Lab Session Not Opening

[Jakob Danner]

Good morning, 

I'm sorry to ask such a trivial question but for some reason pivLab won't let me reopen a previous session that I saved. 

Some other important information:

I used a video as my data

I used a mask in the previous session

The previous file is a .mat file and I have the video I analyzed in the same folder as all other Matlab related files. Not sure if the mask was saved in the .mat file when I saved the session.

When I try to open the session I go to file, load PIVlab session, and then when I select my file PIVlab says busy loading session but then it never loads - even if I wait a couple hours. I would share the .mat file and my video but they exceed the 24 mb limit.

The error I'm getting in Matlab is this:

Unrecognized field name "pass2".

Error in import.load_session_Callback (line 94)
set(handles.checkbox26, 'value',vars.pass2);
                                 ^^^^^^^^^^
 
Error while evaluating UIControl Callback.

And the fields contained in the .mat file:

 % This shows the fields contained in the file
                  calxy: 9.5897e-05
                   calu: 0.0029
                   calv: -0.0029
                  units: '[m] respectively [m/s]'
             u_original: {4060×1 cell}
             v_original: {4060×1 cell}
                      x: {4060×1 cell}
                      y: {4060×1 cell}
    typevector_original: {4060×1 cell}
             u_filtered: {4060×1 cell}
             v_filtered: {4060×1 cell}
    typevector_filtered: {4060×1 cell}
             u_smoothed: {4060×1 cell}
             v_smoothed: {4060×1 cell}
              vorticity: {4060×1 cell}
     velocity_magnitude: {4060×1 cell}
            u_component: {4060×1 cell}
            v_component: {4060×1 cell}
             divergence: {4060×1 cell}
         vortex_locator: {4060×1 cell}
             shear_rate: {4060×1 cell}
            strain_rate: {4060×1 cell}
                    LIC: {4060×1 cell}
            vectorangle: {4060×1 cell}
        correlation_map: {4060×1 cell}
            information: {7×1 cell}

I'm not sure what other information might be needed but any help would be very appreciated - I have little experience with Matlab.

Sincerely,

Jakob Danner

[William]

Hi, the problem is that you did not save a PIVlab session. You exported the data as mat file. These are two different file types.

[Jakob Danner]

Sorry, I'm having two more issues.

1  I seem to be having the same issue regardless of whether I save the PIV settings or the PIV session neither seem to be openable (both are .mat files though). Not sure if that's simply user error but I'm stuck on how to fix it.

2 Instead of doing the v_rms frame I settled for the mean (Plot < Temporal Derive Parameters < Mean) but for some reason I can't access it after making the velocity field plot of the v_x velocity. Specifically I get this error:

Index in position 1 exceeds array bounds.

Error in plot.temporal_operation_Callback (line 219)
framenum (size(framenum,1)+1,1)=framenum(1,1);
                                     ^^^^^^^^^^^^^

 
Error while evaluating UIControl Callback.

----------------------

I thought initially it was a problem with my mask but I redid the set up without a mask and I'm getting the same error. I also have tried it for a variety of frames but none work and I can't do the sum or std dev options either.

Would appreciate any advice, and thank you so much for your help thus far!

Sincerely,

Jakob Danner

[William]

Hi, there is a bug with video files in the latest version:

https://groups.google.com/g/pivlab/c/D6gIEtRI1EI

I generally recommend to never use video files for PIV, but always image files. PIVlab perfromance is much better with image files.
Concerning your first question: There seems to be another bug when trying to load session with video files. Please never use video files, I'll fix that bug in the next version.

[William]

I have fixed this bug here:

https://github.com/Shrediquette/PIVlab/commit/de486355176fed8065c183ffbde069654b74f087

[Jakob Danner]

Ok, thank you for this crucial piece of information. I went and used a .mov to .png converter and uploaded the images and everything works now. I was able to calculate the mean frame, export my video and the mean frame, and save and reopen the PIVlab settings and session.

Thank you so much for your timely help!

Jakob Danner

[Sharadhi N Raj]

Hello,

I am using the latest version of the PIVlab. I am facing similar issue even though I am using image sequence. I am not sure where the issue is arising from.

Thank you
Sharadhi 

[William]

Hi, the command window will tell you the problem.