Why am I getting a timeout when using getsnapshot?

I'm currently using a GigE camera using a pleora PT1000 IP engine with Matlab 2012a. I've successfuly been able to grab and display images as a realtime video with Matlab's image acquistion toolbox. However, I'm running into a timeout error when I use my code. It's not predictable since the amount of time it took for the error to occur went from anywhere between 9 seconds to 7 minutes with no apparent pattern. When I get the error, all I do is imaqreset and then run the code again to display video until I get the error again. My code is shown below. If anyone has has an idea as to what is going on, help would greatly be appreciated. Thank you.

%Camera setup

vid = videoinput('gige',1,'Mono16'); src = getselectedsource(vid); vid.FramesPerTrigger = inf; vid.FrameGrabInterval = 3; src.PacketSize = '9014'; start(vid);

%image setup

h = imagesc(zeros(480,640)); axis image; axis off;

%Load .mat files of processRAW parameters

load 'gain.mat'; load 'bias.mat'; load 'r.mat'; load 'badmap.mat'; load 'bbimages.mat'; load 't.mat';

tic

while 1,

    %Error check so buffer doesn't overflow
    if imaqmem('FrameMemoryUsed') < 100000000

        %Check memory
        imaqmem

        %Grab a frame, if timeout occurs display how long process took
        try
            liveFeed = getsnapshot(vid);
        catch
            toc
            return;
        end

        %Process image
        [S rawData] = processRAW(liveFeed,gain,bias,r,badmap,bbimages);

        %Format data for displaying
        R = single(S(:,:,1));
        R(R<280)=275;
        R(R>300)=285;

        %Display image, end program if window is closed
        try
            set(h,'cdata',R);
            drawnow;
        catch
            break;
        end

        %If buffer nearing capacity, clear the data and continue process
    else
        flushdata(vid);
        liveFeed = getsnapshot(vid);
        [S rawData] = processRAW(liveFeed,gain,bias,r,badmap,bbimages);
        R = single(S(:,:,1));
        R(R<280)=275;
        R(R>300)=285;
        set(h,'cdata',R);
        drawnow;
    end

end

%Reset camera

flushdata(vid); stop(vid); delete(vid); imaqreset;

Answer 1

[Mark Jones]

Hi Jonathan,

I would encourage you to try setting the camera to use manual triggering when using GETSNAPSHOT in a loop, as shown here:

https://www.mathworks.com/help/imaq/examples/acquiring-a-single-image-in-a-loop.html

Also, you may need to properly set the PacketDelay property on the source given the expected bandwidth for the image size and format, and PacketSize in order to avoid reliability issues. Also, you should ensure you have set the receive buffers (descriptors) as high as possible (likely 2048) as described here:

http://www.mathworks.com/help/imaq/network-adaptor-configuration-notes.html

The technical support department can assist you with calculating a proper PacketDelay value.

Mark

[jonathan]

It seems that setting the PacketDelay to the correct value fixed the issue. I'm still unsure if my PacketSize is set to the correct value, but setting a high enough delay allows my PacketSize of 9014 to work fine. Here is what I used to determine the PacketDelay:

http://www.mathworks.com/support/solutions/en/data/1-F36R0R/index.html

Thank you for your advice!

Jonathan