAQdx, there were examples that embodied this model, but a quick search of the current shipping examples didn't seem to show how to do this.  But there's always the web ...

Bob Schor