I would distinguish the dimming aspect from the selecting syntactic units of text aspect. The former clearly isn't new[1], and adding an obvious technique to the equation doesn't make the entire method non-obvious.
So then the question should be: Is selecting syntactic units of text unique?
I don't know of any specific applications that do this, but I imagine that there are programs or libraries used in the field of machine learning that do exactly this or make doing it trivial and obvious.
[1] It's basically applying a dimming effect to an inverse selection. Off the top of my head, this is a common technique for highlighting passages from documents in video documentaries.
So then the question should be: Is selecting syntactic units of text unique?
I don't know of any specific applications that do this, but I imagine that there are programs or libraries used in the field of machine learning that do exactly this or make doing it trivial and obvious.
[1] It's basically applying a dimming effect to an inverse selection. Off the top of my head, this is a common technique for highlighting passages from documents in video documentaries.