Is there a way to obscure the license plate, some semi transparent film or something to make the automatic reading difficult?
The way ALPR systems typically work is that there's a camera running OCR against rectangular objects in frame. What you're asking is whether there's a way for a only human eyes to be able to see the plate. That doesn't exist for obvious reasons. Products that attempt to do this anyway usually try to reduce viewing angles or blur things, but these aren't very effective strategies.
Furthermore, obscuring your license plate for any reason is illegal in every jurisdiction.