Dear Mr. @marpet,
the Opening filters look to fit very well with my purpose! The documentation regarding filtering you sent me (https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_imgproc/py_morphological_ops/py_morphological_ops.html) is great! The Closing filter as well will be very helpful for my work.
Anyway, i did some research on the forum on the possibility to use the morphological filters with the GraphBuilder + command line and unfortunately, as you said in 2018 [Where is Image Filter option in Raster menu?] it is not possible.
In any case, I’m going to perform some tests about it and I’ll back with some comments!
Thank you very much for your help!