Creating exclusion masks for PIVlab – ‘no mask found’ error

[Andrea Pasqua]

Hello everyone,

I’m working with PIVlab and trying to create exclusion masks via a MATLAB script. The script generates a cell array per frame, where each cell is itself a 1x5 cell array structured as follows:

• cell{1,1} = the string 'ROI_object_polygon'

• cell{1,2} = the polygon vertex coordinates (x,y)

• cell{1,3}, cell{1,4}, and cell{1,5} = unclear to me

When I load my generated .mat file into PIVlab, it throws an error saying “no mask found”. I suspect the issue lies in the contents or format of cells 3, 4, and 5, but I haven’t found clear documentation or examples describing what those should contain.

Could anyone share insights or examples on the required format or contents of these cells so that PIVlab correctly recognizes the mask?

Thank you in advance for any help!

Best regards,
Andrea

[William]

Hi, the error message is thrown because your mat file does not contain a variable named masks_in_frame:

https://github.com/Shrediquette/PIVlab/blob/main/%2Bmask%2Fload_Callback.m
I would recommend to draw a mask in pivlab and save it, then learn the structure in the mat file from there.

[Andrea Pasqua]

Thank you William! Now it is working! 

Thanks for your help!

Have a great day