validation of tk_gui

[Xunchen Liu]

Dear Alex and other developers openpiv :

Thank you for developing the openpiv package. I was a LaVision DaVis user, but I just decided to switch to openpiv python to have more flexibility and automation of the process.

I mainly measure high repetition rate PIV images so later I would like to try the time smoothing function.

But first I need to learn using the package. I think the tutorial and the windef example are good starting points?

Also I tried the tk_gui and studied the youtube video of the GUI. I am not sure what the red vectors mean after validation.  after putting a simple signal to noise filter with 1.06 (recommended value), all vectors are marked as red. I am not sure what does that mean.

These are calculation of the test example. The issue is the same for my own data.

can I export all the setting from the GUI ? So that I can automate the following calculation?

Thanks again

[Ivan Nepomnyashchikh]

According to your screenshots, you only chose to validate if your velocity vectors are valid based on the signal to noise ratio, for which you picked the threshold of 1.06. In this case, all the vectors that are based on the correlation that have a value of signal to noise ratio less than your threshold will be deemed invalid and marked red. Otherwise, they will be marked blue. Since all of your vectors are red, they all are invalid. I.e., their signal to noise ratio is less than 1.06.

It's good that, having validated your field, you didn't choose to remove the invalid vectors - your entire field would've been removed.

Try lowering your s2n threshold till you get about 95% of the blue (i.e., valid) vectors.

I personally don't use GUI and I don't know how to work with it. If - as you claim - you want more flexibility and automation options, I suggest you should switch to Python. Personally, I use the Python version of OpenPIV and it gives me all the flexibility I can dream of.

Ivan