is it possible to give a function (like find_blobs) a ROI that is in the form of corners, or any other shape that is not a horizontal/vertical rectangle?
However, you can use perspective correction to make something not in the shape of a box into the shape of a box. Please see the rotation_corr() method. Pass those points to it and then it will stretch the area inside your points to be a box. If you need to keep the source image intact make a copy first.
i understand that it is possible to draw such a rectangle, though - could i create a mask and use that to determine my roi?
I guess also.