activation

[alexlib]

@royekorolik

when an user presses Start, a new thread is opened (read about threads and GUI here https://nikolak.com/pyqt-threading-tutorial/) and in this new thread we run openpiv using this example:
https://github.com/OpenPIV/openpiv-python/blob/master/openpiv/examples/tutorial_notebooks/tutorial_part1.ipynb

u0, v0, sig2noise = extended_search_area_piv( frame_a.astype(np.int32), frame_b.astype(np.int32), window_size=winsize, overlap=overlap, dt=1, search_area_size=searchsize, sig2noise_method='peak2peak' )

where winsize is width_A x width_A (meanwhile we use equal size, later will add something else and searchsize is width_B x width_B

hope it's clear.

When user presses Stop - the thread stops and clears (memory shall be released, otherwise we'll blow the computer memory with every click)

At the end of the run (successful or not successful) we plot Quiver plot on the image, see here an example:
https://github.com/OpenPIV/openpiv-python/blob/master/openpiv/tools.py#L37