Hello Support
We are having a few difficulties with our vision system and Labview and would like some assistance.
We are using an AVT Marlin camera with NI IMAQ for 1394 2.0.2. and Vision Assistant 8. We wish to acquire 36 images to the camera using an external trigger and partial scan mode format7. The distance between the trigger time can be as low as 2ms.
Our process is as follows
1) Initialise camera
2) Use IMAQ1394 Configure Trigger to set trigger mode
3) Set Format 7 parameters
4) Set IMAQ1394 Configure Acquisition to Single shot mode with 36 buffers
5) Run IMAQ1394 Start Acquisition
At this point I expect the camera to wait for triggers and capture images into the 36 Buffers.
6) Following issuing the triggers IMAQ 1394 Get Image is called 36 times to extract each captured image to the previously configured IMAQ buffer created using IMAQ create for 36 images of the same size as defined in the format7 configuration.
This system seems to operate correctly. However we have found a couple of problems that maybe you can help with
Question 1
If we wish to capture 36 triggered images in quick succesion. Then would setting a single shot mode with buffer of 36 be the best method for this?
Question 2
We set a IMAQ configure acquisition with 36 buffers and an IMAQ create with 36 buffers. How does this work? Does the camera acquire into the IMAQ configure acquisition buffer and then transfer to the IMAQ buffers. Where is the memory allocated from for these two sets of buffers.
Question 3
Periodically when using IMAQ Get Image the following error is seen -1074364414--. To remedy this we have to reset the IMAQ buffers and restart the triggered acquisition between sets of images (IMAQ clear acquisition, IMAQ Configure Acquisiton, and IMAQ Start Acquisition), this causes a large time overhead for our application. It seems that for each set of images the buffers are not overwritten and require re-allocation. Is there another way to do this that does not involve a total reset? We have tried changing our acquisition mode to grab instead of single shot so we do not need to restart the acquisition. However this is difficult as Grab requires a minimum of three buffers and our acquisition trigger is 2ms. Also with grab the IMAQ Get Image always gives the error specified -1074364414--. What is this error?
Finally Question 4
Our Marlin Camera gives some hot pixels (white pixels) during acquisition. Is there a way to stop this happening.
Please do not hesitate to ask for more information if it is required.
We look forward to your response
Simon Orchard MSc
Software Engineer
